Can I charge multiple batteries at once?

[aczlan]

Yes, starter batteries are paralleled in diesel vehicles.
There has been MUCH theoretical discussion about this over the years, but they tend to NOT discharge into each other - at least mine never have. As a pair they last about as long as a single battery on a gas car, but it is recommended to replace them in pairs anyway.

as I understand it the OP was talking about putting several DIFFERENT batteries in parallel, not a matched set like what is in your truck, if the batteries are matched, it works great, however if they are dissimilar batteries you can have the problems with batteries dieing like has been mentioned.

Aaron Z

 

[Reg]

as I understand it the OP was talking about putting several DIFFERENT batteries in parallel, not a matched set like what is in your truck, if the batteries are matched, it works great, however if they are dissimilar batteries you can have the problems with batteries dieing like has been mentioned.

Aaron Z

Ooops, on re-reading the original post I guess there is some possibility that the O/P doesn't know the rules of series & parallel.
So;
2 6 volt batteries in series can be regarded as one 12 volt battery IF they are of similar capacity and similar state of discharge - rationale; they will be getting the SAME current through them for the same amount of time, so they had better "need" the same re-charge.

Two or more batteries of the same voltage can be hooked in parallel on a charger and will achieve an equilibrium.
Their initial state of charge is relatively unimportant, since each will charge according to it's need.
Since the charger voltage will be higher than any of them they won't "discharge into each other".

But, BUTT, BUTT, BUTT !!!
The O/P has only a 6 amp charger, so moving it from vehicle to vehicle is probably more practical than removing batteries to hook them up in parallel.

 

[al b]

Ooops, on re-reading the original post I guess there is some possibility that the O/P doesn't know the rules of series & parallel.
So;
2 6 volt batteries in series can be regarded as one 12 volt battery IF they are of similar capacity and similar state of discharge - rationale; they will be getting the SAME current through them for the same amount of time, so they had better "need" the same re-charge.

Two or more batteries of the same voltage can be hooked in parallel on a charger and will achieve an equilibrium.
Their initial state of charge is relatively unimportant, since each will charge according to it's need.
Since the charger voltage will be higher than any of them they won't "discharge into each other".

But, BUTT, BUTT, BUTT !!!
The O/P has only a 6 amp charger, so moving it from vehicle to vehicle is probably more practical than removing batteries to hook them up in parallel.

Thanks for the rules of series and parallel. I didn'n know about them. What I was thinking was since I have the tractors bunched up and 3 good sets of jumper cables plug the big one first and then run cables to the rest.

 

[fordman6442]

I have tryed this several times, as a mechanic we had trucks and crawlers with 4 batteries in series. The big problem is if 1 battery is a dud the charger picks up the faulty battery and will charge forever hence over charging the other 3. Found this only worked with 4 good batteries.

 

[SnowRidge]

You can charge multiple batteries in parallel safely by using isolation diodes. The commercial diode isolators made for RV and marine applications are expensive overkill for maintenance charging, but they will work. It's a lot cheaper to build your own, but it does take a little electrical knowledge.

 

[tallyho8]

My six 6 volt batteries in my golfcart are in series and I charge them with my 36 volt charger and they usually last several years with no problems.

 

[Wayne County Hose]

I have a 6 amp charger and I'm thinking about connecting 5 batteries at once either series or parallel and letting it stay for these really cold days. The reason is that i have to move the tractors around time to time to gain assess to thing so i don't want to take batteries out and put them inside the basement. But I don't know if it will work or should I do it in series or parallel. Any ideas? Also I have 2 motorcycle batteries in the basement and a deep cycle I'm thinking about doing it too with a 1 amp charger.

You want to hook these in parallel. That means to hook all the positives together and all the negatives together, Theoretically, you shouldn't do this with unequal amp hour batteries, but for a couple months, you should be okay. I ask this question, if it's only for the winter, why not leave them in the tractors? I leave mine in all winter. I leave the batteries in probably 3 or 4 months until spring and they start right up. If you have a discharging problem, unhook the battery and leave it in there. It won't hurt anything.

 

[al b]

I plan on leaving them on the tractors because I have to move them sometimes. I want to keep the batteries fully charged so they start. What I done in the past is about once a month I take the 6 amp charger and put it on each battery for a day and I take the 1 amp and put it on the bike. Then I thought if I connect them all together could I leave them plugged in. They should start better and last longer if plugged in right? I just don't know if I'm over charging them or not enough.

 

[Sherweld]

Yeah, note that these are for really heavy duty chargers.
In general it is not a good idea to run multiple batteries. If one of them fails it can kill the other batteries and the charger. Plus, depending on the design of the charger, if you place multiple depleted batteries on it, it will overload the charger.

If it is a smart charger, it might not work at all depending on the state of the batteries. If it does work, you will not really be able to depend on it fully charging the batteries since it will not be monitoring the batteries individually.

I would suggest getting a bunch of those small chargers that are meant specifically for tending batteries in storage. They are little smart trickle chargers. They are pretty cheap so you can get one for each tractor. Since they have a very low draw, you can put them on cheap extention cords.

I would definitely second this suggestion. An unbalanced load for whatever reason (age, size, condition etc) is potentially going to mess things up with your battery system(s).

Google for battery maintainer, here's an example SureCare Battery Maintainer | Battery Maintainers | Northern Tool + Equipment

They are designed to do exactly what you are aiming to do.

 

[Bedlam]

these
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