how do you charge a 24v system?

[The motor guy]

my friend just bought a used lift with the same 4 series battery configuration. Chances are one battery is weaker than the rest. the big charger will have to kick on and off, that’s how they work. some of the batteries are topping off while others still need more. You can try to charge them individually and it will help but you’ll still be limping along.

yeah but not immediately restart like mine does. every single battery disconnected shows 5.7 volts, it was 6.2 about a month ago, but I used a good bit since. Those charger wires are totally rusted, explains why the charger was getting super hot, probably overheating and shut off only to repeat the cycle. similiar to my truck batteries. one cable was loose and it was putting out 18v on one side to get the other side up. Now with that being said, I never did bother to put a multi meter on these scissor lift batteries to see what the onboard charger was doing. They were boiling for sure though, you could hear and smell it. Although that is supposed to be somewhat normal i've heard.

 

[The motor guy]

why do they have two charging cables on the two outer batteries versus a set on each one individually? Is that how you hook them up when it's in series? Then if it's a parallel setup, you attach a negative and positive for each battery?

 

[eljefino]

If you have a 6V charger, you'll have to unhook them and charge separately. However, it will probably take a long time to charge each one so be prepared.

No, you won't. With the lift not drawing a load, the 6V charger on the 6V posts will only be delivering a charge to that particular battery regardless of it's connected to the others or not. Explain where the "rest" of the current is going to go, and how, in a complete circuit.

 

[eljefino]

It's just a 6amp charger. I'd prefer to just charge each one for a couple hours, then move onto the next one. Give it enough charge to move it into my shop where I have power, then I'll work on changing out these corroded ring terminals, which I bet is the reason why the onboard charger runs for 20-30 minutes then restarts. It's just a hunch, though. I'm probably wasting my time and need a new charger.

Solid plan. I would also test each battery, I suspect they're nearly dead and why you got a good deal on this unit. You also want your batteries to be "balanced", a weak one will run flat or even reverse-charge which is quite bad for them. By "balanced" they should each start at the same voltage and drain at the same speed.

 

[eljefino]

why do they have two charging cables on the two outer batteries versus a set on each one individually? Is that how you hook them up when it's in series? Then if it's a parallel setup, you attach a negative and positive for each battery?

Go read about parallel and series wiring until you understand it. This is basic electrical work and you should not have a forum spoon feed it to you. And you should know it before you potentially blow up a battery in your face.

 

[The motor guy]

No, you won't. With the lift not drawing a load, the 6V charger on the 6V posts will only be delivering a charge to that particular battery regardless of it's connected to the others or not. Explain where the "rest" of the current is going to go, and how, in a complete circuit.

I would think if a bad battery can drain a good one, then it can also charge a bad one. Kind of like when you put a dead AA battery in a remote control with a good one, then the bad one will drain the good one. Maybe it doesn't work in reverse and charge the bad one. Just my thoughts, this could be wrong

 

[The motor guy]

Go read about parallel and series wiring until you understand it. This is basic electrical work and you should not have a forum spoon feed it to you. And you should know it before you potentially blow up a battery in your face.

I know they blow up in your face, hence why I asked all you fine people before I even touched it

 

[The motor guy]

Series adds voltage, parallel adds amperage I know that much

 

[SHOZ]

yeah but not immediately restart like mine does. every single battery disconnected shows 5.7 volts, it was 6.2 about a month ago, but I used a good bit since. Those charger wires are totally rusted, explains why the charger was getting super hot, probably overheating and shut off only to repeat the cycle. similiar to my truck batteries. one cable was loose and it was putting out 18v on one side to get the other side up. Now with that being said, I never did bother to put a multi meter on these scissor lift batteries to see what the onboard charger was doing. They were boiling for sure though, you could hear and smell it. Although that is supposed to be somewhat normal i've heard.

Boiling and gassing is probably because the batteries have too low specific gravity acid from being overwatered. Need checked with a hydrometer but that only tells the story, hard to fix.

 

[MSCH]

The charger went out on my scissor lift which has four 6v batteries connected in series. I want to charge them just using a standard 6v charger. Now with that being said, I have two questions:
1. Do I have to unhook them and charge them all separately?
2. Is unhooking them any different than a regular 12v battery? Do you just remove one cable at a time? negative first, then the positive side of the cable? Or do you unhook all the negative sides, then do the positives?

if all you have is a 6 volt charger, connect all 4 size volt batteries in parallel and charge them at once
or disconnect each of the batteries at one connection ( or both) each and charge individually.

generally speaking, the best place to start disconnecting a negative ground is at the most negative connection point in the system first.

 

[SHOZ]

You do not need to disconnect any cables to charge the batteries individually.

