Adding a fourth battery

Iamwildman · **Posted:** Thu Jul 05, 2012 9:03 am

I'd like to add a fourth battery to my vista. I'd like to have one for each engine and two for house batteries and for running my 3000w inverter. Do I just add this fourth battery to my current house battery in parallel?

Sanmiam · **Joined:** Sat Mar 24, 2012 9:05 pm **Posts:** 84

If you are lot interested in isolating the two house batteries from one another than yes, wiring them in parallel will have both batteries charge/discharge as one unit.

This is how I have done it in the past for car audio and dual battery setups for running winches/etc.

ric · **Posted:** Thu Jul 05, 2012 10:27 am

before you purchase a 2nd 12v deep cycle to add to the 1st house battery see what it is. Most likely it's just a standard 75 amp hour. Adding a 2nd will give you a total of 150 amp hours (divided in half so u don't damage batteries) so you'll have around 75 amp hours worth of power.

I would look into two 6v batteries in series. They provide much much more capacity for the price. The Trojan T105 golf cart battery is 225 amp hour and cheapppp. Two of those will give you roughly 120 amp hours of power. If that's not enough, you could step into something bigger like the L-16H that's rated at 420 amp hours.

6 volt batteries are much better at running things for a long time, that's why golf carts, scooters, etc all use em

Iamwildman · **Posted:** Thu Jul 05, 2012 11:07 am

I already have all four batteries. The two I was going to use for the house batteries are the Kirkland deep cycle 845ca 120ah.

ric · **Posted:** Thu Jul 05, 2012 12:06 pm

Iamwildman wrote:

I already have all four batteries. The two I was going to use for the house batteries are the Kirkland deep cycle 845ca 120ah.

120ah isn't bad when you have two together. More then enough for a night's worth of power with a fridge and tv on.

elmwood · **Joined:** Fri Aug 28, 2009 6:02 pm **Posts:** 47

You say you are adding a fourth for the house and have two separate for the engines. I don't know the setup of your boats electrical system but are you sure that you already have a separate system. Three years ago I did a complete separation of the engine and house batteries. There was one wire going into a fuse panel for the boats 12v system that had to be disconnected. This wire came into the ignition and also was used as the main power for the house. After isolating this wire a new wire had to be run to the fuse panel and now I have a separate system.

One thing about adding a battery. Are you adding onto an existing battery? If so you might want to get yourself another house battery. It's not a good idea to add a new battery to an older one. The older will weaken faster than the new and will draw from the newer battery. I know you said you already have the batteries but when buying batteries for the house you are not looking at CCA you need to look at the amps. If you need to replace these batteries in the future consider going with 6v batteries as ric stated. This is what I'm running for my house batteries. I've replaced all my batteries with Lifeline batteries. A little pricey but have a 5 year warranty. Many people are saying they’ve had theirs for 8 years. This is my third year with mine. Anything past five years and I start saving money. I would have to replace my batteries every year in the past. You also might want to consider your on board charger. Xantrex Truecharge series can charge 3 banks at the same time and deal with each battery as it is needed. If one only needs trickle and others 3 cycle charging it can do that. It will take on different types of batteries also all at the same time. Many chargers can do multi banks but actually cycle back and fourth charging each battery and don’t like mixing types. The Xantrex does it all and simultaneously. I also added a Blue Sea add a battery switch. Now with this switch and it’s ACR I added an extra relay to disconnect the ACR for when I’m in the slip and charging. This will allow the Xantrex to do its thing. If you contact Blue Sea they will tell you that you don’t need to disconnect the ACR for charging but when I told them I had a Xantrex charger they knew what I was talking about how that charger works and pointed me to a schematic on adding a relay to disconnect the ACR. They know of the Xantrex chargers and agree to disconnect the ACR when using on board Xantrex charger.

Hope I didn’t ramble on too much. Just food for thought.

Eric

www.iFourWinns.com

Adding a fourth battery

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