EV Digest 6081
Topics covered in this issue include:
1) Re: CURRENT ELIMINATOR DRAGSTER News
by [EMAIL PROTECTED]
2) Altairnano tests batteries to 15,000 cycles
by John Nicholson <[EMAIL PROTECTED]>
3) SEMA Automotive Show in Vegas
by Peter Eckhoff <[EMAIL PROTECTED]>
4) Re: 2X Alltrax = Curtis ?
by Lee Hart <[EMAIL PROTECTED]>
5) Re: Sunrise: Midnight
by Lee Hart <[EMAIL PROTECTED]>
6) Re: AGM battery charging
by Lee Hart <[EMAIL PROTECTED]>
7) Re: EV controllers? the 4th option...
by Lee Hart <[EMAIL PROTECTED]>
8) Re: Non Traditional EV Drivetrains
by [EMAIL PROTECTED]
9) Re: ceramic fin repair
by Dave Cover <[EMAIL PROTECTED]>
10) Re: Internal spline shaft forklift motors
by James Massey <[EMAIL PROTECTED]>
11) article: Nano-Tech Batteries May Rival Lithium-Ions In Hybrids
by Paul Wujek <[EMAIL PROTECTED]>
12) Forklift motors
by [EMAIL PROTECTED]
13) RE: AGM battery charging
by Cor van de Water <[EMAIL PROTECTED]>
14) Re: EV controllers? the 4th option...
by [EMAIL PROTECTED]
15) RE: Internal spline shaft forklift motors
by "Roger Stockton" <[EMAIL PROTECTED]>
16) Re: article: Nano-Tech Batteries May Rival Lithium-Ions In Hybrids
by "Peter Gabrielsson" <[EMAIL PROTECTED]>
17) Parallel charging?
by <[EMAIL PROTECTED]>
18) 50ah batteries
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
19) Re: EV Controllers, Option 5
by David Dymaxion <[EMAIL PROTECTED]>
20) Re: 2X Alltrax = Curtis ?
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
21) Re: SOC from battery voltage
by "David Roden" <[EMAIL PROTECTED]>
22) RE: EV pusher Trailer
by "David Roden" <[EMAIL PROTECTED]>
23) Re: Lithium-ion batteries & Valence Group buy
by "David Roden" <[EMAIL PROTECTED]>
--- Begin Message ---
Dennis,
Is that Saturday the 11th for the NHRA WALLY?
If so what time?
Shawn Lawless
-----Original Message-----
From: [EMAIL PROTECTED]
To: [email protected]
Sent: Mon, 30 Oct 2006 6:55 PM
Subject: Re: CURRENT ELIMINATOR DRAGSTER News
The CE will race the last ADRA race of the year this Sat. at Speedworld
in
witman az.Its for a thousand dollars.Starts at 9am.Then the following
sat.at
speedworld a super pro race for a NHRA WALLY.Its NHRAs most coveted
trophy!
Dennis Berube
________________________________________________________________________
Check out the new AOL. Most comprehensive set of free safety and
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--- End Message ---
--- Begin Message ---
The press release is at
http://home.businesswire.com/portal/site/google/index.jsp?ndmViewId=news_view&newsId=20061026005107&newsLang=en
*****************************************************************
Altairnano Tests Confirm Extended Battery Cell Life
Altairnano Battery Cells Complete 15,000 Charge/Recharge Cycles with
Minimal Loss of Charge Capacity
RENO, Nev.--(BUSINESS WIRE)--Altair Nanotechnologies Inc. (NASDAQ:
ALTI), a leading provider of advanced nanomaterials for use in energy,
automotive, life sciences and industrial applications, announced today
that, in ongoing testing, it has completed 15,000 deep charge/discharge
cycles of its innovative NanoSafe battery cells. Even after 15,000
cycles the cells still retained over 85% of their original charge
capacity. This represents a significant improvement over conventional,
commercially available rechargeable battery technologies such as lithium
ion, nickel metal hydride and nickel cadmium. These other commercially
available rechargeable batteries typically retain that level of charge
capacity only through approximately 1,000 deep charge/discharge cycles.
The battery cells were tested in Altairnano’s labs at 10C (6 minute)
charge and discharge rates. They were deep charged and discharged
meaning they were taken to 100% charge and 0% charge respectively during
the 6-minute cycles. Although tests involved full charges and
discharges, partial charging and discharging of the battery does not
appear to impact the life or the holding charge capacity of the
batteries i.e. they exhibit no memory loss.
