EV Digest 6488
Topics covered in this issue include:
1) Re: Looking for Electric Mower Suggestions for 1 acre
by "Dave Wilker" <[EMAIL PROTECTED]>
2) Re: Looking for Electric Mower Suggestions for 1 acre
by Mark Hastings <[EMAIL PROTECTED]>
3) RE: Looking for Electric Mower Suggestions for 1 acre
by Cor van de Water <[EMAIL PROTECTED]>
4) Re: Looking for Electric Mower Suggestions for 1 acre
by Mark Hastings <[EMAIL PROTECTED]>
5) RE: Looking for Electric Mower Suggestions for 1 acre
by Mark Hastings <[EMAIL PROTECTED]>
6) Re: Blind EV's
by "Michael" <[EMAIL PROTECTED]>
7) RE: Well, how is the AltairNano Pack working?
by Sam Maynard <[EMAIL PROTECTED]>
8) Re: Questions on EV
by "Michael" <[EMAIL PROTECTED]>
9) RE: EV vs. ICE (was: Re: May issue of Car and Driver confirmed)
by "Roger Stockton" <[EMAIL PROTECTED]>
10) RE: Looking for Electric Mower Suggestions for 1 acre
by Cor van de Water <[EMAIL PROTECTED]>
11) RE: EV math is not my strong point
by "Dale Ulan" <[EMAIL PROTECTED]>
12) Re: Looking for Electric Mower Suggestions for 1 acre
by Danny Miller <[EMAIL PROTECTED]>
13) Re: EV math is not my strong point
by "Peter Gabrielsson" <[EMAIL PROTECTED]>
14) Re: Looking for Electric Mower Suggestions for 1 acre
by <[EMAIL PROTECTED]>
15) Re: Looking for Electric Mower Suggestions for 1 acre
by "Peter VanDerWal" <[EMAIL PROTECTED]>
16) KillaCycle YouTube video over 33,000 views
by Bill Dube <[EMAIL PROTECTED]>
17) Re: A few new KillaCycle photos (battery assembly)
by [EMAIL PROTECTED]
18) Re: contactor controllers
by Bill Dennis <[EMAIL PROTECTED]>
19) RE: Well, how is the AltairNano Pack working?
by Bill Dube <[EMAIL PROTECTED]>
--- Begin Message ---
Weird Idea:
Use a very long, heavy duty extension cord and an electric tractor. Just
have to be careful not to run it over.
David C. Wilker Jr.
USAF (RET)
----- Original Message -----
From: "Mark Hastings" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Wednesday, February 28, 2007 10:13 AM
Subject: Looking for Electric Mower Suggestions for 1 acre
I'm not sure if gas mowers have improved much over the
years but my my hacked together electric craftsman
mower is batteryless and I haven't found a reasonable
replacement for my acre yard.
Is there anything new out there I'm just not finding
for an electric mower that would handle that area
without taking days to mow?
I can only think of two options and I'm not sure
either would work.
I have thought about converting a gas reel mower. I'd
think the reel mower would be more efficient then a
tractor with a hydrostatic transmission. I don't mind
the walk but would it do at least half an acre if I
used two batts instead of the one the evalbum one has.
http://www.austinev.org/evalbum/546
It just says 2 small yards. Here in some towns a small
yard is the 10ft to the curb in my town it is an acre.
My 2nd option is a trailer for the sears and stick
some big batts in there. There isnt' much if any space
up front I only had 42 volts of 30amphr bb600s as all
that would fit and that took about 4-5 charges to do
my lawn. The mower normally pulled 60-80amps when
mulching. If I put 4 EV145s in a trailer that would
add roughly 400lbs which I don't know if it could
pull. If it could and it didn't up amps that much it
may mow my yard.
If I had another use for the batteries, had a free
reel mower sitting around or had spare batteries I'd
just go do it. But it is all a little expensive to get
the stuff only to get disappointed that it won't work
and be stuck with stuff I can't use or return.
--- End Message ---
--- Begin Message ---
Ideally that would be great.
However I have a large acre, approximately 40,000
square feet of lawn (800sqft house), and a few dogs.
Plus our puppies would have a conflict with it. For
the big $1600 model it takes up to 3 hours to mow 5400
square feet per the website and then it charges. So
that could potentially be 2-3 days where it goes off
to mow the lawn where we'd have to keep the dogs in
and living right at the center of town by the school
doesnt' help either.
If my wife ever goes and takes the dogs. I may just
have to get one or two of these :-)
--- End Message ---
--- Begin Message ---
Did I read you use BB600?
They should be able to supply 40Ah in real life,
so your draw of 60 - 80A should give you 30 to 40 min of mowing?
How long does it take to cover your larger-than-normal acre? ;-)
Cor van de Water
Systems Architect
Proxim Wireless Corporation http://www.proxim.com
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Second Life: www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Mark Hastings
Sent: Wednesday, February 28, 2007 12:00 PM
To: ev@listproc.sjsu.edu
Subject: Re: Looking for Electric Mower Suggestions for 1 acre
Ideally that would be great.
