I have an old Makita 12vdc 2.6amp battery impact driver that I want to convert to plug in power. I hooked it up to a radio shack converter that puts out 13.8vdc and 3 amps but all I get is about 30 to 40 rpm. I would have thought that with the 1.8v extra juice I’d get at least a little higher rpm or maybe a little over heating . So, any ideas on how I can make my impact driver run like it’s got a permanent battery in it.
Edited 3/29/2008 8:13 pm ET by mika
Replies
The problem may be that the little converter puts out scarcely any amps. It's amps that drives the drill motor at low voltage.
Mike D
P.S. Someone who knows more about this than we do can answer, but I think that the 2.6 amps on the battery is actually amp hours - a rating of storage capacity, and not of current output.
Edited 3/29/2008 9:01 pm ET by Mike_D
Mike D has given you the answer, the 2.6 amp rating on the batteries is their storage capacity, equivalent to the size of a gas tank on a car. The battery capacity doesn't tell you anything about how fast the power needs to be drawn off to run the motor.
I would guess that you probably need something like 15 amps and a fairly heavy gauge wire from the power supply to the drill to carry that much amperage at a low voltage without a fair amount of voltage drop.
A midsize car battery charger would give you that capacity but most of the modern ones contain electronic charge controls that will go nuts with the power draw of the tool.
You could just hook it up to a car battery but it should have a fuse at the positive battery terminal. A car battery can dump all of its stored power in a matter of seconds into a short circuit, the surge is easily enough to vaporize the driver or the connecting wire.
John White
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