Roll Up Solar Panels / Ogre MPPT Controller
I would LOVE to get 10-12 amperes of 12 volt grade charging for my new group 31 Lifeline. But I have a motor-scooter size toad, that forces me to the roll-up kind of solar panel, and woe is me, the...
Forum Discussion
pnichols wrote:BFL13 wrote:
am shocked, just shocked, that you haven't been reading all these solar threads over the last few years!
The advertised 20-30% gains with MPPT vs PWM are taken very early and late in the day, not at the mid-day hours of most solar intake, when the MPPT is more like 10% better. IE, 1 amp more than 2 amps is 50% gain. but 1 amp more than 10 amps is 10% gain.
Hmmmm ... what parts of this article are Smoke-N-Mirrors?:
http://www.wholesalesolar.com/Windy/MPPT-article.html
I'm not so concerned with what is good enough. I'm more interested in what the optimum is - for maybe only a few dollars more. Solar is inefficient enough without making it worse trying to save a few bucks, IMHO. Remember that with portable panels, if you want you can walk up to them and tweak them towards the sun from sunrise to sunset way better than can be done with roof mounted ones. I think that harvesting max energy from early morning to sunset as best you can requires a MPPT controller - from what I've learned.
Phil, all I know is what I have measured myself using both systems and the big thing is how temperature knocks down panel output, negating any MPPT gains to the point that PWM does better.
You can cherry pick times that MPPT does better or when PWM does better. It is situational. Even the definition of "better" is not the same for everyone.
I don't worry about energy efficiency. I just want the most amps to the battery for the least cost and bother. Best thing is to do your own due diligence based on your own idea of "better", pay your money, and live with the results same as everyone else does.
