It’s taken a couple of months since we bought our first solar power system kit to realize where the problems lie and that one of them isn’t being addressed well enough yet. I can’t speak for systems that are professionally set up as I don’t have any knowledge about them. I’m talking about the ones you order and set up yourself.
The first problem is absolutely critical to the life and functioning of the battery array. The battery array stores all of that sunshine for your use. Deep cycle batteries that are used in a battery bank must never be discharged below 50% or 12.1 volts as it can damage them and shorten their lifespan and storage capabilities. It can ruin them necessitating a replacement of the whole bank.
You need a way to monitor the voltage level of the batteries and way to shut off the power draw when they hit that 50% depleted level.
Important here is that solar power systems can run an AC or alternating current system (120 volts) and/or the DC or direct current system. The DC is more of an auxiliary system.
If you live in an RV you have a DC system built in that runs the smaller appliances such as the lights and the water pump either off of the 12 volt house batteries or through a direct connection to a solar setup. The DC system is what you would use while out camping but RVs incorporate both a DC and an AC system for use if an outside source of power is available at a campground, for example. The AC is a 120 volt system that supplies power to larger appliances such as an air conditioner, a ceiling fan, washer and dryer etc.
Our main goal and most folks, I imagine, when buying a solar power system, is to run the BIG stuff with an option of also plugging in those smaller appliances.
When we bought our first set of solar panels, we saw that the control charger that came with the kit (the brains of a solar power system) could be programmed to disconnect the power draw from the batteries at whatever depletion level you set. By doing that, it would theoretically prevent the batteries from being discharged below the 50% (12.1 volt) level (recommended) thus preventing over discharge and the resulting damage to the batteries.
It took us this long and a conversation with the solar company we bought from to find out that the controller they sent only monitors and controls the DC or auxiliary system. The one we never used.
There was no way to program it to monitor and shut off the power draw being funneled through the primary AC system. This particular charge controller was effectively useless to us in protecting our main power storage asset; our battery bank. I have no idea why it would have been designed this way. It makes absolutely NO sense!
The only way to prevent battery damage as we use the system, is to visually look at the voltage level display on the power inverter itself (the component that converts the 12 volt power from the battery bank to usable 120v energy) and turn it off/or unplug the extension cord to our trailer when the batteries get low on voltage. Stupid.
I had to search the internet for a special low-voltage disconnect relay that I bought from another company and I installed it. It worked for awhile then something happened and it started to shut down the inverter altogether and to this day, we can’t figure out why.
We had to remove the relay so the inverter would work again but now we are back to square one. We now have no way to watch the battery voltage levels but we kind of don’t care right now. I could press forward in getting the answers but for now, we’re back to using just two gas powered generators.
Inverters that are programmable to actually work properly with a solar setup are 700.00 and up. The rest (the ones that come with DIY solar panel kits) are preprogrammed to disconnect from the battery bank at 10.5 volts; after your batteries are already dead and/or damaged.
My understanding of why they are set to disconnect power at such a low voltage is to prevent the inverter from tripping off with a load spike when first plugged in. I can’t believe someone hasn’t come up with a work-around for this.
By the time we got a clue as to what was going on, we were worried about our batteries as we were having HUGE problems getting any kind of significant power out of each cycle (day of sunshine). Our batteries had been over depleted so many times by now they were almost surely damaged. We had them tested and although we believe their performance has somewhat been compromised, they are supposedly good.
Here’s another issue I noticed about the planning stage of going solar. This is specifically for those living in an RV. Logically, you have to figure out how much power you’re using in order to estimate the size of the system you plan to purchase. I consulted website after website on how to do this. You make a list of appliances and the amps and/or watts each one uses, total it up, and size your setup accordingly.
We did this and still had a huge problem with a power drain that we couldn’t account for. We would plug in the solar at night, for example, and we would be lucky to make it through the entire night before the solar would shut down.
We came to suspect that our RV had some sort of parasitic drain so we flipped the breaker switches one by one while the solar was plugged in. We watched the voltage readout and noted the drain as we went from one to the other.
Finally we found the culprit: Our RV house battery recharging system. If you live in an RV, when you plug into an outside power source, your house battery charging system automatically kicks in and starts to charge your RV batteries. This turned out to be a HUGE extra energy user that not one website had mentioned. We were charging one set of batteries off of another set of batteries.
To make it worse, we discovered our house batteries were bad. We’ll replace them and either disconnect them from our RV charging system and charge and monitor them independently, install a separate charge controller for them, or just flip the breaker switch in our RV that controls the battery recharging system when we plug our solar into our RV.
The last issue was completely our own fault. Our batteries are getting cold with the onset of lowering temperatures. The charge control units came with temperature sensors that attach to the batteries and they send more power to them when recharging at low temperatures as needed. If it’s too warm, the sensors tell the charge control unit to send less power to recharge. It makes the charging system more efficient.
I attached the temperature sensors to the batteries yesterday and the bank is now charging faster and more completely.
I also found out that a Maximum Power Point Tracking or MPPT type of charge controller is more efficient than the ones we have (Pulse Width Modulation-PWM) so I’m considering switching those out too.
The moral of this story is that a lot of factors contribute to how well or IF a solar power system works. Added together, they can have a profound effect on performance. Solar power is a fantastic concept but until the industry makes these kits more failsafe, they’ll continue to be riddled with problems and users are going to keep going through batteries like disposable razors.
Believe it or not, we are still completely sold on solar energy. Our plan at this point is to double our panels and battery bank, switch to MPPT controllers, and invest in a programmable power inverter to preserve our battery array. This is going to take a little more cash so we’re waiting for the sun to come back out in the spring.
Until then, here’s a poem I wrote: Rant Poem On DIY Solar