This is the second season to use solar panels on our 3023 TM. I’m pleased with the capability and it has met my expectations but it may not be the solution for everyone.
A quick summary: Two 90 watt solar panels mounted on the rear shell with a BZ Products charge controller mounted next to the converter. The other component is a Bogart Trimetric battery monitor. The Trimetric allows monitoring current, voltage, AH used, and % battery capacity.
I mounted the panels on the rear shell using the adhesive technique that RockyMtnRay described. I did fabricate custom mounting brackets from aluminum. The combination worked well and I didn’t have to penetrate the TM roof. Thanks Ray! The aluminum mounts are still solid on the TM roof with the Loctite Depend adhesive. These appear as strong now as when initially installed. The panels are mounted flat. I didn’t make any provisions for tilting the panels since I will primarily use them during the summer months.
Last winter I left the batteries in the TM. Since the TM is stored in the driveway and gets a few hours of sunlight per day in the winter this is more than adequate to keep the cells charged. It would be safer to remove the batteries and store them charged in a warm location.
Since I use flooded lead-acid batteries, it’s absolutely essential to water the batteries every few months. I try to check them once a month but they seem to go for at least two months in the summer. They didn’t use much water over the entire winter. I use one of those auto-fill devices for the distilled water. This makes quick work of filling the batteries to the proper level.
The biggest thing I would do differently is to install the charge controller closer to the battery and use a larger gauge wire between the charge controller and the batteries. The relatively long run of 10 gauge wire is limiting the maximum charge current.
For my next installation I would prefer to use AGM batteries so I don’t have to keep checking the water level but this will require some changes in the solar charge controller and also the converter. The ability to rapidly charge batteries is inconsistent with automated techniques to sense battery condition and prevent overcharging. I’ve spoken to several manufacturers of RV converters and charge controllers and most recommend using flooded batteries and adding water as required.
During a four day boondock campout over Labor Day weekend, by the first morning I had used 40 AH of battery capacity. This was a record for me and was due to running the refrigerator on battery while en-route. That was about 10 AH. I left an outside light on all night for my kids and over a thousand fellow tent campers. I also made two pots of coffee with an electric drip coffee maker that uses 4 AH per pot. The batteries were back at 99% capacity by the end of the day due to clear skies and full sun exposure. In fact over the four days there was no reason to try to conserve battery power and the batteries were fully charged by the end of the day. We even ran the electric ceiling fan for part of each day. Multiple days of cloudy weather would have required more of the available AH capacity. You don’t want to regularly use more than 50% of your battery capacity or it will reduce the number of available charge cycles.
Solar may be right for you if:
- You do a lot of boondock camping
- Camp in a place where there is direct sun exposure
- Can’t or aren’t interested in running a carbon fuel based electric generator
I’ll be interested in updates from other solar users. For those interested in solar there is a wealth of information at this forum:
http://www.wind-sun.com/smf/index.php
Ray