School me on DC/DC chargers and systems

[MudRunnerTD]

Hi guys,

I am looking to set up my camper properly with a DC/DC charger and thinking i should also have something on the GUIV too.

Looking at the CTEK but don't really understand the product? or linking in series or it appears there are a couple of products to build a system with?

The Redarc looks sweet too but boy there is some Coin involved!

Was in the local ARB yesterday and they had them on the shelf and spoke with the bloke. He was selling the Redarc systems. He suggested a 12v X 40amp Redarc on the camper and a 12v X 25amp under the bonnet.

Really keen to develop a good thread here. Or..... point me at an existing thread i have over looked please.

Cheers in advance

MR

p.s.KISS Seriously, Keep it Simple please

[PeeBee]

Hi guys,

I am looking to set up my camper properly with a DC/DC charger and thinking i should also have something on the GUIV too.

Looking at the CTEK but don't really understand the product? or linking in series or it appears there are a couple of products to build a system with?

The Redarc looks sweet too but boy there is some Coin involved!

Was in the local ARB yesterday and they had them on the shelf and spoke with the bloke. He was selling the Redarc systems. He suggested a 12v X 40amp Redarc on the camper and a 12v X 25amp under the bonnet.

Really keen to develop a good thread here. Or..... point me at an existing thread i have over looked please.

Cheers in advance

MR

p.s.KISS Seriously, Keep it Simple please

Mark,

I can only say I have both of the CTEK units, being the D250S Dual and the Smartpass. I selected these as they offered a range of advantages for battery management and charge control. having said that, they are sitting on my shelf in the garage waiting for the patrol to get back from WA to fit - so i guess i will be interested to hear from those in the forum if they are as good as i think they are! Mt neighbor across the road has the redarc system and he spends 6 months a year caravanning and he has no complaints.I looked at the Redarc and gained the opinion the CTEK offered more. I wasn't looking from a cost perspective, pure performance and features. I might also add I have a couple of the ctek battery chargers and found them trouble free and also liked the attachments for different battery connectors.

[mudski]

Ok. I run the Redarc BCDC1225 in my camper. With two 110AH batteries. And I am able to hook up multiple solar panels. Currently have 1 x 180W and 1 x 120W I use. Within this I can also charge the system from my car, and via mains voltage, but using a main charger for this. Whilst the camper sits there the batteries a kept topped up using a little 10w panel. Yes its little, but they are constantly at 100% charge the whole time now.
The Redarc is a bit confusing to wire in too if your not savvy on this stuff.
With my car. I run a Ctek 250 dual. this is mounted under the dash on the pax side. I also have a perma mounted 100w panel on my roof rack, which is connected to the Ctek. The Ctek is ship easy to wire in too. four connections and your done. But its a fairly large unit. The smart pass is an optional addon to the 250dual, and its the same size as the 250. so you need room for it.

All in all. I'm pretty happy with how the both work. If I had the coin, I would swap out the Ctek for a Redarc. Just so they are the same. something stupid in my head tells me this..... Lol.

Hopefully ET, cuppa etc will see this thread and be more help.

[Cuppa]

What do want to power from your aux battery in the GU4, & what sort of battery is it? A dc to dc may or may not give any benefit, depends a lot on usage & usage pattern. What is your usual driving time/camping time ratio?

Whether a dc to dc for the GU aux battery is worthwhile depends on how you tend to use it. It’s good for ensuring the battery gets topped up to 100% provided you drive for sufficient time, however if you tend to run the battery pretty low it will get charged quicker (up to around 70% to 80% full) via a VSR from the alternator. I have the ability to bypass my Redarc BCDC1240 in those circumstances, but have never needed to use it yet.
A dc to dc charger in the camper to charge the camper battery makes sense as it will compensate for any voltage drop over the distance between engine bay & camper.

I don’t really buy the 25amp dc to dc recommendation unless it’s on the basis of cost alone. The higher the current rating the faster the charge, or to put it another way, the lower the current rating the longer you need to drive to fully charge the battery.

I have had no experience of the Ctek unit, only the Redarc which does seem to do the job on my reasonably large (for a 4wd) battery bank (360Ah) which rarely get discharged below 12.4v to 12.5v. When camping our batteries are brought back to 100% by solar (425w) each day. On the day we return home, with both fridge & freezer running, & the usual power used in the morning (water pump & maybe lights) the alternator, via the dc to dc charger have the battery back to full in less than a couple of hours driving.

