EV Digest 6506
Topics covered in this issue include:
1) Re: High Voltage / Low current,
was: High Current / Low Voltage Drive
by "Peter VanDerWal" <[EMAIL PROTECTED]>
2) RE: My latest attempt to get a few extra miles ... never seen thi
s one done before
by Cor van de Water <[EMAIL PROTECTED]>
3) Re: swamp cooled EV?
by Jeff Shanab <[EMAIL PROTECTED]>
4) Re: Best way to run battery cables
by Lee Hart <[EMAIL PROTECTED]>
5) Re: swamp cooled EV?
by Lee Hart <[EMAIL PROTECTED]>
6) RE: My latest attempt to get a few extra miles ... never seen this one
done before
by "Roger Stockton" <[EMAIL PROTECTED]>
7) Battery watering?
by "Ryan Stotts" <[EMAIL PROTECTED]>
8) A Must See - Portland Roadster Show and White Zombie
by "Ted C." <[EMAIL PROTECTED]>
9) Minimalism
by "Randy Burleson" <[EMAIL PROTECTED]>
10) Re: A Must See - Portland Roadster Show and White Zombie
by John Wayland <[EMAIL PROTECTED]>
11) Motor mods
by James Massey <[EMAIL PROTECTED]>
12) RE: A few new KillaCycle photos (battery assembly)
by Cor van de Water <[EMAIL PROTECTED]>
13) Re: Batteries for small high voltage conversion
by Tom Parker <[EMAIL PROTECTED]>
14) Re: Batteries for small high voltage conversion
by Tom Parker <[EMAIL PROTECTED]>
15) Re: Best way to run battery cables
by Frank John <[EMAIL PROTECTED]>
16) Re: Batteries for small high voltage conversion
by Ian Hooper <[EMAIL PROTECTED]>
17) Re: Best way to run battery cables
by "Joseph H. Strubhar" <[EMAIL PROTECTED]>
18) Re: My latest attempt to get a few extra miles ... never seen this
one done before
by "Joseph H. Strubhar" <[EMAIL PROTECTED]>
--- Begin Message ---
A couple things to consider.
1) These batteries have much lower energy density than normal EV batteries.
2) Many more points of failure, lots of: batteries, connections, wires.
3) The reason the batteries are so cheap is probably because they are
useless.
4) Not only is a controller complicated, charging is going to be VERY
complicated.
5) Dispersed as you suggest will mean long cable runs between batteries.
So either lots of extra weight, or lots of extra resistance.
> Yesterday evening I had the opposite idea:
> Why not use small batteries (like the popular 12V 7Ah gel cell
> that almost every small UPS is equipped with) and string not 25
> but 250 in series to get a 3000V, 7Ah pack?
> The cables could be rather thin because they only need to carry
> a small current, the batteries can be placed in all those nooks
> and crannies that normally are unused, although the idea that
> appealed to me was to make a belly pan 3 inches lower than the
> frame and stack those batteries in modules of about 300V under
> the car. (This leaves all other areas of the car available,
> though weight distribution and available under-car space could
> make it necessary to mount some battery modules in the engine
> bay, close to the firewall. The belly-pan prevents water and
> dirt in the engine bay and battery modules, which is required
> due to the high voltage.
> The other three reasons I thought of this concept are:
> 1. I saw an ad offering these batteries per pallet from old stock
> for $1.50 each ($375 for a 21kWh pack, not bad)
> 2. The low amps and high volts make it easy to switch batteries
> in and out of the series when the module BMS detects they
> pass the threshold for minimum voltage (10.5V)
> 3. This voltage is a challenge to build a controller for, but once
> it is done and a high voltage AC motor can be used, it is also
> trivial to use the EEstor instead of or in addition to the
> battery bank.
> Note that the AC motor not necessarily runs on 3000V, as the
> same concept that limits a DC motor voltage works here too,
> so possibly a standard 400/600V AC motor can be used.
> (I have a junker in the garage that I got for free with some
> equipment that I liked to buy, I had to take it all, so now
> I not only have a 400V 3-phase variable speed drive but also
> the motor that was driven with it.
>
> 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 Ian Hooper
> Sent: Friday, March 02, 2007 7:11 PM
> To: [email protected]
> Subject: Re: High Current / Low Voltage Drive
>
> On 03/03/2007, at 11:42 AM, Bruce wrote:
>
>> It seems that fewer cells would simplify battery management. If taken
>> to the extreme, a single cell battery pack would be the simplest. Two
>> volts total and you would never have to worry about equalization.
>>
>> But it might be hard to find a 2 volt cell that could deliver ten
>> thousand amps. And controllers capable of handling that current won't
>> be common either...
>
> Not so hard as you might think: http://www.thunder-sky.com/pdf/
> 200712715238.pdf
>
> Tho the controller would be a problem, yeah. Obviously have to custom
> build
> something. Some power MOSFETs can switch 100A continuous, so you'd need a
> hundred of those.. I guess that's only a few grand worth.
>
>> A not quite so extreme solution could be 4 cells. Still the pack
>> would have to be able to provide thousands of amps, but this might be
>> possible with lead-acid cells weighing hundreds of pounds each. For
>> the controller you could go with a contactor setup. Two volts all
>> parallel with a resistor for starting, then two volts no resistor,
>> four volts series/parallel and finally all eight volts in series.
