Solar – For Dummies

In battery basics we talked about battery charging, and monitoring, not so much on solar, why you might be wondering. Well here is my rational, a new battery bank for our coach with 4 new AGM 125 amp hour batteries would cost approximately $1000. This was the expense I was faced with a two years ago, when I realized that if I wasn’t getting the old battery bank charged properly, so left if left uncorrected I would soon be in the same situation again. So how do I put an end to this destructive cycle?

I became real good friends with my volt meter, and soon realized that until I started taking care of our batteries it would be just like throwing money away and that’s not something I do (the last name is Buchanan not Rockefeller). So my research proved that we were slowly destroying our batteries and probably had been since we started. I have always believed that you can not get to your end goal until you know your starting point and know if you are actually making progress, and how do we track that?

We needed to do something and quick, we were in the desert near Quartzsite so we purchased a Zamp solar suitcase for $750, this gave us 200 watts of solar panels with a solar controller, call it a solar starter kit for dummies. But what it did was prove to me the power of solar and the benefits of any solar. Someone had added a couple of panels on the coach roof at some point but it never seemed to do anything. And the reason it never seemed to do anything was because it was so poorly installed, so this kind of gave me first hand information on what happens and how. So I set up the suitcase and pointed the panels at the sun, hooked the cables to the batteries with the clips and through the power of solar magic we were making power, about 10 amps of power and my first thought was, what is this going to do? Only 10 amps but it was 10 amps all day long so 10 amps times 10 hours that’s 100 amp/hours, but the neat part was it was getting us closer to fully charged everyday not quite full but close. My volt meter was much happier, now the realization that 12.8 was full and 12.0 was half (voltages vary by manufacturer) ours 12.8 is full. Now by running the generator for an hour in the morning during the bulk charge portion of the recharge and then let the solar finish the bulk and work on the acceptance level of charging and all of a sudden we were able to hit the fully charged level. Yah! So by now I’m starting to understand the benefits of solar and even more importantly the benefits of properly charging the batteries. Now I’m totally into the condition of the batteries almost to a unhealthy level of obsession, so now I’m attending seminars on batteries, inverters, and solar controllers and what each can and will do for us.

Here is where the solar thing starts to get complicated for most people, but it’s really just learning what power you use during the day and using a little math to determine how you get there. If you just want to be able to watch a little tv and have a couple of lights on how much solar will you need, if you watch four hours of television and your set draws five amps and your two lights draw an amp each and you have them on for five hours you need a 30 amp/ hour source (tv 4 hrs @ 5 amps = 20, 2 lamps @ 1 amp for 5 hrs = 10 amps) so a 100 amp/hour battery will carry the load and in a sunny world a single 100 watt 12 volt panel with 10 hours of sun should fully recharge the battery. No it is more complicated than that but not really, all the solar operated lights that we all have work on the same principle, small battery, little solar panel to operate a light bulb. Simple right? It’s just when we add so many variables that it starts to get complicated, unlike the solar light our power demands change, as we need to toast my bread for breakfast or have to charge our phones, or pop some popcorn in the microwave, the demands vary which makes the calculations more complicated.