I have a 24volt (2 12 volt lead acid batteries in series) on a bike going to a electric motor via chain. iT?

is done. Here is how i have it laid out= first battery red goes into switch,(temporary to bench test it) then to motor. i have the second battery last black into black negative into motor. I have a fuse between the two batteries .. All the switches i have used work, but quickly fry within a minute, i tried a rehostat, it didnt work, i heard you may need a relay because of the high voltage? unsure, Can anyone help, thanks

o, also , the motor is a 400 watt motor.

It is the current that is the problem. Current causes heating and melts components if they are not physically large enough.
24V is a low voltage, but when the SLA batteried connect to a big motor, lots of current will flow. This currents heats the wires and anything it flows throuh, if the switch has only small metal contacts inside, they will get very hot quickly and melt. You need a pyhsically large switch, a relay is not neccesary unless it is important that you activate the motor with a tiny switch. To buy a correct switch is needs to be rated for the current drawn by your motor or more. If you have no idea, then I would guesss it will be a bit less that the rating of your fuse. Maybe 20 amps? You can learn more about current and voltage on this page...
http://www.rmcybernetics.com/science/cyb...

It's not the voltage it's the current that is killing your switch. I think. How many amps is the motor rated at? How many amps is the switch rated at? The switch should be rated at at least twice, preferably 4 times the rating of the motor.

I'm unsure of your layout, so it's possible you have it wired wrong and the switch shorts out one of the batteries.

Here is how it should be wired.

battery 1 neg to motor neg
battery 1 pos to battery 2 neg
battery 2 pos to switch, first terminal
switch second terminal to motor pos.

Did you try it with just one battery, what happened?

feel free to email me.


edit: that is 16 amps, and there will be a startup surge of as much as 50 amps. You will need a very hefty switch. A relay driven by a small switch may be best.

If you just want a temporary fix you can put a light switch. You can also put a Cole Hersee (Cole Hersee is the manufacturer) switch, it's a great switch, you can buy it at West Marine (this should fix your problem).

Every thing should be connected in series, The motor will pull around 17 amps so you will need a switch that can handle at least twice that amount. I once used a 6volt generator from a tractor as a ebike motor It survived 12 volts, and pulled around 50 amps going up hill, but it burned up every switch I used. Finally had to use a relay. The bike wasn't practical, but it was a fun experiment.

, Should not need a fuse. between the two batterys. fuse should go inline on battery 1 lead to switch. be sure and use heavy gauge wiring to run 24 volts. U can use relay probably good idea. when looking at 5 pin relay i know for 12 volt you would see top87, center87a, left86, right85, and bottom30 male connectors . it would wire like so constant neg light gauge to 85 - constant positive heavy gauge to87a - switched positive to86 light gauge - positive lead to motor heavy gauge to 30 - 87 is unused. if you run this inline to just the positive side of the motor from battery 1 and heavy gauge wire from battery 2 to ground the motor and a heavy gauge wire between the both and i believe this should work. I have never tried this particular application so you should fuse it to test it atleast but if it works you should be able to remove it later you may be able to find a 24 volt relay as well but im unsure about that. good luck