DIY lithium battery cell replacement

[JOEPRO]

I won this as new condition Stihl battery leaf blower on fleabay for £30. Problem is the charger charges by LED indicator but the battery holds no charge. Replacement Stihl battery is £100.



Am I going to die if I try this method?

Aka carefully trim the plastic away from the old cells. Then cut the tabs and remove them. Order new matching replacement cells on ebay and replace the cells myself to repair it.

I already have a Stihl petrol leaf blower. I think this smaller battery one is bound to be handy to help dry a car after washing.

 

[dobbslc]

Have you checked the voltage of each individual cell yet?
It might not be a bad cell but problems with the electronic gubbins.

 

[Migmac]

I use solder when I’m doing batteries, Stihl here
I was given a hedge trimmer with the same internals, internal battery is a crap idea on a tool that doesn’t get much use.

 

[Stupoty]

I revamped my old lidl led work light that had a cell go bad , only issues you might ruin into soldering wires is the cable being a bit chunky for the enclosure. the flat conductor strips are very space efficient

(use flux , more flux and more)
(also a very high power soldering iron will alow you to get it soldered quickly)
Stu

 

[voipio]

If the plan is to do quite a few battery pack replacements in the future, it might be worthwhile getting a spot welder for putting solderable conductor strips onto the cells, or to join cells together. Spot welding puts far less thermal stress on the cell internals.

 

[RWD3M]

I won this as new condition Stihl battery leaf blower on fleabay for £30. Problem is the charger charges by LED indicator but the battery holds no charge. Replacement Stihl battery is £100.

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Am I going to die if I try this method?

Aka carefully trim the plastic away from the old cells. Then cut the tabs and remove them. Order new matching replacement cells on ebay and replace the cells myself to repair it.

I already have a Stihl petrol leaf blower. I think this smaller battery one is bound to be handy to help dry a car after washing.

Before you go to those lengths, you may be able to recover the cells without replacing them.

I've managed to save a couple of battery operated tools by charging the cells directly for a few minutes before reconnecting the charger.

The problem is (often) that the battery goes so dead, that the charger can't see it so therefore, won't charge it.

I'll have a dig about to see if I can find a YT vid (unless Gaz beats me to it! ).

There are tons of vids like this one:

 

[frank horton]

BLOW UR CAR DRY after washing.....!!!!!!!!!!

 

[julianf]

I got a spot welder from Ali express (as recommended by YouTube!)

It died after a single weld.

I read up a bunch, and bought another, powered it by a much larger power source.

It also died.

I gave up after that. I have all the parts for a m18 battery, but I wasn't keen on soldering the batteries.

 

[Chippie]

Soldering directly to the ends of the cells can damage the seals…if you didn’t already know this…

 

[voipio]

I got a spot welder from Ali express (as recommended by YouTube!)

It died after a single weld.

I read up a bunch, and bought another, powered it by a much larger power source.

It also died.

I gave up after that. I have all the parts for a m18 battery, but I wasn't keen on soldering the batteries.

Hmmm. So the cheapie spot welders are not so good, then! The reviews on Amazon seem mixed, at best.

 

[bricol]

BLOW UR CAR DRY after washing.....!!!!!!!!!!

WASHING !!!!!!

 

[bricol]

Soldering directly to the ends of the cells can damage the seals…if you didn’t already know this…

Used to do with a massive thermal store iron of my dads with nicad packs for model cars in the 80's with no particular problem. Lithium ones now I might think rather more than twice about.

 

[tigdlo]

If you can live with 2ah, lidl and aldi batteries are cheap, the cells are already connected and you would only have to solder to the nickel strips.

Shame the motor control and battery management appears to be all one board as an external adapter for whatever 18v batteries you already have wouldn't be a bad option.

 

[JOEPRO]

BLOW UR CAR DRY after washing.....!!!!!!!!!!

Is this question?????????????.......

 

[JOEPRO]

Soldering directly to the ends of the cells can damage the seals…if you didn’t already know this…

The more.immediate concern I has was the potential for them blowing up. I presume it they don't explode then you're golden

 

[julianf]

Hmmm. So the cheapie spot welders are not so good, then! The reviews on Amazon seem mixed, at best.

I got the red one that's supposed to be on if you give it enough current.

It was not.

 

[optima21]

if you do the soldering the Li-ion cells correctly the joints are cool enough to touch after a couple of seconds. I use a 50W antex temperature controlled iron and 3/16" bit

 

[Barking Mat]

I tried soldering batteries like that, total failure.

Think the battery became a heat sink, and the solder and wire never attached, then I gave up.

 

[Kram]

The risk of delayed fire is enourmous if you do it wrong. "Reviving" a cell by forcing a charge into it, bypassing a chargers safety precaution is a bit like pouring a couple gallons of petrol into a dish washer before using it overnight as a parts washer. It may work, or explode in a fireball while your sleeping.

Quaranteen the pack in a safe area initially and for a few days after a sucessful full charge.

All I would try is to use a proper lipo charger to check and individually charge each cell without disconnecting from the pack.

 

[JOEPRO]

All I would try is to use a proper lipo charger to check and individually charge each cell without disconnecting from the pack.

I figure since the cells are spot welded in series I cannot individually charge them? Or how is that done please?