Lithium Batteries

[Greg Guarino]

I have two of the Ryobi 4AH batteries. I charged them in December, but not again since - until yesterday.

I had 256 3/8" holes to drill in oak. I would normally use a corded drill for something like that, but I was curious about the batteries, so I used a cordless.

After perhaps a hundred holes the drill stopped working, all at once. In other words, I noticed no obvious slowing down of the drill; it worked at (or near) full power, then stopped. I looked at the "meter" on the battery (you press a button to see it) and it showed 1 LED (out of 4 or

5). I switched to the other battery, which did most of the rest of the job before stopping in the same fashion. I switched back to the first battery, which was now charged and it worked fine.

While it's possible that the batteries stopped because of a thermal cutoff (I hear the LI batteries have that feature), I think this was simply a low-charge cutoff. Interesting.

I'm pretty pleased that these batteries, charged six months ago and used a number of times in the interim, drilled 100+ holes apiece before running out.

[Leon]

For the most part Li-Ion batteries require a special charger and the built in circuitry in the battery pack typically will not let you run the battery down to dead. This is not good for these type batteries. So these type batteries do tend to go strong and will quit when they reach a predetermined point of discharge.

[adsDUMP]

I think you're correct. better to have the battery shut down than have it damaged.

The lithium batteries in electric/hybrid cars typically run between

20% and 80% charge.

[-MIKE-]

It can takes getting used to the fact that you get no warning of a depleting battery. However, once you go back to a NiCad and have to deal with the decreased power for half the battery cycle, you realize it's a welcome change.

I've had my Ridgid Li-Ion batteries for a couple years and they still operate like new.

[Leon]

Some of the Li-Ion battery packs have a fuel gauge/state of charge indicator. Some have to be checked as an extra step, some like the Festool shows the state of charge every time you pull the trigger.

From what I understand also, because of the smart chargers required for the Li-Ion battery packs and the circuitry in the packs you can leave the battery in the charger with out fear of damaging or overcharging. I, out of habit, remove the battery with in a couple of hours if I can remember. ;~)

And the nice thing about those particular batteries is that they have a life time warranty.

[Baxter]

Greg Guarino wrote in news:llt4u0$acr$ [e-mail]:

Rapid drop-off is a characteristic of Lithium batteries. And they hold their charge - I have cordess shears that I charged last spring then set on the shelf - still going strong this spring. Just don't let them freeze.

[krw]

That's typical of LiIon batteries. They have a rather flat discharge curve until the last 10%, or so. Then the cell voltage drops like a rock. The battery controllers often cut out at this point to save the battery. There isn't much energy left after that point so it's generally not worth risking the cells.

LiIons also have a rather low self-discharge, so it's not surprising to have them still be close to "full" after six months. They have a comparatively (WRT other secondary cells) long shelf life, too, so are good for seldom-used tools. At my previous job, we had some that were purchased, for one of our products, four years before and they still had well more than 80% capacity.

[PV]

My Milwaukee and Makita Lithiums reside in my work truck year round and that includes all winter long. They take a little warmup time but so far (2 Makitas are 9 years old) all are going strong,

[krw]

I wouldn't worry about the cold affecting the batteries much, but heat will kill any battery. Contrary to popular opinion, car batteries die in the summer, not winter. It's just that the full capacity isn't needed until Winter so the degradation isn't noticed until then. It's not a good idea to store them in the vehicle (not much choice for your starting battery). I make sure all of my batteries are in the house (or better, the basement) during the summer months.

[woodchucker]

Needed. LION, and LIPO's are destroyed by pulling the volts down.

My hitachi's do not have that for the 10 volt units. Wish they did. I monitor them.

[Puckdropper]

Greg Guarino wrote in news:llt4u0$acr$ [e-mail]:

*snip*

*snip*

I get just a tiny bit of warning before my batteries cut off. The signs are subtle, like the impact driver starting to impact sooner. When I notice that, I usually get 2-3 more screws before the battery dies.

There's no need to run the battery to low-voltage cut out. If you notice the driver slowing down, don't feel bad about charging it immediately. You're not going to get all that much more out of it anyway.

Puckdropper

[Doug Winterburn]

True. In the Arizona (Phoenix and surrounds) desert, auto lead-acid batteries that live in the desert full time have an average life span of

2 years, no matter the guarantee/warantee. Apparently, the heat can cause the plates to warp and short out.

When I lived in Seattle, a car battery could last 8 years.

[Doug Miller]

Doug Winterburn wrote in news:53827e4a$0$22486$c3e8da3 $ [e-mail]:

I bought a used 1984 LeSabre in the fall of 1991. In the summer of 1997, the battery needed to be replaced. The factory original battery. (Date code showed it was manufactured November

1983.) This was in central Indiana.

[Victor H.]

Life time warranty only if you registered them when you purchased them. And if you happen to exchange them make sure you register the new ones. No registry, no warranty. read all the fine print.

Vic

[Morgans]

"Leon" wrote

I went as far as to buy some Li-Ion battery packs and a charger, and take them apart and stuff them in an old B&D NiCad battery case, so I could have the benefits of the better battery. Works great.

I will never own or buy another NiCad tool, again.

[clare]

Ditto. NiMh, possibly, but NEVER Ni-Cad ANYTHING.