Ignore the pricing of the BCDC1240 on the Redarc website, it can be bought much cheaper
http://www.ebay.com.au/itm/REDARC-BCDC1240-DUAL-BATTERY-ISOLATOR-SYSTEM-DC-TO-DC-MPPT-SOLAR-4X4-4WD-AGM-/400394187906?hash=item5d395a7482:g:wrsAAOSwCGVYAFX 2

There are a couple of things I don’t like about the BCDC1240 - no temperature compensation & a float voltage lower than just about every battery manufacturer recommends. (The latter being a cheap means of doing without the former as far as I can tell - to avoid the risk of thermal runaway). I can’t recall if the Ctek has temperature compensation, but if it does I’d probably pick it if setting up again. Time will tell if the low (13.3v) float voltage makes any difference. My batteries are now approaching 5 years old & read 12.7v after a couple of weeks in the shed (i.e.. with no charging via driving or solar) & returns to float within a couple of kilometres driving. I’ll be cheesed off if I don’t get at least 10 years out of them.

[Robo]

Ctex has temp compensation as std.
Had 1 in our old millard, & happy with it.

Just bought a redarc 40 amp bcdc to fit in our paramount while away over the long weekend.
But it requires chassie earth connections "only" which I couldn't do with out the correct crimping tools and then drill into chassie while away from home.
I think chassie earth is required so the unit can self diagnose.
It doesn't say why only chassie in manual.
other than do not connect earths direct to battery.
this makes you wonder "why chassie only" but there has to be a reason hay.

Ctex 5 stage charge, redarc 3 stage and no temp compensation.
quick search best price on both units are found in ebay.
ARB rec ret over $650 + fuses etc, and a relay kit if ya want to fit solar which is another $80.
Ctex can handle alternator & solar as std and easier to install imo.

[MudRunnerTD]

Thanks guys, can someone explain the CTEK smart pass? I read the description but it lost me at hello!

[MudRunnerTD]

Cuppa I have 2 Optima D34 batteries under the bonnet of the GUIV I know the Alternator output is not great for hem but they have been great for over 5 years now. The second battery does norhing most of the time but when touring it runs the fridge. And will run the roof light bar when it goes on. The GUIV in now the wife's daily and does only about 600 kms a month now which is great.

I have a 120 amp Solar set up when base camping which I've have for 2 years now.

[Cuppa]

Just a means of increasing the charging current. The D250s is a 20 amp unit, adding the Smartpass allows for a combined charging rate of up to 100amps. Good for larger battery banks.

[Robo]

Just a means of increasing the charging current. The D250s is a 20 amp unit, adding the Smartpass allows for a combined charging rate of up to 100amps. Good for larger battery banks.

without smart pass up to 300ah.
with smart pass 80 amps and 28-800ah.

from memory ctek is no good with smart alternators.
I'm fairly sure redark can handle smart alt as the low volt switch off compensate being something like 10v.

I know for fact ford ranger and ctex don't work together, the smart alternator function can be turned off to fix it but at $400 lol.
rangers smart alt saves all of 400mls of fuel over 100klm what a waste of time, fitting manual hubs to disengage front diff would easily save more than that.

[Cuppa]

Cuppa I have 2 Optima D34 batteries under the bonnet of the GUIV I know the Alternator output is not great for hem but they have been great for over 5 years now. The second battery does norhing most of the time but when touring it runs the fridge. And will run the roof light bar when it goes on. The GUIV in now the wife's daily and does only about 600 kms a month now which is great.

I have a 120 amp Solar set up when base camping which I've have for 2 years now.

I reckon the alternator output (around 14.4v?) is probably ok for the Optimas, & if they are still going strong after 5 years that’s reasonable evidence it’s not doing them any harm.

