charging a 24v system

[The motor guy]

So this kind of goes along with my other thread of connecting one charger to dual 12v batteries connected in parallel and let the charge carry over to the other battery. Personally I think that's fine, but trying to do 4 batteries while only being directly connected to two seems a bit much. Now with that being said, I have a scissor lift and it has (4) 6v batteries wired in series to add up to 24v. Anyways, It has an onboard charger on it and it and i'm not sure they wired it up right, but only the two outer batteries are hooked up to the charger. After a while I noticed the case near the posts on the two outer batteries were swollen up. Maybe the charger was overcharging idk, because it's got something wrong with it too and I bought a new charger I need to install one of these days. why can't I connect charging wires to each battery? I could also be totally wrong and nothing could be wrong with the way they have it set up, but I've learned to not always trust that things were done correctly.

 

[eljefino]

You need some basic electrical theory.

https://en.wikipedia.org/wiki/Series_and_parallel_circuits

Don't monkey with anything thinking you're smarter than the last guy until you have a much more thorough understanding.

You should have interconnects, a "master" positive and "master" negative that both go off to power the lift, and off to charge it. As you describe it, the two outer batteries.

Connecting additional wires to a charger will result in a dead short across one or more batteries if you do it wrong.

 

[dnewton3]

If only two of those four are hooked up, are you SURE those two connected are 6v and not 12v?
My point being that maybe someone previously connected two 12v in series (24v) because those are much easier to source than four large 6v batteries.

 

[samven]

There is no way to connect a 24v charger to 4 separate 6v batteries. The problem with charging series batteries is the same as old Christmas lights that were in series. If one burns out the others dont get any power but worse is if one shorts out the other 3 will get 8v instead of 6v. This could cause the 3 good ones to overheat during charging. You really need to disconnect the batteries from the charger and check their internal resistance. If they are not close the high resistance battery will rob the others of voltage and prevent them from charging completely.

 

[The motor guy]

So what's the deal with the case swelling up on the two outside batteries?

 

[fsdork]

So what's the deal with the case swelling up on the two outside batteries?

Didn't your first post say there's something wrong with the charger? A quick google search gives two likely causes of swelling at the terminals - over charging, or providing too much current to the batteries. That sounds like a couple things a defective (or incorrect spec for the system) charger might do.

 

[The motor guy]

Didn't your first post say there's something wrong with the charger? A quick google search gives two likely causes of swelling at the terminals - over charging, or providing too much current to the batteries. That sounds like a couple things a defective (or incorrect spec for the system) charger might do.

That's what I think. Charger was overcharging