Dual Batteries for dummies

[2007Lux]

I posted this in the "alternator" thread but thought I'd add it here. Had this set up going all summer for about 5 trips away and no issues. However it seems from the above comments that the ctek is working a treat for all those who have them. I must add that having an aux battery with extra terminals is really handy for wiring in extra things.
.....................
A word on the Redarc BCDC1220 install I recently did

I removed main battery and fixed it to the side of engine bay with screws and then put the battery back in. Yep you've gotta drill holes in your beloved to do this.

I also installed a continuous duty solenoid in order to join the two batteries with a momentary rock switch if the main dies. Redarc have a wiring diagram for the install and can also be contacted over the phone for advice. It is a fair bit of work and you have to get some thick cables made up unless you can do that yourself. For the effort you could instead just buy good jumper leads but I was looking for a challenge

The link below shows you how to do this.
http://redarc.com.au/handy-hints/wiring ... tery-setup

I did a bit of research for my needs (ARB 47ltr fridge for 3 day camping trips) and I came up with the following set up:

-ARB tray. It has bolt holes exactly where you need them, including for the extra solenoid
-Redarc BCDC1220
-Bosch 95A deep cycle maintenance free Ca battery.
-40A resettable breaker distributed by ABR for the aux power going to the tray

I choose Redarc over Ctek dual because:
-The battery I chose requires a 14.7v to gain a 100% SOC but the cteck only goes to 14.4V
-The Cteck reduces its output above 26 degrees (I think this is the correct temp) but the redarc keeps going up to much higher temps
-The Ctek is splash proof but the Redarc is sealed
-The Redarc is Australian made and has good over the phone service
-I don't require solar input and if I do in the future it will be when the car is stationary so I will just hook it directly to the battery.

Also Redarc recommend the BDCDC1220 instead of the SBI12 for the D4D engine because of the alternator it runs.

[Qwerty]

Do you find your redarc hits 15v when charging (standard lead acid mode)?


** Sent from smartphone using Tapatalk, excuse fat fingers on small keyboard. **

[pjtaylor03]

I have been researching a bit about getting my first dual battery setup on my 06 D4D. I put a volt meter on my terminals last night after the 20km trip home and it was reading 13.65 volts idling. I was just going to go with an isolator rather then a dc dc charger to keep costs down. So correct me if i am wrong but at this voltage my alternator will charge the second battery faster with an isolator but only to about 65%. Where a DC DC charger will take a lot longer but get the battery to 100% charge.

[Wing]

Should measure the voltage next day. full charge is around 12.7-8V.

I think an alternator with isolator will charge to 80% and quicker than a low amp DC DC charger.

[Qwerty]

wing, it might charge it to 80% a little faster than say a 20amp DC-DC, though I'd think a 40amp unit would be on par. My 20amp DC-DC has no dramas getting me charged in good time. (i have reasons for not wanting 40amp).

The thing is, the "useable" part of your battery capacity (even on deep cycle) is basically 60% - 100%

Taking any battery lower than 50-60% is bad news, and generally damages batteries.

Any battery solution will need to aim at the 60 - 100% SOC range as the useable.

So, if your alternator DOES manage to get to 80% SOC, youve still really only got HALF the useable runtime as you would if you used a DC-DC charger .. and the DC charger will most definately "win the race" to 100%

Not to mention the chemical health benefits of being able to use proper staged charging to 100% on each cycle, and not dipping too low.

I'd actually think it's closer to 70% SOC max with alternator ... so even worse really. It's like only filling your fuel tank to half.

Sure, you can run batteries down further (down to 11v if you want), but you're greatly reducing lifespan. (you can of course do this with a DC-DC envirnment).

My aux battery, the next day (with no load at all) will still be sitting around 13.2v.

my starter usually sits around 12.7 (unless i put an AC-DC charger on it at home, and give it a proper charge ... then it will "sit" over 13v easily.

[Wing]

Yes, agreed, I used an isolator before, fit for the purpose. But I did not like the heat it generated.

Now I use a CTEK DC-DC dual. Like Qwerty said, 20 AMP with no drama ever. If I discharge my 100 AH aux battery to the minimum allowable 50 AH, I will have 50AH for use during camping with the CTEK. If I used an isolator, I only have 80 AH in my battery and I only had 30AH at the camp site. The CTEK increases my available power by 67%.