>
> I'd predict your contactors would weld themselves together if you tried
> switching that sort of current mechanically!
>
> A whole lot of power MOSFETs should be able to handle it, or you might
> even
> be able to find some kind of massive industrial IGBT for the job. This is
> getting close: http://au.farnell.com/jsp/
> endecaSearch/partDetail.jsp?SKU=1208671
>
>> The battery cables and contactors would have to be sized larger to
>> carry the
>> increased current, but this sounds possible. How about the motor?
>> Where
>> would you get a motor rated for 8 volts and thousands of amps?
>> Maybe you
>> could rewind a regular motor with thick wire and less turns? What
>> about the commutator? The low voltage might keep the arcing down, but
>> the voltage losses could be more than desirable. Perhaps a brushless
>> motor would help?
>
> I think all your cables/contactors/etc would need to be prohibitively
> large..
>
> How about just use a very beefy DC/DC converter to step up the battery
> voltage, e.g from 8V 2000Ah to 160V 100Ah equivalence, then you could juse
> use normal motors and controllers, with sensible cable sizes etc. It'd
> have
> to be one heck of a big DC/DC converter though, maybe too hard to build.
>
> Interesting concept..
>
> -Ian
>
>
--
If you send email to me, or the EVDL, that has > 4 lines of legalistic
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--- End Message ---
--- Begin Message ---
Note that Peter is talking about the voltage while driving, under load.
As soon as the load is gone, the pack must come back quickly and reach at
least 96V after a while, as at 12V resting voltage, the batteries are empty.
Normally they will sit above 12.3V (2.05V per cell) and freshly charged AGM
batteries can sit as high as 13.2V (2.2V per cell)
105V for 48 cells is 2.19V per cell, or 13.1V for a 12V battery - sounds
good. 100V is still 12.5V per battery and certainly not dead, absolutely not
dead if you use this threshold under load - you can go as low as about 80 to
85V under (heavy) load, to keep the cells above 1.75V which is the limit
that they are tested at for capacity.
1.75V x 48 cells = 84V.
(Some manufacturers set a different, lower voltage limit under high
discharge voltage, arguing that the resistance in the battery interconnects
and plates adds to the voltage drop.
For example if you have a decent battery it may have 4mOhm (0.004 Ohm)
internal resistance.
When you draw 300A through this pack, the internal resistance of 8 batteries
in series will make the pack voltage drop 8x 300A x 4mOhm = 8x 1200mV = 8x
1.2V = 9.6V.
So, the minimum pack voltage under 300A load while keeping 1.75V per cell as
lowest limit is 84 - 9.6V = 74.4V
so you see that the absolute lowest level of 75V that Peter suggested has
some background in keeping the pack safe while driving, while it allows you
to make the most of your range. Note that it is only allowed to go this low
while driving. As soon as you take your foot off the throttle, it must bouce
back to above 90V (11.5V per battery) or it is already dead and you have
begun to reverse cells in the pack.
If this happens once on accident during the last mile to get home, no
problem, simply put the pack immediately on a charge and it likely will be
fine.
Doing this repeatedly will certainly damage your pack and reduce your range
quickly - this is the way "stinkers" are created!
Hope this helps,
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 Peter VanDerWal
Sent: Saturday, March 03, 2007 9:09 PM
To: [email protected]
Subject: Re: My latest attempt to get a few extra miles ... never seen this
one done before
Huh? No wonder you are getting so little range. You can safely drive a 96V
pack until it drops to 84V. If you only drive until it drops to 100V then
you are barely taking the surface charge off the pack.
When the pack gets to the end of it's life you can drive a 96V pack down to
75-80V. It's pretty much shot anyway, so you can't hurt it.
But this doesn't apply to your pack, apparently you haven't even stressed it
yet. It should have plenty of life left.
> So, I have the Festiva, and I'm driving it on the 96 V pack of 12 V
> Deka Group 24's that are way past their usable life. Even with the
> Curtis controller, easier on the batts than the GE EV-1, I'm getting
> only about
> 4.5 mile range. I was getting about 3.25 with the EV-1. Those batts
> are 80 AH at a 20 A discharge rate. Derate about 50% for EV discharge
> rate and not killing them, that's 40 AH. Voltage varies between 105
> (full) and
> 98 (totally dead). I try not to go below 100 V. So, about 4kW-hr of
> usable energy. The car is 2200 lb. I'd say 300 Wh-hr / mile. So,
> with a brand new pack on a bright sunny day here in GA, I should be
> able to safely go 13 miles. Really, that is pretty lame for a pack
> that must cost about $1200. In flooded, the pack is about $550.
> Flooded has its own issues. Like parking on a slight grade and trying
> to charge the batts when the plates aren't evenly covered ... My
> flooded batts are actually set in at a very slight angle to match the
> grade of the driveway. I literally used a level to put them in the car.
>
> So, I could spend $1200 on a fresh set of the Deka Group 24, and
> some day, it may come to that if no one comes up with a decent battery
> solution.
>
> For now, I bought one (soon to get a second) 12 V / 120 Ah (at 20 A
> discharge) battery for $65. I also bought a 700 Watt inverter off
> ebay for a buck. I put the batts in my car, run the inverter, through
> my BC-20 and try as best as I can to keep the pack charged.
