DIY Battery Spot Welder - Update & Demonstration

I've created another video go explain my DIY spot welder and to cover a lot of the most asked questions I've been getting on previous videos and dispelling solve of the myths surrounding this method of spot welding.

**Nickel Strips**

**Solenoid Relay**

**Choc Block (Electrical Connector)**

**Copper Nails**

**Heavy Gauge Cable**

**Momentary Switch**

[The-Advent-Sabre]

You sir have just built a time machine! Here's why. Surfing my way through Youtube, this very video comes into play... within minutes i'm going back in time watching my dear old Granddad build something almost identical. He was an electrical engineer working for the Fawley Power Station. He would make battery packs for stuff he needed at work (No I know they weren't lithium modern stuff) but he also used a much bigger one to spot weld panels for heat shielding. SO on this particular day I was with him in his workshop, when suddenly he exclaimed to himself he needed to spot weld the panel seams.. I had no clue of course what the hell he was talking about as I was only 10. I then, with great interest watched him MacGyver two huge truck batteries with wires and big copper prongs, a few other bits and bobs bolted here and there and within about an hour he was spot welding panels together.
This video just sent me back to a fond memory of my Granddad, and his wisdom and sheer ingenuity and resourcefulness.
Thank you.

[JerrySmiler]

I would just like to thank you. I was given an old ebike that would not charge. The cells had been left for years and had discharged beyond repair. To get a new battery would have cost me nearly £500. I watched a couple of YouTube videos including yours. I purchased new cells for just over £100 and made this spot welder. Today I set about dismantling and rebuilding the battery pack. Hey presto I now have a working bike. Thanks again.

[bobcoburn]

Wasn't gonna make my own batteries because I couldn't be arsed soldering and couldn't afford a welder. Thanks to this video I think I'll give battery building a go as this seems pretty simple and cheap. Thanks man.

[viktorspeiser]

Thank you man, I was on the edge of buying one for a fortune, now I am making a parts list! Wonderfull work, great explanation. Not the fist video of your's I have seen, but this earnt my sub.

[acmehighperformance]

i love the job youve done. im copying it to lern the skill now. i have a tip for ya. im a mechanic. the relay may eventually fail and one of the failure modes is thermal runaway. on my nearly identical system ill build tomorrow ill put a 5.00 dorman 140a fuse between the battery and relay. those things save me on truck systems often behind a relay. cheers and thank you. i did subscribe!

[handyhippie]

this is the simplest, most effective spot welder, and explanation video of how it works, i've seen. good job, and thank you.

[phoobar]

I used the battery out of my car and an old motorcycle solenoid. It literally took 15 minutes to build. Mine's not as clean looking as yours, but it works.
Good stuff.

[stanleytolle]

I would make sure you have a good battery. I was working as a mobile auto mechanic and a older woman called to her house because her car would not start. I stopped by and her car was in her open garage. Now the hood was closed and I did not see any charger around. She told me she tried to start the car several times that morning but it would not do anything. Hearing this I decided to confirm the failure by trying to start the car myself. With her standing by the car and myself in the driver's seat I turned the key attempt to start. Instantly a big blam, dent in the hood, acid fumes coming out from underneath the hood and luckily the hood didn't open. Luckily she was there to see it or I think I would have some hard explaining to do. Yes I never seen anything like that before or after. I asked if she charged the battery before I came but she claimed she did not. After hosing out the engine compartment I removed the battery and replaced it everything worked fine, no overcharging or anything. All I can say is make sure you have a good battery and that if it is not sealed type, has water in all it's cells, has not been changed for several hours, you should be safe. Also have the battery tested too. Never figured out why that battery exploded or why it did not for the older lady.

[NJmalibu]

Thank you for explaining this man! Im learning more about this stuff everyday, and wanting to make a alternator motor ebike/cycle using a ford 3g alternator (130amps) that ive had laying around for years.
Ive got experience building 4 stroke gas motors and bikes (welder by trade), but wanting to get into electric power.
Im wanting to build everything including battery, and found your video here. Thank you for going over everything for electric dummies like myself. I have an understanding of starter solenoids from being a backyard mechanic, so this makes perfect sense.
Ive even used a spot welder over the years being a welder, but never anything this small. Awesome!

[bobhong]

Thank you very much! I had watched several YouTube clips on this topic, none of them provided good explanation like you did.

