Solar Controllers--Don't be a Sucker! :(
Just got to say it again, how it is we are sitting here for five months off grid on solar with no problems at all (third season on solar like this), using the non-programmable, non-MPPT, solar control...
Forum Discussion
5% or 8%; all about the same. Temperature and battery voltage have a huge effect on mppt gain. I just looked at some measurements I took a few years ago when I held battery voltage constant at 12.25V. This is where mppt is at its best. It doesn't get better than this. At 9am gain is about 20%. With panel warming up gains drop from here, down to 11% at noon. In the afternoon gains are about 8%. At 9am panel temp is 30C, and at 1:30pm temp is about 50C while ambient is 21C. The 29C temperature rise just killed mppt gains. If I were to let battery voltage rise, gains would be much lower.
20% of battery charging time could be in boost mode, while 80% is in absorption. That means you're only using the mppt feature for only 20% of the daily charging cycle. If you're in boost for 3 hours with mppt, then you're only 3.15 hours @ 5% gain or 3.3 hours @ 10% gain when using pwm. The rest of the time both systems charge at the same rate. MPPT is getting plenty of hype.
Sal
20% of battery charging time could be in boost mode, while 80% is in absorption. That means you're only using the mppt feature for only 20% of the daily charging cycle. If you're in boost for 3 hours with mppt, then you're only 3.15 hours @ 5% gain or 3.3 hours @ 10% gain when using pwm. The rest of the time both systems charge at the same rate. MPPT is getting plenty of hype.
Sal
pianotuna wrote:
Hi Salvo,
I thought you said 8%?
