question

ksaltman avatar image
ksaltman asked

Isolate two battery banks from alternator and each other

I have a F-350 truck that has basically 3 battery banks.

Bank #1 is the starter batteries.

Bank #2 is a set of 2 AGM batteries that are used power a ARB fridge

Bank #3 is a set of 6 lithium batteries which are charged using the Victron Buck Boost DC-DC converter


Bank #1 is always connected to the truck alternators.

Bank #2 & #3 are isolated from the alternators via a 500Amp solenoid. The high current is necessary to allow for a large draw from the Buck Boosts.

Bank #2 & #3 are connected to the solenoid via a marine style A/B/A+B switch which allows me to charge either bank #2 or #3 or both depending on switch setting.

The issue I would like to solve is when the truck (or solenoid) is turned off and the A/B switch is set to A+B bank #2 and bank #3 are connected to each other. When this happens the AGM batteries end up charging the lithium batteries which is not good for them.

What can I use to isolate bank #2 & bank #3 when the truck is not running with out manually switching the A/B switch?

battery chargingBattery Protect
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1 Answer
Charlie Johnson avatar image
Charlie Johnson answered ·

Recommend a Blue Sea Systems Automatic Charge Relay with manual over-ride. Here is the link: https://tinyurl.com/yy8wxg4s. Magnetic latching so only uses power when changing state and 500A continuous. There are several models available: without manual over-ride; flying leads; Deutsch connector; etc.

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