However I have a large acre, approximately 40,000 square feet of lawn
(800sqft house), and a few dogs.
Plus our puppies would have a conflict with it. For the big $1600 model it
takes up to 3 hours to mow 5400 square feet per the website and then it
charges. So that could potentially be 2-3 days where it goes off to mow the
lawn where we'd have to keep the dogs in and living right at the center of
town by the school doesnt' help either.
If my wife ever goes and takes the dogs. I may just have to get one or two
of these :-)
--- End Message ---
--- Begin Message ---
Hm between this email and looking again at the
robomower site made me think of using multiple
trailers with smaller batteries. When I don't mulch I
bag. And when I dumped off one load I could switch
trailers. Sadly this probably doubles the cost but at
least I don't have to tow 400lbs and I could try it
first with only one trailer and get the second if it
worked. Now I just gotta find a cheap sturdy small
trailer thingy, or off to northern tool to buy some
wheels.
I could even do this with the reel mower. Go get a
drink of water and switch battery packs.
If anyone has any other ideas I'd welcome them and
thanks for the responses so far.
--- Dave Wilker <[EMAIL PROTECTED]> wrote:
> Weird Idea:
> Use a very long, heavy duty extension cord and an
> electric tractor. Just
> have to be careful not to run it over.
>
>
>
> David C. Wilker Jr.
> USAF (RET)
>
>
> ----- Original Message -----
> From: "Mark Hastings" <[EMAIL PROTECTED]>
> To: <ev@listproc.sjsu.edu>
> Sent: Wednesday, February 28, 2007 10:13 AM
> Subject: Looking for Electric Mower Suggestions for
> 1 acre
>
>
> > I'm not sure if gas mowers have improved much over
> the
> > years but my my hacked together electric craftsman
> > mower is batteryless and I haven't found a
> reasonable
> > replacement for my acre yard.
> > Is there anything new out there I'm just not
> finding
> > for an electric mower that would handle that area
> > without taking days to mow?
> >
> > I can only think of two options and I'm not sure
> > either would work.
> >
> > I have thought about converting a gas reel mower.
> I'd
> > think the reel mower would be more efficient then
> a
> > tractor with a hydrostatic transmission. I don't
> mind
> > the walk but would it do at least half an acre if
> I
> > used two batts instead of the one the evalbum one
> has.
> > http://www.austinev.org/evalbum/546
> > It just says 2 small yards. Here in some towns a
> small
> > yard is the 10ft to the curb in my town it is an
> acre.
> >
> > My 2nd option is a trailer for the sears and stick
> > some big batts in there. There isnt' much if any
> space
> > up front I only had 42 volts of 30amphr bb600s as
> all
> > that would fit and that took about 4-5 charges to
> do
> > my lawn. The mower normally pulled 60-80amps when
> > mulching. If I put 4 EV145s in a trailer that
> would
> > add roughly 400lbs which I don't know if it could
> > pull. If it could and it didn't up amps that much
> it
> > may mow my yard.
> >
> > If I had another use for the batteries, had a free
> > reel mower sitting around or had spare batteries
> I'd
> > just go do it. But it is all a little expensive to
> get
> > the stuff only to get disappointed that it won't
> work
> > and be stuck with stuff I can't use or return.
> >
> >
> >
> >
> >
>
>
--- End Message ---
--- Begin Message ---
I never really got much more then 30 usable ah out of
the BB600s. One issue may be I have a bum doner mower
but in my experience it would take me days to mow my
lawn. I'd mow one corner and charge the batts. Maybe
get a second mow in and finish the front of the lawn.
Then charge and I'd be able to mow one side lawn and
charge again and mow the back side lawn. That is if
lawn mowing hit the weekend. If it was during the week
I'd be mowing monday through thursday after work each
day. This meant different sections would be at
different heights and if it wasn't for the drought
last year that stalled the grass I don't know what I
would have done.
The last couple passes on each charge would be pretty
slow with the voltage dropping and the hydro really
drops speed when my PM motor dropped RPMs so there
wasn't much more I could get out of it.
According to the robomow website a typical acre has
around 24,000 square feet. So my lawn areas is large
for a typical acre. Compared to my neighbors with much
larger houses, larger drives, patios, pools and such I
just have more grass to cut.
--- Cor van de Water <[EMAIL PROTECTED]> wrote:
> Did I read you use BB600?
> They should be able to supply 40Ah in real life,
> so your draw of 60 - 80A should give you 30 to 40
> min of mowing?
>
> How long does it take to cover your
> larger-than-normal acre? ;-)
>
> Cor van de Water
> Systems Architect
> Proxim Wireless Corporation http://www.proxim.com
> Email: [EMAIL PROTECTED] Private:
> http://www.cvandewater.com
> Skype: cor_van_de_water IM:
> [EMAIL PROTECTED]
> Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD#
> 25925
> Fax: +1 408 731 3675 eFAX: +31-87-784-1130
> Second Life:
>
www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On
> Behalf Of Mark Hastings
> Sent: Wednesday, February 28, 2007 12:00 PM
> To: ev@listproc.sjsu.edu
> Subject: Re: Looking for Electric Mower Suggestions
> for 1 acre
>
> Ideally that would be great.
