Dual Battery Relay Confusion

[one way]

Hey All

I just installed a relay for a second battery I got from GoWesty in my '81 Westfalia camper. It's not charging the battery. The wire that activates the relay (skinny blue wire) is only getting 2.5 volts when the key is on. Power is zero when the key is off. Can this be normal? Is there anything that would reduce the voltage to the relay switch? There is full power to the relay (big red wire that actually charges battery). I didn't want to run a new activator wire that would deliver 12 volts if it's going to blow the relay.

Thanks,
Frank

[Amskeptic]

Hey All

I just installed a relay for a second battery I got from GoWesty in my '81 Westfalia camper. It's not charging the battery. The wire that activates the relay (skinny blue wire) is only getting 2.5 volts when the key is on. Power is zero when the key is off. Can this be normal? Is there anything that would reduce the voltage to the relay switch? There is full power to the relay (big red wire that actually charges battery). I didn't want to run a new activator wire that would deliver 12 volts if it's going to blow the relay.

Thanks,
Frank

Frank, you want the relay to be energized only when the alternator is putting out from the regulator's blue wire to the relay's 85 terminal I believe. The 86 terminal needs to have an excellent ground. Engine has to be running. Then it should connect the main battery 30 to the auxiliary battery via 87.
Colin