Milwaukee cordless shut down

[Ironrosefarms]

Purchased a bag full of Milwaukee cordless tools some time ago. Paid $150 for 2 drills, 2 1/4" impacts, 1 circular saw, 1 sazall, 2 chargers, 8 batteries.

So drills and one impact work flawless. Second impact I repaired brushless card and it's perfect now.

But I'm having issues with both the circular saw and sazall. Either one will run perfectly until blade gets pinched, hit a knot hole or some other extra resistance comes into play. Once this happens the battery instantly goes from 100% to zero. Plug a different battery in and your good to go. Charge the effected battery and it is again fine.

I'm assuming the "computer" is detecting a short circuit and is saving itself. Any idea on diagnosing where or what is the culprit?

This occurs with all batteries which in turn work fine in other tools once charged.

 

[LB-1911]

Cut from manual, link below.


To protect itself from damage and extend its life, the
battery pack’s intelligent circuit monitors current draw
and temperature. In extremely high torque, binding,
stalling, and short circuit situations, the battery pack
will turn OFF the tool if the current draw becomes
too high. All the fuel gauge lights will flash.

Release the trigger and restart.


Under extreme circumstances, the internal temperature of the battery could become too high. If this happens, the fuel gauge lights will flash in an alternating pattern and the tool will not run. Allow the battery to cool down.



Battery Pack Protection pg 5 @
https://documents.milwaukeetool.com/58-14-1801d8.pdf

 

[Mr_fixit]

You might also have some batteries that are too old to hold a full charge, even though the led lights might say otherwise.

 

[MushCreek]

I have a couple of my first M18 batteries that are like that. Looks like a full charge, but go dead very quickly.

 

[jgromada]

Lithium batteries only have a finite number of Charge/Discharge cycles

 

[Ign]

OP, what are the date codes on the batts in question?

For that matter, what are the batts? M18, M18 Red Lithium, High Demand etc and what amp hour ratings?

Based upon your post I don't think you're this dumb but if you're running an old 1.5 on a circular saw I wouldn't expect much

 

[All]

Lithium batteries only have a finite number of Charge/Discharge cycles

Is there not a difference between the number of fully discharged/recharge cycles (finite), versus the number of partially discharged/recharge cycles?

I try to switch out batteries when they are only at the half way mark, in the hopes that the finite cycle life is more of an issue with deeper states of discharge. With shallower partial discharges, any "limit" in recharge cycles might be extended, thus prolonging the useful life of the battery.

Am I only kidding myself in this line of thinking?

 

[Mr_fixit]

I have some new MIkwaukee lithium ion batteries that were never charged and are garbage cause they won't take a charge.

 

[Danglerb]

Never charged I "might" take a chance using some manual power source to put a minimum charge on them with a fairly low initial current and not near anything flammable.

When the charge on a Lion battery drops below 2 or 3 volts per cell, depends on type, they can have permanent damage. The caveat is that the lower the discharge current, typically the less the damage and self discharge is low current.

OTOH its a dumb idea vs using known good batteries.

 

[Ign]

I have some new MIkwaukee lithium ion batteries that were never charged and are garbage cause they won't take a charge.

So did I from a HD wall display (got them to sell me the floor unit). Included my receipt only because the date code would have put it out of warranty otherwise, and warrantied it.

 

[Ign]

Is there not a difference between the number of fully discharged/recharge cycles (finite), versus the number of partially discharged/recharge cycles?

I try to switch out batteries when they are only at the half way mark, in the hopes that the finite cycle life is more of an issue with deeper states of discharge. With shallower partial discharges, any "limit" in recharge cycles might be extended, thus prolonging the useful life of the battery.

Am I only kidding myself in this line of thinking?

I don't know on the specific chemistry, but the battery ticks off each charge as a charge cycle, period. Milwaukee can pull this information as the battery does keep track of total number of times of charge cycles.

Now from a less-geeky perspective, I'd personally say yeah, you're kidding yourself. I run all my batteries 'til they shut down, leave 'em on the charger, in the cold, in the heat. I've never had significant problems, and whatever problems I have had have been covered by warranty plus there's no control to know if my minor problems would not have occurred if I geeked out on "best practices."

For me, life's too short. Li-ion is quite reliable and the major manufacturers build for pretty much use it and forget it. I use my tools and move on with life (shrug)

 

[Dingleburry]

Using a 1.5ah battery on the high torque impact, it had such a high current draw it would only impact for about 10s then shut down and read dead, then give it a few seconds, the voltage would recover and read full again. I just couldnt sustain the current draw.
Put a 5.0 on there, more cells in parallel = same voltage but = higher current output. The impact ran fine after that. Circ saw and sawzall both use large motors (in comparison to drills/ 1/4 impact) so i think a 4 or 5 ah battery will fix your problem, if your trying to use smaller batteries.

Also the people asking about partial charge/discharge cycles
That is true for lead acid batteries used on forklifts
Every time you plug it into a charger wether its for 20 mins (opportunity charging), or full charge it "consumes a cycle." Letting them Discharge past 80% also harms the logevity of the battery.
I believe most forlift batteries are rated at approx 2000 cycles. With proper care
Your also supposed to let then cool for approx 8hrs after a charge.
And water added only after a full charge

But i dont know about lithium ion.
From what i remember full discharges dont really effect them.

 

[Danglerb]

Two factors for Lion beyond too low of voltage damage, charge rate, and charge range. Lion likes to stay in the 20% to 80% charge range, not fully charged, and not fast charged.

OTOH I buy Lion for use so I fully charge my batteries.

 

[bob15]

Which line of Milwaukee tools do you have? the older German-made tools or the newer line of tools?

 

[Ironrosefarms]

Thank you for the replies.
I will have to get the additional info on the batteries in a few days. Have been away for a few days.

I know the batteries are getting older but I don't really think they are the culprit this time as I can fully stall the drill without the shut down. I'm wondering if bad brushes, bad switch, bad what ever. Don't want to just pour money into these but if I could repair them reasonably... why not.