> However I have a large acre, approximately 40,000
> square feet of lawn
> (800sqft house), and a few dogs.
> Plus our puppies would have a conflict with it. For
> the big $1600 model it
> takes up to 3 hours to mow 5400 square feet per the
> website and then it
> charges. So that could potentially be 2-3 days where
> it goes off to mow the
> lawn where we'd have to keep the dogs in and living
> right at the center of
> town by the school doesnt' help either.
> If my wife ever goes and takes the dogs. I may just
> have to get one or two
> of these :-)
>
>
--- End Message ---
--- Begin Message ---
I was sort of in agreement with the complaints (EVs shouldn't make noise).
An event happened today that made me think that, perhaps, EVs should make
noise. I was walking down the sidewalk when a personal mobility (totally
silent electric) scooter nearly knocked me down.
Maybe they should put noise makers on these things... starting with their
members??? <g>
--- End Message ---
--- Begin Message ---
The basic specs are all on their website:
http://www.altairnano.com/markets_amps.html
In a nutshell, the energy density is about halfway between conventional
Li-Ion and Lead-Acid, without the characteristic of thermal runaway.
Additionally, the raw data I have seen (I do not have copies and their
confidentiality is reasonable) indicated superior expulsion,
absorption, and life cycle performance to any chemical battery I know
of. According to their Pheonix order, the cost once they make it to
production rivals high end Lead Acid. All these things are GOOD for
Killacycle. It appears now that A123 has the edge in the energy density
department, but the nano-titanates will be considerabley more affordable
and have better expulsion and absorption (good for racing and fast
charge), and probably life cycle.
There is 1 major drawback: You can't get them yet!
I haven't seen a test pack yet, and I own at least part of that.
Between Godaddy's crappy hosting (making my emails look like spam to
their CEO, who wasn't there when they agreed to give me a test pack),
and my own communication inadequacies, I can't really blame them for
being cautious about what sensitive information they let out to a freak
with a scooter.
Writing this email just now prompted me to call them, and I did get
through to the technical advisor who was there at the conference when
the test agreement was made on a handshake. He asked me to re-send the
test pack requirement parameters, and that he would do the "best he
could" with company decision makers (he impresses me as a technical guy
with a very objective unbiased thought process) at getting a test pack
to me.
While I had him on the phone, I asked if they had solved the production
problem with the Titanate powder, and he said that they had
accomplished that breakthrough. They are still under exclusivity with
the Pheonix order, but I am requesting a pack that is remnant of their
in-house prototype testing.
So, there is the status. I would be foolish to state at this time when
to expect a test pack, or when they will be available to private
individuals and hobbyists. I'm just trying to get my hands on
something real and test it so I can separate myth from fact like the
rest of us.
"Life is like a box of chocolates,
except for those days when it tastes
more like total crap."
-Sam
-------- Original Message --------
Subject: Well, how is the AltairNano Pack working?
From: Bill Dube <[EMAIL PROTECTED]>
Date: Mon, February 26, 2007 6:51 am
To: Sam Maynard <[EMAIL PROTECTED]>
Hi Sam,
Since I'm always on the lookout for hotter batteries for the bike
(and other projects) I'd really like to know more about these new cells.
Can you give me the basic specifications for the cells or batteries?
Thanks in advance,
Bill Dube'
--- End Message ---
--- Begin Message ---
As a thought... wouldn't it be better to replace a $100 battery, than to
prop it up with $1000 in solar panels?
> What if you used a solar panel to prop up the weakest battery in the
> string? Let's say you have 19 batteries that can go 30 miles, and 1 that
> can only go 15 miles. You can only drive the car 15 miles. You prop that
> battery up with solar panels while the car is parked all day, and get a
> few more miles. The solar panels could even help while driving, relieving
> the load on the bad battery by 5 or 10 amps. The downside is you need a
> fairly $ophisticated BMS to do this.
--- End Message ---
--- Begin Message ---
[EMAIL PROTECTED] wrote:
> ICE racing has been in development for over a century. The
> EV racing pioneers like John Wayland and Roderick Wilde, has
> been at it for less than 20 years. Do you suppose any of the
> ICE racers were in the 11's 20 years into their early development?
There is no doubt that the EV racing pioneers are advancing the state of
the art and learning new ways to go fast, but there is also no doubt
that they are also benefitting from the years of ICE drag racing
experience. Making the power may be different, but getting that power
to the ground poses similar challenges regardless of the source of
motive power and the same suspension, rear end, tire, etc. 'tricks' that
are available off the shelf for ICE racers are available to EV racers.
John Wayland wrote:
> PS: Without sponsorship of any kind, anyone could reproduce
> White Zombie for about $18,000 and go out and kick $75,000
> production car butt...
