An in the process of adding another battery to my boat. I was looking at Batt selector switches and my question is what are the switches with alt leads used for ??
Battery switch??
- Thread starter Cmp1110
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Do you mean "alternator field disconnect"? It is a safety feature to prevent alternator damage should the switch be turned to Off while the engine is running. I never had a switch with that feature and don't think is something I would pay extra for. I don't have any curious kids that would be messing with it. Just knowing the consequences and being careful does it for me. I feature I would insist is "make before break" which allows the switch to be operated with the engine running to select either bank or both. It makes a connection with the new setting before disconnecting the old one. I would also look for a switch that has the Off position offset to one side so there would be no need to pass Off before engaging any other setting.
The alternator field disconnect (AFD) feature only works if you have an easily accessible field wire to interrupt. With an external regulator this is easy but with a stock regulator not quite as easy. The AFD circuit breaks the field circuit a split second before the load is disconnected thus avoiding disconnecting a load from the alt with the alt pumping out current and blowing the diodes.
The far easier solution with a stock alt is to feed the alt directly to the house bank then let an ACR or Echo Charger charge the start battery. Now you can switch the battery switch all you want and the alternator will always see a load. Or just don't ever pass through OFF with the motor running.
If all you are doing is adding another battery just connect in parallel to one of the existing batteries. I'm not thinking you would need 3 separate battery circuits (start, house 1, and house 2???) Just make the house bank bigger and use the existing wiring.
Just Paring an old battery with a new battery is not good for new battery. Because as a battery ages its charge rate and state at rest changes. Always make sure batteries are of the same age make and size. See that they are equally charged. Then you can tie 1,2,3,4 batteries together to create one large battery bank.