12v MPPT and 24v MPPT vs 24v PWM Test
Got a chance to try out comparing amps to the battery using MPPT vs PWM on a 24v battery bank and comparing those with the usual MPPT on 12v with my 230w panel. The bank is four 6s, so it was easy ...
Forum Discussion
full_mosey wrote:
In the summer 0f 2013, I let the magic smoke out of my MS SS 10 PWM controller. Within a week, I had installed an MS MPPT 15.
I rewired the two 85W panels to series.
The maximum I ever observed from the PWM was a little over 9A. Almost immediately, I observed over 10A with MPPT. That is about an 11% increase.
I believe I get more daily AHs now with MPPT.
HTH;
John
170w of "12s" should get you 170/130 x 8.2 = 10.7 amps going by my old Sharp 130w which had 8.2 amps to the battery (also was its rated Isc) in "full sun"
It then turns on what the Isc of those 85s is, and whether they were in "full sun" to get that many amps to the battery.
I do see a lot of panels nowadays with lower Iscs in proportion to their watts than my Sharps had. (eg the Sharp 80w had 5.1 Isc and I got that to the battery. My Sun (brand name) 120v panel had 7.6 Isc which is same as the Sharp ratio. My Sun 100 watters had 6.3 Isc and I got that too. It is all in proportion.
Many panels now with Vocs above 22 have way low Iscs so that can be a factor. Many of those are Monos, but now polys are coming down in rated Isc too. No idea why. For PWM, I go by the Isc to get the most amps per dollar cost of the panel, never mind the watts, which don't tell the true story.
