New lesson learned this weekend.

On Mon, Jul 28, 2014 at 10:59 PM, Michael K Johnson <[email protected]> wrote:
> Talking myself into doubling my 4awg welding cable for the equivalent
> cross sectional area of 1awg was almost certainly overkill. Joe
> Lorenzi has 8awg in his JD with the same motor, and he told me that it
> gets a little warm and thicker than 8awg would be useful, but I really
> don't think I need 1awg equivalent. Even immediately after mowing
> through thick grass with no breaks for nearly half an hour (down to
> 50%DoD) my cables are cold. If I were doing it over, I would just use
> the 4awg cable. Would be easier and use lighter, easier-to-manage
> lugs, and routing would be less of a challenge than it was.

I changed my mind this weekend.

To prepare for aeration and overseeding, I mowed my lawn short. I
normally mow with the deck raised to maximum height (good for
fescue lawns), but to prepare to aerate and overseed, I nearly
scalped the lawn. I still mulched while doing this to create cover
for the seeds when overseeding. Cutting the grass low takes far
more power; so much so that a few times the cutting blades
nearly stalled. Normally I can mow front and back without exceeding
50% DoD while mowing up to 26 minutes. Cutting just the front,
taking well under 20 minutes (going slowly), I significantly exceeded
50% DoD. Don't know exactly how much because I couldn't let
the battery rest to get a precise measurement; I had to charge right
away to keep going in order to finish the project this weekend.

What clued me in to bring the mower back in to charge very early
was that the 2 4awg cables (1awg cross sectional equivalent)
were quite warm to the touch. Not too hot to touch, but perhaps
50⁰C.

I don't know how much current I was drawing, but in any case I
now feel that 1awg equivalent was a good choice, and if I ever
get stiffer batteries, I'll want to consider even larger wires.

Roland, thanks for recommending that I double the wires!

> I bought both 400A and 200A fuses, not sure whether it would blow the
> 200A fuse. I needn't have worried. I do see over 100A continuous, but
> the 200A fuse hasn't blown. The batteries just can't push that much
> current through that motor...

Even while bogged down, with the blades occasionally almost stallling
when the deck started getting clogged, and the wires getting warm, the
200A fuse did not blow.
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