A client of mine just asked if I could make up a couple of battery packs for an obsolete unit. Manufacturer does not make them any more and even the third party he got the last batch from does not supply them any more.

He send me the raw batteries (he still could get them) ... 2 volt lead acid D with .187 tabs on the top (like a side on connector).

Long story but to make it fit (very tight package), I see they spot welded a strap across the battery tabs and then folded the batteries on top of one another (to make a longer tube shape) .

Simple enough but I don't have a strap welder.

I tried just soldering a wire across but the solder wicks into the wire (it needs to be very short ... like a 1/2" .. so I can "fold" the batteries on top of each other) and then you can't bend it over on each other.

So, started looking at a battery strap spot welder ... wanted one for myself anyway, I have three cordless tools that need battery packs rebuilt.

WOW ... too many choices! I looked on Amazon ... $30 to $3000!

Can anyone recommend a unit I should look at?

I see some say Nickle only ... some say copper, nickle, steel, ....

Some say 5000 W .. some 15, 000W

Just have never used one and not sure where to begin.

Thanks!

 

A client of mine just asked if I could make up a couple of battery packs for an obsolete unit. Manufacturer does not make them any more and even the third party he got the last batch from does not supply them any more.

He send me the raw batteries (he still could get them) ... 2 volt lead acid D with .187 tabs on the top (like a side on connector).

Long story but to make it fit (very tight package), I see they spot welded a strap across the battery tabs and then folded the batteries on top of one another (to make a longer tube shape) .

Simple enough but I don't have a strap welder.

I tried just soldering a wire across but the solder wicks into the wire (it needs to be very short ... like a 1/2" .. so I can "fold" the batteries on top of each other) and then you can't bend it over on each other.

So, started looking at a battery strap spot welder ... wanted one for myself anyway, I have three cordless tools that need battery packs rebuilt.

WOW ... too many choices! I looked on Amazon ... $30 to $3000!

Can anyone recommend a unit I should look at?

I see some say Nickle only ... some say copper, nickle, steel, ....

Some say 5000 W .. some 15, 000W

Just have never used one and not sure where to begin.

Thanks!

Can you share some photographs of all this?

 

A spot welder is the right way to do this but...

You can solder the nickel strips used for spot welding which will not take up the solder.

Drill a small hole (about ⅓ the width of the strip so you can have the solder flow to both sides of the strip and heat it more easily.

Are these Cyclon cells?

 

Can you share some photographs of all this?

A spot welder is the right way to do this but...

You can solder the nickel strips used for spot welding which will not take up the solder.

Drill a small hole (about ⅓ the width of the strip so you can have the solder flow to both sides of the strip and heat it more easily.

Are these Cyclon cells?

Wow ... yes they are. I had not even looked at the name on them!

The pack fits an old PLC .... the plc's are going to be changed out in a year or two but for now they want to keep them going ... which means keeping a good battery in them.

I just posted a few pictures.

Thanks

 

Can you share some photographs of all this?

Really a very simple project. Just have never had a spot welder before.

 

Really a very simple project. Just have never had a spot welder before.
View attachment 360772View attachment 360773

Wow, I've simply never seen lead acid batteries that small, very unusual.

But I see no reason why soldering isn't sufficient, no need to actually weld (welding involves actual melting of both parts to be joined).

 

Wow ... yes they are. I had not even looked at the name on them!

The pack fits an old PLC .... the plc's are going to be changed out in a year or two but for now they want to keep them going ... which means keeping a good battery in them.

I just posted a few pictures.

Thanks

Cyclons are really good cells. Try are spirally constructed and have really impressive specs. There is a good chance the packs being replaced can be recovered with close to original performance with some clever charging.

That said, If you buy a well reviewed spot welder in the ~$300 price range it should handle the job. The biggest problem you will have is dealing with thicker metal, so measure the thickness and be sure it falls within the manufacturer‘s specs for the welder—preferably not close to the top end.

 

Going way way back to the early 80's I could swear I came across some batteries that looked exactly like that. I can also swear they were "Mercury" cells. I had never heard of such a thing. And the ones I came across were dead. I tried to charge them but made a potentially disastrous mistake. However, that mistake, which I won't share, ended up charging the batteries. While playing with them I accidentally shorted the battery and the wires welded themselves together and the battery got very hot very quickly. I was fortunately able to pull the wires apart. It was then that I decided I shouldn't be messing with those batteries - the ones I came across that look a lot like the ones pictured.

 

The nickel strips can be soldered. Give the area to be tinned a good scrubbing with medium (80) sandpaper. Then rub the tip of the iron over it as the solder is applied. Once they are tinned they can be soldered onto the battery terminals. I used to use this method successfully for years to make up nickel-cobalt battery packs to power my large 400W R/C planes.

 

caution!! When soldering to batteries it is easy to melt the end seals. The batteries die within a couple weeks.