Re: (ET) Snow at last (blower data)

["Pestka, Dennis J" <Dennis Pestka TycoHealthcare com>]

Chris;

Sounds like you had a fun time with your tractor.
I just have a blade, but I always enjoyed going out and pushing some snow
with it.
Nice not to have to hassle with getting it started, and a lot of people
won't believe me, but it has always out performed a 1952 vintage Farmall
that I have.
So far, I haven't had a snowfall it wouldn't handle, ~ 12".

May be a repeat, but could you share some additional info on the NiCD's.
No. of batteries in each pack, how you set them up, where you bought them,
approx cost?

Thanks;
Dennis
Elsberry, MO

-----Original Message-----
From: elec-trak-bounces cosmos phy tufts edu
[mailto:elec-trak-bounces cosmos phy tufts edu] On Behalf Of Christopher
Zach
Sent: Sunday, February 12, 2006 10:40 AM
To: 'elec-trak'
Subject: (ET) Snow at last (blower data)

Well, we finally got some snow here in MD. About a foot and a bit of the
wettest, heaviest, thickest stuff you can imagine. It's been in the 30-40's
so the ground was warm but it still blanketed everything.

So I fired up the E20 with the two strings of BB600 NiCDs (36v, 30ah rated
each, more like 35ah) and started blowing. Got about 2 feet before I
realized you *always* need chains. Put chains on. Rubber straps are nice 
for
chains. Put the third battery pack on (third string of BB600's) and went to
town.

Using the E-meters I noticed that I was pulling way over 240amps when
driving uphill in LL and blowing this snow. Very thick and heavy stuff. 
The blower motor was struggling at times (and that's a big motor) so I
backed off a bit speed-wise. Reading the power meter is a bit pointless
since it is buried in the red. So my goal was to keep the auger spinning at
a reasonable speed.

The blower never clogged. I'm sure now the POR15 paint is exactly what you
need. Slick as glass, much better than crisco or anything. And after two
winters, not a scratch on it.

Snow comes out like thick soup. But it does work.

On one of the downward runs the blower cut out. Great. So I pulled over and
checked the breaker. It looked to be not set, but according to my ohmmeter
it had failed open. So I bypassed it temporarily; and continued to blow.

After finishing everything, I checked the E-meters. I had pulled well over
75ah from the pack, and it wasn't sagging below 35 volts. Well over an hour
of blowing snow. One of the stings was about 5ah lower than the other two,
so they are discharging slightly out of sync at high current draws. But
without a doubt the BB600's can handle the load.

In fact I think they are a little "too" good. Their voltage doesn't sag 
when
you have 400 amp spikes, so although they really *do* kick butt with the
blower auger, they do heat up the pack wires. In addition they will not 
"sag
out" and drop the relays on a serious overload.

Another issue is duty cycle. I could probably blow another hour at full
blast, and at some point I'm going to exceed the 1 hour rating on these
motors. Especially the blower motor; it's a sealed model and is rather warm
right now. Also I think unless I upgrade the main wiring to the contactor
and the accessory plug I will overheat the main power wires. 
Might upgrade those lines to 6 gauge in the spring or better.

So overall the batteries and the blower seem to work well, given the low
temps and the high current draws.

Chris

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