[MrLuxx]

Hi guys I'm currently fitting a Redarc BCDC1220 and was wondering of anyone can help me
With finding the easiest spot to splice the blue ( ignition voltage sense ) wire would be?
Thanks in advance Pat

[Steveyb]

Hi guys I'm currently fitting a Redarc BCDC1220 and was wondering of anyone can help me
With finding the easiest spot to splice the blue ( ignition voltage sense ) wire would be?
Thanks in advance Pat

Hey mate, the blue wire goes to the battery positive when setting it up on a 12v system (it is measuring voltage level to know when/what to do about charging) it only goes to an ignition point on a 24 volt system.
EDIT:!!!! the positive on the feed battery (starter battery)
read here:
http://redarc.com.au/static/files/Spec_ ... t-A5-2.pdf

[MrLuxx]

Hi guys I'm currently fitting a Redarc BCDC1220 and was wondering of anyone can help me
With finding the easiest spot to splice the blue ( ignition voltage sense ) wire would be?
Thanks in advance Pat

Hey mate, the blue wire goes to the battery positive when setting it up on a 12v system (it is measuring voltage level to know when/what to do about charging) it only goes to an ignition point on a 24 volt system.
EDIT:!!!! the positive on the feed battery (starter battery)
read here:
http://redarc.com.au/static/files/Spec_ ... t-A5-2.pdf

Ah thank you now that I re read it I don't know how I got confused in the first place it's so easy! Thanks again mate

[Hilux Max]

Has anybody fitted a 2nd battery in the tub of their hilux and if so what sort of setup did you go with?

i.e. battery box, inside another tool box, on top of rear wheel arch etc....

Im looking for ideas.

[white_hilux]

Has anybody fitted a 2nd battery in the tub of their hilux and if so what sort of setup did you go with?

i.e. battery box, inside another tool box, on top of rear wheel arch etc....

Im looking for ideas.

when i had my last lux with a styleside, I had my second battery in a battery box located on the floor of the tray right up against the passenger side between the rear of the tub and the rear wheel arch

[Hilux Max]

So the battery box was bolted through the floor and you ran the wiring through the rear tail light to the front?

[white_hilux]

So the battery box was bolted through the floor and you ran the wiring through the rear tail light to the front?

exactly

[PluckA76]

Most portable folding panels you buy these days already come with regulators attached to the back of the panel. I just bought one a few months back from the Brisbane Caravan and Camping show with thoughts of later on installing a dc-dc charger (Redarc of Ctek charger). The panel I got has 3 panels and a regulator for each but bridged to the centre one if that makes sense and then a lead with anderson plug.

Last month we had the grand opening of ARB in Bundaberg and a redarc rep was here showing off the latest stuff and their charger with the MPPT but said you have to use their solar regulator or it wouldn't work with the dc-dc charger.

To cut a long story short ) how do you plug a panel into a ctek or redarc charger that already has the solar regulator built in. Do you need to cut the wiring and join the negatives and positives together and feed that into the input or can you just plug it in but wont be as efficient.

[outbackjoe]

Has anybody fitted a 2nd battery in the tub of their hilux and if so what sort of setup did you go with?

i.e. battery box, inside another tool box, on top of rear wheel arch etc....

Im looking for ideas.

Hey mate mine is in the tray, check it out here, scroll down theres a picture and description of the battery about half way down:

http://outbackjoe.com/macho-divertissem ... omponents/

Mine is wedged in there with some carpet underlay between the drawers and the side of the tray. I drilled a hole in the back corner of the tray, cables route under the tail light and then under the vehicle, similar to what was already described by white lux.

Also, a general comment regarding charging to 100% using DC-DC chargers. There is no inherent 100% fundamental charge to the battery. Full charge voltage is a compromise between capacity and grid corrosion. The more you charge it, the more you wear out the battery.

My system only provides an elevated charge when I'm actually cycling the battery and can use the extra capacity - when stopped and using the solar panels. The rest of the time it charges straight off the alternator which provides faster charge rate and lower voltage to protect the battery.

[mitch_893]

Hey guys,

I've acquired an Electro BI-80 dual battery isolator for free. How can I use this to set up a dual battery kit in my 06 d4d? Will it be suitable? What else do I need besides a battery and tray?

Cheers

[PluckA76]

Jut bought the 20amp ctek dual dc-dc charger. Has anyone got photos of where they installed them under the bonnet. I'm thinking of velcroing it ontop of the fuse box which sits central to the two batteries.

[buffo69]

My Ctek is mounted under the passenger seat.

[Hellbound]

My Ctek is mounted under the passenger seat.

I thought that your meant to mount them as close as possible to the second battery for some reason....

[2007Lux]

Jut bought the 20amp ctek dual dc-dc charger. Has anyone got photos of where they installed them under the bonnet. I'm thinking of velcroing it ontop of the fuse box which sits central to the two batteries.

Have a look in this thread as I'm sure there is some discussion about this
viewtopic.php?f=11&t=4102

I seem to recall someone putting theirs also on the fuse box.