Comments on: Practical Motor Home Inverter Applications

By: Lug_Nut

Lug_Nut — Thu, 28 Jan 2010 01:43:09 +0000

Michael, I agree, 6 volt batteries are the best for large house banks. Sounds like you have plenty of battery power for boondocking. Thanks for your informative input.

By: Michael

Michael — Thu, 28 Jan 2010 00:14:12 +0000

I did a little research, and found general consensus on 6V golf cart batteries offering the best performance per dollar. They literally perform according to the weight; more lead = more plate surface = more storage = more weight. I bought a pair of “145″ golf cart batteries (140 pounds of lead combined), and rewired a 4 KW inverter with 3 stage charger into the system with 4 gauge between the batteries and the inverter. The old charger is sitting on my workbench- it was one of those cheap, one-stage battery ruiners that come with most trailers. Everything but the AC and ‘fridge are powered through the inverter, and it switches automatically between shore power and batteries. “Primitive” camps are suddenly not so primitive, generator use is now limited to hitting the batteries, and I haven’t been able to put a dent in the batteries in a single day. It was hardly a little job (splitting the AC power bus, etc.) but the best thing I’ve done to the trailer.

By: Lug_Nut

Lug_Nut — Tue, 06 Jan 2009 13:17:38 +0000

Philip Basham, The cable size you are referring to should be more than adequate for the application, however, it is important to always follow the manufacturer’s guide lines for such installations. Wire size is also dependant on the cable run, or length. Good luck.

By: Lug_Nut

Lug_Nut — Tue, 06 Jan 2009 13:14:04 +0000

David Weekley, Good information, and thank you. Thanks for your input.

By: Philip Basham

Philip Basham — Sun, 04 Jan 2009 02:01:03 +0000

I want to mount a 2000 watt inverter in my motor home and use while I’m driving. To do this, I want to use the motor homes 30 amp plug in my inverter. Is there any concerns for me to worry about? I will be using 1/0 gauge cable from my inverter to my batteries. Please help.
Philip Basham

By: David Weekley

David Weekley — Wed, 26 Nov 2008 07:14:42 +0000

I have a 2000 watt inverter/charger. The manual very clearly specifies what gage of wire to be used for AC connection (10 awg) and 12 volt DC connection to the batteries (2/0 awg).
My calculations show that an 1100 watt microwave will require about 110 amps.
Please advise people to look very closely at specifications for inverter/chargers. I found one unit that only supplies about 3 to 5 amps of charging current. These folks: http://www.topsalesdepot.com/poinwinchamo.html
Thanks for your blogs.

By: Lug_Nut

Lug_Nut — Sun, 17 Aug 2008 12:44:05 +0000

Joe, Sounds like a great set-up. You might consider installing a relay that is triggered by the engine running that switches the inverter on to the frig. That way, if it is an auto switching unit, it will run on propane only when you are stopped and without 120 AC power.

By: Joe Kleinsmith

Joe Kleinsmith — Fri, 15 Aug 2008 23:46:13 +0000

I just had my 08 Damon Outlaw out-fitted with solar including monitors, four solar panels, 2000 watt inverter w/remote and four 6 volt – 300 amp hour AGM batteries. One advantage of having solar and inverter application is that while driving (engine running) I can take the refrigerator Off of propane and have it operate on 110 without negative battery draw. Thus $aving propane while driving. When stopped for over an hour, I put the refrigerator back on LP unless plugged into shore power.

By: Lug_Nut

Lug_Nut — Tue, 22 Jul 2008 22:56:30 +0000

Jeff, 11 amp at 120 vac draw will require 10 times the input plus efficiency loss on the 12 vdc supply, or about 120/125 amp hours. When sizing up your battery bank, remember you can only use about one half of the dc amps available as you want to always not exceed drawing your batteries below a 50% charge level. Drawing them down below this will substantially shorten their usable life.
For you second question, it depends on the size and battery type of the battery bank and the output of the charger unit. Also some chargers come with 3 or 4 stages. If it’s a new installation, first figure out the size of the battery bank you require to operate the loads. From the total amp hours you can now calulate the amp output required for the charger to have the needed ability. Generally, you will probably end up with a battery bank and charger combination that will recharge from a 50% level to near 100% in about 2 to 2 1/2 hours.
I hope this is of some help, There are many variiables that have to be dealt with, but that is a short quick view.

By: Jeff K.

Jeff K. — Tue, 22 Jul 2008 19:15:01 +0000

How do I determine the battery requirements to support a inverter?
if an appliance draws 11 amps AC @ 120v how many 12 volt DC amp hours
will that draw? By knowing that I can calculate the total available power per battery.
Also, how do I calculate the amount of time it will take to re-charge a battery once it is depleated?
Thanks so much for your help,

jeff K