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Re: (ET) Batteries- the weak link
Pieter,
Yes, that's about how I sum it up too. Batteries are the killer not
question, this is why I'm designing precise charging algorithms. We have
about an acre of garden to cultivate and I expect I'll do it in sections to
keep the charge cycles low ( I like to keep the charge to no less than 20%
of full), when you start to reach 50% depletion the charge cycle life of
batteries drops drastically. This is why hybrids keep battery depletion
shallow. Even in my off grid system I cut in the batteries in during the
day and switch to the grid at night, my batteries never see less than 90% of
full charge even in the winter. This is the best part of having an intertie
and an off grid system. I'm always selling power back to the grid even
though my off grid is only running half the day with the added benefit that
it kicks in when we have power outages here several times year. My Rolls
batteries are about 6 years old now and still going strong.
This summer I'll be building windmills and micrhydro. I'm excited to see
how they will affect my power. Right now I can run heaters during the day
while off grid and I'm thinking I can really cut my heating costs next year.
Rob
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Today's Topics:
1. Re: fuel costs (Robert)
2. Re: ET running costs (jim)
3. Re: fuel costs (Pieter Litchfield)
----------------------------------------------------------------------
Message: 1
Date: Mon, 7 Jan 2013 08:39:24 -0500
From: "Robert" <euclid delhitel net>
To: <elec-trak cosmos phy tufts edu>
Subject: Re: (ET) fuel costs
Message-ID: <25C1BC50EAED4F038BF2C007C751E5DA@RobaroniHP>
Content-Type: text/plain; charset="iso-8859-1"
Pieter,
I know about diesel tractors, they are great! I have a JD 3320 with a 485
back hoe. I bush hog an 8 acre field for pennies BUT a couple of caveats.
Don't ever blow a distributor pump on a diesel, the cost can run into the
thousands, aside from that they are hard to beat for big jobs. To the credit
of the ETs, they are made for smaller plots. My JD ztrak with a gas engine
sucks up fuel, it's the hydo box, I would say to do about 2 acres it takes a
gallon and a half of fuel, maybe a little more or a little less depending on
the height of the grass. That job will be replaced by my ET when it's done.
Also my wife is going to get and ET, she absolutely hates gas anything. I
bought her a lith-ion weed whacker and she smiles every time she uses it. No
starting problems like her mini tiller, low noise and she isn't blowing gas
fumes all over our organic gardens. For smaller plots you just can't beat
the ETs, what a great and well thought out machine! When ours are finished
they will
till the gardens, mow the lawns, blow snow and be charge by my 10.6 Kw solar
array. I can't wait!
I think the important thing to consider is that the ETs compliment the
tractor, neither replaces the other. Had we continued with electric
technology in tractors this wouldn't be the case but then if we had stayed
with electric cars the world would be a different place today too!
My four cents (adjusted for inflation)
Rob
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Message: 2
Date: Mon, 7 Jan 2013 06:14:59 -0800 (PST)
From: jim <jiminwis yahoo com>
To: "elec-trak cosmos phy tufts edu" <elec-trak cosmos phy tufts edu>
Subject: Re: (ET) ET running costs
Message-ID:
<1357568099 14125 YahooMailNeo web160301 mail bf1 yahoo com>
Content-Type: text/plain; charset="iso-8859-1"
I though that I should comment on battery costs. ?I bought a new set this
fall, just after the price went up, and they were about $100 each, $638 for
the set including sales tax. ? A week earlier, they would have been at least
$5 each cheaper. ?The batteries are ?East Penn/Deka, sold by Fleet Farm. ?
Having just sold our John Deere riding mower this summer, I have good feel
for the costs. ?I spent an average of less than $50 a year on parts,
maintenance,oil filters, etc., including the?occasional?repair part, belt or
blade replacement over 15 years. ? Never paid to have a tune up or oil
change or other work done, ?everything was easily done by me with reference
to a shop manual that was an early purchase. ?I mow from less than an acre
up to 4 or 5 acres, depending on whether it is just the yard or if I mow
around the orchard and pole shed, which is less often, and could use 30 to
40 gallons of gas in a summer if it was wet and the grass grew
fast--not the case in the last couple of years. ? I switched to using an
Elec-Trak because our electricity is "free" (wind and solar systems since
1977) and I don't like storing or using gasoline, disposing of used oil,
etc., any more than necessary. ?We also use a car converted to all electric
for local driving.
