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Old June 28th 05, 12:36 AM
George Ghio
Posts: n/a

wmbjk wrote:
On 26 Jun 2005 19:48:32 -0700, "Too_Many_Tools"

If you have more to contribute on subject, please feel free to offer

Thanks in advance,


Here's a sample day's work (yesterday's) in an off-grid workshop. The
project was building the last 2 of 5 scissor trusses for a friend's
aircraft hangar. All material was scrap - chords of 2" and 1.5"
schedule 40 pipe. Long braces from T posts, shorter ones from 5/8"
sucker rod. Most of the material was cut a few days ago. I wore out 3
chop saw blades (medium quality ones) which should give you an idea of
run time. The trusses are 40' wide, but built in halves. Each half
took about 30 minutes to lay out and prep, including about 15 minutes
use of a 4" side grinder. Then 26 welds per side, flip, another 26
welds. Layout, prep, and welding - about one hour total per half, with
a long break between each one to cool off. I built 4 halves, about 100
minutes welding for the day. I didn't check the current draw, but the
machine was set at 280 inches per second, 18 Volts, with .035" solid
wire. Perhaps 5kW input. Charging rate was medium, there was good sun,
but almost no wind, which was nice because I could leave the shop
doors open. When I quit for the day, my wife commented that battery
state of charge had dropped 6 Amp hours, and that she'd used the AC in
the office for a couple of hours. On this project, like most others
here, there wasn't any penalty for being off-grid, which is way cool


Ah Wayne, it looks like your saying 5kW for 1.6 hours and claiming that
it equates to 6 amp hours.

Would you like to refrase that amd perhaps look at the maths.

You use of units may be suspect. And your numbers would suggest that you
can only work when the sun is out.

5Kw input for 1.6 hours at 24V looks suspiciously like 333Ah.