EV Digest 5172
Topics covered in this issue include:
1) RE: Busted in Blue Meanie!
by "Hacker Joel-QA6240" <[EMAIL PROTECTED]>
2) Re: Busted in Blue Meanie! (OT - but funny)
by Dave Stensland <[EMAIL PROTECTED]>
3) Has anyone done research on mini/micro turbines to recharge a battery pack?
by "Hacker Joel-QA6240" <[EMAIL PROTECTED]>
4) Re: Jesse James & Monster Garage Go Lithium!!!
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
5) Battery price increase
by Cor van de Water <[EMAIL PROTECTED]>
6) Re: Busted in Blue Meanie!
by Ryan Stotts <[EMAIL PROTECTED]>
7) Re: Has anyone done research on mini/micro turbines to recharge a
battery pack?
by Danny Miller <[EMAIL PROTECTED]>
8) Re: What an EV filled day!
by "John Westlund" <[EMAIL PROTECTED]>
9) Re: Jesse James & Monster Garage Go Lithium!!!
by Lee Hart <[EMAIL PROTECTED]>
10) Re: What an EV filled day!
by Ricky Suiter <[EMAIL PROTECTED]>
11) Re: Fwd: re: UHMW in heater core
by Lee Hart <[EMAIL PROTECTED]>
12) Re: Fwd: re: UHMW in heater core
by Danny Miller <[EMAIL PROTECTED]>
13) Gone Postal Van
by "Tom Shay" <[EMAIL PROTECTED]>
14) RE: C?
by Cor van de Water <[EMAIL PROTECTED]>
15) RE: Jesse James & Monster Garage Go Lithium!!!
by "Roger Stockton" <[EMAIL PROTECTED]>
16) Re: Jesse James & Monster Garage Go Lithium!!!
by Danny Miller <[EMAIL PROTECTED]>
17) Re: Lift beds for an electric truck.
by Christopher Zach <[EMAIL PROTECTED]>
18) Re: Battery price increase
by Matt Milliron <[EMAIL PROTECTED]>
19) Re: Gone Postal Van
by "Roderick Wilde" <[EMAIL PROTECTED]>
20) Re: Fwd: re: UHMW in heater core
by Victor Tikhonov <[EMAIL PROTECTED]>
21) Re: Fwd: re: UHMW in heater core
by Lee Hart <[EMAIL PROTECTED]>
22) Re: Jesse James & Monster Garage Go Lithium!!!
by Victor Tikhonov <[EMAIL PROTECTED]>
23) capacitor packs
by Matt Milliron <[EMAIL PROTECTED]>
24) RE: capacitor packs
by "Hacker Joel-QA6240" <[EMAIL PROTECTED]>
25) Re: Fwd: re: UHMW in heater core
by Lee Hart <[EMAIL PROTECTED]>
--- Begin Message ---
Do you have a URL on them because I am having a hard time Googling
them....
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of John Westlund
Sent: Monday, February 13, 2006 1:50 PM
To: [email protected]
Subject: Re: Busted in Blue Meanie!
Joel Hacker wrote:
>John,
>Could you or someone else comment on Hawker >AeroBatteries.
What they are and what technology >makes them so "effecient"
or desirable to you?
I do know the ones John is using are rated to 26 AH at the 20 hour rate,
each weighing 24 pounds. I don't know what 1 hr rate or reserve capacity
is, but I'd more than love to have that data.
I imagine about 40 minutes reserve capacity, or basically in John
Wayland's car, using 25 amps to cruise 60 mph, would equate to 40 miles
range. 25-30 miles if you throw some lead foot into the mix.
As for 'efficiency', they appear to have very low Peukert's numbers
compared to other AGM batteries, along with a very low internal
resistance.
>I'm just curious as to what they are that makes them so attractive!
Specific power out the ass.
Someone correct me if I'm wrong, but I recall that at 2,000 amps, they
sag to about 8V each. So that's 16 kW/battery, or for 29 of them under
the hood 464 kW from the batteries.
Basically, 630 battery horsepower out of a pack weighing 696 pounds.
This is nearly 50% more power than Exide Orbitals per unit weight.
A dedicated drag car with about 1,200 pounds of these babies and the
motors and controllers to use it would be pulling high 6s or low 7s. I
have a hunch Dennis Berube is going to go this path.
These same batteries could just as easily be placed into a street car,
but I don't see anyone with deep pockets ready to aim for 10s or 9s yet.
It would take a very careful choice of glider, that's for damn sure.
