Solar Update

He said…

During a stop at Island Park Campground (an Army Corps of Engineer park just off of Pine Flats Lake in California) we put our solar/battery system (installed by AM Solar) through our first real test.

We could have had hook ups (water and electric) but we decided to go ahead and do the whole “boondocking” thing.  No hook ups at all. The cost, with Mariel’s Golden Access Pass was $10/night!

First Solar Test
First Solar Test

One of the main loads in our RV that is all electrical is the refrigerator. Unlike many RVs, ours can not be run on propane. So… the batteries are continually keeping our fridge running!  This is the biggest electrical draw we have throughout the day (not counting the short time use of the microwave/convection oven or the electric water kettle).

For the first night and day we decided to NOT minimize our electrical use. The plan was to operate as we normally have when in campground with electricity. The only exceptions to this is our use of propane. Instead of using the electric water heater – we kept our water hot using propane. And, instead of using our electric fireplace to keep the chill out at night, we used the propane furnace.

Night 1

We got to the campground with full batteries. But, by the time we went to bed, they were down to about 96%.  The next morning, we were down to about 67% battery capacity and by the time the sun was up enough to start charging the batteries it hit 62%.  Our electric water kettle really sucks up the power!  We used up about 34% of the batteries’ charge.

Day 1

We’ve stayed home and watched TV all day and used the microwave to cook lunch!  That being said… The solar system charged the batteries up to about 72% capacity while the sun was still out.  By the time we went to bed, we were back down to about 65% of state of charge.  We basically broke even on the energy coming in and the energy going out.

So… the solar provided enough power throughout the day to not only let us live “normally”; it also charged the battery some. This was a good thing since we used up that extra bit of charge by continuing our TV watching binge.

Night 2

The next night I wanted to try something different. We unplugged all the computer/phone chargers and the TVs to try to remove as many vampiric loads as we could. It made a bit of  difference in the discharge of the battery. Instead of losing about 30% like we did the previous night – we only lost 22% of the batteries’ charge.

Day 2

The test this day was to see how fast the generator would charge the batteries back up.  The morning sun and generator took 2.5 hours to charge the batteries from 41% to 91%. By the evening we had the batteries back to 100% of charge.

Generator charging the batteries.
Generator charging the batteries.

Night 3

During the 3rd night we still had most everything unplugged and we lost about 19% of the batteries’ charge throughout the night.

Day 3

This is the day that we stayed off the TV for much of the day (with them unplugged) and the solar charged us from about 71% to 90%.

To sum it up…

 Normal Energy Use  Light Energy Use
 Night  34% drop 19-22% drop
 Day 0% drop/increase 19% increase

It appears that if we’re energy stingy – the system will keep us going indefinitely as long as we don’t hit any cloudy days. If necessary, however, our batteries can be discharged to about 20% (since they’re Lithium) before we’d have to charge them back up which would take 3-4 hours (about 3-4 gallons of gas).

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