# Problem with 16V Sears Craftsman Lithium-Ion Batteries and charger



## nopcbs (Dec 3, 2011)

I bought two 16V Sears Craftsman Professional Li-Ion drills a couple of years back at different times. One was the 320.29036 with a 320.29006 battery pack and the other was a 320.10320 with a 320.11208 battery pack. Also got a 320.10321 Universal charger.

My habit was to keep one battery in the charger at all times.

After a couple of years of very light use (I mostly use my DEWALT 18V drills), I went to use one of the drills and found that the battery was totally dead. No problem, I go to the charger, take the charged battery and swap it for the dead one. Drill does not work! Hmm. So I pop the charged battery into the other drill…nothing. I notice that the status lights on the charger are not lit with either battery in place. Like it does not know a battery is even present. I put the other battery back in the charger. No signs of charging. Very disconcerting.

Dead charger? I buy another one at Sears and try it, same thing. It's the batteries! I look at the labels, notice the same build date 08/2007.

I am seriously PO'd at Sears at this point that these batteries would go dead after very light use and with one in their smart charger all the time.

I discover a friend at work has the 20V Sears Li-Ion drill set and, I ask him to check my batteries and charger with his stuff. He has the sloped front charger…like the one I had bought to see if mine was bad. He puts the 320.11208 battery on his charger first and noted a popping noise when he first did this…and the battery charges! It charges right up. (And will now charge in my charger and runs my drills fine.)

Then he tried the 320.29006 battery pack and that one will not charge. He also tried putting his 20V battery back on the charger and then putting on my 320.29006, but no luck. He returns the batteries and my charger to me.

We speculate about what the heck is going on. Best speculation is that his charger remembered that it had last been used with a 20V battery when he put my first 16V battery on and it had to switch back to 16V after sensing that my battery is a 16V…hence the "pop". So the 16V battery got a momentary over-voltage which "shocked" it back into working. Not sure why this did not work with the 320.29006.

Anyway, I am pretty much convinced that I am the victim of not-so-smart circuitry in the batteries and/or the chargers that is preventing that other battery from being recognized as being present by my charger. I don't even get the dead battery light on the charger. I don't think the charger recognizes that a battery is present. I do not know why the battery that was already on the charger when I first went to do a swap was dead. Again, I suspect that the charger's logic about whether a battery is present and in need of charging is at fault.

Any thoughts…especially solutions?


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## nopcbs (Dec 3, 2011)

OK, you other folks with the same problem with these POS Craftsman Li-ion batteries prepare to than me.

Update, the 320.29006 battery continued to not work and the 320.11208 cpntinued to work.

Decided to measure the voltage on the 320.29006. There are three terminals: +, -, and T. Accross + ans - I measured 1.4 V. Accross + and T, I measured 1.4 V. Way too low and leads to a suspicion that the charger simply does not sense that a battery is present when the battery is mounted on it. It sure reacts that way, it totally ignores the battery.

So I conneccted the + and - terminals to a 12 V automotive battery. Put a voltmeter accross the terminals, too. Battery was putting out 13.3 V. After a few hours the 320.29006 battery was up to 2.4 V. A few more hours gave little additional improvement. So I tried adding another line from the - of the 12V battery to the T terminal on the 320.29006. In other words, the 12V battery + to the 320.29006 + terminal and the 12V battery - connected to bothe the - and T terminals of the 320.29006. DVM accross the 12V battery terminals, too.

Again, the 12V put out 13.3V. After about an hour I measured the voltage accross the + and T/- of the 320.29006 and read 5.4 V! Low, but much better. Gave it another hour with no improvement. Then I QUICKLY removed my charging wires from the 320.29006 and popped it into my Craftsman charger.

The charger started to work! It went into charging mode and the lights on the battery front started to flash in series!

It seems to be back from the dead.

Likely problem is that both my 16V Craftsman Li-ion batteries had decayed to such a low voltage that the charger did not rcognize that they were even present when mounted. Trick was to get the battery voltage up high enough to make the charger realize that a battery was present.

Poor battery and charger design, but, hey, this is Sears not DeWalt or P-C or Makita or Bosch.

- nopcbs


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## BillWhite (Jul 23, 2007)

Don't leave the batts in the charger after they have been refreshed. Don't buy from Sears.
Just a couple points I've learned over the years.
BTW, you have WAY more patience than I.
Bill


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## Finn (May 26, 2010)

This is not such a strange story. Li-ion batteries do not do well when used to run a motor. Great in phones and laptops. I have 12 year old nicad batteries that I used every day and I just now had to replace 2 of 45 of them. Nicads are MUCH more rugged batteries. Nicads will not store as much power but they will recharge in 1/2 hour. I have used them for over 30 years in my work.


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## JAAune (Jan 22, 2012)

What Bill said. You're better off taking batteries off the charger when they finish charging. With Lithium Ion there's no reason to keep them charging anyhow since Li-Ion batteries don't self-discharge like the Ni-Cads.

Generally speaking, only high end cordless tools (Festool is one but there are probably others too) come with smart chargers that slow the charge rate as the battery approaches full capacity. The ones packaged with cheaper tools (Craftsman) will usually overheat and damage fully-charged batteries that left on for long periods of time. I've seen and heard plenty of reports about batteries dying prematurely due to people leaving them on the charger. DeWalt even had a reputation for supplying cheap chargers with their tools for awhile. I don't know if they started using good ones or not since I last looked into it.


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