Air conditioning on solar
So today I put together the three solar systems on the 8-D, hooked up the PowerJack inverter and then the 5000 BTU air conditioner. The Air conditioner is a Frigidaire unit that uses 446w/ 3.9a @120v....
Forum Discussion
Phil, panel efficiency has nothing to do with its amps output. Panel efficiency is to do with its watts per square inch so a smaller panel with the same wattage is more efficient. Both can have the same amps.
Solar for Rving is hugely inefficient and inconsistent due to the weather, so you can't fine-tune it. Just grab some and use it. It will give you more amps than not using it. Forget efficiency and just get the most Isc per dollar (forget dollars per watt --you are buying Isc amps not watts with PWM)
Or buy whatever, play with it, discover what we told you here was right after all, and then play solar-set trading on Craigslist like Jim does till you get it right :)
EDIT--missed Phil's above-- the 120w panel gets its wattage rating by looking at its IV curve where you get the Vmp at its knee. The Imp is whatever the amps are at that Vmp point.
Poly panels have typical Voc of 21.x and monos 22.x Polys have higher Iscs with the lower Vocs (and the Vmp/Imps) Iscs are pretty much proportionate to wattage with the polys at that same voltage.
An 80w will be 5.1ish, a 100w will be 6.3ish, 120w 7.6, 130 8.2.
That is how I can use my 130w panel specs to estimate the "expected amps" from any wattage---it is all in proportion. Monos are less amps of course with that higher voltage.
However Imp means nothing in either PWM or MPPT. With PWM you just care about Isc and with MPPT you care about watts and Vmp.
The Roc thing is so expensive because it has MPPT which costs way more than PWM. It likely has a Tracer MPPT since it mentions that 13.8 Float voltage. They cost about $140 just for the controller.
A PWM 120w kit with the same panels will have a controller worth about $20.
Solar for Rving is hugely inefficient and inconsistent due to the weather, so you can't fine-tune it. Just grab some and use it. It will give you more amps than not using it. Forget efficiency and just get the most Isc per dollar (forget dollars per watt --you are buying Isc amps not watts with PWM)
Or buy whatever, play with it, discover what we told you here was right after all, and then play solar-set trading on Craigslist like Jim does till you get it right :)
EDIT--missed Phil's above-- the 120w panel gets its wattage rating by looking at its IV curve where you get the Vmp at its knee. The Imp is whatever the amps are at that Vmp point.
Poly panels have typical Voc of 21.x and monos 22.x Polys have higher Iscs with the lower Vocs (and the Vmp/Imps) Iscs are pretty much proportionate to wattage with the polys at that same voltage.
An 80w will be 5.1ish, a 100w will be 6.3ish, 120w 7.6, 130 8.2.
That is how I can use my 130w panel specs to estimate the "expected amps" from any wattage---it is all in proportion. Monos are less amps of course with that higher voltage.
However Imp means nothing in either PWM or MPPT. With PWM you just care about Isc and with MPPT you care about watts and Vmp.
The Roc thing is so expensive because it has MPPT which costs way more than PWM. It likely has a Tracer MPPT since it mentions that 13.8 Float voltage. They cost about $140 just for the controller.
A PWM 120w kit with the same panels will have a controller worth about $20.
