Battery bank

[bdude13]

I am confused on how the battery switches work. I have a 2002 maxum 3100 with 2 switches and 3 batteries. #1 battery seems to be for starboard engine, and #2 battery for port engine and genset with the 3rd for the house. What do the 2 switches control? (they have 1,2,both and off positions)
Thanks

[tackleshep]

ok just got done figuring this out on my 2000 3300. Mine might be in totality set up a little different but I think I can answer your question.

The two battery switches are wired to each engine. You should have a starboard switch and a port switch. On my boat the starboard switch is also wired to the house.

Mine has a total of four batteries with a seperate battery for the genset so that might be different for you.

Here's the deal, the batteries are wired to both switches but seperately. You will find two large red wires one going to each of two batteries. On is the #1 position on the switches and the other is for number 2. This gives you the ability to figure out which battery you want to use or both.

My boat also had an additional battery that was wired just to the windlass.

Unless the 2002 models are set with isolators your probably set up the same way. Because of recent battery issues with mine I just gone re-wiring the batteries to provide myself with a backup plan out at sea.

I have two batteries setting side by side that are hooked up the switch position #1 and are connected together. These are for both the house and will crank the engine. I am replacing this week with Group 27 batteries for some extra power.

I then took my new group 24 battery and hooked it up to switch position number 2 by itself. The plan here is to use switch position #1 for everything. It will always charge in the slip and should have a full charge. Only when I kill off those batteries on a long day or battery problem I will then switch over to #2 which will enable me to start the engine, go to both, and recharge the entire bank. After having to switch out batteries by hand at 1am in front of a water bar last weekend I've gone this route.

I have those two banks and the genset battery hooked up to my 3 bank charger for shore charging constantly.

Hope this helps.

[Bella Sera 3300SCR]

Originally Posted by tackleshep

Mine has a total of four batteries with a seperate battery for the genset so that might be different for you.

My boat also had an additional battery that was wired just to the windlass.

I am replacing this week with Group 27 batteries for some extra power.


I have those two banks and the genset battery hooked up to my 3 bank charger for shore charging constantly.

Hey ther T'shep,

Got a coupla suggestions for ya,

1. Dump the fourth battery for the windlass; you really don't need it since you have a genset. You'll save the weight.

2. In lieu of the fourth batt, upgrade to group 31 instead of 27. They pack 25% more punch in reserve power than the 27. I run all (2 house / engine and 1 for the genny) gell cell group 31's they are fantastic totally maintenance free and can be even mounted upside down because of their gelled acid. They recover full charge much faster and provide more cycles than any other type of battery available and thats what you want on a boat. They are spendy but well worth it.

3. I hooked the 3rd bank of the battery charger to my genset batt like you did thinking that I would keep it charged all the time (and it did). BUT, That is until I started to blow the 8 amp fuse in the 12 volt circuit of the Genset charging system as a result. It drove me nuts trying to figure out why the fuse was blowing and what’s worse is it would not repeat itself; sometimes the genny would blow on after starting and other times after 30 minutes. I tried in vain to figure out the problem. I contacted Westerbeke and did web searches to try to end the problem but it was luck that I am a member here when I FINALLY found another Maxum owner with the same problem of blowing the 8 amp genny fuse (mounted on the side of it). The Problem was the fact that the Genny naturally has its own charging system, combining the extra amperage of the onboard battery charger that was feeding the power into the genny battery along with the genny's power too overloaded the 12 volt charging circuit and blew the fuse. (DUH!, Being an engineer myself, I should have known better, live and learn!)

Sooooooo, I took the suggestion of removing the battery charger 3rd bank, and VIOLA!! problem SOLVED!! Start running that genny a few hours a day and you'll never have a low house battery problem.

Take care,

Bella Sera 3300SCR Out.

[tackleshep]

thanks for the advice, seeing I'm two days into owning my 27's I'm going to run with the three until they go and then convert to your method.

[intelleq]

the 12 Volt system on my 2000 Maxum 3300SCR was wired like this:

[intelleq]

And after the addition of 2 house batteries, a larger charger and some additional accessories it is now wired like this: