Redarc or Ctek. Which one.

[Tonks]

What should i buy for my camper trailer set up,
I have a pretty basic set up, 1 x 60 litre ARB fridge and a few led strip lights,
I want to get a DC-DC charger,
The Redarc BCDC 1225 @ $ 339.00 or
The Ctek D250s @ $ 219.00,

What do you reckon,

Cheers Tonks.

[kevin07]

me I have the ctek and if you look harder you will get it cheaper than that

[Drewboyaus]

I'm looking at adding one of these.
At the moment I'm just using the Redarc SB12 isolator. Do either of these replace that or do they operate together with the Redarc isolator?

[Tonks]

Im on the understanding that it will replace the SB12 as the new one is an isolator & a charger as well.

I'm looking at adding one of these.
At the moment I'm just using the Redarc SB12 isolator. Do either of these replace that or do they operate together with the Redarc isolator?

[Tonks]

Ive looked harder but can't find.

me I have the ctek and if you look harder you will get it cheaper than that

[Family4x4]

The evil twin knows alot about power set ups. He pointed me in the direction of

REDARC SBI12D DUAL SENSING DUAL BATTERY SYSTEM ISOLATOR SUIT 4X4 4WD SBI12


http://www.ebay.com.au/itm/321089669090?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

Very similar to the SB12 but it monitors both batteries.

Here is his post from another thread.

"If the batteries are close together IE in the engine bay using "battery" cable to connect then there is not much point to a DC/DC setup.
They are predominantly to compensate for voltage loss over long and lighter gauge cable runs.
Commonly that is from the Engine bay to a van/camper, different battery technologies between Cranker and House or in situations where the House requires higher charging voltages or has lower internal resistances and would otherwise steal the Alternator output from the Cranker

Don't forget to allow for the mounting of the chosen Isolator, if it is a DC/DC it must be as close as possible to the House or again there is little point. If it is a "standard" isolator it should in theory be as close as practicable to the Cranker

If you are not winching or cranking off the House Battery seriously consider circuit protection at each positive terminal and you can use much smaller gauge wiring.
If you are winching/cranking then you need heavy gauge wiring and circuit protection will be quite expensive and is often not used on the interconnect BUT the cable route and cable protection is given serious thought.

No matter what you end up with I would fit a dual sense Isolator such as a Redarc SBI12D or equivalent.
I use a lot of Intervolt programmable isolators but they are more expensive and an overkill for most reccy users.

Dual sensing is much more versatile and means that if the Isolator detects a charging source on either battery (Alternator/Solar/Charger/etc) it will interconnect both batteries OR if it detects either battery going low it will disconnect the other.
If you do (or plan to do) a fair bit of camping I would definitely go that way.
... I should have added that when my Patrol with the "Fortress of Evil" hanging on the tow bar are rigged for war I have 500 amp hours of battery capacity.
Any battery can be charged from any "source" or interconnected to power any system.
I can use the Camper to start the vehicle if needed or if I am camped up and my Solar is deployed, Mains available orGenny running, I plug the vehicle into the camper then the Battry Management will also charge the vehicle.

All that I use is 2 dual sensing Isolators (Cranker to House and Camper to Vehicle) a Solar Regulator obviously and a manual battery selector switch (to choose which Camper battery bank).

I have set it up that way because I have frig's in the Vehicle and the Camper and the only thing that pisses me off more than a flat battery is warm beer.
Since using this configuration E.T. has been one happy camper BUT what works for me won't necessarily suit everyone"

The Evil Twin.

[kevin07]

far from having any great knowledge of this stuff. the reason for dc to dc is they are a 5 stage charger that tops up the battery where the isolators only charge up to about 80% of its capacity therefore decreasing the life and the output of the batteries. please correct me if im wrong. kev. ps seems the ctek has gone up a mate of mine recently paid $200 delivered sorry.

[the evil twin]

Hiya Kevin,

The 80% is sales talk and will only happen in certain fairly crappy setups, perhaps a better way to look at it is this...

A "standard" Isolator has no effect on battery charging. All they do is isolate a battery if the load is draining it.

Bottom line - If you are using lead acid batteries close to Alternator with correct gauge wiring they are fine and the battery will charge exactly as if it is connected directly to the Vehicle Alternator

The DC DC chargers essentially sacrifice Current to raise Voltage. This is usually no drama because charging a battery doesn't use anything like the full output of an Alternator. It possibly becomes an issue if you have a large battery bank tho as an Alternator will charge that more quickly
The biggest advantage of the DC DC jobbies is that you can run lighter cable over long distances and not need to worry about the voltage drop at the other end affecting the battery charge as the DC DC jobbie raises the voltage back up to a suitable level

Bottom line - these devices are weapon of choice if you have a long run and/or excess voltage drop, a battery technology that is not exactly suited to your Alternator and needs a higher charging voltage or a variable output Alternator

[megatexture]

Ctek for me without a doubt . And if you have more then 300ah of house battery you could buy a smartpass also for not much more then a redarc unit

[Drewboyaus]

I know there is much debate on this topic. When you say incompatible battery types, what are you referring to?
I was thinking about the Redarc or Ctek to also accommodate solar panels down the track too.
Does the DCDC charger replace the SBI12 I already have or can I use the two together?

[the evil twin]

Hiya Drewboy

DC DC converters will directly replace the Isolator in most applications.