You could save yourself the cost of a second dc to dc charger by continuing as you are & connecting the solar as the first priority when you get to camp, to top up the battery from what the alternator has put in to 100%. In crap weather you can always go for a drive if the solar doesn’t keep up (no different with a dc to dc charger). The main reason for putting a dc to dc charger on the Optimas would be to extend their life by having them at , or as close to 100% as much as possible. Connecting the solar as a priority would do the same. However for day to day use when not camping a dc to dc charger would be more convenient than connecting the solar whenever the car is not in use (Unless it’s roof mounted). Alternatively you could just put them on a smart mains charger once a week. In regard to extending the lifespan of the batteries - it’s hard to say how much difference it would make to 5 year old batteries - wouldn’t do any harm, but may not give much benefit either. When you eventually replace the Optimas the replacements will benefit from regular charging to 100%.
Basically if you are happy with what you are getting from the optimas but would just like them to last a bit longer whilst at camp both topping up with solar or having a dc to dc charger should enable this by ensuring they are fully charged. If you think the optimas are approaching replacement time then a dc to dc is worth considering - the D34’s are 55Ah each, so 110Ah & contradicting what I said earlier a 20/25am unit would probably suffice.

As you have the solar the decision is probably about how much you value convenience. The solar regulator function of a Redarc or Ctek is better than the cheapie regulators supplied on the back of panels - so if that is what you have, you should expect to see a bit more going into your batteries with the better regulator (especially if you upgrade the solar to regulator cables from the thin spaghetti generally supplied.

Fitting a dc to dc charger to in the camper is a no brainer I reckon. What capacity battery(s) do you have, or plan to have in the camper? If something like a 100Ah a 20 to 25 amp would most likely suffice. If more you may want a bigger one.

[Cuppa]

without smart pass up to 300ah.
with smart pass 80 amps and 28-800ah.

from memory ctek is no good with smart alternators.
I'm fairly sure redark can handle smart alt as the low volt switch off compensate being something like 10v.

I know for fact ford ranger and ctex don't work together, the smart alternator function can be turned off to fix it but at $400 lol.
rangers smart alt saves all of 400mls of fuel over 100klm what a waste of time, fitting manual hubs to disengage front diff would easily save more than that.

Redarc have two different BCDC1240’s , the ‘standard’ BCDC1240 & the BCDC1240LV (Low voltage) for smart alternators.

[MudRunnerTD]

Correction I have 2 X D31a Optima yellow tops under the bonnet. Not sure that changes anything? Just a bit bigger.

[Cuppa]

Correction I have 2 X D31a Optima yellow tops under the bonnet. Not sure that changes anything? Just a bit bigger.

150Ah. If going with dc to dc to charge them then a 20 or 25 amp unit would still be ok, but could fit a 40 amp unit if you are likely to be heavily discharging them.

Mind you, I still haven’t heard why you think you need one at all for them. Maybe before deciding do the following: 1.Charge the Optimas at home with a mains smart charger until they are full (charger goes into float mode),
2. Go camping & just use things as you normally do. 3. Drive home & park car overnight having ensured that nothing is running off the optimas. 4. Next morning check the Optima voltages with a multimeter/volt meter across the terminals. If you have a voltage of 12.6v+ (if new I’d say 12.7v+, but at 5 years old it is likely that some capacity will have been lost) you wont need a dc to dc charger for them. 12.5v would be a line ball call, but could just be reduced battery capacity.

FWIW I previously had a set with two alternator charged D31 Yellowtop Optima’s as crank batteries (24v) paralleled to a pair of 90Ah aux batteries (Fullriver) via a two way VSR, & topped up with 2x60w solar panels & had no concerns with this despite slightly different recommended bulk charging voltages. From memory Optima say a slightly higher bulk charging voltage than ‘conventional’ AGM batteries can be used, but they give a range, suggesting that charging them at a conventional 14.4v/14.5v is fine. Just that they can be charged a bit quicker at up to 15v provided they are under a specified temperature. I suspect that this is a bit of marketing hype to try to differentiate their ‘spiral wound’ construction, & in reality their requirements are little different to any other AGM battery which could also be treated similarly if battery temperature was monitored.

Besides...... fitting a DC toDC charger won’t raise the bulk charging voltage unless you set it on the Calcium setting, which I wouldn’t advise as it would likely overcharge them (15.1v I think). What it does do is use it’s electronic ‘smarts’ to squeeze in a bit more once the battery is above 80% full, which in most circumstances the alternaor alone wont do.

The ‘raising the voltage’ function is different for circumstances like the camper battery. It can raise the a voltage which has been reduced by the longer wire run to the needed 14.4v/14.5v. Without this the voltage drop in the cabling can prevent the camper battery from being properly charged. It also does the over 80% ‘squeezing in’ function.