 

[MSCH]

You do not need to disconnect any cables to charge the batteries individually.

if you want to charge a 4 pack of batteries that are connected in series at a nominal 24vdc and used a 6vdc charger how do you think that is going to work?
if you wanted to load test the same pack of batteries you would also need to disconnect at least one connection on each battery to be tested.

think about it

 

[SHOZ]

if you want to charge a 4 pack of batteries that are connected in series at a nominal 24vdc and used a 6vdc charger how do you think that is going to work?
if you wanted to load test the same pack of batteries you would also need to disconnect at least one connection on each battery to be tested.

think about it

If you connect the charger clips to one battery all there is 6volts, think about it. Individually is the key word here.

 

[MSCH]

If you connect the charger clips to one battery all there is 6volts, think about it. Individually is the key word here.

I'm thinking about it in the same sense you would test individual resistances in a series circuit... where you need to disconnect at least one end in order to be able to test.

or if you want to load test an individual battery in either a series or parallel setup, you have to break out that one battery at least at one terminal in order to isolate it..

Your method may work, I will admit I am unsure but I'm thinking the reality of doing it the way you suggest is you are just throwing a 6 volt charge into one point in what amounts to a 24 volt total series of resistors and the low side of the charger will try to pass thru any other battery on the low side to ground ( those batteries are essentially conductors) with the same effect on the high side. Essentially the thing is fighting itself.. but I don't know for sure.

one thing for sure is a person could try as a charger doesn't have to worry about chassis ground and such..

 

[The motor guy]

I'm thinking about it in the same sense you would test individual resistances in a series circuit... where you need to disconnect at least one end in order to be able to test.

or if you want to load test an individual battery in either a series or parallel setup, you have to break out that one battery at least at one terminal in order to isolate it..

Your method may work, I will admit I am unsure but I'm thinking the reality of doing it the way you suggest is you are just throwing a 6 volt charge into one point in what amounts to a 24 volt total series of resistors and the low side of the charger will try to pass thru any other battery on the low side to ground ( those batteries are essentially conductors) with the same effect on the high side. Essentially the thing is fighting itself.. but I don't know for sure.

one thing for sure is a person could try as a charger doesn't have to worry about chassis ground and such..

I did think that was odd that with them all connected together it was still 6v. I guess it's just considered a big 6v battery

 

[thastinger]

why do they have two charging cables on the two outer batteries versus a set on each one individually? Is that how you hook them up when it's in series? Then if it's a parallel setup, you attach a negative and positive for each battery?

If you have a 24VDC system, and they got it with 6V batteries, they would all be hooked up in series. You can get the 24V in lots of different battery configurations (12V battery x2 in series), 3 three 8V golf cart batteries in series, twelve 2V fork lift batteries in series etc.

In your case, the ground would be in the (-) terminal at one end, batteries would be hooked + to - until you reached the + of the other end battery and that is where you would hook up your + cable from the lift.

 

[MSCH]

I did think that was odd that with them all connected together it was still 6v. I guess it's just considered a big 6v battery

not in series... if you start at most negative ( ground) and go up the chain of connection in s a series setup each bridge connection
( + to - ) you will add voltage.. and both sides of the same bridge have the same potential, there should be 3 bridge connections in a 4 battery series setup with 6 volts at each battery, essentially ground is zero... bridge 1 is 6V, bridge 2 is 12v, bridge 3 is 18v when you are reading from bridge point to ground.. but across the individual batteries it is just a measurement of the potential across that battery or particular point..

so I understand what Shoz is driving at but I am unsure if it will work if a disconnect is not made. Based on my own experience with 12/24V series parallel battery systems I am having a hard time thinking it will work...

you can't test individually test batteries in series or parallel without breaking the connection on at least one end of the battery so my assumption would be you can't individually charge a battery without doing the same thing, ie isolating it.

need an electrical engineer to explain this one.

 

[thastinger]

I did think that was odd that with them all connected together it was still 6v. I guess it's just considered a big 6v battery

Wait, before you cause yourself a fire, are the batteries hooked to each other + to - or are the hooked up + to + and - to -

To get the 24V, you have to measure at the ground of the first battery and the + of the last battery in the string.

You can charge 2 of the 6V batteries at a time, with a 12V charger, by hooking the two 6V batteries in series, then hook the neg of the charger to one battery and the pos of the charger to the other battery.

 

[MSCH]

Wait, before you cause yourself a fire, are the batteries hooked to each other + to - or are the hooked up + to + and - to -

To get the 24V, you have to measure at the ground of the first battery and the + of the last battery in the string.

exactly, assuming four 6 volt batteries in series, yes.. the plus to minus thing down the string applies.

 

[The motor guy]

Wait, before you cause yourself a fire, are the batteries hooked to each other + to - or are the hooked up + to + and - to -

To get the 24V, you have to measure at the ground of the first battery and the + of the last battery in the string.

You can charge 2 of the 6V batteries at a time, with a 12V charger, by hooking the two 6V batteries in series, then hook the neg of the charger to one battery and the pos of the charger to the other battery.

Oh....I didn't do that. Only + and - on the same battery.