Spot welder wanted (buy or rent)


Apr 27, 2020
I haven't been on here in a while, but I've got the desire to make a single spot welded connection.

It's not actually on a battery, but the back of a solar panel. It has what looks like identical nickel strips with a failed connection that I'd like to weld back together.

If you've got a welder you'd part with or rent out, it would be much appreciated.
Hi 400bird
When do you need the spot welder? I have an old Malectrics spot welder that worked last time I used it. I could meet you in Lodi anytime that works. From what I know about solar panels which is not much I think they use or used to use silver solder(braze) to join the traces. The spot welder should be able to spot weld it if nickel and most likely if it is silver solder. It is yours if you want it.
later floyd
The only big change to the one that italianuser mentions is that you should power the board separate from the welder source. I don't understand why, maybe it's the capacitor not big enough or something, but the board can reset between welds. This happened to me, and after giving it a dedicated power supply, no more issues
I should have posted this pic the first time through. Looks to me like they forgot this joint or the weld failed.


Thanks to a very kind member here (you know who you are and thank you!) I was able to get a spot welder to fix this panel.

I cut back the white back sheet a bit more to get some insulation behind the strip.
In the process I found another spot that either wasn't welded or the weld failed.

It's about 3 times thicker than the nickel strip, and I couldn't get the 3s lipo to work.

So, grabbed a car battery, some extra heavy cables (3/0) I had laying around and I still had to really had to crank up the weld time, I ended up at 50ms.

It looks like it worked!
Tests good, but I blew up the 25 watt resistor I had used for my testing. Big surprise 🙄 the 325 watt panels heats up a 25 watt resistor pretty quickly.

I'm working on something to prove out that it works, but my Solar Edge inverter requires Solar Edge optimizers and I don't have any spares.

I've got a separate solar charge controller I could use, but this panel is rated at less than 48 volts and the panels in the charge controller are significantly higher ratings.

All prepped for welding

After the spot welds

Now I just need to decide what to water proof it with.
There are a couple threads here on repairing solar panels i will see if I can find them.
here is one.
the welds look good but also looks like rust in the welds which wouldn't be good. Hopefully it is just the pic or my eyes playing tricks on me.
later floyd
Thanks for the eagle eyes. The strips appear to be copper coated in something, my sanding/welding exposed the copper core. I don't think it's rust. I agree, that would be bad.