Any hope for dead Lith-Ion batteries

[Bill G]

I have some Milwaukee lithium-ion batteries here that went to hell right away. They sat here a long time so there is nothing the company can do. Is there any hope for them.

 

[Woodwackr]

I have some Milwaukee lithium-ion batteries here that went to hell right away. They sat here a long time so there is nothing the company can do. Is there any hope for them.

Not really

 

[Wilhelm]

Three scenarios with so called dead battery packs:

- they got depleted then not charged, they further self discharged and now the safety circuitry (in either or both battery pack and battery charger!) does not permit charging - often the pack can be "revived" through external input to a voltage that is deemed safe by the circuitry, we are talking volts required not amps

- one or more cells went dead (usually even leaking!) and the safety circuitry is doing its job - the pack needs to be "repacked" and any defective cells replaced with identical ones from another pack (or all cells need to be exchanged with a new set)

- the battery packs BMS/circuitry burnt out, or its built in fuse blew - You need to replace the circuitry

Is any of the above safe?
NO!
It is Li-Ion and as such unsafe by any aspect.

 

[Coupe]

Talked to a mate that repacks them and told me the best thing is to use
them.
They don"t like sitting for any length of time not being used. I have six for my DeWalt
gear and rotate them as much as possible.

 

[Wilhelm]

Also, being "aware" of load, depletion & recharging will prolong a battery packs life cycle!

When You notice a decrease of tool performance STOP using the battery pack stuck in it!
Do not immediately charge the just depleted battery pack, let it "cool down".
If You can choose, use a slow charger rather than a fast charger!
Do not "forget" to charge Your depleted battery pack.

 

[Wilhelm]

This is one of my "defective/dead" Makita 36Volt battery packs.
There is a lot going on, which makes troubleshooting complicated.





These packs are freaking expensive!!!
I buy them "dead" and try to revive them without rebuilding/repacking - success rate is close to 50%.

 

[Woodwackr]

This is one of my "defective/dead" Makita 36Volt battery packs.
There is a lot going on, which makes troubleshooting complicated.

View attachment 441831
View attachment 441832
View attachment 441833

These packs are freaking expensive!!!
I buy them "dead" and try to revive them without rebuilding/repacking - success rate is close to 50%.

What are they using in those? 18650s?

 

[Wilhelm]

What are they using in those? 18650s?

Yes, 18650's, weak & low capacity ones
1.1 or 1.3Ah, 20Amp draw
Dissapointing really.

Basically all battery packs utilize 18650's, very few contain other cells.

 

[Woodwackr]

Yes, 18650's, weak & low capacity ones
1.1 or 1.3Ah, 20Amp draw
Dissapointing really.

Basically all battery packs utilize 18650's, very few contain other cells.

Im guessing the low capacity is for safety. I believe the high end flashlight bats are 4000ah now. I have 3600s but they are pretty old.

 

[Yukon Stihl]

I read that if they are to dead the charger will not charge them as it thinks they are defective. If you boast them from a different battery to get some power in them then the charger will recognize them and charge them.
I tried it with one I picked up at the dump that was dead and it worked.

 

[Wilhelm]

I read that if they are to dead the charger will not charge them as it thinks they are defective. If you boast them from a different battery to get some power in them then the charger will recognize them and charge them.
I tried it with one I picked up at the dump that was dead and it worked.

Definition of jumpstarting a too depleted battery pack.
Get the packs voltage up just enough for the dedicated charger to recognize the battery and starts charging it.

I did that to 3-4 36Volt Makita packs, and about half a dozen 18Volt Makita packs.

If the pack won't pick up jumpstart voltage You may have dead cells within it and should seize revival efforts.

 

[Wilhelm]

Im guessing the low capacity is for safety. I believe the high end flashlight bats are 4000ah now. I have 3600s but they are pretty old.

Doubtful.
1.1 & 1.3AH is just cheaping out on a battery pack that was a short lived pinacle of Makita cordless tools.
Containing 20 cells the packs feature either 2.2Ah or 2.6Ah when they could have easily boasted up to 6.0Ah without increase in size and little increase in weight.

2.5Ah and 3.0Ah cells with a 40A discharge have been on the market for a long time.

Makita abandoned their 36Volt battery system, left their customers high & dry.
Instead they are pushing their 40Volt packs & tools.

 

[Woodwackr]

Doubtful.
1.1 & 1.3AH is just cheaping out on a battery pack that was a short lived pinacle of Makita cordless tools.
Containing 20 cells the packs feature either 2.2Ah or 2.6Ah when they could have easily boasted up to 6.0Ah without increase in size and little increase in weight.

2.5Ah and 3.0Ah cells with a 40A discharge have been on the market for a long time.

Makita abandoned their 36Volt battery system, left their customers high & dry.
Instead they are pushing their 40Volt packs & tools.

I have a lot of Makita 18v tools. The original 3ah bats finally gave up. I have 4s and 5s now.

 

[Wilhelm]

I have a lot of Makita 18v tools. The original 3ah bats finally gave up. I have 4s and 5s now.

I have mostly 3Ah's, just one 4Ah.
I keep the 4Ah on my impact drive and utilize the 3Ah's on my 2x18Volt chainsaw and single 18Volt hedge trimmer.

 

[Bill G]

So how do I "jumpstart " these?

 

[Woodwackr]

So how do I "jumpstart " these?

Just hook up to your truck battery

 

[Bill G]

Just hook up to your truck battery

I did that once with an electric start McCulloch saw.
It spun "reeeeealy" fast

 

[Yukon Stihl]

I jumped mine from a charged battery
+ to +
- to -
Voltage dosent really matter

 

[Bill G]

I jumped mine from a charged battery
+ to +
- to -
Voltage dosent really matter

I will have to give that a try

 

[Bill G]

I jumped mine from a charged battery
+ to +
- to -
Voltage dosent really matter

Well I tried some redneck engineering..........