In theory, a 15,000 charge cycle life would translate into a battery
that would last greater than 40 years if it was charged daily, as would
be the case in an electric vehicle or plug-in hybrid electric vehicle
environment. However, in practice, other wear and tear factors would
realistically limit the actual life of the batteries to probably 20
years.
.......more
****************************************************************
--- End Message ---
--- Begin Message ---
Is any one in the Vegas area planning on attending the SEMA Motor Show
in Vegas Oct31-Nov3?
Phoenix Motorcars and Altair nanotechnologies are planning to exhibit
there. Here's a blurb:
The SEMA show will be the debut for the Phoenix Motorcars' electric
sports utility truck (SUT) powered entirely by Altairnano's innovative
NanoSafe nanotitanate batteries. Like its sister vehicle the SUV, that
was launched at the ZEV symposium in September, the SUT will have a
standard range of 130 miles, a charge time of 10 minutes and be capable
of freeway speeds up to 95 mph.
Altair announced: "it has completed 15,000 deep charge/discharge cycles
of its innovative NanoSafe battery cells. Even after 15,000 cycles the
cells still retained over 85% of their original charge capacity. This
represents a significant improvement over conventional, commercially
available rechargeable battery technologies such as lithium ion, nickel
metal hydride and nickel cadmium. These other commercially available
rechargeable batteries typically retain that level of charge capacity
only through approximately 1,000 deep charge/discharge cycles.
The battery cells were tested in Altairnano's labs at 10C (6 minute)
charge and discharge rates. They were deep charged and discharged
meaning they were taken to 100% charge and 0% charge respectively during
the 6-minute cycles. Although tests involved full charges and
discharges, partial charging and discharging of the battery does not
appear to impact the life or the holding charge capacity of the
batteries i.e. they exhibit no memory loss.
In theory, a 15,000 charge cycle life would translate into a battery
that would last greater than 40 years if it was charged daily, as would
be the case in an electric vehicle or plug-in hybrid electric vehicle
environment. However, in practice, other wear and tear factors would
realistically limit the actual life of the batteries to probably 20 years."
Does anyone know the downsides to this battery?
Peter
--- End Message ---
--- Begin Message ---
Jack Murray wrote:
A Curtis controller is a chopper drive, at least that is what people
have said here, which is one reason it has inferior performance to
the Zilla, which uses a buck converter to multiply current.
A chopper *is* a buck converter; they are the same thing. The only
difference is that the Zilla is bigger and stronger than the Curtis;
bigger and better transistors, diodes, and capacitors. Both multiply
current. The Curtis is actually more efficient than the Zilla at low
current; the Zilla is better at high currents.
The Zilla happens to have exchanged its diode and transistor, so the
other side of the motor goes to pack negative rather than pack positive;
but this is irrelevant to how it operates.
How can current flow through D1? ... There must be something missing
from these diagrams, because it just doesn't match what is being
said as far as I can see.
No; it is all there. You have to remember that the motor is highly
inductive. Current in an inductor changes slowly (at least, relative to
the switching frequency).
Suppose the motor is running at an average of 100 amps. When Q1 turns
on, the motor current ramps up from 90a to 110a. When Q1 turns off,
motor current ramps down from 110a to 90a. Now we're back where we
started, and the next cycle begins.
During Q1's off-time, the motor is effectively shorted through the
diode. It's not just a brief pulse of current, like when you absorb the
inductive kick from a little coil. It's a very long, extended, high
energy current pulse, because the motor has a tremendous amount of
stored energy. It is in fact acting as a generator during this time.
This is the last I will post on this subject.
Stick with it until you understand it. This is an important concept in
understanding how motor controllers work.
____________________________
| _|_
| / \ armature
| \___/
| _________ | series
+48V ________|_____ | |_ motor
| B+| _|_ | _|
| | D1 /_\ | _| field
|+ | |___|_____|
bat | |_| |M-
- | -||_ Q1 |
| | | | |
|0V__________|_____| | Controller
B-|_________|
--
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 ---
Lee Hart wrote:
- Same all-composite chassis and body, but rely more on conventional
fiberglass than on carbon fiber.
David Roden wrote:
Presumably this is to reduce cost.
And, to make it simpler to build. Regular fiberglass is much easier to
work with than carbon fiber.
Curiously, you say "same ... body," but then you go on to describe extensive
alterations to the body design (see below).
No; the body (top half) will remain essentially unchanged. The chassis
(bottom half) is what will get modified for different suspension, motor,
differential, and battery box. The changes still leave the chassis 90%
or more unchanged.
