Solar Battery Charging Part 1
After reading Larry Harmon’s preliminary announcement of this upcoming entry on solar, I only hope I can come close to delivering what he deemed it to be worth. As I stated in my introductory post, “...most of the ideas and information I will present will be taken from sources other than myself...” Let me state here and now that I don’t purport or profess to be any sort of a solar savant. I’ve read a lot about solar and I “think” I get it. If you find me in error, feel free to point that out. That said, let’s talk about SOLAR.
So, do you even need a solar panel? Well, that depends. Solar panels are nothing more than battery chargers and your new Oliver will have (or has) one of the finest 3 stage chargers being manufactured today, the PD 4045 with the handy dandy charge wizard build right in. All you have to do is plug your trailer up and (depending on the type of batteries you chose) let the charger do its thing. Are you the type camper that always goes to campsites that have electrical hookups? If that be the case, then the answer to “do I need a solar battery charging system?” is probably a resounding “Non” (French), “Nein” (German), “Bu shi zhe yang” (Chinese), “Nyet” (Russian) or “Naw” (Texan or most anyplace in the South!!!) For everybody else.....
First a few basics and just how does the sun go about charging a battery? Well, simply put, the solar panels up on the roof grab the sunlight coming down from above. At this point apparently some magic is preformed and the light is converted into volts of electricity which are sent down into the trailer along some humongous wires thru some breakers and switches to a contraption call a charge controller. Inside the charge controller incantations are said over the volts and they are sent on to the batteries to be stored there for you to use later. This may not be exactly how all that works but hopefully you get the picture. We don’t have to understand all there is to know about this stuff to benefit from it.
OK, for whatever personal reasons if you’ve decided you’re the type of camper that can benefit from having the sun recharge your batteries, now what do you need? If you are planning the build of your new Oliver, it’s pretty simple. Just let them know you want the solar option and Oliver will equip your rig with everything you need to drive merrily into the sunset and get your batteries charged for free.
The Oliver folks have made some wise decisions about the equipment provided in the optional solar battery charging system. Everything you need is there and it is all top quality stuff. Up on the roof are two 36 cell mono-crystalline panels with a total of 320 watts. The electricity they generate is linked together in a roof mounted combiner box and then sent inside along two 6 gauge wires through a 30 amp cut off switch and on to the Blue Sky Solar Boost 2512iX-HV MPPT Charge Controller. From there it is passed thru a 30 amp circuit breaker and a 50mv/500amp Shunt which is monitored by the Blue Sky IPN PRO Remote Meter inside your coach. All this is assisted by a Temperature Compensation Sensor at the batteries. Now you have to make a choice... “which battery should I choose?”
Batteries are needed to store all this free electricity. So which ones and how many do I need? First off, the more, the better. More batteries mean more available energy to run all your accessories and charge up all your toys. Luckily, Oliver has the largest battery compartment of any molded fiberglass trailer being manufactured today so you can have up to four 6 volt batteries and easily access them from the massive pull out tray (your batteries may weigh up to 275 pounds per set!!!)
For our purposes here, the storage of electricity in a battery is measured in amp-hours. This is a unit of measurement for battery capacity, obtained by multiplying a current flow in amps by the time in hours of discharge. (Example: A battery which can deliver 5 amps per hour for 20 hours delivers 5 amps times 20 hours, or 100 amp-hours.) The larger the amount of amp-hour storage your chosen set of batteries have, the more you will have to work with during your travels.
Most experts agreed that two 6-volt batteries are better than a single 12-volt battery because the combined 6-volt batteries have more amp-hour capacity as well as generally having a longer life span. Also, many prefer the AGM battery over its less expensive counterpart, the wet cell battery. AGM’s are more expensive, maintenance free (no checking and adding of water), they don't have to be vented and they resist shock better. Realistically, the main reason most folks don’t buy AGM’s is the price. Both are equally acceptable in a solar setup. I personally chose the AGM’s due ONLY to the fact that I do not want to have to worry with having to check the specific gravity of the wet cells (to determine charge state), replace the water that has boiled away and any other nit picking associated with battery maintenance. I just want them to work without any intervention from me. This is nothing more than pure laziness on my part. Since storage batteries are the single most expensive part of the solar battery charging system, if you see yourself here, I strongly recommend spending the money once on a set of AGM’s rather than twice on two sets of wet cells, one of which you ruined by not properly taking care of them.
Four Trojan 6 volt T-105 batteries will provide you with a total of 450 amp-hours.
Four Trojan 6 volt AGM batteries will provide you with a total of 400 amp-hours.
Remember, you should never deplete your battery bank beyond 50%. Each of the above amp-hour numbers should be cut in half to determine the amount you safely can use before recharging.
And so until next time (when we'll look at how to set up your system using the Blue Sky IPN PRO Remote Meter), may your road go ever on…
Steve and Tali
Dogs: Reacher, Maggie, Lucy and our Beloved Storm (waiting at the Rainbow Bridge)