[Rock Trol]

I have to agree with Cuppa in asking the question, do you really need one. I had a Redarc bc:dc 1220 under the bonnet to charge a Deka AGM battery. I was hoping to extend the life of the battery as they are expensive ($400 at the time). My battery only lasted 3.5 years and had lost some capacity in the months before it dropped a cell (battery had expanded). I don't know how long it would have lasted without the charger but it was not cost effective for me to add the charger. I feel that I just spent money for no reason on this occasion.

If the car had a smart alternator then they would be useful or in a camper for voltage drop. Patrol alternators provide decent output and if you charge it regularly with a 240 volt charger when at home then it should keep the battery in good condition. Then again, you might have better luck than I did. If you already have 5 years out of your AGM's under the hood then you must be doing something right.

[FNQGU]

Agree with Cuppa and Rock Trol - your usage will determine the $$ you actually need to spend here. Marketing is a wonderful thing and convinces many of us to buy shit we really don't need.

I am happily using the old Redarc 15A BMS for my main Aux battery in my trucks canopy, but only using a solar reg to charge my 2nd Aux battery (under bonnet) when needed, and if not going for a drive every few days. This has saved me a stack of coin, and works perfectly for what I use it for. ie. I run a 2nd fridge off it that sits on the back seat on longer trips, plus the UHF and a small 350W inverter for camera and laptop charging.

Of note, if you are looking at dc-dc chargers - have a good hard look at another Aussie brand called Intervolt, who make a 25A jobbie that on paper appears to out-spec just about everything else out there at present and at comparable prices.

[MudRunnerTD]

So I've listened to you guys and abandoned the idea of a DC/DC in the car. Don't fix what ain't broke. Like that logic.

After a fair bit of consideration I found the CTEK unit on sale on eBay at a good price so will fit it into the camper supplying 2 new 105AH AGM batteries (found some for $150 each on eBay! Score)

http://www.nissanpatrol.com.au/forums/images/imported/2016/11/27.jpg


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[Robo]

Agree with Cuppa and Rock Trol - your usage will determine the $$ you actually need to spend here. Marketing is a wonderful thing and convinces many of us to buy shit we really don't need.

I am happily using the old Redarc 15A BMS for my main Aux battery in my trucks canopy, but only using a solar reg to charge my 2nd Aux battery (under bonnet) when needed, and if not going for a drive every few days. This has saved me a stack of coin, and works perfectly for what I use it for. ie. I run a 2nd fridge off it that sits on the back seat on longer trips, plus the UHF and a small 350W inverter for camera and laptop charging.

Of note, if you are looking at dc-dc chargers - have a good hard look at another Aussie brand called Intervolt, who make a 25A jobbie that on paper appears to out-spec just about everything else out there at present and at comparable prices.

http://www.intervolt.com/product/in-vehicle-dc-dc-battery-charger/#horizontalTab3

Very nice specs indeedy.
Specifications
Input Voltage –
• Main: 9 – 17 VDC,
• Solar Input: 27 VOC max. (open circuit – no load)

Solar Power – 250 Watts nominal (300 Watts peak)
Continuous Rating – 25 Amps @ 50°C
Current Draw –
• Charging Device: Including LED indicator <10mA
• Remote Display: With backlight off: 10mA max,
• With backlight on: 30mA max

Boost Voltage –
• Standard Lead Acid: 14.4 VDC Nominal
• Absorbed Glass Mat: 14.6 VDC Nominal
• Gelified Electrolyte: 14.2 VDC Nominal
• Lead Calcium: 14.8 VDC Nominal

Float Voltage – 13.2 VDC Nominal
Electrical Protection –
• Thermal overload shutdown – auto reset
• Electrical overload shutdown – auto reset
• Under voltage disconnect – auto re-connect
• Over voltage disconnect – auto re-connect
• Reverse polarity protection of main terminals

Environmental Protection –
• Charging Device: IP67 (internal components only)
• Remote Display: IP40 (not dust or water resistant)
Operating Temperature – -20°C to +85°C
Operating Humidity – Up to 98%
Charging Device Materials –
• Heatsink: E-Coated ADC-3 die cast aluminium
• Blue Plastics: Temperature resistant PC/ABS alloy
• Black Plastics: 15% glass reinforced PBT
• Transparent Plastics: Temperature resistant PMMA

