I want to use a 24 Volt Lawn Mower Battery Charger for CMM1200 to change my two SLA batteries, there are three terminals, how to hook up the control terminal ?

https://picclick.com/new-b-d-24-volt-lawn-mower-battery-charger-200941703759.html

Thanks

 

Two will be the 30V output, the 3rd Terminal is for Temperature control.

Edit...the charger could be designed to charge 2 X 12V Sla batteries together...

 

Or it could be a tap for balanced charging (a good feature, but unlikely), unused, safety ground, or a second negative terminal. I haven't come across SLA chargers that cared about temperature, although AFAIK automotive voltage regulators vary the output according to underhood temperature.

www.lawnmowerforum.com may be a good place to search further.

Personally, I'd prefer to charge the two 12V batteries separately, or add a balancer board, assuming the B&D charger doesn't do balanced charging.

 

Or it could be a tap for balanced charging (a good feature, but unlikely), unused, safety ground, or a second negative terminal. I haven't come across SLA chargers that cared about temperature, although AFAIK automotive voltage regulators vary the output according to underhood temperature.

www.lawnmowerforum.com may be a good place to search further.

Personally, I'd prefer to charge the two 12V batteries separately, or add a balancer board, assuming the B&D charger doesn't do balanced charging.

Thanks,
Checked the three pins, the controller pin output 0, same as GND, shorten it to GND, no output, but the charger function good when plug into the mower. and even no short, there is no normal output, I mean some the red light on, some time not.

attached the inside:

 

Ok how is the charget connected inside the mower to the batteries?

That way we can see what the third wire is for, it could be for temprature, as a temporary measure what voltage or resistance do you get from the mower on the Third wire to the others?