Isolator kill switch

[roffey]

Why would you install a "DUAL BATTERY ISOLATOR KILL SWITCH". Some of the switches I have seen have three setting, 1,2 or both. I am thinking you can use just one battery and if it goes dead you switch it... or if you need the extra power you use both? My boat has two deep cycle batteries.

[Destroyer]

Lots of boaters have dual batteries for different reasons... stereos, speakers, radar, trolling moters, bilge pumps, etc etc etc. So they use one battery just for the engine, and the other battery for when the engine isn't running. That way their engine battery is always fresh and not run down.
And if, for some reason, they need the extra juice from the second battery, it's available with just the turn of a switch to the "both" setting.

Additionally, when set to the "off" position, it prevents any unwanted drain on the batteries by isolating them from the electrical system. (Useful if your boat spends long hours on a trailer between trips to the water).

[roffey]

Thanks,,, more questions to come and more money to spend .. LOL

[spareparts]

first off, you should have starting batteries, not deep cycle, its probably the number one mistake I run into working on boats, deep cycle batteries don't have the cold cranking amps that's needed to start an engine. The reason you use an isolator switch so that both batteries get charged, but you won't run one battery down, you'll allways have one in reserve

[roffey]

I'll check and see what the batteries are, I thought they were deep cycle but maybe they are regular. I had to carry them down to the basement and they seemed to be rather heavy….

[spareparts]

they will say on teh battery what type they are, it will either be starting, dual purpose, or deep cycle. There should be a rating on it for CCA(cold cranking amps), MCA (marine rated cranking amps), and Amp Hours reserve.