Remote Display Materials –
• Dark Grey Plastics: Temperature resistant PC/ABS alloy
• Transparent Plastics: Temperature resistant PMMA

Terminal Material – Tin plated brass
Terminal Fasteners – 304 stainless steel
Conformity – AS/NZS CISPR 11:2004 for EMC
Dimensions –
• Charging Device: 112 x 112 x 75mm (including terminal cover)
• Remote Display: 60 x 36 x 59mm (including mounting bracket)

Weight –
• Charging Device: 690 grams
• Remote Display: 55 grams

[MudRunnerTD]

Of note, if you are looking at dc-dc chargers - have a good hard look at another Aussie brand called Intervolt, who make a 25A jobbie that on paper appears to out-spec just about everything else out there at present and at comparable prices.


I did have a look at these too. I got the CTek for $265 delivered and couldn't go passed it to be honest.

But just having another look on eBay and this is a Bloody Good deal! If id seen this i may have gone this way as i need a couple of batteries anyway.

http://www.ebay.com.au/itm/FREE-BATTERY-INTERVOLT-DCC-DUAL-BATTERY-PRO-DC-CHARGER-REDARC-BCDC-CTEK-D250S-/232132883419?hash=item360c32b3db:g:W44AAOSwcUBYG8r e

[Cuppa]

http://www.intervolt.com/product/in-vehicle-dc-dc-battery-charger/#horizontalTab3

Very nice specs indeedy.



Whilst I have no quibble about build quality (Intervolt are good) I am disappointed by these specs, or more precisely by one specification & the total absence of another. Intervolt have done the same as Redarc did with my BCDC1240.

Float voltage of 13.2v is lower than all the AGM battery manufacturers recommend & is set at this level because they have, like Rearc failed to incorporate battery temperature compensation (7 monitoring). For those who aren't familiar, battery temp compensation means that the regulator will adjust the charging voltage according to battery temperature, usually by around 0.3v for every 5 degrees above or below 20 deg.C. It is my view that temperature compensation is the feature which most helps to extend battery life.
When VRLA batteries get too hot they can suffer from a phenomena called thermal runaway where they just keep getting hotter & hotter resulting in a bulging & destroyed battery (& fire risk). Often dc to dc chargers are used with batteries housed in the hot under bonnet situation & it is my view that the low float voltage is used as a cheap way of protecting from thermal runaway, instead of monitoring battery temp & adjusting charging to suit. Most battery manufacturers specify a float voltage of 13.6v to 13.8v.

Just out of interest what is the float voltage of the Ctek Darren, & does it have Temperature compensation? If not it is on par with Redarc & Intervolt products. If it does then I would suggest it is first preference.

[MudRunnerTD]

Whilst I have no quibble about build quality (Intervolt are good) I am disappointed by these specs, or more precisely by one specification & the total absence of another. Intervolt have done the same as Redarc did with my BCDC1240.

Float voltage of 13.2v is lower than all the AGM battery manufacturers recommend & is set at this level because they have, like Rearc failed to incorporate battery temperature compensation (7 monitoring). For those who aren't familiar, battery temp compensation means that the regulator will adjust the charging voltage according to battery temperature, usually by around 0.3v for every 5 degrees above or below 20 deg.C. It is my view that temperature compensation is the feature which most helps to extend battery life.
When VRLA batteries get too hot they can suffer from a phenomena called thermal runaway where they just keep getting hotter & hotter resulting in a bulging & destroyed battery (& fire risk). Often dc to dc chargers are used with batteries housed in the hot under bonnet situation & it is my view that the low float voltage is used as a cheap way of protecting from thermal runaway, instead of monitoring battery temp & adjusting charging to suit. Most battery manufacturers specify a float voltage of 13.6v to 13.8v.

Just out of interest what is the float voltage of the Ctek Darren, & does it have Temperature compensation? If not it is on par with Redarc & Intervolt products. If it does then I would suggest it is first preference.

Just opened the box and had a read through the owners manual. its thick but is 8 languages.....

It has a Float Function but doesn't declare the voltage. It has a 1.8m long Temperature Sensor that i connect to the side of the battery and has Temp Compensation but doesn't declare at what temp.

[Cuppa]

Good about the temp compensation Darren. They should all have it. Surprised the float voltage isn't given..... & you're right it isn't, I just checked the manual online.

