So I've got a pair of global solar 62W solar panels, a morningstar prostar 30 with the digital display, a 110 AH AGM battery and a truckfridge TF41. I'm on my back porch testing it all out, I plug everything in, turn on the TF41 and the morningstar is reading only 12.7 volts and using 1.1 amps of solar power. Does this sound right? both of those seem low, I thought the fridge would draw more IE around 2.8 amps (its going from 60deg to 20deg) and the float range should be low 13s? The morningstar is set to #2, sealed for AGM and the battery is presumably full as I just took it off the trickle charger. Like I said I'm on the back porch and the sun is just cresting the trees but I'm not seeing much if any shading going on.
Solar question
- Thread starter jdinevens
- Start date
Herbie
Rendezvous Conspirator
I'd disconnect the fridge and evaluate the solar panels/controller and battery first. With no load the battery should be higher than 12.7, I'd think. Either because it's floating at a high state of charge, or because it's not fully charged and the morningstar should be pumping in the current. Check that first.
Then disconnect the solar and connect the fridge. The load of the fridge can definitely pull down the battery voltage when the compressor is running. Not sure about 1.1A, unless the morningstar is guessing at some sort of "net" load if you're drawing more from the fridge but putting some "back" via the solar. Do you have a way to measure the load current without the morningstar connected? I use a calibrated shut and a volt meter for accurate measurements on the bench.
Then disconnect the solar and connect the fridge. The load of the fridge can definitely pull down the battery voltage when the compressor is running. Not sure about 1.1A, unless the morningstar is guessing at some sort of "net" load if you're drawing more from the fridge but putting some "back" via the solar. Do you have a way to measure the load current without the morningstar connected? I use a calibrated shut and a volt meter for accurate measurements on the bench.
I think you mean generating 1.1 amps of charge: about 13 watts.
If you have a multimeter I would shut down the system, and see what you have on voltage on each individual panel.
Under perfect circumstances it seems like you will get 10 amps, but I doubt you will ever see that.
What is the voltage of the battery with everything shut off? With it on?
Are you using the correct size wire? Voltage / Temperature Sense?
If you have a multimeter I would shut down the system, and see what you have on voltage on each individual panel.
Under perfect circumstances it seems like you will get 10 amps, but I doubt you will ever see that.
What is the voltage of the battery with everything shut off? With it on?
Are you using the correct size wire? Voltage / Temperature Sense?
goodtimes
Expedition Poseur
Shading isn't the only thing to watch for - the angle between the sun & panels will have a significant impact on performance. The closer the sun is to the horizon, the lower the output of the panel. Even if you have the panel at a 90* angle to the sun when it's low on the horizon, the output won't be as good as it is when it's directly above.
The 1.1 amps doesn't sound out of line - you're only going to read what the battery pulls. If you're already fully charged (or close to it), you won't pull that much. The demand from the fridge will be pretty close to a square wave (on/off), while the demand from the battery will be a lagging curve (for lack of a better description).
The 12.7v sounds a bit low. IIRC, mine floats higher than that. I'd check actual voltage with a good quality multi-meter to rule out an out-of-calibration meter that you have built into the system. Also, let the whole thing sit there for a day & see if the voltage/amp draw changes over the day.
what is everyone experience/opinions of using traditional solar panels vs the flexible units that are available. I am in the process of upgrading my solar setup, will be mounting permanently on a FWC and with low/moderate loads, a few 12V lights and an efficient compressor refrigerator and occassional laptop.
goodtimes
Expedition Poseur
I like the low profile & ease of mounting with the flexible CIGS panel I bought from Global Solar. A single 100w panel keeps up with loads similar to what you have described. I haven't hooked the camper to the trucks charging system since I installed the panel - it keeps up indefinitely.
As for the install - if you have a smooth roof (IE: new camper), you can just peel the backing sheet off of the adhesive mastic that they put on the back of the panel & stick it down. Since my camper is old ('91), I ended up mounting a sheet of .080" aluminum across the front edge of the roof (screwed to the roof frame, Sikaflex all the way around to seal it off), then I mounted the panel to the aluminum sheet. Easy as you can get.
wrcsixeight
Adventurer
I have a Unisolar pvl-68 in parallel with a framed Kyocera 130 watt panel on my roof.
The unisolar requires twice the real estate to make half the juice. But in low light situations does pretty well.
There are other flexible panel makers out there, likely the ones which stole Unisolars method and drove them out of business.
http://www.amazon.com/Xunlight-71w-Solar-Panel/dp/B00A0VVX5A
http://store.evtv.me/proddetail.php?prod=180wsolarpanel
And don't think Unisolars or other panels can be rolled and unrolled as needed. There are more than a few reports of owners who did this, no longer having operational panels. Also the safe minimum diameter for rolling up a unisolar is fairly large. They are shipped in smaller boxes and rolled tighter than what is prescribed.
Do not attempt any peel and stick in full sun on a hot day. I found once peeled, and stopped, the paper formed an instant bond with the butyl requiring the paper to be peeled from another direction. By the time I finished I had hundreds of bits of paper swirling around and invented hundreds of new curse words, and sent the neighbors packing for the hills at the ranting of the demonically frustrated solar installer.
Also note the panels can bend in only one axis, not two at the same time. They cannot stretch nor compress and will not just magically lay flat and streamlined on a multi curved surface.
The unisolar requires twice the real estate to make half the juice. But in low light situations does pretty well.
There are other flexible panel makers out there, likely the ones which stole Unisolars method and drove them out of business.
http://www.amazon.com/Xunlight-71w-Solar-Panel/dp/B00A0VVX5A
http://store.evtv.me/proddetail.php?prod=180wsolarpanel
And don't think Unisolars or other panels can be rolled and unrolled as needed. There are more than a few reports of owners who did this, no longer having operational panels. Also the safe minimum diameter for rolling up a unisolar is fairly large. They are shipped in smaller boxes and rolled tighter than what is prescribed.
Do not attempt any peel and stick in full sun on a hot day. I found once peeled, and stopped, the paper formed an instant bond with the butyl requiring the paper to be peeled from another direction. By the time I finished I had hundreds of bits of paper swirling around and invented hundreds of new curse words, and sent the neighbors packing for the hills at the ranting of the demonically frustrated solar installer.
Also note the panels can bend in only one axis, not two at the same time. They cannot stretch nor compress and will not just magically lay flat and streamlined on a multi curved surface.
It seems like this might have been it, I let it sit an hour with the fridge off and it crept back up to 13.6 which is the bottom end of the batteries float voltage (13.6-13.8) so it was probably just the fridge pulling it down (I did have it on max not eco) Also the sun got higher in the sky which probably helped, I think it was about 10 in the morning when i started. I didnt get a chance to do a prolonged test with the fridge still connected so maybe if i get back from work earlier this week. On the flip side the batteries lasted a solid two days with just the fridge and no charging.
Jonathan Hanson
Well-known member
Global solar was bought by Hanergy and is doing fine. The 100-watt Powerflex modules Brian and I both have are here. We have two on our FWC and they work superbly.
Jdinevens, I'll bet your system is okay if you got back up to 13.6 volts fairly quickly with no load. With no charge and no draw, most batteries will drop back into the high 12V range while sitting. As Brian mentioned, the angle of exposure makes a difference; so does temperature: PV panels produce significantly less when it's hot.