This is where I think John *proves* Chris' point (as does Rod with
mention of the Maniac Mazda beating Vipers). The White Zombie is a
purpose-built drag racer, stripped to a minimum of creature comforts,
etc., and running it against a production car hardly proves that EVs can
beat 'comparable' ICE vehicles. Likewise the Maniac Mazda, a completely
gutted RX7, non-street legal (but granted, still a steel-bodied door
slammer) purpose-built drag racer just edging out a (very expensive)
production ICE car hardly demonstrates the superiority of EVs over
'comparable' ICEs.
John suggests that when the Zombie races, his competitors get their
doors blown off by a 35 year old Datsun, but this is really misleading,
as would be the suggestion that the Maniac Mazda is a 28yr old RX7.
Neither of these cars is running *any* of the original drivetrain that
came with the vehicle; the motor(s), tranny (where applicable), rear
end, wheels, tires, etc. have been replaced with completely different
parts. When someone loses to the 'Zombie, they haven't lost to a 35
year old Datsun, they've lost to a state-of-the-art 2007 electric racing
drivetrain wrapped in 35 year old Datsun bodywork. (I expect John will
counter that of course the 'Zombie is a 35 year old Datsun since that's
what the registration says ;^). My opinion is that the 'Zombie (and
Maniac Mazda) are more akin to a rocket-powered funny car; sure the
outward appearance may resemble that of some (past) production vehicle,
but no one would try to claim that losing to one is a loss to the
production vehicle make/model.
John mentions that one could reproduce the Zombie for about $18K;
subtract the cost of the donor car ($1K or less?), and this leaves about
$17K spent on peformance mods. I've mentioned my buddy's Duramax diesel
pickup (4 door, fully-loaded 4x4); I don't know how much he's invested
in the performance mods, but it is certainly a fraction of the $17K
available and he has run mid 12's on street tires with this daily
driver. I have no doubt that if he addressed his traction/suspension
issues he would be running low 12's, and were he to invest a similar
amount to the $17K required for the Zombie's performance mods he would
be running with, or beating the Zombie. It is certainly possible to
spend far more than $17K on performance mods to an ICE vehicle and not
be able to match the performance of the Zombie, but it is certainly not
impossible to do so.
For as much as I consider most (if not all) of the exibition runs that
put an EV up against an ICE at events such as the NEDRA Nationals
unfair, they are still probably the most exciting runs for those in the
stands and are the best available tool for demonstrating just how quick
EVs can be.
It is rather surprising just how long (and boring) a 10-15 second run
can be for spectators (especially the last 1/8th mi) without the audible
cues of an ICE vehicle in one lane to allow appreciation of just how
quick the EV is moving. In all fairness, this also occurs because there
are so few racers in some (many) of the NEDRA classes that it simply
isn't possible to line up very many matches between vehicles of similar
class/performance without putting an ICE vehicle in one lane. Problem
is that an ICE vehicle comparable to the Zombie or Maniac Mazda probably
ought to be something from the NHRA Super Street or Super Stock classes,
not a production ICE vehicle.
I expect that most of the friday/saturday night races that John and Tim
run the Zombie in are probably much fairer in the sense of pitting the
Zombie against ICE vehicles at a similar state of modification (or at
least a similar dollar investment in performance mods), and so are much
more effective at demonstrating the potential of EVs.
Whether or not we are yet at the point where Evs can demonstrate
superiority over comparable ICE vehicles may be arguable, but there is
no disputing that John, Rod, Bill, Dennis, etc. do a *huge* service for
all EVers when they get out there and in the faces of the ICE racers
with their high performance EVs!
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Hi Mark,
Some piece is still not making sense, this probably has to do with the speed
that you are moving forward with.
Now a disclaimer: I don't have a lawn here, so I don't know about the
automated mowers and their speeds, but I used to have a push-mower that was
almost 2 ft wide (I believe 50 cm).
Walking speed if you are active is about 20,000 ft per hour (active walk,
not a stroll) so with a 2 ft wide mower you can cover your entire lawn in
slightly over 1 hour.
This tells me that a walking (or slow jog) speed, you would cover the lawn
in 2 charges.
If you want to work out, a push-mower may be a solution ;-)
I usually raked the cut grass afterwards, but at 40,000 ft that may become
impractical.
There are several owners of Elec-trac and mowers on this list, so you should
be able to get more feedback from experience from them.
Since there is 43560 square feet in an acre, this means that you have
nothing but grass around your house ;-)
Another alternative could be to cut back on the grass (pun intended).
Cor van de Water
Systems Architect
Proxim Wireless Corporation http://www.proxim.com
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Second Life: www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Mark Hastings
Sent: Wednesday, February 28, 2007 12:26 PM
To: ev@listproc.sjsu.edu
Subject: RE: Looking for Electric Mower Suggestions for 1 acre
I never really got much more then 30 usable ah out of the BB600s. One issue
may be I have a bum doner mower but in my experience it would take me days
to mow my lawn. I'd mow one corner and charge the batts. Maybe get a second
mow in and finish the front of the lawn.
