I have a bike light thats a few years old (8?) that needs a replacement battery pack which is no longer sold. I was able to disassemble the battery pack and buy new cells. There are a couple of steel strips which connect the batteries to a small circuit board that appear to be my main obstacle to assembling this. How annoying is it to solder or otherwise make an electrical connection to steel? If its not that bad then I should be able to get this working pretty quickly. I know I've tried in the past but my technique might have been lacking.

---

Shouldn't harder than anything else? Is there a good mechanical connection?

It has been ages since I've had to solder anything, but if memory serves correctly different metals or combinations thereof can require specific types of solder for the connection to remain solid.

---

WARNING- If I posted a link in the above message, assume it is at minimum "NSFW- Language". Occasionally you'll be wrong.

Lie to me if you must, but don't lie to me and insult my intelligence in the same sentence.

Resist the Thought Police: George Orwell's book 1984 was meant as a warning, not an instruction manual.

"Political correctness is just intellectual colonialism and psychological fascism for the creation of thought crime" - Steve Hughes

What's my "Super Power"? I can make active threads go stone-dead with a single post. I try to use this power only for good and not for evil but, you know... stuff happens.



Edited 1 time(s). Last edit at 08/26/2021 11:50PM by Thrift Store Scott.

Quote
anonymouse1
Shouldn't harder than anything else? Is there a good mechanical connection?

no, and bikes create a lot of vibration

---

For me, when all else fails, silver solder with separate flux. And you can use wire instead of the steel straps. They use a spot welder probably to assemble them originally.

---

********************************************
“A sword never kills anybody; it is a tool in the killer's hand.” Seneca the Younger

The police have no duty to respond. See Castle Rock v. Gonzales, 545 U.S. 748 (2005) or Warren v. District of Columbia[1] (444 A.2d. 1, D.C. Ct. of Ap. 1981)

Judge Lee wrote that “we cannot jettison our constitutional rights, even if the goal behind a law is laudable." 9th Circuit Court of Appeals

[www.youtube.com]

macphanatic asked about this two months ago. Maybe send a PM... [forums.macresource.com]

There are a couple of different ways to make the connection. The easiest is buy a spot welder but the decent ones are $300 - $400. Bez-azon has a bunch of battery powered models for around $60 but I have never tried one.

Silver solder and paste does work but it can be frustrating if you don't have the temp just right. I found it works a little better if you almost clog 800 grit WetOrDry sandpaper with a copper penny, then use that on both sides of the metals to be bonded. Flux, then tin each side with solder, then solder together.

---

In tha 360. MRF User Map

What they all said, but after ascertaining the right solder/flux combo, if you decide to use the strips, sand 'em and clean 'em good first.

Good luck, and enjoy.
==

Look up Jehu Garcia on YouTube. He rebuilds and reassembles battery packs for EVs and DIY power walls. He talks about making the connections occasionally. I believe it is more of a spot weld than a solder.

---

**************************************
MacResource User Map: [www.zeemaps.com]#

[youtu.be]

---

**************************************
MacResource User Map: [www.zeemaps.com]#

I've tried something like this. No amount of sanding/flux could get the wires to stick. It was very frustrating.

So, I took the batteries to a shop -- I think it was "Batteries Plus" -- and the guy there charged me a modest fee to do it. They had a machine for it. Took a few seconds for him to set it up, pulled a lever and the job was done.

---

I have done this by drilling a small hole in the bus strip to give a mechanical advantage. But I second the Batteries Plus guys... spot welding is so much better.

Soldering batteries is not recommended. The duration of heat needed isn't good for the batteries. Spot welder is the way to go. Unfortunately, I didn't pursue this further due to other more important things to deal with.

cbelt beat me to it. What I've done a long time ago was to drill holes, wrap copper wire through the items to be soldered, and use that as a really good conductor and a solderable bond to augment the lack of a spot weld. It held, really well.

Quote
cbelt3
I have done this by drilling a small hole in the bus strip to give a mechanical advantage. But I second the Batteries Plus guys... spot welding is so much better.

---

Good Luck!
Jamie Dresser
Other World Computing

See if you can rent or borrow a spot welder and do this right.
Or just buy an entry level model. Used us fine.
Then you can rebuild battery packs for friends.
You will be a hero.

Soldering batteries is not recommended. The duration of heat needed isn't good for the batteries


Exactly.

I've soldered leads to battery packs with a gun, not an iron, for the quicker, higher heat, while using a pair of needle nose pliers as a heat seat.

As soon as I got a good solder joint, I immediately cooled the connection as should as the solder set.

If you get a bright shiny solder joint, you're golden.

If you get a dull, almost gritty joint, it's a cold solder joint and will separate with almost any strain on the wire(s).