- Replace the light-but-weak Geo Metro McPherson strut front suspension
with Mustang II A-arm suspension, which is widely available in the
kit car market.
Are you sure it's readily available?
Yes. Pick up any kit car magazine.
- Change to rear wheel drive. Essentially all high performance sports
cars and sedans are rear wheel drive.
But the Sunrise was developed as a family car, not a sports car.
Actually, it was designed as a high-efficiency economy car. Imagine a
"stretch" Geo Metro.
There are other high performance EVs in the pipeline. Notice how Prius
sales improved when it became a family car in its second generation.
We aren't trying to build an all-out sports car like the Tesla, Tango,
or Fetish. We're aiming more at a sports sedan -- a good handling, good
performing car that still has good economy and efficiency. The sort of
car that's fun to drive, and useful for a family every day.
Prius sales have improved slowly, being mainly controlled by how fast
they could ramp up production. There really isn't much difference
between the first and second generation versions. Both are small,
economy cars.
Carrying the whole drive in the nose is a proven strategy for moderate
performance vehicles and promotes a stable (understeering) handling
characteristic.
With conventional cars, front engine means it is front-heavy. With
electric cars, the batteries weigh more than the engine. Front engine
means the batteries are farther aft, so it is tail-heavy. Tail-heavy
cars handle much differently than what most people drive and expect.
Switching to rear engine shifts the batteries forward, making the car
nose-heavy, like almost all modern cars. The rear wheel drive is also
good for improved handling.
- A large, quick-change battery pack... slides out the front
Excellent idea, but it seems to me that it could slide out the back
just as easily if the vehicle were front-drive.
Yes, it could. However, the overhang in the rear is greater. The same
length battery tray would stick out farther to the rear, and thus has
more effect on weight bias.
- Rather than a single one-piece nonrepairable body, the front
and rear are replaceable "clips" to make crash testing and
repairs easier.
I'd think you'd increase mass significantly by doing this.
No; it does not appear so.
Overall, I think you have some outstanding ideas, but I also think that
the resulting vehicle will be a Sunrise in appearance only.
Not at all! The body, which is most of the car, is unchanged. The
chassis is nearly unchanged, except for moving the suspension mounting
points slightly. A larger motor and differential do not change the
design. Front- vs. rear-wheel drive is a much smaller change than you'd
think in an electric car that already has independent front and rear
suspension to begin with.
It remains to be seen how much of the car's almost legendary efficiency
will be lost (or improved!) by these changes.
Yes indeed. You have to remember that the Sunrise design is over 10
years old. There are many improvements that have become possible since then.
Part of the Sunrise's efficiency comes from an obsessive attention to
detail. Perfect suspension alignment, meticulous brake adjustment, thin
differential oil, fixed side windows, no wipers, etc. Many of these can
still be practiced by interested builders; but I think most people will
prefer a more normal car, with more amenities.
I also wonder whether you won't obviate the prototype crash testing
We're trying hard not to affect this, though of course we won't know for
sure until we build enough to afford crash testing. It is also a
certainty that government crash standards will keep changing. Just
because it passed in 1996 doesn't mean it would pass today, or in 2016.
--
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 ---
Storm Connors wrote:
If you can see the batteries, build the Lee Hart charge regulator with a
light bulb and a night light controller.
I understand Lee's light bulb regulator, but what is this?
I used an inexpensive automatic night light to operate a relay to turn
off the charger.
When there is no light, these night-lights turn on a little 7w lamp.
When it sees light (from other than the night-light itself), it turns
the night-light off.
Replace the lamp with a 120v relay coil. Now, when there is no light,
the relay pulls in and the charger works. When any battery regulator's
lamp lights, it shuts off the relay, and the charger stops. You wire the
NC contact of the relay to cut power to the nightlight as well, so once
the charger turns off, it stays off.
--
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 ---
Rod Hower wrote:
How much margin is built into the PCB traces that
connect the bus bars to the MOSFET source and drain?
Not much. Curtis depends on the foil traces to carry current from the
MOSFETS and diodes back to the lengthwise buss bars that are bolted to
the PC board and extend out the end to become the external terminals.
Of course, PC traces aren't like fuses -- they don't have some critical
current that they carry indefinitely, and suddenly blow open if you
slightly exceed it. All that happens when you run a little more current
is that they get a little hotter. Over time, the board discolors, the
foil loosens from the board, and the solder joints crystallize and
become intermittent.
I presume that all Jim is doing is installing lower
Rds on MOSFET's and higher current rated freewheel
diodes.