Then charge and I'd be able to mow one side lawn and charge again and mow
the back side lawn. That is if lawn mowing hit the weekend. If it was during
the week I'd be mowing monday through thursday after work each day. This
meant different sections would be at different heights and if it wasn't for
the drought last year that stalled the grass I don't know what I would have
done.
The last couple passes on each charge would be pretty slow with the voltage
dropping and the hydro really drops speed when my PM motor dropped RPMs so
there wasn't much more I could get out of it.
According to the robomow website a typical acre has around 24,000 square
feet. So my lawn areas is large for a typical acre. Compared to my neighbors
with much larger houses, larger drives, patios, pools and such I just have
more grass to cut.
--- Cor van de Water <[EMAIL PROTECTED]> wrote:
> Did I read you use BB600?
> They should be able to supply 40Ah in real life, so your draw of 60 -
> 80A should give you 30 to 40 min of mowing?
>
> How long does it take to cover your
> larger-than-normal acre? ;-)
>
> Cor van de Water
> Systems Architect
> Proxim Wireless Corporation http://www.proxim.com
> Email: [EMAIL PROTECTED] Private:
> http://www.cvandewater.com
> Skype: cor_van_de_water IM:
> [EMAIL PROTECTED]
> Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD#
> 25925
> Fax: +1 408 731 3675 eFAX: +31-87-784-1130
> Second Life:
>
www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Mark Hastings
> Sent: Wednesday, February 28, 2007 12:00 PM
> To: ev@listproc.sjsu.edu
> Subject: Re: Looking for Electric Mower Suggestions for 1 acre
>
> Ideally that would be great.
> However I have a large acre, approximately 40,000 square feet of lawn
> (800sqft house), and a few dogs.
> Plus our puppies would have a conflict with it. For the big $1600
> model it takes up to 3 hours to mow 5400 square feet per the website
> and then it charges. So that could potentially be 2-3 days where it
> goes off to mow the lawn where we'd have to keep the dogs in and
> living right at the center of town by the school doesnt' help either.
> If my wife ever goes and takes the dogs. I may just have to get one or
> two of these :-)
>
>
--- End Message ---
--- Begin Message ---
I'll gladly admit that I sometimes miss the finer points of motor
dynamics, so if the great madman would care to explain what I missed
I'd be happy to listen and learn.
Hopefully this is about right - I don't deal with brushed motors often (my
motors are BLDC's).
On a sepex motor (let's start with that) motor inductance is only present in
the armature.
A PWM (MOSFET or SCR) controller applies full battery voltage (or as close
as possible) to the commutator during the 'on' time. The armature inductance
causes the current to ramp upwards. Once the current hits the set current
limit of the controller, the controller turns off (hopefully). Across the
commutator you have full battery voltage until it turns off.
With the controller off, the motor's inductance pushes the current back out
the motor (remember, inductors don't like to change current). The voltage
across the motor wants to go very, very, negative. The free-wheeling diode
in the controller conducts this current and keeps the voltage from dropping
much below a couple of volts negative. Across the commutator you have one
diode drop (a couple of volts or hopefully less at these current levels).
The current will ramp downwards, by the way.
The average voltage is (BATTERY_VOLTAGE * ON TIME) - (DIODE DROP * OFF TIME)
divided by (ON TIME + OFF TIME). The peak voltage seen across the commutator
is still battery pack voltage - in the case of a sepex motor.
The current ramp rate going up is roughly proportional to battery voltage
minus motor back-EMF (pretty close to average voltage), divided by
inductance. The current rate going down is roughly proportional to motor
back-EMF, also divided by inductance.
In a series wound motor, things get a bit more difficult. The field winding
acts as an inductor, too, so the voltage swings seen across the commutator
will not be full battery voltage, but rather, smoothed by the ratio of
armature inductance and field inductance.
-Dale
--- End Message ---
--- Begin Message ---
It is fairly slow moving, low to the ground, and has contact bumpers on
front and back.
So while the image of mowing a puppy is quite disturbing, I'm not sure
how likely or even possible this actually is. My dog was never inclined
to be near it while running to start with. It moves at about half
normal walking speed so he'd have to be asleep to begin with. That
ground clearance makes it really hard to roll over such an obstacle, and
contact with the bumper will make it reverse anyways.
Also take a look at the underside. The cutting deck is actually 3
recessed wells with relatively small blades, and they're not near the
edge. Like if you did let it start running over your foot it seems it
would be unlikely to cut it, though I wouldn't be the one to try it with
my foot.
Danny
Mark Hastings wrote:
Ideally that would be great.
However I have a large acre, approximately 40,000
square feet of lawn (800sqft house), and a few dogs.
Plus our puppies would have a conflict with it. For
the big $1600 model it takes up to 3 hours to mow 5400
square feet per the website and then it charges. So
that could potentially be 2-3 days where it goes off
to mow the lawn where we'd have to keep the dogs in
and living right at the center of town by the school
doesnt' help either.
