dual battery relays

[Taz]

what is the purpose of relay #2? in this diagram? Why can't you just connect terminal 85 on Relay #3 directly to ground and not use relay #2. Doesn't this give you the same results?

http://sleeoffroad.com/technical/images/dual_batteries.PDF

 

[RavenTai]

It looks like relay two is there to activate relay 3 only when the engine is running, if it were not for relay 2 then anytime the winch was powered relay 3 would be drawing power engine on or not,

you could delete relay 2 if you were certain that you would not accidentally leave the winch powered for extended periods draining the battery. Leaving it in would be safer.

There are many many ways to go about a dual battery setup each with pro's and cons

 

[Taz]

Thanks...I couldn't figure that out for the life of me...it all makes sense now. I forgot relays draw power to hold them open.