Solar Panel Voc-MPPT?

ktmrfs wrote:

BFL13 wrote:
To clarify, by four batts I really mean 440AH whether four 6s or four 12s. The acceptance rate is wrt AH capacity and batt voltage.

Not exact but a rule of thumb. 10a per batt is 86%, 5a per batt is 90%, and 3a per batt is 97% SOC at 14.5v

thanks for the rule of thumb. Back to the charge current. when my batteries are near 80%SOC per trimetric, and on my PD combo good for 100A, IIRC I'm still getting 60+A, into them.
But with the solar, I was seeing 10A and mid 13's for voltage, limited in this case by the panels.

Looking at your rule of thumb, I'd say it matches my bank pretty good from my recolection. by 90%, charge current is definitely on the way down, don't recall the exact current, but 20A is probably in the range.

I usually stay on solar until I'm in the 40-50%SOC then just hammer the batteries for a few hours at 100A with the generator, then let the solar top it off. Once it's down to 20-40A charging current, may as well let the solar finish it off rather than let the generator run for hours.

So, using your analogy... since it's just me in a 21 foot travel trailer, and I will continue to use my single Group 24 at whatever Ah is has (75 at 20 hour test, 98 at 1 ah test rate) until it needs replacement, lets assume that I am going through 45 AH per day. I should then start my Honda EU 1000i in the AM and run it for a couple of hours through my WFCO 8955 55 amp charger, then let the 120W PWM controlled portable solar top it off all day, 6-8 hours worth, 9 Am to 4 or 5 pm and then maybe run the Honda again the last hour before going to bed?

Portable Solar PWM specs...

120W
17.2V VPM
6.98A IMP
21.8V VMC and
7.76A ISC.

What can I expect total amps output on a march 21st day with the panel tilted at about a 45* angle due south?

Since I usually venture to W yellowstone around the 10th -30 of June, Lattitude 44.66 N and won't have trees where I am camping to block the panels, and will have a few rainy days in there, with clouds...I have the genny for back up on those days, but on the sunny days, with sunrise so early and sunset so late, I should have plenty of solar panel juice that far north, regardless of panel temps. Mid days there are 50's through 70's depending on the snow pack for the season, altitude in the 6000's.

My next "find" needs to be 8 really bright LED's for the overhead lighting, something that really puts out the lumens and will match or exceed the 18w power hungry bulbs they are to replace.