House Battery

[Clipperlover10-04]

Hey folks, I need to purchase a battery for the coach and am not sure which size I need. I know I need a deep cycle but not sure which group number I need. Any input on which brands to buy or not to buy is appreciated as well. Thanks.

[Toedtoes]

Hi ClipperLover.  I just went through this same deliberation.  The main choices are:

1. Get 2 6v golf cart batteries and run them in serial;
2. Get 1 12v deep cycle battery
3. Get 2 12v deep cycle batteries and run them in parallel

The 2 6v are generally considered better as you will get more amp hours, but you will have to buy them both at the same time (don't add a new one to an old one), and if one battery goes bad, you don't have enough power with the one working battery to do anything.  Many people counter that risk by using 4 6v (2 each in series, the 2 series in parallel) - you aren't likely to blow 3 batteries, so you will almost always have at least 2 6v batteries.  But 4 batteries takes up a LOT of room and you may not have it available in the clipper.

The 1 12v battery will give you less amp hours than the 2 6v, but it will fit easily into your battery compartment.  If you're running basic lights, water pump, etc., the 12v will likely be enough power for a 7-10 day trip (you're more likely to run out of fresh water before you run out of battery power).

The 2 12v batteries are a good option, especially if you go with the group 31 AGM type.  You'll get the same amp hours as the 2 6v (+/- 30 amp hours) and if one goes bad, you can still run everything (just for a shorter amount of time).  The downsides are again: 1) space required to put them; and 2) you have to buy them in pairs (don't add a new battery to the old battery). 

With all that, I deliberated and discussed it with my mechanical engineer boss, and decided to go with 1 12v battery.  I went with the top of the line AGM (Optima 8052-161).  Since I was changing to an AGM, my boss recommended (and I agreed) to also replace the engine battery to an AGM type also.  For the engine I went with the Optima 8025-160.  It is the basic Optima starter battery.

I bought my batteries online at Streetsideauto.com.  The price was the best I found.  Amazon had the same price for the batteries, but Streetsideauto had a 20% off coupon code, so I got the batteries for $30 less than Amazon prior taxes ($338 total).  They shipped quickly and I had the batteries within 4 days.  The house battery fits in fine in my battery compartment (I did turn it lengthwise for easier access).

Here is a good breakdown on batteries (http://www.marxrv.com/12volt/12volt.htm).  One thing to remember is that when you run batteries in serial, you add the volts; when you run them in parallel, you add the amp hours.  So, two 180-220ah 6v batteries will give you 180-220 amp hours at 12v.  Two 95-125ah 12v batteries (group 31) will give you 190-250ah 12v (and you can still run if one blows).

Hope that helps you decide.