School me on DC/DC chargers and systems

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

Quote:

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Originally Posted by 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

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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.

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.

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-BC...sAAOSwCGVYAFX2

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.

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.

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

@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.

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.

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Originally Posted by 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.

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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.

Quote:

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Originally Posted by 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.

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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.