Wonder what this is/does?

[csootsman]

Wondering if anyone might know what this is. It has 3 wire attached to it. One looks like it comes off the altenator and the other two attach to the battery. It also has the word GUEST (mfg ?) in the lower right corner. The motor is a 5.0 mercruiser.

 

[SuzukiChopper]

Re: Wonder what this is/does?

Looks like a regulator/rectifier to me.

 

[csootsman]

Re: Wonder what this is/does?

Thanks. Do both the red leads attach to the positive side of the battery?

The reason is when I took my batteries out for the winter I forgot were they go.

 

[Silvertip]

Re: Wonder what this is/does?

That is an isolator. One lead comes from the alternator (charges the batteries). Each of the other two wires goes to the positive terminal of the batteries. An isolator allows charging both batteries but separates the two so the house load does not discharge the starting battery.

 

[csootsman]

Re: Wonder what this is/does?

Thanks for all your help. You guys make this a great site.

 

[csootsman]

Re: Wonder what this is/does?

A quick question in regards to this isolator. I am a guessing that maybe the previous owner installed this, to insure that both batteries get charge.

One change that I want to do is add a Perko switch. One battery is a cranking battery and the other is a deep cycle. So if my thinking is correct when I install the switch I can connect the main wire from the starter to the COM terminal along with the main from the fuse block (house) so I get power to all accessories. Then just use the switch to select to the deep cell #2 battery after I start the boat and I am under way to power everything .

So in theory would I still need this isolator? or can I just do away with it all together? Or just add the switch and keep the isoltor connected to each positive terminal on the two batteries.

Thanks

 

[lmannyr]

Re: Wonder what this is/does?

With the isolator, you won't need to add a switch. You could if you want, but think it would be redundant. Adding the switch will also add to your workload. The isolator is nice, (wish I had one). The isolator will charge BOTH batteries automatically. With an Off-1-both-2 switch, you will have to do the switching (choose which gets charged - isolator job).

I would install an ON-OFF switch to isolate the batteries from engine and house accessories. When your done for the day, switch it off and there are no worries of dead batteries next time.

Hopefully your batteries are separate meaning, one ONLY for engine, and the other ONLY FOR HOUSE.

Some isolators have a button at the helm that electronically connects both batteries together (if engine batt is dead) to start the engine. With your Off-1-both-2 switch, you'll switch to both to do this.

Hope I made sense. Good luck, and happy boating!