[adriang]

I was about to buy a spot welder from China when I found this video, instead of spending £150 I built one of these using a spare car battery and other bits sitting in my garage. Total cost was about £30 and it works perfectly :-). My battery is a Ford OEM brand rated at 700CCA and i bought a 500A solenoid (same as the heavy duty one in the link). I tried .3mm nickel strip but it was a bit too thick, 0.15mm works perfectly and gives good, strong welds. Thanks for sharing :-).

[DJBelbe]

Love U man!!! Just gave this a try this eve with a 19€ bike selenoid, half dead pickup truck battery and junkyard cables and switch! Had a dead Dewalt battery lying around for ages with 3 new cells waiting to replace the fryed ones cos a spot welder costs a fortune! Well, with 30€ and your blessed genious I saved a 120€ battery in a single eve.
Jollyest hollidays friend! <3

[powerbatterychannel]

I suppose, this is the best and the most reliable solution I have ever seen. Great job!

[handyhippie]

i made one of these from a 230cca. mower battery, a ford starter solenoid, a 4 ga. battery cable, a momentary push button, a plastic connector block like he uses, and 10ga. single strand copper wire for the contact points. all of the parts except the connector block were used and i had on hand, so total cost for me was about $10 for the connector block with shipping. it works great, with no issues, and i've been using it for over a year. this is the best design i've ever seen. i just quickly tap the button like he does, and presto! a functional weld.

[alapon]

This worked out very well for me, THANK YOU. Believe it or not, 2 of the 3 solenoids I tried out, didn't even work, so definitely make sure those are working before giving up. What's really important that I would add here is that you have to have the terminal connectors clamped down very TIGHTLY, otherwise the solenoid will seize (not permanently). A lot of us are comfortable using vice clamps but BE CAREFUL - because if you have two (oppositely charged) metal vice clamps sticking up in the air next to each other, that's an opportunity to short the battery while un-clamping and get the $#!+ shocked out of you. Also there is some chatter about using a timer relay switch. Don't bother. The quick tap is all you need as long as the CCA isn't too high (mine is 340). I've also learned that arc-ing is a common problem, resulting in burning through the nickel. This is usually because there is a gap or some 'air' beneath the strip. Two fixes for this is to make sure that your nickel strips are perfectly flattened and to put extra pressure on the offending lead.

[aswingsharif]

Lots of information before I start to build my own lead acid-solenoid-push on button SIMPLE YET EFFECTIVE SPOT WELDER ! Thumbs up!!

[mp]

You have explained everything perfectly I’m a trained electrician I love the spot welder kind regards liked and subbed

[szentmihalyiautodiagnosztika]

Your DIY is the most convincing spot welder tutorial on youtube ( I have not found anything better and easier to make). I am still waiting for 4 weeks to crate a suitable one. I have tired with a 45Ahm car battery but the amperage was too much, I have also tried with a motobike battery 12v, 5 Ahm and that welding was quite poor.
Now I am waiting for a higher amperage motobike battey ( about 7-10 Ahm).
I am about to make an e-bike battery pack for my Bosch 36V bike and can`t wait to have it ready in the meantime gathering old laptop batteries.

[inso]

Are you still using this spot welder?
If you do and the design hasn't changed since this video, I have some tips for you.

- those two electrodes should be separated. Applying pressure separately gives you much more consistent welds and eliminates sparks, which appear when there is not enough surface touching the nickel stripes.
- make those electrodes thicker with roundly pointed edges. I use 5 mm copper rods, point them with a grinder and make the ends nicely round with a file and sandpaper. The ends should be about 1.5-2 mm in diameter.
- as for the timer controller I recommend XY-LJ02. Shortest pulse time you can set it to is 1/100 of a second (10ms). The one you showed isn't very useful, because the shortest pulse time is 1/10s (100ms) which is far too long and it burned through my cells.
This way you'll have a very efficient heat transfer interface (thick electrodes) and a big contact surface (rounded pointy ends), which when used with equal pressure (sparate leads) will give you almost perfect welds.
Well, they will never be perfect, because 12V is a bit too much for a spot welder, but they will be consistent at least.

[richardingle]

You sir ...are a bloody genius and true to British inventors of the past ...just ordered all this on Amazon...I have so many projects waiting for a welder which are to expensive and yours is so cheap and easy to build ...thank you from me and all the happiness my projects will bring now i can make the packs 😀👍