>
> I drive that whole 2 miles to work. Let it sit and recharge itself
> off the spare batts, go out for lunch, let it charge itself, back to
> work, more self charging off the aux batt, and back home. I should be
> able to get 8.5 miles (as long as I don't go more than 4 miles in any
> given 2 hour period). That is OK, because when I go somewhere, I am
> usually there for a few hours. It's like driving with a 4 mile range
> and plugging in all the time, every time you stop. Not a great
> solution, but it cost only $150 and I got a 8.5 mile range (I think)
> and I didn't have to drop $1200 on a new set of Dekas yet. It may
> last 6 months or a year like this. Maybe only a few weeks. Either
> way, it was worth a try.
>
> This got me into other stuff. I am working on replacing my lead
> acid secondary pack with NiMH. Again, limit the discharge rate. I
> could put in a 3300 Watt inverter if I wanted to ... But, not use
> them as the primary motive force. A friend lent me some 13 Ah F cells
> (40 of them) to play with. I was going to try 4 sets of 10 each of
> those in parallel with my one lead acid 120 AH aux battery. That
> would be 12 V / 172 Ah (at a 20 A discharge rate).
>
> I also have 850 1.2 V / 1.6 AH NiMH cells that I picked up 2 years
> ago when I started the last Festiva project. I could maybe do
> something with those as well.
>
> I looked at prices, and it seems like I can get flooded lead (not
> Trojan
> though) for $0.045 per Watt-hr. Again, that is low discharge rate,
> not Optimas or anything EV worthy. I can get NiMH for about $0.31 per
> Watt-hr. I don't even dare price Li Ion, but my best bet would be
> DeWalt packs off E-bay. I'm not comfortable making a BMS for those,
> so I'll stick with NiMH. I believe you can get one of those 36 V
> LiIon packs for about $100 on e-bay. Again, the BMS is the issue.
>
> Where am I going with all this? Maybe a good solution is like what
> I have -
>
> 8 x 12 V AGM +
> a 5000 Watt-Hr aux pack of NiMH (or Li Ion) and a 3300 Watt inverter.
>
> I think you could get an easy real 30 mile range and some decent
> performance. I am not a fan of flooded lead golf cart batts at all.
> Why? Years of cars with poor acceleration. It wasn't until I got the
> super light car and the AGMs that I got acceptable (to me that is)
> performance.
>
> With my soultion, you can also add an alternator on the tail shaft
> of the motor (geared appropriately for charging at very slow motor
> RPM) and kick it on when the start switch is off to charge the aux
> batt that goes through the inverter / charger ... and back to the
> pack. Efficiency of that whole system maybe 65% (with the alternator
> and all) Worth it? I don't know.
>
> I'm open to comments, suggestions?
>
> Steve
>
>
> ---------------------------------
> Don't be flakey. Get Yahoo! Mail for Mobile and always stay connected
> to friends.
>
>
--
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 ---
The coating on the glass is a very good point and the one that is now
put in newer cars works wonders. If you have a post 95 car and have had
the windshield replaced and your air conditioner just doesn't seem to
keep up like it used to that can be the problem. Manufactures are
reducing the AC size depending on that coating and better headliner
insulation(insulated board instead of suspended cloth.
--- End Message ---
--- Begin Message ---
From: [EMAIL PROTECTED]
> To avoid electromagnetic fields, is it necessary to put cables inside
> a STEEL tube, or is any metal (non magnetic) enough?
See my earlier post today. It depends on what you are trying to accomplish.
Putting a wire in a ferrous (iron or steel) tube will *increase* its
inductance. Sometimes more inductance is good, as it slows the rapid rise/fall
of current (for example, in the motor leads). Other times, more inductance is
bad (such as in series with the batteries).
Putting a wire in a NON-ferrous tube (copper, brass, aluminum etc.) will
*decrease* its inductance, and so have the opposite effect.
Putting *two* wires in the same ferrous tube will increase the coupling between
them. If the currents in the two wire are exactly equal and opposite (for
example, the two wires to some load), then their magnetic fields exactly
cancel. If the two wires are unrelated signals, then noise from one is coupled
into the other.
--
Lee Hart
--- End Message ---
--- Begin Message ---
From: Jeff Shanab
> The coating on the glass is a very good point and the one that is now
> put in newer cars works wonders. If you have a post 95 car and have
> had the windshield replaced and your air conditioner just doesn't seem
> to keep up like it used to that can be the problem. Manufactures are
> reducing the AC size depending on that coating and better headliner
> insulation (insulated board instead of suspended cloth.
The carmakers are taking *tiny* steps in the direction of improving insulation.
On a scale of 1-10 I'd give them a 1 in older cars, and a 2 in new ones.
To put it in perspective, cars have typical R values (thermal resistance) of R1
for glass and R2 for the roof, doors, and floor. A 30-year-old home had R2
windows and R4 walls; and a modern house is more like R4 windows and R12 walls.
That's why it takes *10 times* the power to heat/cool a car as it would for an
equivalently sized room.
--
Lee Hart
--- End Message ---
--- Begin Message ---
Steve Powers wrote:
> So, I have the Festiva, and I'm driving it on the 96 V pack
> of 12 V Deka Group 24's [...]
