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Topic: Fixing solar panels, I did something stupid (Read 93 times) previous topic - next topic

Fixing solar panels, I did something stupid

Every once in awhile I do something really dumb.  Yesterday was one of those days.  I was hooking up a solar cattle water pump system in a hurry, and hooked 24v batteries up reverse polarity straight to the solar panels.  Wow, it's even more stupid when i write it.  There was some bad noises and escaping of magic smoke.  I think i blew up all the bypass diodes in the panel.

The pump control box has the same mc4 connectors as the solar panels, so on a battery system, there are leads that go to battery with mc4 plugs on the end.  That's how it happened. 

I'll try digging in to the diodes in the next few days.  I remember sparweb had a great post back in the day about fixing panels by replacing diodes.  I have done about 4 panels since then with a 100% success rate.  Hoepfully this one goes well too. 
 

Re: Fixing solar panels, I did something stupid

Reply #1 –
My buddy Pierre will be pleased to hear that - about the repair, not the damage of course.
He's really keen on this, like right-to-repair and preventing these things from going to scrap.
I now have a whole bunch of panels that he picked up free and gave to me. More than are actually installed on my garage.
6.5 kW PV solar array + 12k Sol-Ark Inverter
10ft (3m) diameter custom-built wind turbine

Re: Fixing solar panels, I did something stupid

Reply #2 –
No pictures because I can't seem to resize them right now.  The fixing went great again.  This was a 290w Silfab panel and all 3 bypass diodes were very smoked.  The cases were cracked.  4v open circuit when I started. The nameplate says 39v should be voc. 

Oddly enough, the diodes just clip in on these.  No soldering required.  I even had diodes in stock because i have done these before.  The tough part is cutting into the plastic box where the diodes are, and chipping out the silicone in there.

After i clipped new ones in, i siliconed the box back shut with grey rtv silicone gasket maker (because i had one open) and it had exactly 39v in the sun.   I haven't actually hooked it up yet, but I'm sure it will work. 
 

Re: Fixing solar panels, I did something stupid

Reply #3 –
Quote from: bigrockcandymountain – on
No pictures because I can't seem to resize them right now.  The fixing went great again.  This was a 290w Silfab panel and all 3 bypass diodes were very smoked.  The cases were cracked.  4v open circuit when I started. The nameplate says 39v should be voc. 

Oddly enough, the diodes just clip in on these.  No soldering required.  I even had diodes in stock because i have done these before.  The tough part is cutting into the plastic box where the diodes are, and chipping out the silicone in there.

After i clipped new ones in, i siliconed the box back shut with grey rtv silicone gasket maker (because i had one open) and it had exactly 39v in the sun.   I haven't actually hooked it up yet, but I'm sure it will work.

Note: If your silicone smells like vinegar when curing it is NOT for use on electronics! It will dissolve enough metals to cause issues. Stuff is corrosive. I have ran into gasket maker that was acidic and some that isn't in a different brand so a nose test is in order!

Re: Fixing solar panels, I did something stupid

Reply #4 –
Quote from: MaryB – on
Note: If your silicone smells like vinegar when curing it is NOT for use on electronics! It will dissolve enough metals to cause issues. Stuff is corrosive. I have ran into gasket maker that was acidic and some that isn't in a different brand so a nose test is in order!

I have personal experience with this, too! 
Had a customer bring a storage box that they wanted a customized mount built for, to attach to the belly of a helicopter.  We did the custom-mount, tested the installation, called it good.  Well they must have had some water get inside because later they sealed all the edges with caulk without calling us.  Then a guy from Transport Canada came to inspect, opened the case, and they were grounded.  The box was horribly filled with corrosion, and you couldn't get within 10 feet of it without gagging.
6.5 kW PV solar array + 12k Sol-Ark Inverter
10ft (3m) diameter custom-built wind turbine

Re: Fixing solar panels, I did something stupid

Reply #5 –
Now i need to go smell my silicone.  That's good to know and I'm grateful for the advice.   The panel is still in the shop so it won't be hard to rectify if it is the wrong stuff.

Re: Fixing solar panels, I did something stupid

Reply #6 –
Quote from: bigrockcandymountain – on
Now i need to go smell my silicone.  That's good to know and I'm grateful for the advice.   The panel is still in the shop so it won't be hard to rectify if it is the wrong stuff.

I have seen ham radio operators use it to seal coax connectors... when they peel it off because the antenna quit working the metal is literally dissolved, turned into something nasty and non-conductive. Even using it to seal the lid on a box of electronics is bad news, the acetic acid fumes get inside and eats the copper off circuit boards!

Re: Fixing solar panels, I did something stupid

Reply #7 –
I'm pretty sure it is ok the stuff i used.  It says "sensor safe" and smells rubbery, not like vinegar. 

Permatex ultra grey rtv gasket maker i think is what it was.  I know the orange stuff smells like vinegar, but this stuff did not. 

Re: Fixing solar panels, I did something stupid

Reply #8 –
For many years I've been using Permatex anti-sieze compound on parts (bearings, shafts) and it seems to work really well.  Even bare steel parts, out in the elements for years, come back in with no rust.  Mo more than they went out with, I should say.

One thing I've noticed is that this substance doesn't exactly wipe off, or go dry.  If you wipe it, you just make the coating a bit thinner by applying it to the other surface that wiped it.  Only when you apply solvents can you get it off.  This applies to metal parts, and your hands, clothes, face, etc.
6.5 kW PV solar array + 12k Sol-Ark Inverter
10ft (3m) diameter custom-built wind turbine