Solar panel comments, suggestions, musings...

Posted By: Chris & Lenore - Mac 26S Teliki
Date: 4/9/09 5:25a.m.

Report: outside forum guidelines

In Response To: solar panels off the rear (pic) (walt26scolorado)

I recently found extremely small 30 watt panels (10 X 22 inches) that fit perfectly on hone half of the stern rail. It's out of the way of outboard, BBQ and swim ladder. Not sure if this should be a new thread - but someone mentioned solar. The previous generation (only a year ago) were 2 1/2 times this size!!!! We spend every weekend on Teliki plus several week long trips each year. The old 5 watt panel coupled with a few minutes of outboard use each day (8 amp output) and we have never in 3 years run even low on power. The 30 watt should support a lot more toys and "'slack use". Interior lights are LED, anchor light is LED and we use depth, speed, gps and VHF on receive while cruising. The old panel could run this without the battery on a sunny day (can't transmit or use the water pump though). We now have a small DVD for the kids plus my "ultra low power" music/radio/SSB described on our website, so the extra juice will be more than enough. I guess my point is that it made me think about how much solar capacity I really needed. Picking low power equipment (drain REALLY varies - you need to check specs on anything you buy) really reduces the need. I also prefer simple on the battery side. Last thing I wanted was multiple batteries that I have to monitor and fiddle with switches to ensure that charge and drain evenly. Went with a single 120 amp/hr battery and rarely ever see it go below 90% charge. You might also be interested in what I rigged up for the new 30 watt panel. When the battery is fully charged, the solar panel runs all electrics isolated from the battery. If the main bus voltage falls below 12.8 then a relay kicks in the battery. So far, during an average day, the battery supplies nothing. The reason behind this is from an experiment by our local universities solar car project. They found the batteries lasted longer and had higher capacity in that top 10% of charge region (where you need to be to realize long battery life) when in a true "maintainer only" mode. Not sure if it really makes a difference but it is cool to be 100% "real time solar" during most days. Chris