The dynamic braking on DC lawnmowers is accomplished by the "shorting"
the motor with a length of wire, believe it or not.
When you turn it off, the power switch on the handle disconnects the
battery from the motor and connects a "resistor" to the motor which is
simply a bundled hank of perhaps ten feet of 20 AWG wire. Seems to be
quite effective, but not very efficient.
Bill D.
On 7/28/2021 7:28 AM, EVDL Administrator via EV wrote:
On 25 Jul 2021 at 13:12, Seth Rothenberg via EV wrote:
what would it take to replace the cord + rectifier with some number of these
40V packs which are available at 6Ah?
If memory serves, Lee Hart did something similar with small Gates Cyclon
lead cells many years ago. I hope he'll chime in with the details.
Years ago, I converted a 120vac B&D mower to DC, replacing the 120v PM motor
with a 36v one. I didn't try to use the handle switch for DC - I can't
imagine that it would have fared well - but instead used it to operate a
small golf car type contactor. The downside of that arrangement was that it
sacrificed the dynamic blade braking that the mower had originally, and thus
some safety.
I powered mine from a 38v 10ah LiFePO4 battery. Instead of putting the
battery on the mower, I carried it in a backpack, which made the mower
easier to maneuver.
One thing that surprised me was how much current the motor used just
spinning the blade in free air, not even cutting. It was 6-8 amps, if I'm
not mistaken. Seems like a lot, doesn't it?
David Roden, EVDL moderator & general lackey
To reach me, don't reply to this message; I won't get it. Use my
offlist address here : http://evdl.org/help/index.html#supt
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This raises a number of questions, such as "what's actually wrong
with people?," and "is this legal in Spain?"
-- Found on the net
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