That's all I would guess he's doing, too. It's fairly easy to buy higher
rated MOSFETs. But the diodes Curtis used are specials; they are hard to
replace. I did find a 200v 40a Schottky in a TO-220 (On Semi MBRF40250T)
that I want to try in a Curtis, but haven't done so yet. They should
have a lower forward drop, and so reduce heating.
Does Jim upgrade the bus capacitors with more capacitance and lower ESR?
He should, but I'll bet he can't -- there's no room! The capacitors are
already undersized even for the stock ratings.
What about gate drive?
Curtis uses a soft gate drive, for relatively slow turn-on and turn-off
speeds. Keeping this circuit reduces noise, but adds heat from switching
losses. Without major changes, he's just going to have to live with it.
The higher rated current control will also need an
improved cooling system to ensure adequate life of the
control.
That's the hard one. The Curtis thermal design is a weak point. I don't
see a way to improve it short of starting over.
--
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 ---
I looked at doing hydraulics and the losses were too great. In the range of
20% to 30% or more. I would cut down your range and if you used any
accessories on your vehicle you would not be going far.
Don
In a message dated 10/30/2006 4:14:28 PM Pacific Standard Time,
[EMAIL PROTECTED] writes:
Anyone done a hydraulic link?
Hydraulic hoses make motor placement unrestricted.
On Fri, 27 Oct 2006 10:54 pm, Bruce wrote:
> What EV car conversions use something other than the traditional
> adapter
> plate and coupling?
>
> Here are three to start the list:
>
> Pro EV Electric Imp Subaru, direct drive to IRS differentials in
> front and
> rear:
> http://www.austinev.org/evalbum/464
>
> Gone Postal, conventional front drive plus two motor chain drive in
> rear:
> http://www.suckamps.com/index.php?page=life_of_the_postal_van
>
> Bill Bruder's Wind Wagon, air propeller drive (not a conversion but
> very
> cool!):
> http://www.austinev.org/evalbum/309.html
>
> Osmo S wrote:
>> I think it´s important (and fun) to try to find fresh approaches ...
>> and to questionize common solutions, even if it doesn´t always
>> lead to anything useful.
www.GlobalBoiling.com for daily updated facts about hurricanes,
globalwarming and the melting poles.
www.ElectricQuakes.com daily solar and earthquake data.
--- End Message ---
--- Begin Message ---
--- mike golub <[EMAIL PROTECTED]> wrote:
> http://www.flickr.com/photos/mikeak/284026259/
>
> I drilled that hole into the heater, and followed with
> a screw and some jb weld.
>
How would pop rivets work instead of a screws? They can't be retightened, but
might take up less
space. Unfortunately I don't think I have enough room for a screw or rivet on
mine. The tab broke
off a fat 1/8th of an inch high. I might have to scrap it and get another.
Still looking for that
magic aluminum solder.
--- End Message ---
--- Begin Message ---
At 04:11 PM 30/10/06 -0800, John Bart wrote:
Is there any reasonable way to make a internal spline shaft forklift motor
feasable for an ev conversion? My original idea was to find a splined
shaft that would fit into the motor and then somehow key the end of the
shaft that would stick out from the face of the motor, but im not really
sure how to secure the shaft into the motor permanetly. Any ideas?
G'day John, and All
Well that depends on what you consider "reasonable", doesn't it?
Option 1) Send it to Jim Husted to press a new shaft into it (probably the
best option).
Option 2) Have a splined section of shaft made that is an interference
(press) fit & press it in with some loctite or similar. Have a hole EDM
(spark eroded through) and put a pin in to add securing if desired. If the
shaft face up inside the spline (the face at the back of the splined hole)
is not hardened, you may be able to drill and tap this and put a retaining
bolt through the stub shaft (second best way if you can do this).
Option 3) have a new end plate made for the motor that takes a bearing with
a larger I.D. and have a hollow shaft made that fits over the motor shaft &
press fit it on the same way. The shaft O.D. would need to match the
bearing I.D. You can't get the fan off later if that were needed if this
were done.
Option 4) set the motor up with an external blower, remove the fan and have
the fan mounting location machined to take the bearing. Shorten the DE
housing by the same amount as the moved bearing position or have a new end
plate made that is also the transmission adaptor. Machine some vent holes
in the DE plate face to let the air out. This will give some shaft sticking
out, but may not be enough to get a taperlock onto (and isn't keyed
anyway). May be the most appropriate way if the motor needs to be made
shorter to fit into a space (e.g. FWD vehicle) so may end up being the most
cost-effective when done as the method to shorten the motor.