You cannot/should not use them as a direct substitute in hi current applications IE winching etc
SBI12 and its various iterations and competitors handle 100 to 200 amps depending on models
You can switch the Isolater to supply cranking power

DC DC converters are a "one way" jobbie that supply up to 40 amps but most common are 20 to 25 amps
You cannot switch the DC DC converter to supply cranking power
You need a seperate circuit or jumper leads (no biggee really)

Incompatible battery types are batteries that require different charging voltages EG calcium likes 15.3 nominal
In parallel with an SLA you either fry the SLA or do not charge the Calcium correctly.
Also different technologies have different internal resistances and will "steal" charging current from a battery that is actually a lower state of charge

[threedogs]

Interesting subject I leave my camper hooked up to a 20watt panel all the time.
and charge it via an Anderson plug from the rear of the Patrol, I have yet to run out of battery at camp
so I take it my set up suits my needs, At camp I use an 80 watt panel to top up any usage during the day.
I have a 115 Trojan wet cell as my Aux, awesome battery and an AC delco 100 AH sealed battery in the camper
I was led to believe solar will top my battery right up, is that correct?

[Tonks]

If I have the Ctek D250s in the camper trailer, when in camp & the Anderson plug is un plugged from the tow vehicle, can I then just plug my portable solar panel with its own regulator straight into the Anderson plug on the trailer so then the solar panel will charge the battery via the ctek charger or do I have to put the solar panel direct to the battery via alligator clips
Cheers Tonks

[kevin07]

on the ctek it has a separate connection for the solar reg,easy fix run a separate plug from the solar reg connection

[megatexture]

If I have the Ctek D250s in the camper trailer, when in camp & the Anderson plug is un plugged from the tow vehicle, can I then just plug my portable solar panel with its own regulator straight into the Anderson plug on the trailer so then the solar panel will charge the battery via the ctek charger or do I have to put the solar panel direct to the battery via alligator clips
Cheers Tonks

The earth is shared on the ctek but the pos is different for the solar input , either run another 50 amp Anderson to the front or you could just run a separate pos and use a split Anderson plug to connect it putting the earth to the original plug.

http://www.jaycar.com.au/productView.asp?ID=PT4406&w=anderson&form=KEYWORD

[the evil twin]

If I have the Ctek D250s in the camper trailer, when in camp & the Anderson plug is un plugged from the tow vehicle, can I then just plug my portable solar panel with its own regulator straight into the Anderson plug on the trailer so then the solar panel will charge the battery via the ctek charger or do I have to put the solar panel direct to the battery via alligator clips
Cheers Tonks

The D250S has its own MPP Solar regulator in the unit.
It is much more efficient to connect your solar panel output to the D250S solar input (thats the panel output not another solar regulator output).
The next best is an external regulator using battery clips but why would you when you have the D250S
The least efficient way is to run an external Solar Regulator output in the same plug as the vehicle feeds to the "Alternator" terminal.
You have a regulkator feeding a regulator which is very lossy

[Tonks]

The D250S has its own MPP Solar regulator in the unit.
It is much more efficient to connect your solar panel output to the D250S solar input (thats the panel output not another solar regulator output).
The next best is an external regulator using battery clips but why would you when you have the D250S
The least efficient way is to run an external Solar Regulator output in the same plug as the vehicle feeds to the "Alternator" terminal.
You have a regulkator feeding a regulator which is very lossy

Thanks ET,
I know the D250S has it's own solar input, but I would like to use the solar panel for the 2 nd battery in the car when needed, ie alternate from camper trailer to car, so the panel already has it's own regulator so when needed for the deep cycle in the car I can just plug into the Anderson plug on the rear of the car and when needed for the camper trailer plug into the Anderson plug on the camper trailer through the D250S ( but not the solar input on the D250S the other input, so it won't be going through two solar regulators only the one on the panel it self) does this make sense ? Or should I just install another Anderson plug on the camper trailer straight to the battery in the trailer and plug the my portable panel into that one,
Cheers, hope you can understand what I'm trying to explain.

[Yendor]

It would depend on how the solar panel regulator works with no load on it. Most regulators need a load such as the battery to start charging. I'm not sue if the Ctek would produce this load.

Easiest way would be to plug the panel in and check with a voltmeter. You can't blow anything up (as long as you have the positive and negative correct in the anderson plug) it will either work or it won't.

Where is the second battery mounted in the vehicle? under the bonnet? If so the solar panel will be more efficient charging this battery if it was connected closer to the battery. The shorter the wiring the better.

[Yendor]

You could also bypass the solar panel regulator with a bridge wire that you connected when you wanted to use it on the camper trailer. Depending on what regulator is used on the panel you might be better off using the Ctek solar regulator instead.

You would just need to make sure you disconnect this bypass when you wanted to use the solar panel to charge up the battery in the vehicle.

[Tonks]

You could also bypass the solar panel regulator with a bridge wire that you connected when you wanted to use it on the camper trailer. Depending on what regulator is used on the panel you might be better off using the Ctek solar regulator instead.

You would just need to make sure you disconnect this bypass when you wanted to use the solar panel to charge up the battery in the vehicle.

Thanks Rodney for your advice, where on the solar regulator would this bridge wire go ?

[Yendor]

In the wire that runs between the panel and the regulator.

[the evil twin]

Thanks ET,
I know the D250S has it's own solar input, but I would like to use the solar panel for the 2 nd battery in the car when needed, ie alternate from camper trailer to car, so the panel already has it's own regulator so when needed for the deep cycle in the car I can just plug into the Anderson plug on the rear of the car and when needed for the camper trailer plug into the Anderson plug on the camper trailer through the D250S ( but not the solar input on the D250S the other input, so it won't be going through two solar regulators only the one on the panel it self) does this make sense ? Or should I just install another Anderson plug on the camper trailer straight to the battery in the trailer and plug the my portable panel into that one,
Cheers, hope you can understand what I'm trying to explain.

