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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

-----Original Message----- From: elec-trak-request cosmos phy tufts edu
Sent: Monday, January 07, 2013 10:08 AM
To: elec-trak cosmos phy tufts edu
Subject: Elec-trak Digest, Vol 11, Issue 9

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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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End of Elec-trak Digest, Vol 11, Issue 9
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