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Old 03-12-2013, 09:12 PM   #49
Scraping Paint
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Originally Posted by Per View Post
i believe the combiner separates the banks when start button is pushed, this helps to protect housebank and related electronics.
The combiner relay I am talking about on our boat does not do this. It's sole purpose-- according to the manual and the way it is wired--- is to connect both the main batteries on the boat (originally two 8Ds but now two banks of 6vdc golf cart batteries) together for engine starting only. The relay connects the two batteries (or battery banks) together only as long as a start button is being pushed.

This is to ensure that there is plenty of battery power available to start the engines. It also ensures that even if a battery fails due to a bad cell or whatever, there will be sufficient power to start the engines. This relay has gotten us going once when we did, in fact, develop a failed cell in the "start" battery.

It is a very simple device and was used on all the early GBs. At some point they stopped using it, I suspect when the battery capacity on boats began getting greater and greater with multiple banks and so forth.

But the ealier GBs simply had two batteries, both 8Ds, and either battery could be designated "house." The "start" battery was "start" only by virtue of it not being used for house loads because of the position of the battery selector switch.

It was a very simple system and we've retained it desipite the upgrade to our actual batteries.

There are "combiners" that are used as part of the battery charging system. The "combiner relay" on our boat is not one of these. It is simply there to connect all the boat's batteries together to start the engines whenever a start button is pushed.
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