Yet Another Dual Battery Wiring Question

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Mar 6, 2009
Between pixels
I am about to wire up my dual battery set-up (schematic attached) and I have a few questions:

1. Can I "jumper" terminals "1" and "2" on my diode type battery isolator for emergency starting/ winching?
2. Has anyone else wired up their auxillary battery to provide power for the vehicle chassis, as well other electrical add-ons?

Any help/ advice much appreciated.



  • Dual Batt Schematic.pdf
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I checked my Surepower isolator instructions and could not see where they allowed that. You might want to ask the manufacturer of your isolator. If they're reputable, their tech support will be able to let you know quickly.
1. Can I "jumper" terminals "1" and "2" on my diode type battery isolator for emergency starting/ winching?
From your diagram with "no numbers", I'm not sure why you would need to.
You have in the circuit an "Emergency Switch". This is connected directly across both batteries. If you close this you join both batteries for starting or winching. (This switch should be suitably rated)
If your diagram relates to terminals 1, 2 next, 3 next L to R, then jumping 1 & 2 just gives the alternator output priority to the starting battery.
Thanks for mentioning that I forgot to label the numbers for terminals on the isolator.
Terminal "1" is the circuit (org wire) for the starting battery, and terminal "2" is the circuit (dark blue) wire for the aux battery, or in my case the "chassis" battery.
I e-mailed Surepower this morning and they informed that it is not a problem as long as the emergency switch is not closed all the time. This of course is not my intention as this would defeat the purpose of the isolator. He did tell me that they prefer if I did not use the terminals on the isolator as a "junction" for wiring my winch and chassis battery to the starter battery.
The switches I purchaserd are from Blue Sea Systems (P/N 6006; M-Series) and they are rated for 300A (continuous), 500A intermittent (5 min), and 1500A (10 secs).

Now to find a home under the hood for the isolator and switches:doh:

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