> Those batts are 80 AH at a 20 A discharge rate.
You are confusing hours and amps; the 80Ah C/20 rate is the *20 hour*
rate, that is, the batteries (at their prime) will deliver 80Ah when
discharged over a 20 hour period. This means 80Ah at a 4A discharge
rate.
If you really want to know the rated capacity near a 20A discharge rate,
then look at the manufacturer's "reserve capacity" rating. This is the
number of minutes the battery can be discharged at 25A.
> Voltage varies between 105 (full) and 98 (totally dead).
How/when are you measuring this voltage? As others have noted, 98V
(2.04V.cell) is nowhere near dead if measured under load. It isn't even
totally dead if measured no load...
> The car is 2200 lb. I'd say 300 Wh-hr / mile.
Similar to what my own car seems to be consuming. I finally got around
to jacking up the front end and confirming my suspicion that the
calipers were dragging: 50A (@120V) to spin the wheels in the air at
40kph (25mph) in 2nd. This dropped to 40A after prying back the pads,
which still seems way too high. Installed a new set of calipers and it
seems to be holding at 40A, though the driver's side is still dragging
slightly (new brake hose is next). Have you tried checking your
current/power requirements with the wheels off the ground? It'd sure be
interesting to hear what others are seeing.
> For now, I bought one (soon to get a second) 12 V / 120 Ah
> (at 20 A discharge) battery for $65.
120Ah C/20 = 120Ah when discharged for 20 hours at 6A.
> I also bought a 700 Watt inverter off ebay for a buck.
> I put the batts in my car, run the inverter, through my
> BC-20 and try as best as I can to keep the pack charged.
Is this just the plan, or have you tried it yet?
700W is a bit over 58A @ 12V; this battery would likely run the charger
less than 1hr. Assuming the inverter and charger are 100% efficieny,
this puts about 700Wh into the battery, which is about 2mi.
If this battery is $65 and holds enough energy for 2mi of range, why not
simply buy 8 of them for a total of $520 and enjoy 16mi of range without
any fiddling?
Cheers,
Roger.
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--- Begin Message ---
Fuel: Filled up my truck twice this week. $30 the first time, $20 the second.
Using those numbers, lets say $200 a month in fuel.
$2550 for the Zilla, $1700 for the 9" WarP, $1,550 for the PFC-20.
$5,800 so far.
In 2-1/2 years, that stuff will have been paid for in fuel
savings(quicker if higher fuel prices).
Now... Which batteries and what size pack?
'01 reg cab Ranger(2wd). 40 mile round trip commute. Most of it on
the interstate(70mph).
US 125's? How many? How often would they have to be watered?
Mount them under the bed using standard angle iron? 1/4" or 3/8"?
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--- Begin Message ---
So I saw the posting on the list about the White Zombie at the Portland
Roadster Show. I thought to myself, "Am I going to do the two hour drive from
Olympia, WA to Portland, OR, pay for parking and the entry fee just to see one
car (I'm am not that in to the hot rod thing) that is probably tucked back in
some corner of the event?" AHH what the hell. So I talked my wife in to going
and off we went. We made it to Portland in good time. As we're getting the
tickets I say to my wife " I hope it isn't to hard to find where the White
Zombie is". We now make it to the top of the stairs where you go down into the
convention center. There at the bottom of the stairs in the main lobby on the
carpeted area before you even make it into the convention center main floor is
one car - The White Zombie. At this point I turn to my wife and say "well that
was hard, it's right there." There is the car with a 52" plasma TV next to it.
The large TV is showing video after video of gassers fallin!
g victim to the White Zombie. Mind you that this is only car that was in this
carpeted lobby area. You can not get in to the event floor with out passing
this setup. I did get to talk with John, meet his family and Tim Brehm. He was
very helpful in convincing my wife that I HAD to replace my Curtis controller
with a Zilla. That alone was worth the drive and entry fee. We had a great time
talking EVs with them. The rest of the show was really well done. There is a
lot of love put in to those cars.
All in all it was great to see an EV put out there front and center. Not in the
back corner like I was expected. I also want to give a big pat on the back to
Video Only for letting John use the 52" plasma. It was a really impressive
display on a big screen of what an electric can do for those who are not use to
even seeing an electric car in person. John also told us his White Zombie is on
the cover of the May 2007 issue of Car and Driver. You should all check it out!
Ted
Olympia, WA
N47 03.442 W122 49.108
Thank GOD for Thomas Edison. Without him we would all be watching TV by candle
light.
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--- Begin Message ---
What is the minimum collection of bits needed for an electric roadster
(just a hair this side of a motorcycle)?
True minimum that I can think of:
* Battery, controller, motor
* Steering wheel, throttle, brake pedal, seat, seatbelts
* Frame/Body-pan, suspension, steering, brakes, tires, wheels
* Electrics to support directionals, brake lights, running lights, and
headlight
Nice-to-haves
* Body
* Windscreen
* E-meter
* Lock
* Speedo/odometer
Things I don't need (and don't want to bother with!)
* Doors
* Roll-up windows
* Climate control
* Radio
I'm using this as a checklist for development... I know there are some
ultra-lightweight folks out there. Let me know if I'm missing something
or I need to recategorize.
