Dual Battery Operation. (1 Viewer)

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Joined
Aug 6, 2004
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I need to ask you guys for help again.

I am finishing up my dual battery system, I followed George's scematic's and instructions. I used the Blue Seas switch, the 200 amp relay and the two 30 amp relays.

When the truck is running I can push the switch in the cab interupting the Alt good signal and watch the voltage drop of the second battery as the relay disengages. The same thing happens when I turn the BS switch to Battery one or Battery two. So the 30 amp relays are doing there thing.

My question is, When I put the switch on the both position the volts go back up to the 14+ volts on the second battery indicating a charge. My thinking is since the Both position attaches the two batterys together for say jump starting, that even with the volts going back to 14+ volts in the Both position, the system is working right???

also is my assumption that in the both position my 200 amp relay is isolated correct, and the increase in volts is only related to the switch physicaly connecting the batterys instead of the relay connecting them???

Well thank you guys.
Steven
 
S -

1. Right
2. Correct
3. Yes ;)

You've got it down and, yes, it's working the way it was designed.

Whether or not you have a winch connected to the BS switch (I cannot recall if we discussed this...), selecting "both" does indeed put the batteries in parallel for jump starting as you mention... as well as creating a second path for dual charging.

Additionally, selecting "both" takes the solenoid out of the circuit by closing the second relay, thus preventing a huge current surge from the winch from flowing through the solenoid and frying it.

The system I use is very similar, with the exception that I use a third relay for a kill switch. That way, you do not have to be concerned with "alt good" voltage flowing to the cab through the kill switch at all times (an idea I picked up from Christo long ago.)

Cheers, R -
 
Last edited:
Thanks -R-
I will have a winch hooked up but not yet, I havent burnt the truck down yet, but thanks for the reassurance:grinpimp: . We did travel with a fire extingusher today though.
Another project done.:flipoff2:
Stay warm -R- , it's in the 40's here today.:flipoff2:
Steven
 

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