Rodney has already pretty much covered everything.

Whilst it may work it almost definitely won't do so to anything like full efficiency.
It may not work at all or even worse, may appear to be working with happy lights, voltages etc but minimal current flow (unlikely but possible).

As I posted elsewhere I run up to 4 batteries with 500 odd amp hour capacity using a Solar Reg, two dual sensing Isolators (a Redarc SBI12D and an Intervolt) and a battery Selector Switch
The Alternator can charge any of them
The Solar can charge any of them
I can winch off the Camper batteries if worst possible case occurs
The Redarc protects the Cranker from any load (Aux battery or Camper if connected)
The Intervolt protects the Vehicle from the Camper load (if the Camper is connected)
The battery switch selects Camper 1, 2 or both

[Tonks]

Should i wire the Ctek D250S in the Camper Trailer off the Start or 2nd battery in the vehicle,
Cheers.

[the evil twin]

Should i wire the Ctek D250S in the Camper Trailer off the Start or 2nd battery in the vehicle,
Cheers.

Doesn't overly matter but the Starter would be preferably if all things are equal

If you come off the start battery then that saves some extra wiring length (from the Alternator) and therefore less voltage drop, less connections and less to go wrong

[mudski]

I just bought the Redarc BCDC1225 25A dc to dc charger with inbuilt MPPT solar charger to run dual batts in my camper. Problem is my panels are 24V so until I get new panels I can't use the reg....
42714

[megatexture]

Change your panels from being 240w 24v for example to 2x110w 12v

[the evil twin]

Unless I am missing something... Why change the panels? Just use them like you have been.

Putting the panel input thru the BCDC won't improve anything unless you have a crap Solar Reg.

The BCDC takes low voltage (say 11.5 volts) high current from the Alternator and ups the Volts at the expense of the current.
Solar is high volts low current so no advantage

[mudski]

Change your panels from being 240w 24v for example to 2x110w 12v

I wish I could. I have spent enough in the last week. Next on the list.


Unless I am missing something... Why change the panels? Just use them like you have been.

Putting the panel input thru the BCDC won't improve anything unless you have a crap Solar Reg.

The BCDC takes low voltage (say 11.5 volts) high current from the Alternator and ups the Volts at the expense of the current.
Solar is high volts low current so no advantage

I have a 180w system. 3 x 60W panels that are 24V. Being the cheaper Chinese kit it had a crap controller on it so I replaced it with a 20A Suntrans controller. Still mounted on the back of the panel.
Before purchasing this 1225 I wasn't aware that it won't accept 24v panels. I still bought it as I eventually want to upgrade my panels. So I need to figure out how to run both the 1225 and the Suntrans. I may need to start another thread instead of posting here.

[mudski]

Thought I'd add too, that I rang Redarc themselves a few times and the help these guys are willing to give is outstanding. Even the disty I bought it from made a comment on how good the tech guys are at Redarc.

[Cuppa]

The BCDC1225 can operate on a solar voltage from 9v to 32v, so will charge your 12v battery just as well from 24v panels as it would with 12v panels. Forget the Suntrans.

[megatexture]

I got a cracked Bosch 240w 24v pannel off gumtree for free and changed it to 12v to suit my reg in the camper and permanently put it on the garage roof to maintain my camper when not in use.

[the evil twin]

The BCDC1225 can operate on a solar voltage from 9v to 32v, so will charge your 12v battery just as well from 24v panels as it would with 12v panels. Forget the Suntrans.

I don't know why but the specs say it is only compatible with 12 Volt panels and from memory a while back a siilar issue was discussed and whoever it was talked to the techies at Redarc and was told the same.

Might be different now and my memory is as reliable as Lada so not 100% on teh above

I think it is because 24 volt panels will put out over 32 volts in some conditions and the Solar is only rated to 28 not 32

[mudski]

The BCDC1225 can operate on a solar voltage from 9v to 32v, so will charge your 12v battery just as well from 24v panels as it would with 12v panels. Forget the Suntrans.

Can you decipher this then cuppa from the manual? The BCDC1225 is a multi stage, 12v 25a, DC-DC charger that operates from an input of either 12v or 24v nominal or a 12v nominal solar panel input. The input voltage of the BCDC1225 can be above, below or equal to the output voltage bla bla bla.

[Cuppa]

Before posting I tried to check up on the Redarc web site, but it seems to be not functioning at the moment, I think it may have been hijacked. However I found this (http://www.jtsonline.com.au/redarc-bcdc-1225-battery-charger-solar-charge-regulator-dual-battery-system-mppt.html) & this (http://www.homeof12volt.com/shop/index.php/page/shop/flypage/product_id/622/category_id/54cb89307a7e4b3dd4c502242fa8aef2/offset/0?ps_session=0fcfe7b8b6a9e6096721b9782c9e5e6e), both of which say input voltage of 9v to 32v. The first specifically refers to charging 12v batteries from 24v input.

[mudski]

Just to add to my above thread. The mob I bought it from rang Redarc and they said to him that you cannot use 24V solar panels on this. It can receive a 24V supply to charge the batteries, i.e a 24v alternator, but not a 24v solar charge. I'm far from an expert but maybe the variation in amps on a 24v panel due to cloud coverage changing may affect it in someway??? Really grabbing at straw there...

[Drewboyaus]

So here's a question a bit off topic but....where do you guys store your panels in the 'troll when you're travelling? Are they ok on the roof rack? What happens if it's pudding rain, ate the bags they come in waterproof? Etc.