Randii
--- End Message ---
--- Begin Message ---
Hello to All,
Ted, thanks for the kind words, and thanks for coming to the show to
both you and your wife. It was great meeting both of you.
John also told us his White Zombie is on the cover of the May 2007 issue of Car and Driver.
Ted, you may have misunderstood me. I told you that the photo in that
poster was from the magazine's story. The poster you saw was one I put
together (with permission granted by Car and Driver) especially for
this show. It may have looked more like a magazine front cover shot
because of the way I used the photo and surrounded it with special fonts
and such, but it was not a cover shot, for sure....I can only wish for
that. The photo 'is' one from many that will be in the May issue's
article. To repeat....we are not on the cover of the May issue. We 'are'
in the issue though, along with Rod Wilde and Father Time, with what
should be a four page spread about NEDRA and their night drag racing in
White Zombie.
Thanks for taking the four hour round trip to Portland and back home, I
appreciate it very much. Sorry for any confusion I may have caused.
See Ya.....John Wayland
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--- Begin Message ---
G'day All
I've been busy modifying Prestolite motors (well, the first one of a pair).
Seperate the fields from 4 windings in series to 2 + 2, and for convenience
bringing the new connections out via the old A1 & A2 terminals. New
armature terminals through the end plate so that they do not need any
flexible cables to the brush holders, with new cross-connection bars. The
bars sit against each other for nearly 1/4 the way around the motor, so
will need good insulation between them!
Pics at: http://jcmassey.gallery.netspace.net.au/Electric-vehicle-pics in
the album "Dons' EV Parts build-up"
Mods include an industrial temperature sensor jammed into the windings (in
a space between the pole shoe and the field winding, not ideal but a simple
fit). Don will time his motors once they get back to him (his friend who is
the transport leaves in 10 days). Hopefully I'll get a control panel built
for him in that time, too, so no spare time for James at the moment!
Comments welcome
Regards
[Technik] James
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--- Begin Message ---
Using just one chain requires a very stiff tensioner spring and sprocket,
such that the chain from the rear wheel makes a 180 deg around the first
motor sprocket, runs back to the tensioner sprocket and makes another 180
deg to run over the second motor sprocket with another 180 deg and ends up
at the bottom of the rear wheel sprocket.
If the tensioner spring is not stiff enough, the second motor will pull it
forward and drop the chain going back to the rear wheel sprocket, so it's
easy to see when that happens.
Advantage is that the chain is always tensioned and wear will not cause
problems until it gets so bad that the chain does not seat properly on the
sprockets. (Chains always stretch while used)
The tensioner can be attached to the frame or to the horizontal fork if you
have a hardtail.
In ASCII-art it looks like this:
_____________________
/ \ _____O Motor 1
| X | v^v^v-O________________
\___/____________________________O Motor 2
X is the rear axle with the big sprocket
v^v^v is the tensioner spring, attached to the small tensioner sprocket
Motor 1 and Motor 2 have equal sized sprockets, but do not need to be
mounted above each other, as long as the chain is not touching, they can be
almost side by side. Here I showed Motor 2 further forward.
Hope this gives some ideas,
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 BadFishRacing
Sent: Friday, March 02, 2007 3:30 AM
To: [email protected]
Subject: Re: A few new KillaCycle photos (battery assembly)
Bill,
Looking at the pictures, it looks like the comm end of the motors is farther
outboard than the shaft end. Or is the intent that the 'center of mass' of
the motors is in the center of the bike? Anyhow, I'm looking at putting a
L-91 motor in my bike, but the thing is so long, I'll need a jackshaft to
bring the drive back inboard to drive the rear wheel. Did you just get
lucky that the motor lines up with the wheel? Knowing you, probably good
design. Even running a JrDragster rear wouldn't be wide enough to line
up...... Suggestions?
Darin
BadFishRacing
----- Original Message -----
From: "Bill Dube" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Friday, March 02, 2007 12:56 AM
Subject: Re: A few new KillaCycle photos (battery assembly)
> I'll take a photo of that this weekend as I reassemble the drive.
>
> I bought two twin-row 18 tooth (and 16 tooth) #60 sprockets. I then
> machined the inner sides to thin down the #60 (0.5 inch wide) to fit #630
> motorcycle chain (0.375" wide.) A short loop of chain on the outside
> sprockets links the motors to each other. The inside sprocket of the rear
> motor drives the rear tire sprocket.
>
> The motors are spaced 7.5 inches apart. This makes ten links of #630
> exactly.
>
> Bill Dube'
>
> At 09:49 PM 3/1/2007, you wrote:
>>I'd still like to see how the 2 motors are coupled together to drive
>>the rear wheel as I've never seen that particular detail before.
>
>
>
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--- Begin Message ---
On Thu, 2007-03-01 at 23:16 +0900, Ian Hooper wrote:
> 240V, 27Ah = ~6.5kWh battery pack. Thunder Sky lithiums (for example)
> are a little under US$0.50/Wh, pretty much bang on $3K for 6.5kWh.
>
> For comparison with Optima Yellowtop D51s:
>
> - 66x Thunder Sky TS-LFP40AHA lithium cells = 240V 40Ah @ 1C. Weight
> is 99kg / 218lb. 2000 cycle life @ 80% DOD (claimed, anyway).