If my wife ever goes and takes the dogs. I may just
have to get one or two of these :-)
--- End Message ---
--- Begin Message ---
Thanks Dale, thinking about it over lunch I realised this as well. So
the commutator wouldn't nescesarily fireball in a series motor running
off 720V, my mistake. Wether the rest of the motor can handle the high
voltage remains an issue though.
On 2/28/07, Dale Ulan <[EMAIL PROTECTED]> wrote:
I'll gladly admit that I sometimes miss the finer points of motor
dynamics, so if the great madman would care to explain what I missed
I'd be happy to listen and learn.
Hopefully this is about right - I don't deal with brushed motors often (my
motors are BLDC's).
On a sepex motor (let's start with that) motor inductance is only present in
the armature.
A PWM (MOSFET or SCR) controller applies full battery voltage (or as close
as possible) to the commutator during the 'on' time. The armature inductance
causes the current to ramp upwards. Once the current hits the set current
limit of the controller, the controller turns off (hopefully). Across the
commutator you have full battery voltage until it turns off.
With the controller off, the motor's inductance pushes the current back out
the motor (remember, inductors don't like to change current). The voltage
across the motor wants to go very, very, negative. The free-wheeling diode
in the controller conducts this current and keeps the voltage from dropping
much below a couple of volts negative. Across the commutator you have one
diode drop (a couple of volts or hopefully less at these current levels).
The current will ramp downwards, by the way.
The average voltage is (BATTERY_VOLTAGE * ON TIME) - (DIODE DROP * OFF TIME)
divided by (ON TIME + OFF TIME). The peak voltage seen across the commutator
is still battery pack voltage - in the case of a sepex motor.
The current ramp rate going up is roughly proportional to battery voltage
minus motor back-EMF (pretty close to average voltage), divided by
inductance. The current rate going down is roughly proportional to motor
back-EMF, also divided by inductance.
In a series wound motor, things get a bit more difficult. The field winding
acts as an inductor, too, so the voltage swings seen across the commutator
will not be full battery voltage, but rather, smoothed by the ratio of
armature inductance and field inductance.
-Dale
--
www.electric-lemon.com
--- End Message ---
--- Begin Message ---
I have one of those! i got it from a buddy after the batteries croaked. Does
that make me a real EV owner?
---- Danny Miller <[EMAIL PROTECTED]> wrote:
=============
Well yeah, the Friendly Robotics Robomower.
It's designed to run unattended. Earlier models you'd put in the yard
and press Start, later models have a docking station that they leave and
return to on a programmed schedule (can't automatically go between
unconnected lots like back to front of course). You have to stake down
a closed loop permeter wire to indicate your yard. It is slow, can take
hours or even multiple charges for a decent size yard, but being
unattended runtime is not especially important.
It's a pretty good system. Also it's just freakin cool. It is
expensive however.
Danny
Mark Hastings wrote:
>I'm not sure if gas mowers have improved much over the
>years but my my hacked together electric craftsman
>mower is batteryless and I haven't found a reasonable
>replacement for my acre yard.
>Is there anything new out there I'm just not finding
>for an electric mower that would handle that area
>without taking days to mow?
>
>I can only think of two options and I'm not sure
>either would work.
>
>I have thought about converting a gas reel mower. I'd
>think the reel mower would be more efficient then a
>tractor with a hydrostatic transmission. I don't mind
>the walk but would it do at least half an acre if I
>used two batts instead of the one the evalbum one has.
>http://www.austinev.org/evalbum/546
>It just says 2 small yards. Here in some towns a small
>yard is the 10ft to the curb in my town it is an acre.
>
>My 2nd option is a trailer for the sears and stick
>some big batts in there. There isnt' much if any space
>up front I only had 42 volts of 30amphr bb600s as all
>that would fit and that took about 4-5 charges to do
>my lawn. The mower normally pulled 60-80amps when
>mulching. If I put 4 EV145s in a trailer that would
>add roughly 400lbs which I don't know if it could
>pull. If it could and it didn't up amps that much it
>may mow my yard.
>
>If I had another use for the batteries, had a free
>reel mower sitting around or had spare batteries I'd
>just go do it. But it is all a little expensive to get
>the stuff only to get disappointed that it won't work
>and be stuck with stuff I can't use or return.
>
>
>
>
>
>
>
--- End Message ---
--- Begin Message ---
Find out who repairs riding mowers in your area and see if they have a
dead one they want to unload.
I purchased a riding mower sans engine for $25 recently from a repair
shop. He even went through his stock of used tires to find me a good set.
Then you can mount 4 GC batteries onboard and have plenty of mowing
power/range. No trailer and a large cutting swath. You might set it up
like an old Elektrac, one motor for propulsion and a separate motor for
the deck, or use a large single motor for both.
> Hm between this email and looking again at the
> robomower site made me think of using multiple
> trailers with smaller batteries. When I don't mulch I
> bag. And when I dumped off one load I could switch
> trailers. Sadly this probably doubles the cost but at
> least I don't have to tow 400lbs and I could try it
> first with only one trailer and get the second if it
> worked. Now I just gotta find a cheap sturdy small
> trailer thingy, or off to northern tool to buy some
> wheels.