[Cuppa]

This is from the BCDC1225 owners manual. Suggests to me that it will work with 24v solar, not just 24v alternator. However the 28.2v cutoff after 20 seconds is a tad low. So I would suggest that it would do no harm to try with your 24v panels, but it is possible that 12v panels may do a better job.

42726

[mudski]

So here's a question a bit off topic but....where do you guys store your panels in the 'troll when you're travelling? Are they ok on the roof rack? What happens if it's pudding rain, ate the bags they come in waterproof? Etc.

Mine go in my camper or I stand them up in the back on the Pootrol. But usually in the camper. The bag that came with my kit isn't water proof, well I don't think it is and the zip was busted from day one anyway, soooo. Just seen the kit I have is still over $400. I have added the Suntrans 20A controller and much thicker cable with an Anderson plug. Big difference those two things made.
As for cuppa's comment. While you are probably right mate, I will take the advice from Redarc themselves and not use my panels. I will sell mine an just get something compatible.

[Cuppa]

If permanently fixed on the roof rack the panels will be fine, but if they are portable panels then I think some care in carrying them over the sort of rough roads we travel on is wise. I carry my portable ones in an upright position, slotted into a ‘rack’ I made. On the underside I have some high density foam covered with thin ply to help reduce any shock. Has worked well to date. Not very practical for wagons though, where I reckon carrying them inside, or up top, would be best with the panels wrapped in something soft. If you can mount them on the roofrack it would save a lot of stuffing around, but of course restricts what else you can carry up there. If you do carry portables up top I suggest restricting their size would be wise, otherwise the weight becomes an issue. My folding ones are 120w (2 x 60w) & I reckon this is the max practical size for portables, but half this if having to lift them up & down from the roof rack.

42727

[Cuppa]

As for cuppa's comment. While you are probably right mate, I will take the advice from Redarc themselves and not use my panels. I will sell mine an just get something compatible.

That is wise, but I suggest that you email or phone Redarc’s tech dept yourself & get the the info first hand, just to be sure. They are very helpful.

[mudski]

That is wise, but I suggest that you email or phone Redarc’s tech dept yourself & get the the info first hand, just to be sure. They are very helpful.

I was standing right next to the guy when he was on the phone to Redarc. So thats pretty well first hand I reckon. Lol

[Cuppa]

I was standing right next to the guy when he was on the phone to Redarc. So thats pretty well first hand I reckon. Lol

Fair enough. Perhaps I’m wrong. I have just sent the following email to Redarc myself & will report back when I get their reply.

Hi,
Please could you clarify whether it is ok to use the BCDC1225 to charge a 12v auxiliary battery from 24v solar panels in a 12v vehicle?

Some say that this is part of the BCDC1225’s design brief, but others say that whilst it will handle a 24v alternator, that it should not be used with 24v solar.

I note that the solar cutoff voltage is 28.2v after 20 seconds which does seem slightly low if that refers to battery voltage, or definitely too low if it refers to panel output voltage.

I look forward to your clarification.

Thank You

[megatexture]

So here's a question a bit off topic but....where do you guys store your panels in the 'troll when you're travelling? Are they ok on the roof rack? What happens if it's pudding rain, ate the bags they come in waterproof? Etc.

My 120w folding panel came with a bag that I've since glued in two camping foam mats on the inside to give some extra protection and keep it on the roofrack when we don't have the camper

[mudski]

Change your panels from being 240w 24v for example to 2x110w 12v


My 120w folding panel came with a bag that I've since glued in two camping foam mats on the inside to give some extra protection and keep it on the roofrack when we don't have the camper
Yeah I have cut some thick cardboard for mine and they sit on either side of the panels.

[threedogs]

They are pretty tough my trailer went 100mtrs down a hill did a flip with the panel bolted to the roof .
a little out of square but pulled it apart applied fresh silicon and still works a treat, I mount mine for travelling backwards in front of my camper, Flat on a roof plugged in would be ideal for travelling
.
You can nearly hit these things with a hammer, they should have a storm rating or similar I think for hail.
Plenty sitting on rooveswith not damage

[Cuppa]

Redarc, as usual have provided good service & been very prompt with their reply to my email enquiring about using the BCDC1225 with 24v solar panels.

I have egg on my face, ET was correct & Mudski was smart to be cautious .

Below is the reply from Redarc which makes it clear that 12v solar panels ARE required.

Thank you for your enquiry.

The input range of the BCDC chargers is 9-32v DC, this voltage range enables you to charge from both 12v and 24v alternator systems because the voltages produced by these systems are within the 9-32v input range, a 12v solar panel is also within this voltage range. A 24v solar panel can produce anywhere between 30-45v which is out of the BCDC’s 9-32v input range and is therefore not compatible.

I trust this information has assisted with your enquiry, if you need any further clarification please don’t hesitate to contact me directly.

Best Regards,


Wayne Wall
Customer Service Technician
Battery Analyser Specialist
Redarc Electronics

Cuppa



Ps. I would also like to add, having just read the entire thread, that the advice given by ET throughout this thread is excellent & well written. His use of the dual sensing VSR's in place of DC to DC chargers is a valid way of ensuring his batteries are fully charged. This works when the user has a permanent solar set up, so the alternator charges both batteries up to the 70% to 80% level (if driving for long enough) & the solar then tops up the batteries (solar regulator is a smart charger). I have this setup on one of my 3 solar setups & it works very well as long as there is sufficient solar wattage to ensure a balanced system.

