If the isolator switch is in the BOTH position then charging one will also flow to other. Seems like a good way to ensure both tip top if you normally don't get around to swapping the charger to the other battery.
After a search I saw this might be bad if one battery has an issue.
Does anyone do this?
My batteries are both newish and I think healthy.
I wouldn't combine in that way.
For the princely sum of $US64.95 plus postage you can get this VSR with lifetime warranty, waterproof and is the size of a credit card, and simple to wire up with 3 wires.
http://www.yandina.com/c100InfoR3.htm
You can then put the charger on one of the batteries and let the vsr do its work.
I'm currently wiring one of these in myself.
I disconnect the VSR when charging (By taking the earth / black wire from the VSR off the battery terminal) and charge each battery seperately with isolator swith set to "off". (It's really not that hard to charge seperately for the peace of mind it gives) - once the cycle is complete on one batt you just swap the +ve lead from over to the other batt...-ve is common). If I'm going to leave the batts on charge for any length of time I will switch the batt isolation swith to 1+2 and leave it at that but only after I have run a full charge cycle on each batt.
The reaon I do this is because if they are connected in paralell and one battery is poked but the other is good, the charger will only "see" the good battery. Sure with new batteries probably not a such a problem but remember also that once one battery gets to full charge the c-tek will stop charging (Will go into maintain mode) even if the other battery is still not fully charged. I got caught out once before, I used the charge in paralell (Like you are saying) and thought both batts were good but one was actually really poked when I had it checked...c-tek only ever saw the good battery.
Another option WL if you want to do it in paralell is just charge each one seperately now and again to let the C-tek do its thing.
If I'm right I dont think the VSR helps here, from my understanding the batteries are connected in paralell by the VSR when charging (So same issues as above) but then isolates them once charging stops or voltage drops to 12.8...thats why I disconnect the VSR when charging because it simply connects them in paralell when charging whatever position the isolator swith is in.....I think....the bloke who told me to do this was an electrical engineer so I assumed he knew what he was talking about.
Good luck with it...
Thanks guys.... I currently have both batts set up with an Ctek plug each so with isolator to OFF I guess thus is safest.
I had a low charge on one of them initially. I am wondering about setting the Ctek to Recondition mode...
Can that harm a good battery if its not in need of that cycle?
I charge two agm's separately similar to you, with switch on OFF. Crank is an optima that rarely needs a charge anyway unless more than maybe 2-3mths. House is an odyssey that holds a charge even better but it gets drained maybe 40-50% on average every trip. So the ctek goes onto the house when get home, and only test the crank to see if needed....if havent gone out for a mth i might put it on the crank plus if going out next day i might but not necessarily switch it over to the crank.
Cant see too much wrong with charging on 1+2 if u wanted to, but i;m sure there's some sort of remote possibility it may bugga something up.
Be very careful with VSR's. They can hide a problem.
Here's what has happened to me before. Crank battery is stuffed, house battery is totally charged. Motor starts not on crank but from House thru VSR. However as day goes on house gets drained a bit, VSR disconnects house from crank (as its designed to do)....now try and start the motor on dud crank only.
If you put in a VSR I strongly recommend a manual emergency bypass....Sometimes clever is not as good as simple.
A duel output charger is the way to go. I used to parallel my two deep cycles when charging but started to measure the actual voltage at the batteries and found that one can be higher than the other. I now have a duel channel charger and I find even if the batties sit for a while they take less to get them back up to full charge.
Wal hook your charger to the common terminal on the change-over switch and a battery negative then you can charge 1, 2 or Both just by flicking the switch.
I was considering that originally but the circuit is then connected to the rest of the gear so if there's any leakage it will dribble away and the charger will be consuming more.Originally Posted by Fed
After writing the above I am thinking.., so what. It's easier than swapping leads mid week.
Thanks for the suggestion Fed. I might do that.
Could you not pull the fuse to the other electrics before commencing charging?
Unfortunately there's a bunch of fuses so it's not simple.... Easier to swap the Ctek on to the prefitted charging plug of each battery.
I am leaning towards changeling it to the isolator and ignoring leakage (there probably isn't any anyway)
Much easier to swap mid week. Thanks Fed.
Unless you have an actual fault any leakage will be through diodes and so small it isn't worth a second thought.
Ages ago I was hooking up my battery & noticed a tiny spark, traced it down to two things drawing power.
1) My 27MHz radio was leaking even though it was turned off at the radio, the only way to stop it was to pull the plug out of the back. HMMM, rang GME and found out they put a diode before the on/off switch I guess to protect for reverse polarity ie: blow a fuse instead of blowing a radio. That's one good reason for never increasing the original fuse size even though the supply cable can carry a higher current.
2) the other leakage came from the outboard motor and I put it down to rectifier diodes as well, it was a fair while ago but I think I actually traced it to them.
I measured both leakages and they were pretty much the same and so small that it would take years to drain a battery.
Davo what charger are you using ? Are there any 12v dual output ctek with decent amp output to charge 2 105amp/hr deep cycle agm's that anybody knows of???
Out of interest how long did you leave the batteries to rest before testing the voltage at the batteries.
If you refer to post 7 of this link, the poster found that using a combiner resulted in the batteries having the same voltage after a 24 hour rest, which was also confirmed with a hydrometer. I think he also uses a Yandina Combiner / VSR.
http://www.cruisersforum.com/forums/...duo-47760.html
Obviously varies from battery to battery - i have a Trojan house battery and the user guide also recommends the battery is idle for 6 hours at least and preferably 24 hours before accurate voltage readings can be taken.
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