How many batteries are in "your" bank?

BadBoy · 04-15-2011, 06:57 AM

Just curious to know how many batteries you have in your house bank?

I am connecting my inverter and currently have 2 in my bank. I was considering going to 3 or possibly 4. We will be travelling about 5000 kms, likely with the tv and nintendos plugged in the whole way with few stops to charge up overnight (hope that'll be enough?).

Soooo, whatcha runnin if ya dont mind me askin!

Thanks!
Jason

**Route 66** · 04-15-2011, 07:03 AM

4..

DRosedale · 04-15-2011, 07:20 AM

2, but running the gen off and on during trips.

Mike Canter · 04-15-2011, 07:55 AM

Jason, as long as you are rolling and the alternator is putting out you should be able to power the games and TV ok my the inverter. When stopped then you would have to keep and eye on the battery level. I would never let them get below 40% State of Charge

I have eight 6 volt batteries.

TW · 04-15-2011, 08:12 AM

2 x 6 V

bullheaded · 04-15-2011, 08:13 AM

8..all electric coach.

McDuff · 04-15-2011, 08:17 AM

3. If you have room, add more, can't have too much battery power.

Mike Canter · 04-15-2011, 09:13 AM

Hey McDuff, are your three batteries all 12 volt? The reason I ask is if they are 6 volts then they have to be an even amount. Jason that is also something to consider based on how much battery storage area you have. Six volt batteries are always wired in series in pairs so you get 12 volts then every pair is wired together in parallel so you get 12 volts with lots of amps. If you only have space for an odd number then you will need 12 volt batteries and if you have space for an even number then you can go with 6 volt batteries.

BryanL · 04-15-2011, 10:23 AM

amazing how that 6v mythos perpetuates everywhere .... despite any empirical data.

My main TT and B-Van both have just 1 house battery.

The other TT has 2.

From what I can tell, 2 batteries - about 150 pounds of battery or a bit less - is fairly common for the well equipped TT. Small moho's tend to double that and large mohos double that again.

note that, for all lead acid batteries, the weight energy density is about 45 watt hours per kilogram (re batteryuniversity.com or any spec sheet) for the 20 hour rate. That calculates to 10 to 15 watt hours per pound of usable capacity in the typical RV context at the 50% SoC discharge goal rule of thumb.

For the 'never enough' idea, consider these battery bank sizes in comparison to a typical 30 kWh/day household electrical use. The RV battery bank is usually considered to have 2 days of nominal RV use for energy capacity. By those guides, the typical 150# TT battery bank would provide a bit under 3% of typical household use. The small moho 300# about 5% and the large moho 600# or quarter ton battery bank about 10% of the typical household energy consumption.

As noted above, electrical use while traveling usually isn't much of an issue as the energy is coming from the engine alternator (one reason why larger alternators are often a part of a 'tow' package).

The problem with entertainment during stops is that they tend to consume a moderate amount of power rather steadily. That adds up in a hurry. A few years ago, I figured that watching a movie with a 30 watt DVD and a 150 watt display could just about deplete the nominal usable capacity of a typical RV battery of 60#.