Multiple House batteries on Tom Cat????

Instead of two seperate 12 volt house batteries, how about 2 ea. golf cart batteries. Smaller, more amp hours, last longer. Its what I put into Journey On. 1 backup starting battery, and 2 golf cart batteries. I was able to keep the factory battery switch, and only need a 2 bank battery charger.

If you only have a single battery? you'll need a battery switch and a 2 bank batter charger. Standard stuff, but I assume your Tomcat came with 2 batteries and you want to add a third battery.

Boris
 
The Tom Cat came with three batteries, one house and two starting. The battery charger is a three bank charger. Any help would be appreciated.
Thanks
Gene
 
Gene -

We are in the same boat (pun intended?) - Just bought a new TomCat that came with two starting batteries (34M Optima) and one 'house' battery (D34M Optima). (from your photos - we may have bought from the same place - Sportcraft Marina?).

I have the same questions: (1) should we get a second house battery and (2), if so, how best to go about it.

Thanks
 
Thataway has 3 house batteries, and two engine starting batteries. The origional starting batteries are linked directley to each engine--the house banks are linked to each starting bank/engine with a Relay. The origional house battery was a group 27, as was the starting battery. The second house bank is two group 31 AGM batteries which are under the dinette, aft seat. These power the freezer and inverter (microwave)--but can be switched on line to power any other of the house bank. # 4 wire connnects these house banks with the variable charging relay. There is a 60 amp breaker on each end of this wire (by the batteries, and by the Variable charge relay. This brings it to ABYC standards, and will prevent fire or a short.

I use AGM, because the batteries are inside of the cabin and the AGM's don't give off fumes. I agree that golf carts (two 6 volt batteries in series) are excellent, in-expensive house batteries, and that is exactly what we used on our long distance boats (only 6 to 8 of th1em).

The origional battery charger charges the three initial batteries. I added a 40 amp charger for the second battery bank.

How this all works: When you start the boat, you have the battery switches on "1"--and as the engine alternators (44 amps) come on line and bring the voltage at the starting battery to 13.7 volts, the relay closes and charges the house batteries. You keep the house batteries isolated from the engine start, unless the relays are closed, or you use a switch to bring both battery banks together.

This system works very well for the Tom Cat, and gives several days of battery power under normal conditions with no generator or alternator usage. I also always carry a small garden tractor battery (U1) which will start the outboards under emergency conditions--and this is kept completely isolated from the battery banks.

The same type of system can work in a single engine boat--but there you need only one Variable charge relay, or "combiner"--that is the way the C D 25 is being set up. It will also have a single house battery, a single engine start battery, and two group 31 batteries--with a single combiner. It will give the same redundancy and amount of variable power. (a remote power switch can trip the combiner or variable charge relay, or a manual switch can be used to allow the house batteries to start the engine if necessary). For the most part the smaller C Dories require little power, and a single house battery is adequate. The battery charger supplied is for the most part, too small, and it is advisable to either add a second charger or upgrade that charger, unless you have relitaively low power demands.
 
I feel ripped off -- I only got two batteries with my TC and learned quickly that the refrigerator uses the house battery up quickly. Winter plans for work by Les include a bank of batteries, charger and inverter similar to what Roger did on Dreamer

Warren
 
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