48v parrallel to 96v series battery switching

[jimmyhackers]

i initially plan on getting a 48v lipo and running that. i have plan in mind to get another in future and either have double range or double speed at teh flick of a switch.

so far ive got a diagram with 2x 5 pole relays and a switch.

automotive relays are to hand and cheap but at 12v and 40A im worried they wont take the voltage.

anyone got a better method or a link to some relays that can take it?

thanks in advance
jim

 

[trex]

if you use 12V SLAs, you power your relay's solenoid with just one battery.
As you connect each relay to one 4S block, each needs to cope with 54V/40A max load, automotive relays should be OK provided that you switch off the motor before you change over 4S2P to 8S.
Make a PCB for the relays and post the diagram here, we'll check it for you.