[the evil twin]

I consider Intervolt the high end of the various manuf supplying this type of gear.
I use their stuff for some remote telemetry stations and they are the ducks guts but also have a lot of features not necessarily needed for a reccy application.

There is only about 100 pages less horseshit on the entire WWW about batteries than there is about wine.

Bottom line is after reliability not a lot else matters IE getting an extra 5% battery life from a Charger spec'd in a lab that you never see in the real world 'cause you forgot to turn off your CB a couple of times and drew down the battery to 40% or whatever is in the "Pffft category" IMHO

[MudRunnerTD]

I consider Intervolt the high end of the various manuf supplying this type of gear.
I use their stuff for some remote telemetry stations and they are the ducks guts but also have a lot of features not necessarily needed for a reccy application.

There is only about 100 pages less horseshit on the entire WWW about batteries than there is about wine.

Bottom line is after reliability not a lot else matters IE getting an extra 5% battery life from a Charger spec'd in a lab that you never see in the real world 'cause you forgot to turn off your CB a couple of times and drew down the battery to 40% or whatever is in the "Pffft category" IMHO

Great Strategy! I live there.

[dads tractor]

MudRunner as you can see some time has elapsed and would you mind giving an update on your ctek. I'm going down the same road with CTEK D250SA DC/DC 20A Dual Battery System/Solar Controller and 2 yellow tops running 2x 40 lt engels 2x 4amp/hr work lights, and only a TD4.2T as backup generator .

[threedogs]

How do you know if your model has a "smart alternator"??

[Hodge]

MudRunner as you can see some time has elapsed and would you mind giving an update on your ctek. I'm going down the same road with CTEK D250SA DC/DC 20A Dual Battery System/Solar Controller and 2 yellow tops running 2x 40 lt engels 2x 4amp/hr work lights, and only a TD4.2T as backup generator .

I've had one in my car for a while now. Unit works great. Charges really well. My battery is directly underneath mine and it works incredibly when my 120W solar panels feed it. It also charges the main battery once the Aux is close to full. Neat simple install.

http://www.nissanpatrol.com.au/forums/attachment.php?attachmentid=78450&stc=1

[dads tractor]

How do you know if your model has a "smart alternator"??

sits up the front of the engine bay maybe Threedogs.

[Hodge]

How do you know if your model has a "smart alternator"??

I could be wrong, but with a smart alternator, there is usually some sensor doodah at the battery end, that tells the alternator what to do.

[threedogs]

sits up the front of the engine bay maybe Threedogs.

Drongo, lol lol

[dads tractor]

Hodge I see you dont run a smartpass I thought they ran as a pair what am I missing.

[PeeBee]

I run the double units, the 250a and the smart pass. They work well, lot of money though for what they do. They are mounted in the vehicle on the rear cargo barrier. I have had a smart pass fail after 5 yrs though, unsure what the expected life is though.

[Hodge]

Hodge I see you dont run a smartpass I thought they ran as a pair what am I missing.Smartpass is optional. It just ups the amps and adds a few other functions .
The 250 on its own is just a standalone DC to DC charger.

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[dads tractor]

Thanks for the replies fella's so if I went with just the D250sa into 2 x Aux batteries of say 100 a/hr backed up with a 250 w solar blanket a la kings will it cover me . 2x40lt engels one as freezer one ice cold for beer and 2 camp lights that draw 4a/hr.

All suggestions considered.

[Hodge]

Thanks for the replies fella's so if I went with just the D250sa into 2 x Aux batteries of say 100 a/hr backed up with a 250 w solar blanket a la kings will it cover me . 2x40lt engels one as freezer one ice cold for beer and 2 camp lights that draw 4a/hr.

All suggestions considered.D250sa is only 20A on paper.

If you can , id be adding the smartpass , since youve got 2 X. 100 ampers there.

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[stevemc181]

I've recently changed from a Redarc BCDC-1225-LV to an Enerdrive END3DC40+ unit for my Lifepo4 battery. It's like chalk and cheese now, can pump 50 amps into the battery no problem. User programmable charge settings. The Redarc was never designed for my Lifepo4, but it's been doing the job for 5 years until I decided a few weeks ago to get the enerdrive unit, it is so much faster to charge the battery now, I'm a happy camper so far.
A 20 amp charger on it's own will take forever to charge 2 x 100a/h batteries.

