Need an opinion from those of you familiar and maybe not so familiar with the subject. I have remote property (BOL) with a small solar site, 6 panels 158 W each. A local electronics surplus reseller here in the Big City has a bunch of 230 W Canadian Solar panels used for $99 ea. These are the older Polycrystalline (about 15% efficient) type somewhat less efficient than the newer Monocrystalline (about 18% efficient), but the BOL gets lots of sunny weather. I'd probably need to build new racks, or at least add more mounting surface to the existing ones, which, with the purchase of some angle iron I can do and have done. The rest of the system could easily handle and use the increased power output as it is 24 volt with an Outback FM80 MPPT type charge controller. Could eventually go with 48 volt by changing the inverter and rewiring the battery stack. Presently running two strings of 4 GC-2 type flooded batteries that are supposed to have been designed specifically for solar use. So, question is, given the fact that the solar panels appear to be in good condition physically, not beat up and the cells aren't turning brown, do you think it's worth purchasing them for $99 ea? Also considering making an offer to see if they'll wheel and deal for a lower price on the purchase of say, 8, 10, or even 12 panels.
My 2 cents: Might be worth it, but at 43 cents/watt, it's not much of a deal over new ones. They would have to do a lot better on price for me to consider them. Solar Panels - Prices Another thing to be aware of, Canadian panels I've run into use a proprietary connector instead of standard MC4 on their cable ends.....you might price in the cost of connector cables. Personally, I just cut them off rather than be held hostage to that crap, and use a #10 crimp on connector with heat shrink sleeve and tape over the top of it, but I don't think that meets code.....which may or may not matter to you. I'm sorta code flexible myself......
Older panels can suffer degradation due to age and exposure. I'd like to know the history, and possibly test a couple of them before plunking down my bux.
Take a good battery with you and test each panel. If you don't have a DC amp meter own one, I prefer the clamp on type. In the day I got started back in the 80s I paid $100. an amp for any thing I could find new or used, mostly used. I have old ARCO panels still giving service.
Mixing panels on one charge controller is tricky . You have the specs of your six panels ? its the sticker on the back side , and also the CS 230 sticker is needed to see the voltages and ratings to see if matching will work. FM80 handles 4000 watts max but over panelling will not hurt . at 48 Vdc harvest is the best , lighter wire , and before you add to the system the FM 80 will change up on the reboot ,batterys in one string , .. CS use Mc4 ends since 1995 and later.. To check ANY solar panel ,all is needed is a DVM on a 10 amp scale (if panel can put out more than 10 amps , internal might blow)..put DVM in series with output panel wires , (makes no difference on the polarity ) hook up all connections with panel away from sun and not making power. I use MC4 modified ends for this , has no locks on the ends i made , ground them off ,and just 10 gauge wire tinned pokes out is where my DVM alligator clamps to. now face the panel to the sun as it hits right at the sun amps should be almost to the ISC spec on the sticker . Sloth I is amp sc is short circuit =Isc Edit add !! Make no connections or break connections when in full sun !! Sparks will happen and the MC4s could be damaged!! I turn panel away and shade it ,alligator clamp is removed from Mc4 and now the short is broken , now when seporating the MC4 no chance of a spark/arc welding !! On voltage readings they can be in sun , but here were seeing if amps can be made .. S
Check the max voltage specs - some panels cannot handle being in strings for 48+VDC... Ditto on the connectors, what current rating do the connectors have? Or, as mentioned, you could replace those...
I wouldn't mix the panels. Any new or used panels I get would be a complete set replacement. I'll use the "old" set of solar panels in some other application, probably on a solar well pump or on my old solar site which is semi-portable and has only a small wind generator keeping things topped up. I have a Fluke DMM with AMP function and you're right it's 10 A Max. Yes, I've forgotten when it's in the current measuring mode and tried to check voltage - ended up replacing the fuse. Usually realize what I did about 2.3 seconds after I did it and then stop talking to myself for a few days. The replacement fuses are about 10 bucks. Good point guys on the MC4 connectors. Didn't see what they were using so just assumed they were MC4. My guess is that they are but you never know without looking. I deliberately shorted the leads on another array a few years ago just to see what would happen. They were connected in series and the open circuit voltage approached 180 VDC. The resulting arc was impressive and those were only 50W panels.
Good point on the Price per watt TnAndy. I hadn't realized the the price per watt had dropped so dramatically since the last time I purchased new solar panels. When I bought the present ones back around 2014 or so, got a great deal at $1.15 / Watt which included the cost of shipping. New ones are a bit more efficient since it seems most are monocrystalline. I may eventually want to meet code, but for now I too can be "flexible" since the BOL is in a place where few two legged critters tread, birds being the main exception. I'm sure the rest of the site doesn't meet code. But it won't catch fire or electrocute anyone unless they really work at it.
Post sticker on the back , then were in the KNOW , other than that were all just guessing at out comes . Sloth
Explain this testing for me plz , I know your using a Amp clamp , DC one I hope , most are AC . Clamp on are close if they are tested and zeroed in .The Craftsman one is nice but is off by 5% some days , the others are from my oscilloscope that reads in Picos . Whats the battery for ?Load ? ISA is shorted , max load . If good battery is fully charged and your testing a low voltage panel 60 cell type thats rated at 18-22 VDC whats the amps going to show on a battery at 13Vdc (charged ) ?? This is where im having a trouble to understand to find out if the max out can be obtained ? Sloth
