Roo Power Usage

[rocknroos]

The DW and I do probably 75% of our camping boondocking. It is my goal to be able to camp 7 days without hook-ups. Since it is only the two of us our usage is fairly low. I have determined that the two limiting factors would be the battery and holding tank capacity, particularly the grey tank. I bought a tank tote so I can deal with the grey and/or the black tank if needed. The other problem is power. I have two 12 v group 24 batteries which are rated for 75AHs each. I only use one battery at a time. I also have two 100 w solar panels. The panels are hooked together in parallel which gives me 200 watts or 10AH charge capability in optimal conditions (Full sunlight). So theoretically it would require 7.5 hours of full sunlight to fully charge a depleted battery. The reality is that it is not likely to have 7.5 hours of full direct sunlight, but knowing the optimal gives me a starting point. Next I also determined my loads. I compiled the following list which may also be helpful to others. As expected the water pump is the largest single load.
Ampere-Hours would be any amp value for one hour. For example if a vent fan is running on high speed which is 3.6 amps running for 1 hour that would be 3.6 amp-hours.
You could also determine watts by multiplying amps X 12 volts. So by using ohms law as volts goes down the amps will go up for any given load. What this means is that as a battery starts to deplete it will deplete faster as the volts go down. It is not a linear scale.

Baseline No-Load AmpsThe baseline no-load amps is primarily the CO/Propane Detector.There is an initial warm up period of about 10 minutes for the detector which draws 0.65 amps.After this period the amps go down to a steady state of 0.15 amps.

Water Pump
5.4 amps

Tongue Jack
Up – 2.5 Amps
Down – 4.6 Amps

Power Awning
Out – 2.5 Amps
In – 4.3 Amps

Furnace
3.5 Amps

Vent Fans
Low Speed – 1.8 Amps
Medium Speed – 2.6 amps
High Speed – 3.6 Amps

Range Vent
Fan – 1.8 amps
Light – 2.0 amps

Porch Lights
Amber – 2.0 Amps
Under Awning – 2.0 Amps

Hot Water
1.2 amps

Interior LED lights
1.0 Amps each

IRV Radio
1.0 Amps

Bunk End Fans
Low speed - .15 amps
High speed - .35 amps
Light – 1.0 amps (non-LED)

Refrigerator (Domestic 702 )
0.6 amps

[rockfordroo]

It's my understanding you shouldn't drain your battery more than 50% (do a search here on "batteries"). Therefore, you should only be using about 35AH each. Should be able to recharge one battery easily in a day if you're really getting 10 amps from your solar panels.

You'll learn a lot more during your search here.

[rocknroos]

I agree that you should only draw down the battery to 50% or so. Maybe someone else can comment, but I believe that whatever a battery is rated in AH that is the rating down to 10.5 volts. So a 75AH battery should deliver 75AH down to 10.5 volts, which would be considered fully discharged. It is hard on a battery to be fully discharged, but deep discharge batteries can tolerate this better than a standard battery but it does shorten the life of the battery.
I am getting 10 amps from my solar panel as per measurement.

[stugilmour]

Cool list. Thanks for posting.

Stu