Option 6) make up a piece of shaft that has the normal spline (the spline
that the motor was designed for), one or two carrier bearings and a
dual-faced adaptor to mate to the motor and the transmission. If you got
the part that the motor was driving, you may have a stub shaft to adapt to
this job. If you have low-tech machining available, this may be the easiest
to DIY.
Option 7/8/9?
Hope this helps
Regards
[Technik] James
--- End Message ---
--- Begin Message ---
Altair Nanotechnologies batteries -- so far tested to 15,000 cycles (by
them at least):
http://www.treehugger.com/files/2006/10/new_nanotechnol.php
Altair's site: http://www.altairnano.com/
Unfortunately there doesn't seem to be other useful information about
their batteries, like capacity, cost.
--
Paul Wujek
--- End Message ---
--- Begin Message ---
Are folk lift motors useful in EV conversions? The ones with a splined hole?
They are run on 36 volts in the lifts - what about EV applications?
Thanks
Matt Parkhouse
Colorado Springs, CO
BMW m/c-Golf Cart trike - 48 volts, 30mph on the flat, 35 mile range
--- End Message ---
--- Begin Message ---
NOTE that this way of operation will chronically under-charge
all but one battery, as the nightlight will shut the charger
off as sson as the *first* battery is full and its reg
starts shunting current.
Use this only if you are charging regimen is:
- several times not-completely full, followed by
- one time equalisation charge
Disable the nightlight shutoff for the equalisation.
Some have reported long lifetime from their batteries
when they do not charge to the max every night.
YMMV.
Cor van de Water
Systems Architect
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
Proxim Wireless Networks eFAX: +1-610-423-5743
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Lee Hart
Sent: Monday, October 30, 2006 5:52 PM
To: [email protected]
Subject: Re: AGM battery charging
Storm Connors wrote:
> If you can see the batteries, build the Lee Hart charge regulator with a
> light bulb and a night light controller.
>
> I understand Lee's light bulb regulator, but what is this?
I used an inexpensive automatic night light to operate a relay to turn
off the charger.
When there is no light, these night-lights turn on a little 7w lamp.
When it sees light (from other than the night-light itself), it turns
the night-light off.
Replace the lamp with a 120v relay coil. Now, when there is no light,
the relay pulls in and the charger works. When any battery regulator's
lamp lights, it shuts off the relay, and the charger stops. You wire the
NC contact of the relay to cut power to the nightlight as well, so once
the charger turns off, it stays off.
--
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 ---
-------------- Original message ----------------------
From: Lee Hart <[EMAIL PROTECTED]>
> That's all I would guess he's doing, too. It's fairly easy to buy higher
> rated MOSFETs. But the diodes Curtis used are specials; they are hard to
> replace. I did find a 200v 40a Schottky in a TO-220 (On Semi MBRF40250T)
> that I want to try in a Curtis, but haven't done so yet. They should
> have a lower forward drop, and so reduce heating.
At least in the Curtis unit I'm working on the diodes are such that the anode
is connected to the tab. This connection is used to pass current to the motor.
This makes it difficult to find a replacement as most diodes have the cathode
tied to the tab. The only one I found is from On Semi, MUR2020R (20A, 200V).
Regards,
Chris Brune
--- End Message ---
--- Begin Message ---
john bart wrote:
> Is there any reasonable way to make a internal spline shaft
> forklift motor feasable for an ev conversion? My original
> idea was to find a splined shaft that would fit into the
> motor and then somehow key the end of the shaft that would
> stick out from the face of the motor, but im not really sure
> how to secure the shaft into the motor permanetly. Any ideas?
What is the spline size? One possibility is to get a length of shaft
with the appropriate spline partway down its length, such as listed here
under "Tractor PTO Adapters - Standard Length Splined Shafts":
<http://www.ggmfg.com/product_subsubcategories.asp?subcatParent=284&catP
K=9>
One of the other flavours of adapter might also do the job (there are
male spline to female spline and male spline to round bore/keyway, but
in both cases the OD and thickness of the female end might be sufficient
to allow you to mount an adapter hub directly over it).
Almost certainly one wouldn't get lucky enough to find a male to female
splined adapter whose male end fits your motor and whose female end fits
your tranny input shaft, but it might be possible to rig up such a
clutchless adapter using one of these adapters and the hub from a clutch
disc...
It might be necessary to support the splined adapter with a bearing,
similar to what was done with the aircraft starter-generators when used
in Evs (the adapter plate included a bearing to support the motor output
shaft).