> I could even do this with the reel mower. Go get a
> drink of water and switch battery packs.
>
> If anyone has any other ideas I'd welcome them and
> thanks for the responses so far.
>
> --- Dave Wilker <[EMAIL PROTECTED]> wrote:
>
>> Weird Idea:
>> Use a very long, heavy duty extension cord and an
>> electric tractor. Just
>> have to be careful not to run it over.
>>
>>
>>
>> David C. Wilker Jr.
>> USAF (RET)
>>
>>
>> ----- Original Message -----
>> From: "Mark Hastings" <[EMAIL PROTECTED]>
>> To: <ev@listproc.sjsu.edu>
>> Sent: Wednesday, February 28, 2007 10:13 AM
>> Subject: Looking for Electric Mower Suggestions for
>> 1 acre
>>
>>
>> > I'm not sure if gas mowers have improved much over
>> the
>> > years but my my hacked together electric craftsman
>> > mower is batteryless and I haven't found a
>> reasonable
>> > replacement for my acre yard.
>> > Is there anything new out there I'm just not
>> finding
>> > for an electric mower that would handle that area
>> > without taking days to mow?
>> >
>> > I can only think of two options and I'm not sure
>> > either would work.
>> >
>> > I have thought about converting a gas reel mower.
>> I'd
>> > think the reel mower would be more efficient then
>> a
>> > tractor with a hydrostatic transmission. I don't
>> mind
>> > the walk but would it do at least half an acre if
>> I
>> > used two batts instead of the one the evalbum one
>> has.
>> > http://www.austinev.org/evalbum/546
>> > It just says 2 small yards. Here in some towns a
>> small
>> > yard is the 10ft to the curb in my town it is an
>> acre.
>> >
>> > My 2nd option is a trailer for the sears and stick
>> > some big batts in there. There isnt' much if any
>> space
>> > up front I only had 42 volts of 30amphr bb600s as
>> all
>> > that would fit and that took about 4-5 charges to
>> do
>> > my lawn. The mower normally pulled 60-80amps when
>> > mulching. If I put 4 EV145s in a trailer that
>> would
>> > add roughly 400lbs which I don't know if it could
>> > pull. If it could and it didn't up amps that much
>> it
>> > may mow my yard.
>> >
>> > If I had another use for the batteries, had a free
>> > reel mower sitting around or had spare batteries
>> I'd
>> > just go do it. But it is all a little expensive to
>> get
>> > the stuff only to get disappointed that it won't
>> work
>> > and be stuck with stuff I can't use or return.
>> >
>> >
>> >
>> >
>> >
>>
>>
>
>
--
If you send email to me, or the EVDL, that has > 4 lines of legalistic
junk at the end; then you are specifically authorizing me to do whatever I
wish with the message. By posting the message you agree that your long
legalistic signature is void.
--- End Message ---
--- Begin Message ---
http://www.youtube.com/watch?v=3dRpAZci9m0
I am astounded to see that the "plasma" video of the KillaCycle has
almost 34,000 views. It is getting about 500+ views per day.
With the marvelous job that Jim Husted did on the brush rigging, we
may not be getting these fireworks again. At least we are hoping we don't. :-)
Bill Dube'
--- End Message ---
--- Begin Message ---
In a message dated 2/28/07 7:46:03 AM Pacific Standard Time,
[EMAIL PROTECTED] writes:
<< Subj: A few new KillaCycle photos (battery assembly)
Date: 2/28/07 7:46:03 AM Pacific Standard Time
From: [EMAIL PROTECTED] (Bill Dube)
Sender: [EMAIL PROTECTED]
Reply-to: ev@listproc.sjsu.edu
To: ev@listproc.sjsu.edu
Put up some new pictures on the KillaCycle web site. (It is super
easy to do, thanks to the great job Dave Stensland did building the web
site!)
Here are some showing how we assemble to battery pack modules. (There
will be more as we progress on the new pack.)
http://www.killacycle.com/photos/battery-assembly-110s-x-9p/
I also dropped in a few more showing the motors going into the bike.
http://www.killacycle.com/photos/motor-details/
Bill Dube' >>
Bill,With 123s 1000 cycle life, Why are you building a new pack?How many
cycles did you get? D.Berube
--- End Message ---
--- Begin Message ---
Though not a series/parallel switcher, here's one posted by Lee Hart
recently that is very efficient:
A big rotary arm moves a sliding contact over the bolt heads to
make/break connections. Arcing occurs on the edges, not the faces of the
contacts.
The trick is that there are intermediate contacts between positions. The
shorting bar is wide enough to short two adjacent contacts as it moves.
The intermediate contacts have resistors in series, to always provide a
path for the current as the switch is moved.
