(ET) mower motor amp draw

[Daystar Energy Services <daniel laser net>]

Christopher Meier wrote:
> 
> >Anybody know the hp rating on an electric push mower?
> 
> My B&D 12v 18" model is rated for 3.5hp. I believe the
> power circuit is rated for something like 40amps continuous.
> A 26ah hawker runs it for about 1 hour.  The motor is unmarked
> so I don't know the electrical power rating.  The 3.5hp is
> the gas equivalent number.  It definitely has less power than
> the electrak 3 motor mower deck, which I've never heard struggle
> despite the (grass) load, whereas the B&D will struggle with
> (overly) deep grass (like 2 weeks growth (in MN)).  I normally
> mow every 5-7 days in the summer.  If you want the thing to
> have enough power to cut tall grass, I'd count on something
> like 1kw per 16-18" motor/blade.  If I get around to calibrating
> my power draw meter on my E16 I'll post the current draw for
> my machine.

OK, this begins to answer my question. Someone please show me where my
logic fails. 

A 26ah battery at 100% dod (a ridiculous assumption, but I'm not
familiar with Hawker) will deliver 26 amps for an hour, right? 12 volts
at 26 amps = 312 watts = .42 hp. At 80% dod, 20.8 amps x 12 v = 250
watts = .33 hp.

The power circut is rated for about 40 amp. My assumption is that the
circut should be designed low enough to break if amp draw or heat gets
out of control in order to protect battery and motor. But not so low
that normal use breaks the circut. So, 40a x 12v = 480 watt = .64 hp.

All this melds nicely with my previous info that the ET's 3 motor mower
uses 20-25 amps x 36v = 720-900 watts = .96-1.2 hp. for all three
motors. It also shows that the 3.5hp gas equivalent means nothing. A 6
amp 120v motor from a 1/2" drill is 720 watts, 8 amp from a sawzall is
960. Depending on blade drive efficiency, this is where I'm headed. Any
other real world experience is welcome.

Thanks

Dan

P.S. I was just about to send this and I got this from Tony Ascrizzi

>>does anyone have an idea on wattage draw for a 36 to 48" mower deck?

>About 4500 watts if its worth anything. Been there done that.

WOW! Tony, please expound on this!

Then this from Michael Neverdosky 

>A strong circular saw motor will probably run a mower deck, the 
>question is, for how long? Most saws are not designed for continuous
>duty, so running them more than a few minutes at a time can be
>a problem.

Good point. I hadn't considered that. Boy, I'm sooo confused. Time for
bed.