info advise required

[ade]

hi all i have a 15a battery which i have just wired up , i have fitted a switch and tested all ok until i took the bike for a test run the switch then wouldn't switch the power off however when not under load with just the power on the switch works again i have also tried swapping the switch and the same happened again ,the switch is rated 20a @ 240v am i just using the wrong switch?

 

[z0mb13e]

hi all i have a 15a battery which i have just wired up , i have fitted a switch and tested all ok until i took the bike for a test run the switch then wouldn't switch the power off however when not under load with just the power on the switch works again i have also tried swapping the switch and the same happened again ,the switch is rated 20a @ 240v am i just using the wrong switch?

Hi ade,

What type of switch is it? (i.e. Toggle, push to make etc)

From your post it sounds like you are trying to switch the switch off when under load. If you are switching the full load that's a bad idea with those kind of currents, unless the switch is designed for high current DC. The 240v 20A rating is most likely AC which behaves differently than say 36v DC at 15A. DC is likely to burn out the switch contacts very quickly if used whilst under load. The contacts could be welding themselves on...

 

[ade]

Hi its toggle switch and it is for ac , but when i bought it i did ask for dc so this could be the problem

 

[z0mb13e]

If it works when not under load then I would just make sure you don't operate the switch when under load. Otherwise finding a physically small DC switch that will handle the kind of loads used in an ebike will be tricky.

The other option is to use an active switch. That could be a relay, where your switch switches on power to the relay and the relay switches the full load (again you could have problems with arcing). Or you could go for a solid state option with transistors doing the load switching.

 

[ade]

ok thanks i did wonder why it was so difficult to find a suitable dc switch i have spent weeks trying to source one i really only need to use the switch to cut power when i remove battery for charging so will only use it for that purpose.