Does anyone have a real price for these cells? It seems you are about
right for the 80Ah cells: Rod Dilkes reported a couple of weeks ago that
he paid about AU$10,000 including transport and duties for 45 80Ah cells
and interconnects. This is US$7800.
US$7800 / (80Ah * 3.2v * 45 = 11520Wh) = $0.67/Wh (including
interconnects, transport to Australia and duties).
It has been my experiance with lead batteries that the smaller batteries
are not correspondingly cheaper. But if we assume that US$0.50 is
correct:
40Ah * 3.2v * 66 = 8448Wh * US$0.50 = $4224
Which is more than I want to spend, but I'd be tempted if I could have
some confidance in their cycle life and current handling ability.
http://www.everspring.net/product-battery-LFP40AHA.htm
The 40Ah batteries only provide 160A pulse current, they don't specify
how long the pulse is. At 240V, this is 38kW, which is acceptable in a
mini. I don't really want to spend all this money for only "acceptable"
accelleration. The 60Ah cells would be a better bet performance wise but
add to the cost, perhaps by 50%?
The everspring website doesn't make me very confidant:
On the 40Ah page (linked above), in the table at the top, the maximum
charge current is 12A, but the first graph shows a 33A charge.
On http://www.everspring.net/product-battery-technicalinfo.htm section
2.2 states the maximum discharge current is 3C, but section 9.7 warns
discharge greater than 1C will not bring you a pleasant state of mind.
Perhaps section 9.7 is missing the distinction between the LFP and LCP
models.
Hopefully the device in the background of
http://www.everspring.net/Charging-discharging.htm is not the
recommended charger. They also state the finishing charge is 4.35v until
the current drops to 1A. Wouldn't this current depend on the size of the
battery? Do they give more comprehensive instructions if you actually
buy them?
Thunder Sky themselves http://www.thunder-sky.com/pdf/200725164258.pdf
give less information but contradict everspring. Both max charge and
pulse discharge rates are higher than those specified by everspring.
I will make some enquiries with everspring.
Has anyone had experiance with an off the BMS? I've seen a couple of
posts asking about some, but no comments.
--- End Message ---
--- Begin Message ---
On Thu, 2007-03-01 at 08:39 -0700, Peter VanDerWal wrote:
> > - 20x D51s = 240v 40Ah @ C20, 26Ah @1C. Weight is 236kgs / 520lb.
> > 500 cycle life @ 80% DOD?
>
> I believe something is wrong with your numbers here. As I recall, 20x
> D51s would weigh close to 900 lbs, not 520lb. However, I've never seen a
> D51 (I've only seen the D34 and D31) and I'm finding conflicting info on
> the web.
I have held a d51, and it didn't seem to heavy, but I'm not a good judge
of these things. I would have thought optima would have it right
http://www.optimabatteries.com/publish/optima/americas0/en/config/product_info/automotive/deep_cycle/technical_specs.html
> Tom's not going to achieve his weight goal with anything short of
> Lion/LiPol batteries. However, I think his orignal estimates of power
> consumption might be a little low also.
I hope my power consumption estimate is accurate. It's based on
accelleration while coasting downhill, measured with a GPS. You can see
the results here:
http://carrott.org/cgi-bin/twiki/view/Main/RollingResistance I haven't
yet published the program which generated those graphs, if anyone wants
it, please email me.
Chris (fixitsan at aol) has said here that a mini is generally accepted
to use 9kW at 80km/h, which lies above the line on my graph. I don't
know if my data is good, if my car has wheel alignment problems, nor if
his number is accurate. I am encouraged that my data converges to a
line.
It's a very small but rather unaerodynamic car.
--- End Message ---
--- Begin Message ---
Mike, I was thinking about this (PVC, right?); do you leave the ends open or
try to seal?
----- Original Message ----
From: Mike Harvey <[EMAIL PROTECTED]>
To: [email protected]
Sent: Saturday, March 3, 2007 8:37:04 PM
Subject: Re: Best way to run battery cables
I like carloc tubing the best, hung by aluminum hose brackets. Ids flexible,
durable, and comes in a few sizes with connectors and is typically used as a
conduit for wiring in moisture laden areas such as hot tubs and pools. Any
electrical supply or even home improvement center should have.
____________________________________________________________________________________
Now that's room service! Choose from over 150,000 hotels
in 45,000 destinations on Yahoo! Travel to find your fit.
http://farechase.yahoo.com/promo-generic-14795097
--- End Message ---
--- Begin Message ---
On 04/03/2007, at 8:36 PM, Tom Parker wrote:
<snip>
..Which is more than I want to spend, but I'd be tempted if I could
have
some confidance in their cycle life and current handling ability.
Kokam and GAIA have Lithium cells in capacities closer to what you
were seeking, might be worth a look:
http://www.kokam.com/english/product/battery_main.html
http://www.gaia-akku-online.de/ENG/SEITEN/action.lasso?-
Token.Menu=Produkte&-Token.Link=Link1&-Response=produkte.html
Thunder Sky themselves http://www.thunder-sky.com/pdf/200725164258.pdf
give less information but contradict everspring. Both max charge and
pulse discharge rates are higher than those specified by everspring.