Drilling a hole is a great idea.

It's the wire that's being soldered, not really the battery tab.

A cold solder joint isn't too critical in that scenario, but make a good one is always best.

---

I am that Masked Man.

All you can do, is all you can do.

There’s trouble — it's time to play the sound of my people.

Your boos mean nothing to me, I've seen what you cheer for.

Insisting on your rights without acknowledging your responsibilities isn’t freedom, it’s adolescence.

I've been to the edge of the map, and there be monsters.

We are a government of laws, not men.

Everybody counts or nobody counts.

When a good man is hurt,
all who would be called good
must suffer with him.

You and I have memories longer than the road that stretches out ahead.

There is no safety for honest men except
by believing all possible evil of evil men.

We don’t do focus groups. They just ensure that you don’t offend anyone, and produce bland inoffensive products. —Sir Jonathan Ive

An armed society is a polite society.
And hope is a lousy defense.

You make me pull, I'll put you down.

I *love* SIGs. It's Glocks I hate.

Connection points MUST be CLEAN before you start!

You might try a Dremel tool with a wire brush wheel and maybe some automotive spray BRAKE CLEANER wiped off with a CLEAN rag, paper towel or possibly compressed air.

As mentioned, if there's a place nearby that can do true spot welding, start by talking to them and pick their brains for what they'd recommend. I've heard that some cities have "clubs" where hobbiest / inventor type people can pay to use the "club" facilities, equipment and generally get help / advice from club members.

Another possible source could be commercial TOOL STORES. These places usually cater to professional tradesmen. Such stores supply the pros with PRO GRADE tools AND SERVICE (such as rebuilding / refurbishing tools). If there's such a store is anywhere close to you, you could inquire if they could do what you need (or get a referral if said business doesn't do what you need).

Final thought. Send an email to "ifixit". They have all sorts of online tutorials and although I don't remember seeing what you're looking for on the ifixit site, the folks their LOVE to repair and recycle. I'd be amazed if somebody at ifixit can't recommend how you can successfully achieve your goal.

You can buy cells with tabs attached

My soldering skills are most excellent.

I gave up on rebuilding batteries years ago.

Spot weld or trash it.

---

Staunton, Virginia

Quote
space-time
You can buy cells with tabs attached

Attached tabs can be steel or nickel, depends on the supplier. A bit easier soldering to nickel, but not as easy as to copper.

Soldering to the tabs of cells is fairly easy to do at home.

The problem with soldering directly to cells without tabs is the battery acts as a heat sink, and you won’t get a good solder joint. That’s why spot welding is recommended when connecting directly to cells.

[www.amazon.com]

Quote
mattkime
I have a bike light thats a few years old (8?) that needs a replacement battery pack which is no longer sold. I was able to disassemble the battery pack and buy new cells. There are a couple of steel strips which connect the batteries to a small circuit board that appear to be my main obstacle to assembling this. How annoying is it to solder or otherwise make an electrical connection to steel? If its not that bad then I should be able to get this working pretty quickly. I know I've tried in the past but my technique might have been lacking.

What type of light is it, just fwiw?

Lezyne deca drive

---

Sweet light! I can see why you would want to replace the battery. You probably saw it already, but would this work?

[www.mtbbatteries.co.uk]

I've got an old cygolite (my favorite light) that could use a new battery. Hopefully they still sell the replacement, but if not I'll be doing something similar. This battery thing is very tricky though.

[support.lezyne.com]

Soldering to the tabs of cells is fairly easy to do at home.


All true.

The problem with soldering directly to cells without tabs is the battery acts as a heat sink, and you won’t get a good solder joint. That’s why spot welding is recommended when connecting directly to cells.


matt mentions there were steel straps still attached to the cells, which I would expect of cells in a battery-pack.

Those may not be as easy to solder to as cells manufactured with such tabs, but it's doable.

But if spot welding is available and reasonable, that's how I'd roll.

---

I am that Masked Man.

All you can do, is all you can do.

There’s trouble — it's time to play the sound of my people.

Your boos mean nothing to me, I've seen what you cheer for.

Insisting on your rights without acknowledging your responsibilities isn’t freedom, it’s adolescence.

I've been to the edge of the map, and there be monsters.

We are a government of laws, not men.

Everybody counts or nobody counts.

When a good man is hurt,
all who would be called good
must suffer with him.

You and I have memories longer than the road that stretches out ahead.

There is no safety for honest men except
by believing all possible evil of evil men.

We don’t do focus groups. They just ensure that you don’t offend anyone, and produce bland inoffensive products. —Sir Jonathan Ive

An armed society is a polite society.
And hope is a lousy defense.

You make me pull, I'll put you down.

I *love* SIGs. It's Glocks I hate.