[megatexture]

Mate just modify the pannels you have to be 12 volt to save buying new ones

[Cuppa]

They are pretty tough <snip>
You can nearly hit these things with a hammer, they should have a storm rating or similar I think for hail.
Plenty sitting on rooveswith not damage

Yep they are pretty tough but my caution in carrying them securely isn't about protecting them from impact, but rather is about trying to protect them from the long term vibration & rubbing against other things which long distances on corrugated & potholed roads can impose on everything. Bolted on, well supported to prevent flex & with air gap underneath & not touching anything is no problem. Loose & touching other things is another story. As others have suggested - extra padding would be essential. The cheap bags that many are supplied with won't last. The bags are thin, with cheap zips & the minimal padding they have is usually only very thin expanded polystyrene sheet. Adding extra padding to these bags is a good idea, but for long term use custom made padded heavy duty canvas bags with good quality zips will last a lot longer. Problem is the bags would likely cost as much as the panels.
If mounting 'permanently' it is best to ensure that the panels are mounted on a slight angle to allow rain to run off when stationary.

[mudski]

Mate just modify the pannels you have to be 12 volt to save buying new ones

How do I do that?


I have spotted a 170W Bosch kit on fleabay. I asked the seller if they will sell the panel alone without the reg and wiring and they just responded with " we sell our kits with a quality 20A reg and 10m or wiring". :1087: Not " sorry, well only sell in kit form" So I'm kinda left thinking did they understand me or not. Re wrote message and tried again.

[mudski]

Redarc, as usual have provided good service & been very prompt with their reply to my email enquiring about using the BCDC1225 with 24v solar panels.

I have egg on my face, ET was correct & Mudski was smart to be cautious .

Below is the reply from Redarc which makes it clear that 12v solar panels ARE required.

Thank you for your enquiry.

The input range of the BCDC chargers is 9-32v DC, this voltage range enables you to charge from both 12v and 24v alternator systems because the voltages produced by these systems are within the 9-32v input range, a 12v solar panel is also within this voltage range. A 24v solar panel can produce anywhere between 30-45v which is out of the BCDC’s 9-32v input range and is therefore not compatible.

I trust this information has assisted with your enquiry, if you need any further clarification please don’t hesitate to contact me directly.

Best Regards,


Wayne Wall
Customer Service Technician
Battery Analyser Specialist
Redarc Electronics

Cuppa



Ps. I would also like to add, having just read the entire thread, that the advice given by ET throughout this thread is excellent & well written. His use of the dual sensing VSR's in place of DC to DC chargers is a valid way of ensuring his batteries are fully charged. This works when the user has a permanent solar set up, so the alternator charges both batteries up to the 70% to 80% level (if driving for long enough) & the solar then tops up the batteries (solar regulator is a smart charger). I have this setup on one of my 3 solar setups & it works very well as long as there is sufficient solar wattage to ensure a balanced system.

Cuppa you will never have egg on your face bud. You are allowed to make a mistake, once in your life...Yours, ET's, Megatexture's advice on this thread is worth its weight in gold, if your could weigh it. If it weren't for you guys I would not know what I do now, which is still not much, but I'm getting there.

Thanks.

P.s.
Having just re read cuppa's p.s. Have I now gone and bought the wrong thing? Or is the DC to DC charger the right thing for my setup? Two batt's in the camper, charging via anderson plug from the car whilst travelling and then via solar whilst at camp. When I get the right panels...

[Drewboyaus]

His use of the dual sensing VSR's in place of DC to DC chargers is a valid way of ensuring his batteries are fully charged. This works when the user has a permanent solar set up, so the alternator charges both batteries up to the 70% to 80% level (if driving for long enough) & the solar then tops up the batteries (solar regulator is a smart charger). I have this setup on one of my 3 solar setups & it works very well as long as there is sufficient solar wattage to ensure a balanced system.

Cuppa, very much respect your knowledge in this area but I am continually reading that using a VSR under the bonnet with a dual battery setup and the correctly sized cables is enough to charge 2 wet cell batteries to 100% without trouble. The issue seems to be more when using AGM style batteries that require a higher input voltage.......

[Cuppa]

Cuppa, very much respect your knowledge in this area but I am continually reading that using a VSR under the bonnet with a dual battery setup and the correctly sized cables is enough to charge 2 wet cell batteries to 100% without trouble. The issue seems to be more when using AGM style batteries that require a higher input voltage.......

Hi Drew, would love to read your sources. All I can do is disagree with them, an alternator will not charge any battery to 100% UNLESS the owner were to drive for long enough, which would probably be halfway across Australia. Some folk may find that their auxillary battery is sometimes brought close to 100%, but this is only in situations where the vehicle is driven regularly & the aux battery never used.

With regard to agm batteries requiring a higher charging voltage than wet batteries ..... You have this the wrong way around. Agm's generally require a slightly lower charging voltage (up to 14.4v depending on brand .... US made ones are mainly lower than Chinese made) than wet cells which need 14.8v+. Agm's will actually charge more quickly & more fully from an alternator than wet cells, but still will not charge fully from the alternator alone in 99% of situations.

See http://www.trojanbattery.com/BatteryMaintenance/Charging.aspx
and http://www.fridge-and-solar.net/agm.htm


A VSR has absolutely no impact upon how fully a battery will charge, it is only a fancy switch to ensure priority is given to charging the crank battery & to ensure that the crank battery is is protected from over discharge, so the vehicle can be started.

[munzy42]

Redarc. I see a lot of campers at work (fridgy). And the red arc systems have great reviews by there owners.