I'm actually on the Thunder Sky yahoo group, and people have
confirmed that you can pull 10C (or more) out of the LFP cells. They
probably don't like it too much, of course ;)
Regarding charging, unless you have a 3-phase charger you won't be
able to push more than 2400W into them anyway. (Well, it's 2400W max
for single phase here in oz, 240V @ 10A)
Has anyone had experiance with an off the BMS? I've seen a couple of
posts asking about some, but no comments.
Rod Dilkes is building his own, I'm planning to do the same because
(a) I'm a cheapskate (b) it'll be interesting. But here's a few
commercial ones:
http://www.reapsystems.co.uk/index.php?
option=com_content&task=view&id=23&Itemid=36
http://www.metricmind.com/bms.htm (tho apparently not in production yet)
http://www.ime-actia.de/web_onboard/steuergeraete/bms.htm (anyone
speak German?)
.. and supposedly Thundersky are planning to release their own BMS
and charger soon, but not sure when.
Lack of good, affordable BMSs and chargers does seem to be a real
stumbling block for the Lithiums right now..
-Ian
--- End Message ---
--- Begin Message ---
I think he means Carlon - this is also made by Hubbell under the Kellums
brand, and is a good way to go. All PVC, so no rust, and get the matching
nylon connectors.
Joseph H. Strubhar
E-mail: [EMAIL PROTECTED]
Web: www.gremcoinc.com
----- Original Message -----
From: "Mike Harvey" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, March 03, 2007 5:37 PM
Subject: Re: Best way to run battery cables
> I like carloc tubing the best, hung by aluminum hose brackets. Ids
flexible,
> durable, and comes in a few sizes with connectors and is typically used as
a
> conduit for wiring in moisture laden areas such as hot tubs and pools. Any
> electrical supply or even home improvement center should have.
>
> ----- Original Message -----
> From: "Lee Hart" <[EMAIL PROTECTED]>
> To: <[email protected]>
> Sent: Saturday, March 03, 2007 5:01 PM
> Subject: Re: Best way to run battery cables
>
>
> > From: Frank John
> >> What do folks generally do when running battery cables from the boxes
> >> (on the rear of a small pickup in this case) up to the controller/motor
> >> area?
> >
> > Treat them as you would any home electrical wiring. Normal electrical
> > codes are a good practice. Install them so they do not touch anything
that
> > can burn, or any metal that isn't grounded, and so they cannot be
touched
> > by people or animals.
> >
> > I prefer to run metal conduit under the car, and feed the cables through
> > it. This provides shielding and physical protection from road debris,
> > rodents, and other hazards.
> >
> > If your cables won't be exposed, then bundling them with tie-wraps (and
> > twisting together where possible) is acceptable.
> > --
> > Lee Hart
> >
> >
>
>
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
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2:43 PM
>
>
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--- Begin Message ---
Cor, I occasionally draw my 120V pack of Trojan T-105's down to 86 Volts
under load, but usually it only goes to 94 or so. Is this too low for
floodeds?
Joseph H. Strubhar
E-mail: [EMAIL PROTECTED]
Web: www.gremcoinc.com
----- Original Message -----
From: "Cor van de Water" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, March 03, 2007 9:00 PM
Subject: RE: My latest attempt to get a few extra miles ... never seen this
one done before
> Note that Peter is talking about the voltage while driving, under load.
> As soon as the load is gone, the pack must come back quickly and reach at
> least 96V after a while, as at 12V resting voltage, the batteries are
empty.
> Normally they will sit above 12.3V (2.05V per cell) and freshly charged
AGM
> batteries can sit as high as 13.2V (2.2V per cell)
>
> 105V for 48 cells is 2.19V per cell, or 13.1V for a 12V battery - sounds
> good. 100V is still 12.5V per battery and certainly not dead, absolutely
not
> dead if you use this threshold under load - you can go as low as about 80
to
> 85V under (heavy) load, to keep the cells above 1.75V which is the limit
> that they are tested at for capacity.
>
> 1.75V x 48 cells = 84V.
> (Some manufacturers set a different, lower voltage limit under high
> discharge voltage, arguing that the resistance in the battery
interconnects
> and plates adds to the voltage drop.
> For example if you have a decent battery it may have 4mOhm (0.004 Ohm)
> internal resistance.
> When you draw 300A through this pack, the internal resistance of 8
batteries
> in series will make the pack voltage drop 8x 300A x 4mOhm = 8x 1200mV = 8x
> 1.2V = 9.6V.
> So, the minimum pack voltage under 300A load while keeping 1.75V per cell
as
> lowest limit is 84 - 9.6V = 74.4V
> so you see that the absolute lowest level of 75V that Peter suggested has
> some background in keeping the pack safe while driving, while it allows
you
> to make the most of your range. Note that it is only allowed to go this
low
> while driving. As soon as you take your foot off the throttle, it must
bouce
> back to above 90V (11.5V per battery) or it is already dead and you have
> begun to reverse cells in the pack.
> If this happens once on accident during the last mile to get home, no
> problem, simply put the pack immediately on a charge and it likely will
be
> fine.
> Doing this repeatedly will certainly damage your pack and reduce your
range
> quickly - this is the way "stinkers" are created!
