(10-20-2012, 03:05 PM)Dennis of the NorthWet Wrote: Not to stray too far from CPAP tunes, how does the HF solar stuff compare to other options?
The nice thing about the Harbor Freight solar panels is that they are "Amorphous". Amorphous panels are much less expensive than regular crystalline panels. The HF panels have one disadvantage in that they produce less electricity per square foot than crystalline panels. But the amorphous HF panels also have the added advantage of producing electricity in low-light conditions, like limited overcast skies. The expensive crystalline panels must have unobscured direct sunlight, and produce no electricity at all without direct sunlight... whereas the amorphous panels can utilize diffused light and still produce electricity.
I currently have 3 HF kits wired together (9 panels total) and I still get my batteries charged from a low of 12.5 back up to 13-14+ volts within a 2-3 hours on a slightly overcast day, as long as the cloud layers aren't too thick. And even if you have scattered cloudiness with spurts of sunshine once in a while, that's usually enough to charge up my batteries in a couple of hours. The only thing that isn't currently stock on my system is that I upgraded to a SunSaver Duo charge controller, which has a lot more options (like a built-in desulfator and the ability to charge two different battery banks, and a lot of other setting possibilities) The SunSaver Duo is built much better than the cheapie charge controller that comes with the kit. But the kit's charge controller does work fine... but it's just not recommended to use it for more than one or two kits wired together.
There's a reason that the Harbor Freight kits are so popular: you get a lot of bang for the buck. It's an easy entry-level way to learn about how solar panel systems work. If you'd like a much more indepth look into this trend, there's a specific forum that has a lot of interaction amongst folks who do all sorts of stuff with these kits. Just do a Google search (without the quotes) for "Harbor Freight Do It Yourself Solar Energy Forum". The first link that pops up should be the non-commercial forum that I read a lot when I first started using these solar kits. Lots of info, personal experiences, pics and videos.
One caution and that is to make sure to use fuses with proper amperage-ratings on any 12-volt wiring (both the positive and negative leads coming out of the battery). If 12-volt wiring shorts, it will heat up, melt the wire insulation and start a fire if you're not careful. Proper fusing is an absolute must.
As far as price on the HF kits, they are hard to beat. I personally got three 20% off coupons and used them on three separate transactions to lower my cost. At the time, the local HF here was running the kits on sale for $149, and they allow me to use the 20% off coupon on top of that. So I paid something like $120 plus tax for each kit.
I also upgraded from my lead-acid Wal-Mart deep cycle marine battery to a true deep cycle lead-acid battery (my set of 240 amp-hour Trojan 6-volt golf-cart style, operating in series). I get more amp-hours (capacity) from them that I would have by operating two Wally World 12-volt batteries, which have something like 110 amp-hours I think. More expensive, of course, but you get what you pay for in batteries, generally. Maintenance is simply making sure the battery water level is topped off every so often with distilled water (I check mine once a month).
Apnea Board Administrator