ECN Forum Forums General Topics of the Trade General Discussion Area Lithium-Ion Powered Cordless Tools!

I have to admit I was a little skeptical of the V28 battery system when I first saw it but I figured with a 2 year battery warranty and the five year tool warranty it was worth a shot. While I have only had the bandsaw a couple of months it has surpassed my expectations. Everyone who sees it or tries it falls in love with it. For EMT and unistrut you cant beat it. For aluminum it doesnt do me much good because I have to setup a threading station anyway. I usually recharge the battery during lunch, and with that I can keep going all day long. I will admit I am addicted to power tools (especially cordless) but I think that this milwaukee line is going to do pretty well as more people start to use them and see what they can do.

Lithium-Ion battery packs cannot be rebuilt.

The individual cells are not available to rebuilders..even if they were, the battery pack itself, at least on laptop computers, has "smart" circuitry on it that will disable the battery after a certain number of charge/discharge cycles.

The batteries could probably be purchased for less. Sometimes the hobby shops can have a bit more markup. Shop around some of the electronics suppliers such as Digikey, Mouser, Newark, etc. They usually also have qty discounts when you are buying 10 to 15 or more. May be worth a look.

Lithium Ion cells are available, and custom packs are getting less expensive. I've been using them in my 'homebrew' bicycle headlight for about 9 months now.

Check out batteryspace.com for Li-Ion cells, packs, chargers, and protection circuits.

IMHO I would be very leery of Li-Ion cells in power tool applications, but am willing to believe that they could work in a well designed system. NiCd and NiMH cells are really far easier to use and more robust, but Li-Ion is a better chemistry (lighter, greater energy density, better for the environment, etc.), and if the protection circuitry is carefully designed, and the battery is large enough to supply the load, then they should be quite good.

Battery power tools are often 'specification gamed' with battery voltage. But battery voltage does not tell the whole story; you also need to consider the total _energy_ stored in the battery (watt hours) and the _power_ available at any given time.

In general, of NiCd, NiMH, and LiIon, NiCd is the heaviest and has the least energy storage per unit mass, but has the best power output per unit mass. NiMH has better energy density, but worse power density, and LiIon has the best energy density and the worst power density.

Power tools are generally used in a very bursty fashion, high power for short periods with delays between use. This means that a LiIon power tool will need to be carefully designed to have enough _power_ available for the bursts, but if this is taken care of, all of the other factors (weight, capacity, etc) will be _great_.

-Jon

For what it's worth, I have the drill from the new Milwaukee 28V line. So far, it has been really good. It's not as powerfull as a corded drill (duh), but for sure it has more ass than any cordless that I have owned/used before. I think the real test is coming soon...

How does it work in the winter? How long does the charge last vs. all the 18V, 14.4V, etc. tools available? How do the different battery types line up when subjected to low temperatures? I've read about voltage/discharge ratings for different battery tools, but I don't know of any climate related tests. Anyone...?

just my 2 cents - A new guy on my crew has a Ridgid set, same price range as my Dewalt 18 volt kit - was very impressed with Ridgid's performance - their Warranty is unreal - lifetime including batteries, couldn't believe it until I read their website - next set for me will be Ridgid from Home Depot