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Posted by Bob Adkins on October 23, 2007, 3:16 pm
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>
>>
>>
>>>That said, the Milwaukee and DeWalt Li battery tools kick ass. The Milwaukee
is 28
>>>volts with about twice the ah capacity and yet about 2/3s the weight. Both
use newly
>>>developed (but different) chemistries that deliver quite high currents.
>>
>>If Li batteries are so great, why do hybrid cars use NiCd's in their
>>packs? Maybe because the Li cells are subject to catch fire?
>
>Actually the Prius and similar vehicles based on that architecture use NiMH
batteries
>instead of NiCDs. At that capacity level, they're about as prone to thermal
>decomposition as Li. Take a look sometime at the amount of protective
circuitry in
>the car. At least as much as the actual propulsion circuitry.
>
>The reasons Li batteries aren't used are manifold. First and foremost, they
cost too
>much. Second, they don't have the current capability, even at high voltage.
Third,
>each cell must be individually charge-managed. The BMS would add significant
expense
>to the vehicle. Fifth, Li batteries have a calendar life pretty much
independent of
>the number of cycles. 3-5 years, depending on the chemistry. Since that would
not
>cover the EPA's "emission warranty" period, not a chance of use.
>
>As far as a propensity to catch fire, you watch too much TV. Li batteries can
catch
>fire but only if physically damaged or dramatically overcharged, which is what
the
>Dell problem was. LiPoly chemistry seems a bit more vulnerable than the others,
>probably because of the flimsy packaging.
>
>The chemistry used in the DeWalt and Milwaukee batteries are somewhat different
and
>are very resistant to damage, or so I read in some of the RC forums. Cells from
>these batteries are the new hot-sh*t power source for RC vehicles and they tend
to
>get abused in that environment.
>
>
>>Anyone tried the Ryobi tools? They have a "1 battery fits all" scheme.
>
>So does Milwaukee, DeWalt and the rest. I noticed that Black & Decker has come
out
>with a replacement for the VersaPack line that uses similar sized Li batteries.
>Should be pretty good for casual home use.
>
>>
>>I'm fed up with battery powered tools.
>
>So quit buying them. Problem solved.
>
>>There should be standards so
>>that all 12v, 14v, 18v, 19v, etc. fit all power tools of the same
>>voltage rating. If your drill breaks, you may have to throw away 2 or
>>3 good battery packs. If your batteries die, you may have to throw
>>away a perfectly good drill or saw because you can't find economical
>>battery packs . Phooey on that. Also phooey on $85 battery packs. You
>>can buy a decent drill with 2 batteries and a charger for $40.
>
>Funny to watch an uninformed rant. None of that is true. None of the major
tool
>makers have changed battery formats. My 10+ year old DeWalt 18 volt tool set
still
>fits batteries currently on the shelf. True, they've come out with additional
>formats - kinda obvious why since sticking a Li battery on a NiCD charger
wouldn't
>result in happiness.
>
>If you break your drill, simply go buy another. It'll use the same batteries.
As
>for $85 packs, only if you're dumb enough to walk into a big box store and pay
>retail. Just for kicks, I just googled and found a 2-pack of 18 volt batteries
for
>$100.
>
>I've had several packs rebuilt for around $40. I understand that one of the
retail
>battery outlets (BatteryUSA?) will do it for just a little more.
>
>As for those $40 ChiCom knockoffs, buy one sometime and try it. Awhile back I
needed
>a DC gearmotor for a project and decided that a Harbor Freight 12 volt drill
would be
>adequate. I took the battery apart and found just what I expected - lots of
air and
>little battery.
>
>If that $40 toy will do the job for you then by all means go for it. Don't
come back
>crying when it falls apart or when you can't find replacement batteries, though.
Thank you John, I think.
No, I don't watch too much TV. My tongue-in-cheek remark was referring
to Li's reputation as much as the reality.
I have B&D and Makita drills sitting idle in my shop because I can
no longer find batteries for them at a reasonable price. If that makes
me igernant, so be it. ;)
I have done a lot of business with Batteries America. They build nice
Sanyo Rx and Tx packs for my RC models at a fair price. I'll look into
getting my Makita and FireStorm packs rebuilt.
HF has 1 drill that deserves a look. It has a Johnson high torque
motor and high capacity battery pack. The 1700 mAh 19.2v pack alone is
nearly worth the $40 price.
-
Bob
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