[Drewboyaus]

Cheers Cuppa, not having a go mate it's just that this seems to be such an area of conjecture.
I really don't have enough knowledge to make a proper call and it drives me nuts because both arguments make some sense.
There is Cuppa's view of the battery world and then there is ET's view which differ in the view of the uses of DC-DC chargers. Many folk think the talk of not fully charging batteries is sales talk and not based in fact (including a couple of auto lecky's I spoke to).......while others are just as vehement on the other side.....ahhgh!
I have decided that because of the smaller second battery I'm restricted to under the bonnet with the EFI, that my setup will now include a 3rd battery in an ArkPak with a 180W fold up solar panel to top up while away.....this will allow the fridge to be removed from the Patrol if the wife chooses to stay at camp while I go for a drive.....
Because I have bugger all room in the engine bay for a DC charger, I will stick with my SBI12 as the dual battery isolator.....
As I am writing this another question has come to mind.....if I want to add a connection from the engine bay to an ArkPak (connected with an Anderson plug) in the back, do I need to upgrade the SBI to a larger unit?
Like Mudski, this stuff does my head in.

[Cuppa]

There is Cuppa's view of the battery world and then there is ET's view which differ in the view of the uses of DC-DC chargers.

Not so. I haven't said anything to contradict ET & I don't think he has said anything to contradict me. I believe that he & I are in agreement. There is always more than one way to skin a cat. Both ET's setup & my setup with a Dc to Dc charger (with a bypass switch) achieve the same things. Both are reliant upon a smart charger to ensure the auxillary batteries are fully charged. In ET's case his smart charger is the solar regulator, in my case the Redarc BCDC1240.

With regard to whether you need to upgrade to a larger SBI ...... It depends. :) depends upon what loads you are likely to put on the aux batteries & the output of your alternator. If you are planning to use either of the batteries with a winch & your alternator is capable of putting out more than 100amps then the 200amp model would be worthwhile, if not the 100amp model will do.

[megatexture]

How do I do that?


I have spotted a 170W Bosch kit on fleabay. I asked the seller if they will sell the panel alone without the reg and wiring and they just responded with " we sell our kits with a quality 20A reg and 10m or wiring". :1087: Not " sorry, well only sell in kit form" So I'm kinda left thinking did they understand me or not. Re wrote message and tried again.


Ok here is what I have done and it has worked for me for the last 8 months..
Remove the cover on the back of the panels and you should see something similar to what’s in the photo, each side will be 12 volts simply remove the diodes linking the two sides and test the polarity of each side then simply solder the two positive and two negative to loop them together,

When doing this i also tested the panel when fully covered to see if removing the diodes would have any effect resulting in the panels draining the batteries at night and my multimeter showed no current so i was pretty satisfied.

Hope this picture explains it enough but make sure you test polarity as i can’t remember what side was what.

the red and white are the loops to be added.
42775[

[the evil twin]

The main issue here is that everyone has been given a different coloured Cat to skin.
Some cat skinners are budget driven.
Some cat skinners have their batteries in different places to others.
Some cat skinners have mismatched (or unbalanced if you prefer) systems where the battery capacity is too low for the drain or the Solar is too small for the solar hours available or the Alternator doesn't run long enough for the Battery capacity etc etc.
Some cat skinners mix battery technology or manage parallel batteries differently to others.
Some cat skinners do maintenance charging of their batteries and some don't.
Some Cat skinners like fully Auto BMS but auto setups are like the seat belt argument, they save more that would have died but they kill some that would have lived

Bottom line is that esp with batteries, two or more differing opinions doesn't necessarily mean any one is more correct than the others.

P.S. if I could salvage the egg I've worn over the years I could feed the world on Omlettes

[Drewboyaus]

Both ET's setup & my setup with a Dc to Dc charger (with a bypass switch) achieve the same things. Both are reliant upon a smart charger to ensure the auxillary batteries are fully charged. In ET's case his smart charger is the solar regulator, in my case the Redarc BCDC1240.

Where does the solar regulator fit in as the DC charger? I have obviously missed that somewhere. I thought from his description he was just running a dual sensing VSR in between the 2 batteries under the bonnet.
Where would I connect the third battery in the ArkPak, would it connect at the isolating solenoid?
Sorry for the thread hijack guys.

[Cuppa]

Where does the solar regulator fit in as the DC charger? I have obviously missed that somewhere. I thought from his description he was just running a dual sensing VSR in between the 2 batteries under the bonnet.
Where would I connect the third battery in the ArkPak, would it connect at the isolating solenoid?
Sorry for the thread hijack guys.

Solar regulators are solar powered battery chargers. Almost all are multi stage chargers. When ET switches of his motor his solar panels continue to top up both aux & crank batteries beyond what the alternator has managed. His alternator will be connected to the crank battery & his solar will be connected to the aux batteries. The dual sensing VSR allows the solar to charge the crank batteries via the aux in the same way as it allows the alternator to charge the aux via the crank battery. (Whilst charging the aux batteries too pf course). It retains the ability to protect the crank battery from over discharge. In effect it gives a bit of extra capacity for camp use because the VSR keeps the batteries connected until the crank battery drops to it's disconnect threshold voltage. If for example that threshold equated to 70% crank battery capacity, (plenty for vehicle starting) & the crank battery has been charged to 100%, the 30% 'top' of the crank battery is additional capacity for camp use.


I'm not really familiar with the arkpaks, but from a quick look at them online it would seem to me that you have two choices. They sell an optional dc to dc charger to use with it. I would expect that this would be connected between the crank battery & arkpak battery. ie. separate to & bypassing your isolator.


The other alternative is rather more 'clunky', but you could simply use the arkpak battery like any other battery & connect it in parallel to your existing aux battery, effectively creating one larger aux battery. For a number of reasons this is likely to be impractical though & I wouldn't advise it.