Jim, in Western Wisconsin
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Message: 3
Date: Mon, 7 Jan 2013 10:07:51 -0500
From: "Pieter Litchfield" <pieter_litch yahoo com>
To: "'Robert'" <euclid delhitel net>, <elec-trak cosmos phy tufts edu>
Subject: Re: (ET) fuel costs
Message-ID: <010501cdece8$c3d5f800$4b81e800$@com>
Content-Type: text/plain; charset="us-ascii"
Robert - no argument with anything you said in your reply. It would be
interesting to study the "cost/benefit" analysis of, say, a diesel engine
tractor vs an electric is a holistic sense. The diesel fuel is densely
"packed" energy per pound, more so than the power stored in a lead-acid
battery in particular. However, the electric motor is lighter than the
diesel and has the most torque at stall, which is ideal for a tractor
application. I have seen only home-built attempts at larger agricultural
electric tractors, say the size of my 40 hp diesel 4wd utility. Why? I
suspect that the battery pack needed would bury the tractor. I suspect
that
in smaller (lawn) tractors, electric might be more efficient overall
(including the weight of the motors and "fuel tank"), but at some point on
the larger size spectrum the usefulness of electrics fall off by comparison
to small diesels.
I have an E-15 with a bucket loader run by hydraulic-electrics, and use it
to load gravel out of a pile and into carts for trail maintenance. Two
things become obvious doing this: (1) When you start running heavy power
load accessories like the loader or a snowblower, run time for the ET gets
shorter fast and (2) It sucks to exhaust your batteries out in the woods.
I
have to transport my ET by trailer to and from the job site frequently for
recharges, and have considered the addition of a solar charging station -
which seems very expensive at a size that would be effective. It's easier
to move 5 gallons of diesel in a can to the tractor.
My conclusion: ET's are well suited to suburban lots where they can enjoy
proximity to an outlet and relatively light power loads (like lawn mowing).
Yes - I know the ET snowblower or tiller sucks up power like a sponge but
is
still useful. My loader does too. It was used for materials handling in
a
yard of an industrial firm (with lots of outlets). Unless there are major
advances in battery technology that allow the storage of as much energy per
pound of fuel tank as a hydrocarbon powered machine, I don't see a big off
lawn market for electric tractors.
From: Robert [mailto:euclid delhitel net]
Sent: Monday, January 07, 2013 8:39 AM
To: elec-trak cosmos phy tufts edu
Subject: Re: (ET) fuel costs
Pieter,
I know about diesel tractors, they are great! I have a JD 3320 with a 485
back hoe. I bush hog an 8 acre field for pennies BUT a couple of caveats.
Don't ever blow a distributor pump on a diesel, the cost can run into the
thousands, aside from that they are hard to beat for big jobs. To the
credit
of the ETs, they are made for smaller plots. My JD ztrak with a gas engine
sucks up fuel, it's the hydo box, I would say to do about 2 acres it takes
a
gallon and a half of fuel, maybe a little more or a little less depending
on
the height of the grass. That job will be replaced by my ET when it's done.
Also my wife is going to get and ET, she absolutely hates gas anything. I
bought her a lith-ion weed whacker and she smiles every time she uses it.
No
starting problems like her mini tiller, low noise and she isn't blowing gas
fumes all over our organic gardens. For smaller plots you just can't beat
the ETs, what a great and well thought out machine! When ours are finished
they will till the gardens, mow the lawns, blow snow and be charge by my
10.6 Kw solar array. I can't wait!
I think the important thing to consider is that the ETs compliment the
tractor, neither replaces the other. Had we continued with electric
technology in tractors this wouldn't be the case but then if we had stayed
with electric cars the world would be a different place today too!
My four cents (adjusted for inflation)
Rob
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