Normally same panel. different quality discs.
(they have varying quality\outputs on same wafers?)
Classed after testing to suit output.
Go the 200 if room. and use good quality regulator. NOT a cheap chinee one.
Then use twice the thickness cable you thought you were going to.
Sikaflex cable to roof and through small junct box into roof. as well as rivet\sika the panels.
Then 15 yrs later. all will still be well. No holes worn in roof,
or leaks through at junc box hole.
Well. my last one sold at 14 1\2 yrs with no leaks anyway.
They might look the same in the online pictures because often online sellers use the same pic for different yet similar products.
Look for the dimension data. They will be completely different size dimensions and will have a different number of cells making up the module/panel.
The shape of the cells can also vary depending on the shape of the original substrate they were shaved from.
Corner cut cells are generally more efficient than full square ones and panels made from half sized cells are using cells that were effectively factory rejects.
340 w of panels on roof of van. 2 x 110a AGM battery's.
and a 3.5kva Genny to cover. tools.
Aircond. Microwave. elect kettle Frypan. breadmaker. etc etc.
Remove genny from equation. and ALL will sometimes fail when sun disappears.
But with sun. my solar ran van. lights. TV, Movies. 240 fans.
inverter microwave for a while through inverter. Water pump.
Basically the van less AC requiring motors.
PS.
I'd double think the idea on "Portable" 160\200a panels.
They both very bulky and fairly clumsy, heavy.
Just get hold of one and walk around with it for coupla minutes.
Drop it\wind push it over once.
you lost everything.
Most fix mounted.
with maybe a smaller one or two mobile for when away fromvan.
hi
Go around 200-300 watts or more on the roof eg 2x 120watts etc . You do loose some sun harvesting power on the roof as they lay flat . Many times u may park in semi shade also .
Portable setup at least 160watt easy for most people to shift and economical to buy .
Always check the open circuit voltage and maximum power voltage, short circuit current and max current output. Not all listing have all the information but generally enough to compare one with another, if there are no panel specs look else where, there is probably a very good reason why they aren't there. For a 12v battery you are looking for an open circuit voltage of around 20v to 22v, a Vmp of 16v to 18v. You may well find that one panel has a much higher short circuit current and or Imp but the open circuit voltage is only 16v or less meaning the Vmp of a cold panel would be down around the 12v mark, useless for charging a battery that needs to see 14.8v or so to end the bulk charge phase. Equally you might see a panel with an open circuit voltage of 32v or higher, a waste of potential charging current with a good MPPT controller as well so then the cost is far higher than the closer voltage matched panel and a PWM controller.
So many catches to watch out for, keep in mind also that there are no MPPT controller under the $1,000 mark (well at least none I know of) that can boost voltage up to suitable battery charging voltage, they can only knock it down from a higher voltage and that uses up some of that solar energy you are trying to collect
T1 Terry
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