If you are considering getting arkpak's dc to dc charger it may also be worth considering whether other available dc to dc chargers might be better options in regard to output & pricing.

[the evil twin]

My setup is pretty much what Cuppa said.

I have an SBI12D between the Aux and the Cranker
I have another dual VSR between the Camper and the Aux
I have a mini Cole Hersee Battery selector on the Camper

I run Camper Battery 1 on odd days of the calendar and Camper Battery 2 on even days by manual selecting the Cole Hersee which means I have a Battery on load and another fully charged and off load.

Whenever Solar is available it will assume the load and the excess will charge the "duty" battery.

Whenever the Car is connected to the Camper the Solar charges the Camper first... then thru the VSR the Aux... then thru the SBI12D the Cranker altho the Cranker is usually 95% or better anyway.

Whenever the Solar is plugged into the Car (because the Camper isn't) it charges the Aux and then thru the SBI12D the Cranker.

Because the car is either running on Alternator or plugged into Solar the Cranker and Aux are usually up around 95% SOC or better 'cept the Aux will drop a tad overnight running the Car fridge.

Because (lots of becauses here) the Cranker is 95% SOC or better from the day prior as soon as I start the car next morning the Aux is free to accept as much charge as it will allow from the Alternator.

This next bit is important... A Battery has a Charge Acceptance rate (charging current) that is the maximum current it will allow to flow thru it.
In a standard Lead Acid Battery as a rule of thumb given a bit of sulphation etc this is around a max of 1/3rd the Battery capacity IE a 100 AH battery that is "flat" will only take a max of 30 amps at 13.8 volts BUT this rate drops as the battery gets higher state of charge.
You can have a 200 AH Alternator but a battery about 80% or more state of charge will only accept maybe 10 amps IE 10 AH and it is like a law of diminishing returns IE as the battery gets to 85% it will be less as it gets to 90% it will be less again.

That is where the 'clever' spin from the marketers of BMS sytems comes in. You need to read the fine print of their claims.
Mainly because IF you have a 95% SOC cranker in good nick an Alternator will easily keep it up there given normal use and their claims of only getting 80% are absolute horseshit. The battery capacity does drop over time but it is not really the Alternators fault
What they do is utilise the current the battery won't take it anyway to increase the voltage up past where the Alternator is usually set which forces a higher charge acceptance

[Cuppa]

That is where the 'clever' spin from the marketers of BMS sytems comes in. You need to read the fine print of their claims.
Mainly because IF you have a 95% SOC cranker in good nick an Alternator will easily keep it up there given normal useand their claims of only getting 80% are absolute horseshit. The battery capacity does drop over time but it is not really the Alternators fault
What they do is utilise the current the battery won't take it anyway to increase the voltage up past where the Alternator is usually set which forces a higher charge acceptance



Yes percentages vary with battery type & age & it isn't uncommon for folks without any form of smart charging to be running their crank batteries at significantly less than 95% state of charge. Once down below that 70% to 80% SOC & without a form of smart charging to bring it up, it is down to driving time, which generally is impractical on a daily basis.

Smart (multi stage) chargers (mains, dc to dc, smart alternator regulation or solar) are better at squeezing in that last bit which would take the alternator much longer to do, by as you say increasing the voltage but also matching the amps to what the battery can accept as I understand it. A bit like trying to pass a crowd of people through a narrow opening...... Quicker to ensure one at a time than to just keep pushing as a crowd & getting jammed.

If i have understood correctly it seems that as well as the solar smart charging you also have the ability to alternate the usage of your house batteries daily, giving the one not in use a longer period to fully recharge from either alternator or solar which is particularly useful for days when lots of driving (& thus little solar input) occur. (I may be wrong about that - I'm unclear if your solar is permanently mounted or portable, ie. whether the camper batteries are solar charged whilst driving) Without the extra battery to swap over each day I imagine that there would be days where a dc to dc charger would be useful.

Again it is a horses for courses thing, with differing solutions to achieve the same ends. (Ensuring the batteries are kept fully charged, or close to, on a 24 hour basis). You have the weight carrying capacity for both the additional battery capacity and the solar. The best of both worlds. In terms of weight & size however, a dc to dc charger will be a fair bit less than an additional battery & the overall cost probably much the same, especially as I would hope that a quality dc to dc charger would be a one off purchase whereas batteries are 'renewables'.


Just for the clarity of others, I refer to dc to dc chargers, not BMS (battery management systems). BMS whilst including dc to dc chargers are both something rather more complex & items I have no experience & minimal understanding of. Mostly they provide extra convenience at a cost of both dollars & complexity.

I can't imagine that there would be (m)any battery manufacturers these days who would not recommend the use of a multi stage smart charger if available.

[the evil twin]

Pretty much agree Cuppa.

Soon we will all be using Lithium Iron Phosphate (LiFePo4) Batteries or their successors and won't have to worry about any of the present day bibs and bobs to try and get 150 year old Lead Acid technology to work in the 21st Century.

I am about to start field tests on LiFePo4 in low current deep cycle applications (for work unfortunately).
If they perform half as well as expected I will be all over them for my Camper etc

[Drewboyaus]

My biggest issue with the DC-DC charger is that I don't really have a suitable location to mount one easily, under bonnet space is super tight in the TB42e (especially with the second battery tray under there). The only likely location is on the cargo barrier in the vehicle.
This is the main reason why I'd like to retain the SBI12 as it relieves the space issue a little. I am now curious about swapping my existing one for a dual sensing type as that extra battery capacity that it liberates could be useful.

