[Chester Stone]

While traveling this weekend, I boondocked twice with unacceptable results. The first night, I only had the refrigerator, directv receiver and stereo amplifier on. The inverter shut down after five hours. The next night, I turned off the amplifiers, directv in sleep mode, and after seven hours the gauge showed 12.2 volts and shut down when I turned on the coffee maker. A Xantrex Link-Pro monitor I had installed independently showed the batteries to be at 90% of capacity when it shut down. I am not sure how old the batteries are, but I will put a load test on them later in the week. All cables are tight. Any suggestions?

[ccjohnson]

Only thing I can think of is to run generator a little more often.

[Ozarkguy]

You need to determine total 12vdc load first. Look at the charts in the inverter manual to calculate loads (approx) on the a/c loads. Calculate available battery amp hrs You should be able to calculate how much stuff you can run and for how long. You are using more juice than you think. Lights, pumps etc. another interesting point is that the engine driven alternator dos not TOP off the batteries to the point the inverter charger does therefore you may not have started out with a full load. Newell is sorta a electric hog. So you'll probally find its doing ok at 5-6 hrs. Try topping off with Genny & charger n see if it does better.

[encantotom]

running the fridge and some lights and stereo i have run for 24 hours. nothing else though.

tom

[Ozarkguy]

Tom,

Your lights are mostly LED arn't they? If you were running the stock halagon lights, how much power would you be using?

[Ozarkguy]

Determining your battery bank requirements
1. Converting AC amps to Watts: AC amps x 120 Volts = Watts
2. Convert Watts to Actual DC amps: (Watts / 12) x 1.1 = actual DC amps
3. amp hours consumed between charge cycles:
run-time of appliance (hours) X actual DC amps = amp hours consumed
4. Number of batteries required:
(Total amp hours consumed X 2*) / amp hour rating of battery = Number of batteries required
*Since deep cycle batteries should only be discharged to 50% total capacity, the total amp hours consumed between charge cycles should be multiplied by 2.
Example:
amp hours consumed between charge cycle = 126
amp hour rating of battery = 90 (Group 27)
(126X2) / 90 = 2.8
(Round up to the nearest whole number.)
Therefore, the minimum number of batteries required is three with the above values.

Typical Battery Amp Hour Rating
Battery Size Amp Hour Rating
Group 27 90
Group 31 105
4D 160
8D 220
6V Golf Cart 225

[folivier]

Sounds good Jimmy. We'll be dry camping at Columbia Icefields for a couple days and since I only have 3 good 8Ds that will be a good test. I'll post my results in a few days.

[Chester Stone]

I will settle in the California Delta in a few days and will pursue the issue. Jimmy, I have six 8D house batteries.

[Ozarkguy]

So that means that if you are using approx 400 watts for your stuff you should have about 6-7 hrs on fully charged batteries.

[Chester Stone]

Thanks for the calculation Jimmy. I will try to figure out how many watts I am using when boondocking.