Solar Panel Testing! ET Solar VS ReneSola

Solar Panel Testing! ET Solar VS ReneSola

Solar panels mentioned in the video (affiliate links):
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ET Solar 375W:

Bifacial Solar Panel:

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Carey Johnson says:

Thank you for video and just to let you know your video was great your sound system was great you got a good hook up system very clear

ZzHasbrozZ says:

Is testing a cold solar panel the same as comparing the whiteness of unused toilet paper?

willisarron22 says:

Sunpower is the way to go. Especially the type I have. Each row of cells produces the rated voltage and then all the rows are in parallel. This is great if there's any shading.

wen hao wong says:

hi, do you test Longi solar panel before?

nelio SAMch says:

Yes, nobody need those testers because you can see the output on the solar controller more accurately. I have 10 Canadian solar, 10 Trina 72 cells, 400w each and the output depend of cloudiness, temperature or degradation, however, in some lighting conditions one brand can output more than the other and vice versa and sometimes the output is more than the stated ratings on the 41st parallel north.

Reinhold U says:

Q-Cells? YES WILL …please do some Q-Cells πŸ‘πŸ˜˜

Brian B says:

Like Will said, the meter's OK if you are sorting panels, but not for installers – they will have an expensive meter $$$ Plus Andy from that 'other' solar YouTube channel (Off-Grid Garage) uses a different meter – after he used this meter.

wiedapp says:

I think the Chinese meters come in handy, when you build your system entirely from used panels, like Andy from the Off Grid Garage does. Even if they are not that accurate, they provide a good indication as to if the panels are still good or trash. And with their portability you can use them at the pick up place before you actually buy the panels.

daniel nicholls says:

please test two bifacial panels at a time .. keep a little more vertical [ till they drop off a few watts] and step second panel back a panel width and up till no shade from first panel. then test separate. to see if you get more reflection from second panel to first panel. a good test to do. you need a w shaped reflector behind one bifacial to get best output. thanks for great tests.

Matt Stone says:

I may never buy solar, but I still love watching, learning and being entertained by Will. πŸ‘

Brian B says:

These meters can be had from Aliexpress for @ Β£40!

RCin Fla says:

Normal individual cell processing produces cells with a distribution of performane variation and is result of slight silicon doping variance in manufacturing. Manf. sort the cells to groups of like performance cells for the same panel. This is why you often see same model variation grades with something like three to five grades with different wattage. They all will look physically the same, just grading (and therefore cost) on cells are difference.

I use a DL24 load tester. You need to have a load tester with CV, adjustable constant voltage mode, which is like a variable high power zener diode load. For a little manual CV adjustment it allows you to easily get the different parameter of Isc, Voc, Imp and Vmp, along with the corresponding wattage. Running CV setting down below about 50% panel spec'd Voc gets you close to Isc reading. Running CV up til you get zero current is Voc. You can see the heating progression of panel in sun with Voc reading. Adjusting CV for maximum power reading is Vmp and Imp and you can likely manually adjust CV to max power as fast or faster then an MPPT controller finds maximum power point.

Voc is most important indicator, followed by Isc and should be measured for any panel test. It also ensures you have enough panel overhead voltage to effectively run an MPPT controller for given battery voltage (should have at least 4v overhead). The quality of series resistance and shunt resistance of cells determine the MPPT point for given Voc and Isc. Normally for qood quality cells, I_mp is between 90-95% of I_sc and V_mp will be between 80-85% of Voc. Isc for good cells should be 40-45 mA/cm2, in full sun, per actual silicon cell area. Most common sized cells are from 156×156 mm wafer with rounded corners for about net 215 cm2 area per cell, yielding Isc of about 9 amps. Must not have any partial shading for these relationship to be true. Poor shunt resistance does not effect full sun performance but impacts low light performance. All cells have some shunt defects producing the shunt resistance so the less the defects the higher the quality of cell.

Using one of these load tester also gives the additonal application of battery load testing that the dedicated panel testers do not have which makes the expense of the load tester more justified over just occational use of dedicated panel tester.

Richard Lutz says:

Hi Will, If you will be using a multi-meter to test used panels, consider getting some extra leads and wire them in to an MC-4 connected and an MC-3 connector for the really old used panels. Having it soldered up and shrink wrapped will make it way more convenient so you are more likely to use it and you won't need a 3rd hand. Also I gotta say I almost skipped this video, but as always I learned something and enjoyed the content.

Jack Hammond says:

Be great if you could test some Mission Solar panels from San Antonio. Perhaps a made in the USA compare?

FreeAmerica365 says:

Great review brother thank you for letting us know

Koby Gaddie says:

Im building a 24v battery from 8x 3.2v batteries. I bought 2x Daly BMS each 12v 4s.

Can i use the 12v bms on each battery then wire the batteries to 24v?

Is a 24v 8s daly bms needed or will my system work well with 2x 12v bms? One on each battery?

Dee Larry says:

Anyone interested in 20 jinko 400 watt panels? Or 40. If you want that many. I live in western Texas. Willing to drive a ways or meet somewhere to transfer. I'm asking 100$ a peice. These were used for less than a month on a solar farm. All tested for voltage and randomly tested some for wattage output on a micro inverter. So far everything is perfect.

jwsolarusa says:

Thanks for sharing these solar panels STC Rated test.

JW Rhyne Jr says:

When will you do a video on using just the multimeter to test solar panels in used condition?? Any chance I missed it??

Get lost today says:

Thoughts on amorphous panels Will?

Colin Askins says:

Knowing that Heat causes performance loss… Have you ever made a cooling enclosure for your panels with small exhaust fans to keep them cool?

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