Electrical, Solar, Lithium Batteries on 28' International

[lewster]

Hope you don't mind if I join in? I did Benn's installation. Even with a 200 watt system, I would still use 8AWG solar cable and make your charging connections from the solar controller directly to the batteries and NOT to the bus bars as Airstream does.

We always try to maximize the efficiency of our systems and keep the voltage drop below 2% by using the proper sized cables and minimum number of connection points.


Lew Farber
RVIA/RVDA Nationally Certified Master Tech
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center
Lifeline Batteries**Magnum Inverters
541-490-6357

[Flht2k]

Lew. Would Benn's install power an ac unit and all my electrical needs. What type of cost is this install? You can send me a private message if you prefer.

Thanks

[Vycan]

Lew, please send me the same.

[lewster]

Originally Posted by Flht2k

Lew. Would Benn's install power an ac unit and all my electrical needs. What type of cost is this install? You can send me a private message if you prefer.

Thanks

Powering an RV roof A/C is not a practical use of battery and inverter power. Can it be done......YES! But you will need a ton of batteries (well at least 350-500 lbs worth of AGMs) and a very large, quality inverter and still you won't run a roof A/C for an hour. You can thank the German physicist Peukert for discovering that the larger the draw in amps from a given battery bank, the smaller that bank effectively becomes.......by an exponential factor. This is why even a 600 or 900 amp/hour battery bank will have a very limited run for a roof A/C. I wrote a detailed explanation here some time ago. Let me know if you would like to see it again.

There is a new alternative, however.....the hybrid inverter/charger/ magnum makes the MSH-3012M, which will synch with an incoming 120VAC power source and will supplement the needed 120VAC required from the batteries to.....say.....run a roof A/C with a single Honda or Yamaha 2000 generator. this single genny will not start or run a roof A/C, but using the synchronized boost from the Magnum, it will now.

The hybrid inverter is also useful when plugged in to a 120VAC source that is less than 30 amps, say a 20 amp or 15 amp house outlet. The MSH-3012 will again supplement the deficiency in required 120VAC from the batteries to run the larger load.

PM me for more information on Benn's solar project.

[Tomy]

I thought I'd mention one alternative for batteries. I've not used these in an RV, my only application was an electric bicycle. They're incredibly popular among the radio controlled airplane crowd, for the same reasons as the bike crowd; light weight, great charge times, great discharge, and lastly safety.

The company is A123 systems. They use nanotechnology to make a lithium battery cell that you can drive a nail through without them exploding or catching fire. They also currently offer a module combining cells into a battery that is compatible with automobile batteries and chargers.

The only downside is the only auto-compatible module they offer for sale is small and only gives 4.6 AH. Here are the specs for that module:

Nominal voltage: 13.2 V
Max Discharge Current: 30 A
Charge Current: 10 A
Nominal Capacity: 4.6 Ah
Energy: 60 Wh
Power: 345 W
Cycle Life: >7,500 Cycles at 25°C, 0.8C/0.8C, 100% DOD
Core cell: ANR26650 Cylindrical Cell
Dimensions: 5.95 in/151.0 mm x 3.93 in/99.7 mm x 2.54 in/64.5 mm
Weight: 1.875 lb/0.85 kg
A123 Systems ALM 12V7

The main web site is annoying, they mention a 60 AH module as a replacement for 12v lead acid, but not a lot of info:

A123 Systems

They're purchase site could also use some work:

A123 Systems Cells and Battery Modules

The main thing is the cells can be stacked to around 13V and then can be charged with a standard car battery. They hit 90 percent surprisingly fast, the last 10 takes much longer.

I haven't sat down to do a cost or feasibility analysis for an RV. But I built an electric bike that could go way faster than I ever wanted to go on a bike.

Don't know if it helps, but back when I was involved in the electric bike community, it was hands down the leader.

[ghaynes755]

Lewster is spot on. I just had my solar install done in July with the new Magnum Hybrid. Between a good sunny day, battery and a single Honda very easy to run the 15K A/C.