[Patricapatrol]

I just installed the 250SE into a 97 GQ , so no smart alternator. The sensor (red) according to my interpretation of the fitting instructions you leave disconnected? So how does the unit isolate from the starter battery when ignition is off?

[0-TJ-0]

I just installed the 250SE into a 97 GQ , so no smart alternator. The sensor (red) according to my interpretation of the fitting instructions you leave disconnected? So how does the unit isolate from the starter battery when ignition is off?

Similar to a simple battery isolater it will detect the voltage of the main battery /alternator. It will connect and charge at and above 13.1v and disconnect at and below 12.8v.

The wire for the smart alternator forces the unit to start charging at a lower detected voltage. 11.8v I think the instructions say. So in reality that means it will start charging as soon as power is applied to that red wire.

[Patricapatrol]

So leave red wire disconnected as unit detects starter battery voltage. It is smart. So if I connected to to an Ignition wire it would charge at a lower voltage so I can trick it.
I understand the black wire if connected to earth for AGM battery (solar charge14.7v) and to 12v + if a lithium
Thanks for that , appreciate it 😁

[pollenface]

The Ctek by itself is a great unit, I used a D250S for many years mated to a 100w solar panel. With engine running it would provide a 20amp 5-stage charge to the deep cycle. Without engine running the unit serves as a 3-stage mppt solar charger to the deep cycle and a float charger to the cranking battery. You don't need smartpass, that's just extra complication in my opinion. D250SA is required for smart alternators. While my vehicle was parked in my garage while I was away for work I'd connect an 1.5amp 18v dc power supply to the solar panel input so both batteries were always fully charged.

Personally if I was to buy again I would get a newer 25amp redarc unit as they are compatible with old & new alternators and all types of batteries including Lithium.

[Hodge]

So if I connected to to an Ignition wire it would charge at a lower voltage so I can trick it.

I believe it would still have a voltage cut off... Regardless of what the ignition wire is doing.... I'd have to have a look in the manual to confirm.

Love my Ctek. When it has solar running and the Aux gets to a certain level it trickle charges (backfeeds) the main battery too. At times i've had both batteries more charged at while packing up camp, than it was when I got there.
I have the Smartpass unit sitting in it's box. Don't think I really need it yet as my Aux is only 110AH, the 250sa does the job flawlessly on it's own. It does have other features, but like someone mentioned here, it only adds more wiring and space taken.

http://www.nissanpatrol.com.au/forums/attachment.php?attachmentid=80183&stc=1

[Patricapatrol]

I like the red covers, may have to do the same

[0-TJ-0]

I believe it would still have a voltage cut off... Regardless of what the ignition wire is doing.... I'd have to have a look in the manual to confirm.

http://www.nissanpatrol.com.au/forums/attachment.php?attachmentid=80183&stc=1

11.8 cut in 11.4 cut out.

What mine says anyway. Can't see too many batteries ever getting down that low in purpose so it will be pretty well always on if you connect that wire.

Nice neat setup by the way.

[Patricapatrol]

Had a interesting issue on the weekend. First camping trip in installing the ctek d250SE . Been working ok as cars been parked with solar connected to maintain batteries due to travel restrictions. As it’s a 97 GQ and a 105 amp AGM i connected the black wire on the smart alt to earth . Well it just flashed the current saving mode (green light left side lower) . After much checking I disconnected that black wire (earth) and it started working. Connected the earth back and nothing. Anyone had this issue ?

[0-TJ-0]

(edit because I got it wrong)

Are you talking about the black agm wire or the red smart alternator wire?

Is it charging okay off solar? But not off the alternator?

[Patricapatrol]

Morning, the black wire in the same sheath as the smart alt red wire. No doesn’t want to work when in AGM (earthed) but does when in lead acid . Only thing was done prior to leaving was I connected a 240v battery charger to car night before when I turned 2 fridges on .

[0-TJ-0]

Yeah can't help sorry, if it was all working okay and now it's not it must be a fault. Either in the wiring or the unit.

I've charged mine with a 240v charger plenty of times with no issue.

[Patricapatrol]

Thanks for the feed back. Not a lot of info out their .

[Patricapatrol]

Update, black sensor wire (earth for Agm ) was not a good earth . Was earthed to body where a existing wiring harness earth was . CTEK unit needs a perfect earth (direct battery earth). Have had no issues since .