Re: Front lift and 12-volt batteries

[David Roden <roden ald net>]

Folks, thanks again for all the generous support and advice.  There were
several thoughtful responses, something to learn from each.  Here's a
synopsis of what I heard, and what happened when I installed the batteries.

tonyascrizzi juno com (TONY B ASCRIZZI) wrote:

> Dave,the 12  volt batteries will work fine.  As far as the lift, I have
> always run mine on 12 volts. I think 18 volts is too high. 

Christopher <Christopher Meier MCI2000 com> wrote:

> I've  been wondering this also. I'd guess that 12v would also make
> it try to draw more current to perform the task, and burn it out.

Larry <lelie ford com> wrote:

> Your idea should work fine but you are right in that the lift is too
wimpy at > 12 V.  I have not tried one at 24 V, and am sure it would not
work for 
> continuous duty.  For light duty, you might get away with it.  Another 
> thought; measure the current for typical lifting.  Compute the 
> equivilant 
> resistance, and add a heavy voltage dropping resistor in series to the
lift to > bring the voltage under load back to 18 or say 21 volts (fully
charged 
> batteries are 6.5 to 7.0 V; I'm sure the lift was designed for 3
batteries of > 7 V each).  I suspect you can get away with it.

Walt <dwfh voicenet com> wrote:

> Try looping the strap 2 times. That is to say, instead of only going 
> down to
> the deck, have it loop back to the top of the pulley. this gives a
mechanical
> advantage and causes the lifting action to go up and down slower.

After these notes, I decided to chance it at 12 volts.  I figured that if
it turned out to be too wimpy, I'd take Larry's advice and add a series
resistor to the 24 volt tap.  I'd also monitor the motor for possible
overheating.

I found that the lift works a little slowly, but not intolerably so, at 12
volts.  I suspect that when the pack charge begins to get flaky, it might
get to be a problem -- but it's time to stop working then anyway.  I did
not note any funny smells from the lift motor area (just from the traction
motor speed resistors, which were working overtime until I wised up and
shifted to low).

BTW, I used the tractor a little over an hour tonight, and I didn't detect
any decline in performance.  This is with six group 24 Deka Dominator gel
type deep cycle batteries, connected in series-parallel for 36 volts.  They
are rated either 68 or 86 amp hours at the 20 hour rate (I forget which).

I am not using the onboard charger, but rather three external 12v automatic
shutoff chargers, one for each paralleled pair of 12v batteries.  A little
more awkward to connect, but probably better for the Dominators than the
tractor's timer-shutoff charger.  As valve regulated batteries, Dominators
can be damaged by too high a finish rate and/or too long a charge.

Millions of thanks to those who helped out with this question.

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