Solar voltage help...

NinerBikes wrote:

BFL13 wrote:
Niner,

..." My unit at 120 watts is 3/4 the output that his is. I have seen, at most, 6.62 amps out of mine,on the charge/load side, measured by one of those RC battery charge meters with 4 readings on the screen."

When I had a 120w panel, its Isc was 7.6a and sure enough that's what I got at the batteries as seen on the Trimetric. You need to aim the panel at a high enough sun, disconnect the controller, and take the Voc and Isc on the panel's wires using a multimeter. It is under 10a so that will not fry the meter in amps setting.

You then hook it all back up and see what the amps is at the battery. If not close to the Isc you got, you have wiring issues

Your panels are poly crystalline, the OP's are mono crystalline. They are not as efficient.

my panel

Readings at 34.0 N in Late Oct 2013.

Seems I got 6.84 Amps/hr at peak, sometime during the charging regime, if only briefly with these pulse chargers. Isc is rated at 6.98, on the back of the panels. Perhaps I lost some being the sun was so low that late in the year.

5 feet from controller to battery of 12 gauge wire, rated at 20 amps, at under 7 amps, is not a loss issue. I kept everything as short as possible during these beginning trials, to minimize losses.

Are we talking about the same panels? According to this, you Imp is 6.98 You should be getting Isc.

http://www.solarblvd.com/Solar-Panels-&-Systems-12-Volt-Solar-Panels/c1_269/p2756/W-Solar-120-Watt-Foldable-12-Volt-Solar-Panel/product_info.html

Play with the sliders on here--You are just under the STC on 25 Oct at 34N

http://pveducation.org/pvcdrom/properties-of-sunlight/calculation-of-solar-insolation