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Capacity, 90wh/kg at the moment but they think they can get it up to
150. Price, a $1 per wh has been mentioned but they're still in a very
early stage of their product roll out so it's hard to say what it will
be.
On 10/30/06, Paul Wujek <[EMAIL PROTECTED]> wrote:
Altair Nanotechnologies batteries -- so far tested to 15,000 cycles (by
them at least):
http://www.treehugger.com/files/2006/10/new_nanotechnol.php
Altair's site: http://www.altairnano.com/
Unfortunately there doesn't seem to be other useful information about
their batteries, like capacity, cost.
--
Paul Wujek
--- End Message ---
--- Begin Message ---
What are the pitfalls of parallel charging battery strings?
I thought I saw a post recently that said that if the strings were not
equally discharged they would balance when connected in parallel and then
the charger would be able to charge them together. I tried to find it in
the archive, but it seems like most every post has charging and battery in
it.
My situation is that I have a 48 volt system and only a 24 volt charger.
The batteries are T145s @ 260AH and the charger is a Lester 24 volt 40 amp
for flooded batteries. I had originally intended to use 2 chargers but at
40# apiece that is a lot of weight to haul around not to mention the space
they take up. I have an Anderson Emergency Disconnect in the middle of the
pack so the two strings are not tied together unless I am running and I can
connect the two charging ports together by making a wye cable.
respectfully,
John
--- End Message ---
--- Begin Message ---
There are three batteries I would consider for EV applications in the 50 ah
range. BB, Optima & Exide. The BB is used in the Oxygen Lepton Scooter.
Of these three or any other you can name, which is the best bang for the
buck or just the plain best. Is there a battery I've missed in this size
that might be more cost effective or maybe something half the size that
might work just as well or better? I'm not against multiple strings. I
would go for a bargain if I worked out. Lawrence Rhodes........
--- End Message ---
--- Begin Message ---
I thought about doing something like what I think you are describing. The
problem I saw is you'd need about 100 lbs of motor+generator to control a 100
lb motor. A semiconductor controller is much lighter (like 15 lbs), so that
frees enough weight for another battery or two. Machine shops don't care about
weight, so a heavy phase converter is OK for them.
Lee Hart had mentioned this some time back: A small electric motor drives a
small generator, which is used to drive just the field (I think he called it a
"tickler"). It makes more sense in this case, since the field on a sepex motor
just needs a few amps. I have considered doing this, it would be a fun retro
way to control a motor. Unfortunately, small motors tend to be less efficient,
so a semiconductor controller easily wins on efficiency.
----- Original Message ----
From: Jeff Major <[EMAIL PROTECTED]>
To: [email protected]
Sent: Monday, October 30, 2006 10:10:56 AM
Subject: EV Controllers, Option 5
Alternative DC motor controller for battery powered vehicles.
There has been much posted lately on the EVDL regarding alternative options
to the available DC motor controllers. One post concerned a mechanical device
resembling a commutator which could modulate voltage. I do not believe that
such devices by themselves could be developed successfully; however, when
coupled to an electromagnetic dynamo, possibilities do exist. I attempted to
express this in a response post where I gave a simplified explanation of the
Middlebrook Rotary Transformer (MRT). This drew no further discussion. The
MRT is fairly difficult to implement but relatively simple in concept. I have
noticed posts concerning movable brushes being implemented on traction motors,
but the MRT takes this to the extreme.
My experience with electromechanical voltage control devices did not stop
with the MRT. I worked on several others. One was the Triodyne. This device
was invented by Dr. Joe Tyrner, U.S. Patent 4,383,213. I worked with Dr.
Tyrner for several years and took the device through prototype, dynamometer
testing and finally, vehicle testing. It worked beautifully. It did not have
any movable parts like the MRT except for the rotating armature. From a
cursory look, it appeared that it was a motor which controlled the speed of
another motor. It was about two thirds the size of the controlled motor,
rotated at a more or less constant speed and could power auxiliary mechanical
loads which puts the rotational member to work and increases overall
efficiency. For the life of me, I still wonder why this great device was never
put to use. It just sits in the patent archives.
The Triodyne is a three pole DC dynamo. Seems counterintuitive in the world
of North and South pole pairs. It is basically a motor and a generator in the
same core. It has a motor pole, a generator pole and a common pole. The
armature has a simplex lap winding with a 120 degree pitch. It uses a standard
motor commutator and has three sets of brushes. One brush is connected to the
battery, one brush to the motor and the third brush to the other battery
terminal and other motor terminal. Then, by controlling a relatively small
field current (a few amps) in the Triodyne, you can control the motor voltage
and high armature current (hundreds of amps). Works like a charm.
