DIYbanter - View Single Post - 12 volt lithium battery drill/impact driver- recommendations?

woodchucker[_3_]

On 11/16/2013 6:31 PM, wrote:
On Sat, 16 Nov 2013 16:13:50 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/16/2013 1:00 PM, patrick wrote:
I've been using recycled lithium batteries for the past couple years in those bright chinese LED flashlights (salvaged from dead laptop battery packs) and the chargers all seem to take anywhere from 3 to even 8hrs to go through a complete charge to 4.02 volts(seldom drawn down past 3.5v). How the heck do the current crop of manufacturers get a battery completely charged in 1/2 hr? I'm guessing you are trading # of cycles for the rapid recharge. Do any of the chargers supplied with a typical drill have a slow charge function that might extend the # of cycles b4 the battery shows as defective to an intelligent charger?
Regarding the danger of fire- the radio control guys learned the hard way to make a fire resistant charging station such that if the battery (lithium ion at that time) attempted suicide, the damage would be contained.
I'll probably spring for one of the off brand 18v batteries to allow me to keep using the drill.
Btw- I noticed that dewalt and milwaukee seem to have optional batteries that have a higher amp/hr rating. Does the bosch and the makita offer the same thing?
In the meantime, I'll keep looking for a drill and an impact at a decent price. Thanks in advance, Pat

My Bosch and Festool Li-Ion chargers have a combination of electronics
and or fans to monitor the heat being generated during charging. From
what I under stand the circuitry in the batter packs is sume what more
complex than the standard battery pack. IIRC this circuitry is
calibrated to each cell in the battery.

It's no not so much calibration as it is protection. LiIon has a
nasty habit of bursting into flames if it's not treated well. Note
that all batteries have this problem to one degree or another. Any
time you store that much energy in a small place, bad things happen
when you let it loose suddenly.

The LiIon chargers are more complex than NiMH (which are more
complicated than NiCd) but in this age of ICs, it's all pretty simple
and cheap. Laptops do even more because they're doing a lot more
charge (as in coulombs) management in the laptop itself. The laptop
requires a "gas gauge" to do its thing maximizing run time. This
isn't true for a drill, so calibration isn't needed.

What Leon was referring to is balancing technology. Which makes sure
each cell is in range, and not deviating from the others.
That is actually where most of the problems are, especially with low end
chargers. The better chargers will monitor each cell rather than the
pack and if one cell gets higher than the other it will deplete it while
bringing the others up. If they are too far out it shuts down.

--
Jeff