Community Forums

mgscott4 · 07-21-2012, 04:17 PM

I stand corrected. The OP should measure the specific gravity of the battery using a hydrometer.

To use this Chart.

Take the reading with your eyes level with the surface of the drawn up liquid, and then subtract 0.004 for each 5°C above or add 0.004 for each 5°C below 25°C. Do this for each of the cells of the battery.

State of Charge Specific Gravity

100% charged 1.265
75% charged 1.239
50% charged 1.200
25% charged 1.170
Fully discharged 1.110

I 'll bet it matches pretty close the volt charge chart previously posted. Just my 2 cents worth.

Bottom line--- Don't take the battery below 12 volts (with no load on it.)

Wanderman · 07-22-2012, 07:53 AM

I think the OP was looking toward researching and designing a Solar Charging system for his needs. It's always a good idea to do this. After all, the 7 "P" rule will apply.

"Proper Prior Planning Prevents Piss Poor Productions"

I spent almost a year figuring out my loads and charging needs. It is really important to balance (or exceed) your needs to be happy with your Solar install.

I wrote a 6(!) part article on just this type of thing. You can read it at:

WanderMan: A Better Solar Charging Mouse Trap.PART 1

It's helped quite a few people and points out the pitfalls and mistakes (believe me, I made them all!) that make this type of thing more difficult than it should be.

Rich "The Wanderman"

okmunky · 07-23-2012, 11:01 AM

I have a 276 watt solar array and 2 six volt golf cart batteries. I have been off-grid for 18 mostly sunny days last Spring and had the batteries fully recharged by noon. We even ran the furnace at night.

To me solar was so worth the investment. It allows me to park in national forests and on BLM land. I enjoy the peace and quiet, especially at night. And what I save on campground fees quickly repaid the cost of the solar set-up.

leadman · 07-29-2012, 02:38 AM

To the OP, as suggested if you have incandescant bulbs replace them with LED. I replaced 4 incandescant and added one extra LED and still save about 4 amps.
Also your refrigerator probably needs 12v for controls even when on propane.

I have an older MH also and added 1 Harbor Freight solar panel set (45W) and it almost kept my batteries charged. I added a second set and now I can run the led lights, small tv, the furnace at night, and my batteries get charged up during the day. I have spent 10 days boondocking and did not have to use the generator.
If you find a coupon for Harbor Freight these solar kits are $150 and come with enough parts to set it up on the ground easily. Has 3 15W panels, frame, wires, controller, and the controller has 6v,5v usb,9v, and 12v outlets, and 2 12v flourescant lights.
I will admit that these are not large providers of electricity but it is everything a new user needs to get started. Some of us just don't need to spent thousands of dollars on solar to cover our needs.