To design and fabricate a Triodyne today would be a significant effort. I
would love to see someone do it. That is why I bothered to put it out here.
However, there is another electromechanical control device with which I was
involved that I believe could be a viable solution to the needs I see expressed
on this list. It is documented as “Advanced DC Motor Controller for
Battery-Powered Electric Vehicles”, NASA CR-165171, dated July, 1981. I was
able to find it on the NASA web site and it seems like it is available for
about $30. It does not exist in digital format. It would be great if someone
could digitize it and make it available for members to read. I think Jim H
would be particularly interested as the machine is pictured in the back and
looks remarkably like his Siamese motors.
One might say this is just a Ward Leonard system. However there is a twist.
The load motor is run in series with the generator. This has a dramatic effect
on the required size of the MG, making it much smaller (and less cost).
Another consequence is that the traction motor then runs at twice the battery
voltage. Kind of like the Prius. And again, one could take advantage of the
rotating controller by running accessories with it. Or, consider the shaft a
port, power in or power out. Meaning one could couple energy storage to it
(flywheel or accumulator) or couple it to a heat engine for a HEV.
I know this post will bring the wrath of those obsessed with efficiency or
component weight. The PWM controllers will be more efficient, less mass and
have other advantages over these rotary converters. However, I see the same
concerns expressed today as those which motivated us several decades ago. That
would be “more problems with the controllers than with the motors”. So why not
make the controller look like the motor? Then those who can manufacture the
motor can make the controller, using the same technology, facility, expertise,
tooling, etc. And you end up with a motor and controller which have similar
cost, reliability, durability and serviceability.
Rotary converters are not uncommon power converters. Many are used today,
such as DC to AC and AC to DC converters, frequency converters and phase
converters. The phase converter is a good example. Often small or remote
machine shops have machine tools and other equipment needing 3 phase power but
only have single phase delivered by the utility. Their solution is a phase
converter, which is an induction motor and capacitor bank configured to take a
single phase input and output 3 phase power. This task could be done with a
solid state PWM converter, but you don’t see any of these, just the rotary
converters.
I don’t really think that rotary converters will be the solution for mass
produced EVs, just like I do not think the commutator DC motor will be. But
the rotary converter is a viable approach for DC motor control.
I tell you these things not to boast, but to relate ideas I fear may become
lost. Many of those involved in the development of these devices several
decades are no longer around. Even if you would know what to look for, search
engines will not help. If this subject matter interests you, please obtain the
NASA document. It is only 91 pages and has many diagrams and charts. It is
also interesting in that the simulations were done on analog computer.
Jeff Major, Oct/2006
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Hmmm. I still want to see someone do a contactor bypass from 48v to 96.
Of course cutting out the controller altogether at 96v. . Lawrence
Rhodes........
----- Original Message -----
From: "damon henry" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Monday, October 30, 2006 9:18 AM
Subject: Re: 2X Alltrax = Curtis ?
> Well, I do have a spare Curtis controller, that I just may try this with.
> I'll have to see what kind of time I have this winter to fiddle. I
probably
> won't be going to a full 96 volts however, as I do not want that many
> batteries on my bike, but with BB600 cells, I can pick just about any
> voltage I want to. I currently have 45 cells on the bike, so I would be
> experimenting with something between 46 and 80 cells.
>
> I don't want to try this with my Alltrax. I like it too much to take a
> chance with it, and Lee specifically had a Curtis in mind when he put this
> together.
>
> damon
>
>
> >From: Lee Hart <[EMAIL PROTECTED]>
> >Reply-To: [email protected]
> >To: [email protected]
> >Subject: Re: 2X Alltrax = Curtis ?
> >Date: Sun, 29 Oct 2006 09:44:54 -0600
> >
> >Dale Curren wrote:
> >>Could you please post that diagram again for us newbies?
> >
> >All I did was tell Google to search for "Lee Hart EV Curtis Controller"
and
> >the first "hit" was it:
> >
> >Ev Archive for January 2002: On Tue, Jan 29 2002, Lee Hart wrote:
> >
> >If I really felt inclined to do this (and had a controller I was
> >willing to sacrifice to the gods of experimentation :-) I would
> >try something like this: View with fixed width font:
> > ___________________________________
> > | | _|_
> >__|__ + | / \ armature
> > ___ 48v / S1b \___/
> > | - | _______ | series
> > |____/_____|____________| | |_ motor
> > | S2 | |B+ | _|
> > | __|__ + | | _| field
> > / S1a ___ 48v | M-|_____|
> > | | - | |
> > |__________|____________|B- | Controller
> > |_______|
> >
> >With S2 open, and S1a and S1b closed, you have two 48v batteries in
> >parallel driving a 48v controller and series motor in a completely
> >normal fashion. The controller adjusts effective motor voltage from
> >0-48v.
