Charging 24 Volt lead acid batteries

I have 2, 12 volt 12 amp an hour lead acid batteries. I also have a charger for the batteries. There are three wires though. I don't understand how to connect them.

Here is a picture of 1 of the two batteries.

here is the charger

here is the plug (inside it has a black red and white wire)

Thank you for your help! batteries scare me because they can explode much larger than some small transistors.

Schauer is a trademark of the Brookwood Group Inc.

BATTERY CHARGER OPERATING INSTRUCTIONS

http://www.battery-chargers.com/Instruction%20English.pdf

Are the two 12v batteries connected into one pack, or does each battery have a 3-pin connector?

each batteries just has 2 prongs +12 and ground. The batteries were wired together in series to produce 24 volts.

So I guess there is just +24 and ground.

I cut the charger open and it has 3 wires red white and black the red wire to the black wire is producing 27.3 volts the red wire to the white wire is producing the same 27.3 volts.

how do I charger batteries with this? red on the positive terminal of one lead acid battery and ground on the other and connect the 2 lead acid batteries in series?

I think that the charger is for power wheelchairs.

The charger and the batteries are from an old power wheelchair. I am trying to put them into my robot.

arduinoPi:
I cut the charger open and it has 3 wires red white and black
the red wire to the black wire is producing 27.3 volts
the red wire to the white wire is producing the same 27.3 volts.

how do I charger batteries with this? red on the positive terminal of one lead acid battery and ground on the other and connect the 2 lead acid batteries in series?

You are right to be careful, they can and do blow up!

1. check voltage of each battery should be no less than 10V if lower, battery is shorted or damaged - DO NOT CHARGE!!
2. If battery is damaged, bulging, cracked - DO NOT CHARGE!!
3. Is battery sealed gel type or are there covers to add water to cells? READ BATTERY MANUAL!!
4. Connect batteries in series per PaintCAD drawing.
5. With charger OFF connect charger per drawing.
6. Turn ON charger, listen for bubbling, hissing or weird noises other that charger buzz - if battery is acting sketchy DO NOT CHARGE!!!
6- Batteries are charged when voltage across is 27.3 while connected to charger.
7- Turn OFF charger and allow hydrogen gas to dissipate prior to removing charger leads.
8- Enjoy!

Should I just leave the white wire disconnected?

Yeah, it might be a trickle charge wire or something... dunno. RTFM - if ya got it. if you've got a high wattage low resistance load you could check the amperage out of each, black and white to red. But I'd follow the steps, tape up the white and keep a close eye on it. :cold_sweat:

I am trying to charge them right now. I just connected the red wire to the positive 24 volt and the black to ground. Left the white wire disconnected. I turned it on and the charger went red which is normal saying the batteries are charging. The white wire seems to a “ground” maybe a earth ground? Or could it be some sort of probe to see when the batteries are done?

Did you make out ok?

it seemed to work the light turned green once done.

The third pin in a wheelchair charger connector is a "drive inhibit" connection. At the charger plug it is actually just connected to the B- lead. Inside the wheelchair controller, if that pin is equal to B- rather than floating, the chair can't be driven - keeps you from tearing the charger and wall along with you. For just charging your series pairs of batteries (yes, the WC charger is 24V), you just use two of the pins B+ and B-. If the two B- pins have the same size wires connected to them (or are just connected to each other - open the plug and take a look), it doesn't matter which one you use for charging. If one pin has a heavier wire or more direct connection, that's the one to use as minus. BTW, these XLR plugs, though often rated at up to 12 Amps, generally shouldn't be used at over 8 and will get warm doing even that.

Ciao, Lenny

LROBBINS: The third pin in a wheelchair charger connector is a "drive inhibit" connection. At the charger plug it is actually just connected to the B- lead. Inside the wheelchair controller, if that pin is equal to B- rather than floating, the chair can't be driven - keeps you from tearing the charger and wall along with you. For just charging your series pairs of batteries (yes, the WC charger is 24V), you just use two of the pins B+ and B-. If the two B- pins have the same size wires connected to them (or are just connected to each other - open the plug and take a look), it doesn't matter which one you use for charging. If one pin has a heavier wire or more direct connection, that's the one to use as minus. BTW, these XLR plugs, though often rated at up to 12 Amps, generally shouldn't be used at over 8 and will get warm doing even that.

Ciao, Lenny

thank you that was very informative.