Example (view with a fixed-width font like Courier):
||
12v__________O ||---------to motor
||
__/\/\__O \movable shorting bar
|
24v_|________O
As the shorting bar is moved
1. the motor gets straight 12v, resistor not connected
2. motor gets 12v, resistor connected between 12v and 24v
3. motor gets 24v thru resistor
4. motor gets 24v direct, resistor shorted to 24v
5. motor gets 24v direct, resisto not connected
Crude, but no arcing or noise! 100% efficient if you only pass through
the resistive positions for a fraction of a second.
Bill Dennis
Myles Twete wrote:
Take a look at this 1917 patent of a drum contact controller whose outputs
drive contactor coils that in turn switch series field resistors in/out:
http://www.google.com/patents?vid=USPAT1239840&id=ACoTAAAAEBAJ&pg=PP1&dq=rot
atable+drum+control+westinghouse
-Myles
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Lee Hart
Sent: Tuesday, February 27, 2007 1:29 PM
To: ev@listproc.sjsu.edu
Subject: Re: contactor controllers
Lee Hart wrote:
48v + startup resistor
48V
84V
168V
216V
These are funny voltages.
Tom Ward wrote:
Yes, I know it's strange. I have two banks of NiCads; the factory fitted
watercooled saft STM100 nicads in 4 unequal blocks and then 48V of
secondhand Alcad and Nife Nicads.
I haven't a huge amount of time so I am hoping to avoid dismantling the
saft blocks (I did that a few months ago to fix a waterleak and it took
half a day just to drop one block).
OK. If you are mixing batteries, then I'd use a rectactor setup for your
series/parallel contactor controller. It has the advantage that
dissimilar packs *won't* transfer charge between them when in parallel.
Does the field really need 120v at 10 amps? That's 1.2kw.
I am just quoting what I read in the workshop manual.
Well, it's easy enough to measure its DC resistance. 120v at 10a
is 12 ohms.
I must be missing something, do you mean let the driver directly control
the armature and field current? Isn't that a recipe for a broken motor?
No. Current is torque. The driver uses the accelerator pedal to say how
much torque he wants (based on how fast he wants to go). The controller
will have a current limit circuit, so you can't demand too much; but
beyond that, the driver is the boss!
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
<sigh>
Until they actually produce them, and someone actually tests them
out, they are just charts, graphs, and numbers on a web site, unfortunately.
The fact that they haven't released cells to anyone (that we know of)
is not a good sign. Usually, when a company has a nifty hot new
product, they are very eager to get it out in the hands of potential
customers. At the very least, they release samples to select "beta
testers" that are in a position to publicly tout the marvels of the
new product. (Like you, Sam.)
Bill Dube'
At 01:47 PM 2/28/2007, you wrote:
The basic specs are all on their website:
http://www.altairnano.com/markets_amps.html
In a nutshell, the energy density is about halfway between conventional
Li-Ion and Lead-Acid, without the characteristic of thermal runaway.
Additionally, the raw data I have seen (I do not have copies and their
confidentiality is reasonable) indicated superior expulsion,
absorption, and life cycle performance to any chemical battery I know
of. According to their Pheonix order, the cost once they make it to
production rivals high end Lead Acid. All these things are GOOD for
Killacycle. It appears now that A123 has the edge in the energy density
department, but the nano-titanates will be considerabley more affordable
and have better expulsion and absorption (good for racing and fast
charge), and probably life cycle.
There is 1 major drawback: You can't get them yet!
I haven't seen a test pack yet, and I own at least part of that.
Between Godaddy's crappy hosting (making my emails look like spam to
their CEO, who wasn't there when they agreed to give me a test pack),
and my own communication inadequacies, I can't really blame them for
being cautious about what sensitive information they let out to a freak
with a scooter.
Writing this email just now prompted me to call them, and I did get
through to the technical advisor who was there at the conference when
the test agreement was made on a handshake. He asked me to re-send the
test pack requirement parameters, and that he would do the "best he
could" with company decision makers (he impresses me as a technical guy
with a very objective unbiased thought process) at getting a test pack
to me.
While I had him on the phone, I asked if they had solved the production
problem with the Titanate powder, and he said that they had
accomplished that breakthrough. They are still under exclusivity with
the Pheonix order, but I am requesting a pack that is remnant of their
in-house prototype testing.
So, there is the status. I would be foolish to state at this time when
to expect a test pack, or when they will be available to private
individuals and hobbyists. I'm just trying to get my hands on
something real and test it so I can separate myth from fact like the
rest of us.
"Life is like a box of chocolates,
except for those days when it tastes
more like total crap."
-Sam
-------- Original Message --------
Subject: Well, how is the AltairNano Pack working?
From: Bill Dube <[EMAIL PROTECTED]>
Date: Mon, February 26, 2007 6:51 am
To: Sam Maynard <[EMAIL PROTECTED]>
Hi Sam,
Since I'm always on the lookout for hotter batteries for the bike
(and other projects) I'd really like to know more about these new cells.
Can you give me the basic specifications for the cells or batteries?
Thanks in advance,
Bill Dube'
--- End Message ---