> >
> >With S1a and S1b open, and S2 closed, the two 48v batteries are wired in
> >series for 96v. But the controller still only sees 48v between its B+
> >and B- terminals. The controller still adjusts the effective voltage at
> >M- from 0-48v. But since the top connection to the motor is 48v higher,
> >the motor sees 48-96v.
> >
> >Thus you have two ranges; 0-48v, and 48-96v. Note that the controller's
> >current limit won't work in the 96v range. That's because even if the
> >controller is fully off, the motor is still connected to the upper 48v
> >battery through the controller's freewheel diode (between M- and B+).
> >Thus, you must not use the 96v range unless motor current is below the
> >controller's current limit.
> >
> >In operation, you accelerate at 48v until the controller comes out of
> >current limit, release the throttle, switch to 96v, then re-apply the
> >throttle. If you're in the 96v range and start climbing a hill, you must
> >switch back to the 48v range before the motor current rises above the
> >controller's current limit.
> >
> >Another quirk of this circuit is that the batteries are unequally
> >discharged in the 96v position; the upper battery always carries motor
> >current, while the lower one carries motor current x controller % duty
> >cycle. But the batteries will re-balance during the time spent in the
> >48v position.
> >--
> >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
> >
>
> _________________________________________________________________
> Try the next generation of search with Windows Live Search today!
>
http://imagine-windowslive.com/minisites/searchlaunch/?locale=en-us&source=hmtagline
>
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On 30 Oct 2006 at 16:15, Roland Wiench wrote:
> The minimum safe under load is prefer to be at 5 volts per 6 volt battery.
I've always used 5.25 volts for a 6-volt lead module, 10.5 volts for a 12
volt lead module.
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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On 30 Oct 2006 at 17:25, Lawrence Lile wrote:
> Despite one fellow's skepticism about weight, I think this idea has some
> merit.
Well, you asked, and you got a response. ;-)
But if you think the weight isn't an issue, go for it! Build one, and
report back on the results.
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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On 8 Oct 2006 at 11:29, GWMobile wrote:
> I encourage to actual get the batteries you want from the start and not
> listen to those who say start with what you don't want and upgrade
> later.
I was going through some old unread messages and I came across this note.
It may be that this has already been addressed; if so disregard this.
I think the above advice is inappropriate for new EV hobbyists, unless "the
batteries you want" are either very sturdy and economical (such as golf car
batteries), or else the battery love of your life is a complete system with
charger and BMS (and preferably an integrated controller or at least a
cooperative one too). There are very few such integrated systems, though my
impression is that the Valence comes pretty close (at a substantial price).
There's a certain amount of skill and art to battery maintenance. It's a
great tradition for beginning EVers to destroy their first batteries in the
process of learning these skills. Do you want to kill a $1500 pack, or a
$15,000 one?
>
> One thing you can also remember is you can buy a 5500 watt gas generator
> on wheels at pep boys for about $300. With a trailer hitch you would
> have unlimited mileage in your electric for longer trips.
Three problems, in random order (you decide what the order of importance is
to you) :
1. You'll be polluting to a gross degree, probably on the order of HUNDREDS
of times as much as your ICE. You will also burn more fuel than you would
in the ICE.
2. Unless you have a very light, efficient EV, a 5kW genset won't keep you
going down the road at highway speeds. Most conversions need 12-15kW to
maintain 55-60 mph.
3. The cheap gensets I've seen at the dollar stores at about this price
appear to be crude and poorly made. They're apt to be barely adequate for
use a few times a year. Use one of these, and you're likely to drop your
car's reliability to about that of a Model T. Better make sure your road
service card is paid up.
It's possible to build a somewhat clean, somewhat efficient, reasonably
reliable series hybrid (though it will almost impossible for a homebuilder
to make one as clean, efficient, or reliable as a factory ICE, let alone a
factory hybrid). But it is a lot of work, and the result won't look
anything like these cheap portable gensets. If you're considering running
your EV with a portable genset, please do our lungs (and yourself) a favor
and don't bother with the EV, just keep driving your ICE.
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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