[the evil twin]

My biggest issue with the DC-DC charger is that I don't really have a suitable location to mount one easily, under bonnet space is super tight in the TB42e (especially with the second battery tray under there). The only likely location is on the cargo barrier in the vehicle.
This is the main reason why I'd like to retain the SBI12 as it relieves the space issue a little. I am now curious about swapping my existing one for a dual sensing type as that extra battery capacity that it liberates could be useful.

The majority of DC DC chargers are not meant to go under the bonnet anyway, cobber.
They like a much cooler place to sleep so I'd check manuf specs on temperature closely if I was ever to put one there.

Curious as to what you mean with "an SBI12D 'liberate' extra battery capacity"

[mudski]

Ok here is what I have done and it has worked for me for the last 8 months..
Remove the cover on the back of the panels and you should see something similar to what’s in the photo, each side will be 12 volts simply remove the diodes linking the two sides and test the polarity of each side then simply solder the two positive and two negative to loop them together,

When doing this i also tested the panel when fully covered to see if removing the diodes would have any effect resulting in the panels draining the batteries at night and my multimeter showed no current so i was pretty satisfied.

Hope this picture explains it enough but make sure you test polarity as i can’t remember what side was what.

the red and white are the loops to be added.
42775[
Thanks I will have a look at mine at see if i can do this. so why in the hell would they make the panel output 24v then?

[Drewboyaus]

The majority of DC DC chargers are not meant to go under the bonnet anyway, cobber. They like a much cooler place to sleep so I'd check manuf specs on temperature closely if I was ever to put one there. Curious as to what you mean with "an SBI12D 'liberate' extra battery capacity"

Cheers,
Was referring to a comment Cuppa made about the dual sensing allowing the use of some of the cranker's capacity as well as the 2nd battery.......or maybe I got that totally wrong.....

[megatexture]

Thanks I will have a look at mine at see if i can do this. so why in the hell would they make the panel output 24v then?

I dont see why you wouldnt be able to convert yours, I know out at opalton there is a debate on what is best for solar/ battery set ups be it 12v or 24 also some cars can be 24 so may suit them and grid connected solar setups use 24v panels

[mudski]

I dont see why you wouldnt be able to convert yours, I know out at opalton there is a debate on what is best for solar/ battery set ups be it 12v or 24 also some cars can be 24 so may suit them and grid connected solar setups use 24v panels
Will definately have a look mate. I appreicate your help as if I don't need to spend coin on new panels that means I can spend coin on something else. :)
But I need to get this dc-dc charger wired in first as per my other thread. I need to have all this done including panels by Tuesday and I only have half of tomorrow and Monday to do it. Starting to sweat a little.

[Cuppa]

Pretty much agree Cuppa.

Soon we will all be using Lithium Iron Phosphate (LiFePo4) Batteries or their successors and won't have to worry about any of the present day bibs and bobs to try and get 150 year old Lead Acid technology to work in the 21st Century.

I am about to start field tests on LiFePo4 in low current deep cycle applications (for work unfortunately).
If they perform half as well as expected I will be all over them for my Camper etc


I know a few folk who have been successfully using LiFePo4’s in their motorhomes (ie. daily full time use) for up to 3 years now, all diy'ers, utilising existing (ie. not special) but slightly modified charging set ups. If I were setting up my Patrol now i have no doubt that's the way I'd be going. Still not at a price for the average user perhaps, but for folks with a bit of understanding & a fondness for 'electrical fiddling' the diy approach has them priced close to Agm's & they have several significant advantages not least of which is much lower weight, so particularly attractive for campers such as mine. As yet i don't have my head around the issues in any great detail, as i have had no need to. I will be interested to hear about your field tests. My understanding is that they are particularly good for high current applications, & I can't imagine why they will not be just as good in low current applications.

[Cuppa]

Cheers,
Was referring to a comment Cuppa made about the dual sensing allowing the use of some of the cranker's capacity as well as the 2nd battery.......or maybe I got that totally wrong.....

Nope you got it right ........ if used in conjunction with solar (no point otherwise).

[the evil twin]

Thanks I will have a look at mine at see if i can do this. so why in the hell would they make the panel output 24v then?

Heaps of 24 Volt applications around in Trucks, RV's and especially Industry.
24 Volts means more volts less current for same power.
Less current means much smaller gauge wire so lots cheaper and lots lighter installations


I dont see why you wouldnt be able to convert yours, I know out at opalton there is a debate on what is best for solar/ battery set ups be it 12v or 24 also some cars can be 24 so may suit them and grid connected solar setups use 24v panels

Agree mostly... however a lot of grid connect panels are 36 to 52 Volt (open cct) depending on manuf and application not necessarily 24 Volt because there are no batteries involved.
Again the higher the voltage the cheaper the wiring amongst other things

[mudski]

Ok here is what I have done and it has worked for me for the last 8 months..
Remove the cover on the back of the panels and you should see something similar to what’s in the photo, each side will be 12 volts simply remove the diodes linking the two sides and test the polarity of each side then simply solder the two positive and two negative to loop them together,

When doing this i also tested the panel when fully covered to see if removing the diodes would have any effect resulting in the panels draining the batteries at night and my multimeter showed no current so i was pretty satisfied.

Hope this picture explains it enough but make sure you test polarity as i can’t remember what side was what.

the red and white are the loops to be added.
42775[
No go. Inside mine there is only three rows not four. I have searched and can't find a solution. I may have to just go buy new panels... :(

43061

[megatexture]

What do they come up with a multimeter? Your pannel has 3 parts? Have you checked out in all the pannels to see if they are the same
?