Re: 120 V AC to 120 DC Lawn Mower Conversion. CORDLESS !! boundary="------------C30CF81B1396581A5010EA1D"

["Darryl McMahon" <darryl@econogics.com>]

Conventional corded electric mowers are usually rated at about 
1200 watts (10 amps at 120-volts).  From a 110-volt outlet, that is 
less than 12 amps draw.  Have a look at 12-volt camcorder 
batteries, often available at surplus stores.  Typically available in 5 
Ah to 18 Ah sizes.  10 of the largest might be overkill, but 10 of the 
smaller to middle size might work OK.  Assuming the efficiency of 
the universal electric motor is not affected by DC vs AC power, and 
you are using a 10 batteries of 10 Ah capacity.  10 Ah @ 120 volts 
is 1,200 watt-hours.  So, if you need 1200 watts to operate, you 
have about an hour of run time.  If you use the 5 Ah batteries, you 
should have about 30 minutes of run time.

> Now I know from practical (jump it and try it) that 120 DC will run a 120
> AC brush type lawn mower just fine...   The problem is getting  up to or
> near 120 DC with small lead acid batteries.
> 
> So couldnt a similar weight/size group of small 12v batteries be
> gathered together
> and do about the same ??  Or is there some OHMS Law thing at work that
> would NOT work. Or I havn't taken in to consideration ??
> 
> What I am trying to get to here, is a pile of small 12v batteries, that
> would be CLOSE to the same SIZE and WEIGHT as the two small 12v batteries,
> in a 24v DC cordless lawn mower, except this would be rinning a 120v 
> brush-type mower. (of course with a suitable DC rated   ON/OFF switch ) 
> Ya dont make that error except ONCE.
> 
> Now if THESE assumptions are in line, wonder where some one could get 10
> small 12v batteries for less than $100.
> 
> I guess what I should do is with a clamping ampmeter, measure the AC and
> then DC draw on such a set-up and then get small 12v batteries to
> compliment THAT drain rate.
> 
> Wha-Da-Ya-Think ??
> 


Darryl McMahon          48 Tarquin Crescent,
Econogics, Inc.         Nepean, Ontario K2H 8J8
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