>
> Hope this helps,
>
> 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 Peter VanDerWal
> Sent: Saturday, March 03, 2007 9:09 PM
> To: [email protected]
> Subject: Re: My latest attempt to get a few extra miles ... never seen
this
> one done before
>
> Huh? No wonder you are getting so little range. You can safely drive a
96V
> pack until it drops to 84V. If you only drive until it drops to 100V then
> you are barely taking the surface charge off the pack.
>
> When the pack gets to the end of it's life you can drive a 96V pack down
to
> 75-80V. It's pretty much shot anyway, so you can't hurt it.
> But this doesn't apply to your pack, apparently you haven't even stressed
it
> yet. It should have plenty of life left.
>
> > So, I have the Festiva, and I'm driving it on the 96 V pack of 12 V
> > Deka Group 24's that are way past their usable life. Even with the
> > Curtis controller, easier on the batts than the GE EV-1, I'm getting
> > only about
> > 4.5 mile range. I was getting about 3.25 with the EV-1. Those batts
> > are 80 AH at a 20 A discharge rate. Derate about 50% for EV discharge
> > rate and not killing them, that's 40 AH. Voltage varies between 105
> > (full) and
> > 98 (totally dead). I try not to go below 100 V. So, about 4kW-hr of
> > usable energy. The car is 2200 lb. I'd say 300 Wh-hr / mile. So,
> > with a brand new pack on a bright sunny day here in GA, I should be
> > able to safely go 13 miles. Really, that is pretty lame for a pack
> > that must cost about $1200. In flooded, the pack is about $550.
> > Flooded has its own issues. Like parking on a slight grade and trying
> > to charge the batts when the plates aren't evenly covered ... My
> > flooded batts are actually set in at a very slight angle to match the
> > grade of the driveway. I literally used a level to put them in the car.
> >
> > So, I could spend $1200 on a fresh set of the Deka Group 24, and
> > some day, it may come to that if no one comes up with a decent battery
> > solution.
> >
> > For now, I bought one (soon to get a second) 12 V / 120 Ah (at 20 A
> > discharge) battery for $65. I also bought a 700 Watt inverter off
> > ebay for a buck. I put the batts in my car, run the inverter, through
> > my BC-20 and try as best as I can to keep the pack charged.
> >
> > I drive that whole 2 miles to work. Let it sit and recharge itself
> > off the spare batts, go out for lunch, let it charge itself, back to
> > work, more self charging off the aux batt, and back home. I should be
> > able to get 8.5 miles (as long as I don't go more than 4 miles in any
> > given 2 hour period). That is OK, because when I go somewhere, I am
> > usually there for a few hours. It's like driving with a 4 mile range
> > and plugging in all the time, every time you stop. Not a great
> > solution, but it cost only $150 and I got a 8.5 mile range (I think)
> > and I didn't have to drop $1200 on a new set of Dekas yet. It may
> > last 6 months or a year like this. Maybe only a few weeks. Either
> > way, it was worth a try.
> >
> > This got me into other stuff. I am working on replacing my lead
> > acid secondary pack with NiMH. Again, limit the discharge rate. I
> > could put in a 3300 Watt inverter if I wanted to ... But, not use
> > them as the primary motive force. A friend lent me some 13 Ah F cells
> > (40 of them) to play with. I was going to try 4 sets of 10 each of
> > those in parallel with my one lead acid 120 AH aux battery. That
> > would be 12 V / 172 Ah (at a 20 A discharge rate).
> >
> > I also have 850 1.2 V / 1.6 AH NiMH cells that I picked up 2 years
> > ago when I started the last Festiva project. I could maybe do
> > something with those as well.
> >
> > I looked at prices, and it seems like I can get flooded lead (not
> > Trojan
> > though) for $0.045 per Watt-hr. Again, that is low discharge rate,
> > not Optimas or anything EV worthy. I can get NiMH for about $0.31 per
> > Watt-hr. I don't even dare price Li Ion, but my best bet would be
> > DeWalt packs off E-bay. I'm not comfortable making a BMS for those,
> > so I'll stick with NiMH. I believe you can get one of those 36 V
> > LiIon packs for about $100 on e-bay. Again, the BMS is the issue.
> >
> > Where am I going with all this? Maybe a good solution is like what
> > I have -
> >
> > 8 x 12 V AGM +
> > a 5000 Watt-Hr aux pack of NiMH (or Li Ion) and a 3300 Watt inverter.
> >
> > I think you could get an easy real 30 mile range and some decent
> > performance. I am not a fan of flooded lead golf cart batts at all.
> > Why? Years of cars with poor acceleration. It wasn't until I got the
> > super light car and the AGMs that I got acceptable (to me that is)
> > performance.
> >
> > With my soultion, you can also add an alternator on the tail shaft
> > of the motor (geared appropriately for charging at very slow motor
> > RPM) and kick it on when the start switch is off to charge the aux
> > batt that goes through the inverter / charger ... and back to the
> > pack. Efficiency of that whole system maybe 65% (with the alternator
> > and all) Worth it? I don't know.
> >
> > I'm open to comments, suggestions?
> >
> > Steve
> >
> >
> > ---------------------------------
> > Don't be flakey. Get Yahoo! Mail for Mobile and always stay connected
> > to friends.
> >
> >
>
>
> --
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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
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>
>
>
>
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> No virus found in this incoming message.
> Checked by AVG Free Edition.
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2:43 PM
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>
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