Equalizing battery charges

Hi Batboy,

My favourite topic!! Not so with too many other forumites who lead electrically simple lives. :-)

I have a 24v HJ61 Landcruiser, and tried both a 24v to 12v reducer and the Redarc charge equaliser.

If you have had no problems with the 24V system and battery charging to date, I'd suggest you bought a reducer, or run the Redarc as a reducer. This is on the proviso you want to run low current items, such as your UHF. I bought a 20A unit second hand and it stopped working after I overloaded it. New ones have better internal protection so would be okay I'd imagine.

IF on the other hand you want to be able to pull whatever current you like from the low battery, centre tap, positive pole of the low battery, or negative pole of high battery, whatever you want to call it, then I'd suggest using the Redarc as it's designed, as a charge equaliser.

They work well in balancing the voltage across the two batteries, but your drain is taken from the 12v supply, not via the Redarc - that just looks after the charge equalising. Hook it up with a relay on the 24v feed to your Acc switch and it'll be fine. This is my set up now.

You could set up some switches for your UHF I guess, but I'd be concerned at getting the batteries out of sync and then how do you equalise them again? This would happen with the compressor, unless you pumped up two tyres from each battery, ie equal draw from both batteries.

Try this link for an extensive story on what you are asking.

>To date I have had no battery issues and have 24v auxilaries for my fridge.
Do you have 24v aux batteries set up?

Have fun with the set up!! Running basically a second electrical system has it's moments. :-)

Tim

You may never need to charge them individually. Are the batteries the same A/H capacity?? if they are not you cannot use them together in series or parrallel. If they are identical batteries, hook em up in parrallel, but give them both an initial charge before hooking them up to get them both full. Then hook them up and use them both in charging and discharging them and they will start to get a "feel" for each other and act as one battery. In fact if you want to use several batteries together you should hook them together when new and never charge or discharge individually, this way they act as one large battery. Forget the meters etc, just make sure they are both full when you first put them together. I work with rechargeable batts for my job, it's all quite interesting.

I've been running a Redarc charge equaliser in my Humvee (its 24v too) for 3 years now with absolutely zero problems. You can suck as much 12v from either battery as you want .
I've got mine activated by the accessory postion on the ignition so it only equalises when either in acc or the engine is running.
I much prefer 24v, less current flow etc, the engine starts really easily, the Autofridge runs on 24v direct which brings current drain down to around an amp.