Blog disclosure: Tracy likes to stay hands-off here.
In fact, he reads the blog only when he happens to be sitting around with time on his hands and his laptop in front of him, and he’s already read the rest of the Internet. (Believe me, he reads a lot). Every now and then, he apologizes for not staying on top of the blog, but I tell him that he lives this stuff; he doesn’t need to read about it, as well.
The bummer part is I don’t have a fact-checker, and I really need one. When he was reading my initial post about the solar installation, I think I saw his eyes roll. As in, I had gotten a lot of the details wrong. So I asked him to write it out correctly for me so I could paste in for you. Here goes.
Panels
We now have seven 90-watt panels mounted on the roof for a total of 630 watts. (We started with two panels that came mounted when we bought the Airstream new.)
The five new panels are mounted using 3M VHB tape and Sikaflex 221 (a polyurethane adhesive/sealant). [Shelly here: a lot of solar installers drill into your roof, but we picked our installer in part because he doesn’t.]
The panels are wired in parallel. [I think this means if one or more of the panels are in shade, their decreased efficiency doesn’t affect the efficiency of the others in the sun.]
The individual connections are combined on the roof, and the final wire run enters the trailer through the refrigerator vent and connects to a Victron solar-charge controller (under the sofa) that controls the flow of current to the batteries for optimal charging.
Batteries and Converter/Inverter
The trailer came with two 110-amp hour acid batteries, and we swapped those for two 300-amp hour LifeBlue LiFePO4 (lithium) batteries.
In addition, we swapped out the old converter (converts 120v AC to 12v DC for charging batteries) and inverter (inverts 12v DC to 120v AC to power outlets and some appliances). The new unit is a Victron Multiplus 12/3000/120 combined converter/inverter.
The “Multiplus” feature allows the batteries to supplement the 120v AC input in situations where demand exceeds the supply of the incoming 120v AC power. For example, if we were connected to a 15 amp circuit from someone’s home and wanted to use our air conditioning, which has a continuous draw of about 16 amps, we now can do so.
The inverter can supply 3000 watts for short periods, though continuous use is in the 2200-2400 watt range. While this is sufficient to run the air conditioner, the battery capacity limits its use to only a few hours, so it’s not feasible to run the air conditioner off the batteries for long.
Monitoring
The system is managed via a control panel near the sink. In addition, it can be managed/monitored from a smartphone app that connects via Bluetooth.
The most important thing to monitor is the output of the solar panels and the discharge of the batteries. [Shelly here: I think this means how much potential energy you’re collecting and how much you’re using, plus how much is left in the batteries so you don’t discharge them to dangerously low levels.]
The monitoring system will report real-time as well as historic data.
A nice addition to the system is a connection at the trailer tongue for additional portable solar panels. This would be useful if the trailer were parked under trees, which would limit our collection on the roof. [We could then connect our portable “suitcase” panel and place that where the sun is.]
There is also a direct connection to the batteries, which is handy for powering our 12v air compressor.
The Most Important Question So Far
Shelly again: There you have it. Either you’re keen on the technical stuff here and have geeked out sufficiently, or you’re barely hanging in there and may have questions. If you post those in the comments, I’ll be sure Tracy answers them.
The most important question is: How well does it work?
Well, we don’t know yet. We went straight from the solar installer’s shop to this RV resort in Bonita Springs where we have full hook-ups, and we wanted to get settled before we tested the solar system.
We’ve been here a week now though, so, just today, Tracy unplugged us from shore power and will commence data-gathering. Then I’m guessing he and our friend Bob, who powers his house from solar only, will compare spreadsheets and observations and have a grand ole time.
I wonder? Like having a dog out walking, you meet new people discussing dogs. Is it the same with solar panels, you meet new people discussing solar systems? … over a beer or something?
Here in big RV parks few people have solar systems. These are not the type of folks who go off grid; they have big rigs and need to hook up to shore power all the time. Plus they like the big RV parks for the socialization and don’t have much interest in the more isolated life of being off grid. I’m generalizing greatly, but here at least that’s the norm. When we go out west and need our solar, hopefully we won’t run into people! But if we do, maybe we’ll talk solar with them 🙂