Probably twin 11"
WarP motors and a maxed out HV Zilla 2k, if they can both fit...
--- End Message ---
--- Begin Message ---
On Feb 13, 2006, at 10:12 AM, John Wayland wrote:
Hello to All,
Its' all Otmar's fault.....
Now that he's an Oregonian and is within a 2 hour's drive of Portland,
we get to see each other more often than when he was one of those
Californians. On his last visit to the Wayland laboratory, as usual,
time was spent in his outrageous s-t-r-e-t-c-h VW bus with the tunes
cranked through the Wayland sound system. After abusing me with some
limp, bass-less acoustic earth muffin crap, Oat finally put on some
downright funky stuff. I was immediately drawn to it (he knew I would
be) with its low 5 string electric bass, killer drum mix, gurgl'n
Hammond B3, and the requisite Fender strat clik'n 9th cord grooves :-)
Even though it was sourced off Oat's iPod and formatted in dismal
lo-fi MP3, I could still imagine how it might sound with full
fidelity. Yup, in an instant, I was hooked on Jon Cleary and the
absolute monster gentlemen...had to have that CD!
[snip]
Maybe you were listening to the low-fi copy while on the way to buy the
CD?
I have to wonder... which song was playing when the cops pulled you
over, John?
#1 - "Pin Your Spin"
#3 - "Oh No No No"
#6 - "Doin Bad Feelin Good"
#8 - "Funky Munky Biznis"
#10 - "Got to Be More Careful"
#11 - "Caught Red Handed"
Which one did you listen to on the way back?
Cheers,
-Dave
http://www.megawattmotorworks.com
--- End Message ---
--- Begin Message ---
Maybe I need to be slapped upside the head for such an idea,
But the number one problem that I've notice with EV's is a
Range limited to somewhere less than 100 miles (on a very good
Day).
Here's a solution that crosses my mind...what's the most
Efficient way possible to convert gas/ethanol/biodiesel/natural gas
(fossil fuels) to electrical power.
Since all engines are based on heat differential, the most efficient
Would be a turbine, but that causes problems with noise, heat, and
Safety (possibly).
Does anyone know of successful tests/trials/attempts to make this work?
Also, the second best option would be to get a gennie that is run from
Fossil fuels and run it set at its most efficient RPM (for gas engines,
Somewhere around ~3K rpm, for diesel engines, somewhere around ~2K rpm).
That way, you would never have to stop for recharges, or would never
Have to depend upon a charging station to back you up...
Here's why I ask...Not that I am trying to turn this group into a Hybrid
Power group, but I live in Chicagoland and would like to own just one
Car and not have to own two (a gas model just for distance driving), and
Keep thinking to myself, what are the options for driving an EV car, but
Still having portable power to charge, even if it is a Honda 1000 Watt
Generator that I leave running in the trunk for 4-6 hours just to top
off
The battery pack...
Any ideas out there, has this thought ever run across anyone else's'
mind?
Do they make a gas/diesel turbine generator yet that is a reasonable
size?
Thanks,
Joel
--- End Message ---
--- Begin Message ---
At 22 packs it would make a practical setup. (not moneywise though) Even if
you had to pull them out of the scooter for each charge it'd be a lot less
time consuming. Maybe the chopper show (American Choppers?) could talk
Milwaukee into sponsoring a small chopper like El Chopper. That'd be a lot
simpler and I bet you could arrange the batteries to imitate the shape of a
Harley motor. I hope however you will work on the 18650 batteries. Of the
shelf packs could do the same thing for about 1100 dollars not including
chargers. If you made the packs up yourself at a dollar a battery, 3
batteries make 2ah get the BMS chip etc.etc...We're only talking a few
hundred dollars to do the 64ah pack. I really hope you work on the
18650's.......Lawrence Rhodes....
----- Original Message -----
From: "Rich Rudman" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Monday, February 13, 2006 11:49 AM
Subject: Re: Jesse James & Monster Garage Go Lithium!!!
OK... the packs are 3 amp hours each at 28 volts,
Umm that's 22 Lion V28 packs.
OK... each pack lists for $150 That's $3300 for your scooter's pack.
I don't have that kind of cash for a small EV. That out buy me A LOT of
Optimas....
Look at that cash for the return... not a good value I contend.
Madman
----- Original Message -----
From: "Lawrence Rhodes" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Monday, February 13, 2006 11:03 AM
Subject: Re: Jesse James & Monster Garage Go Lithium!!!
Rich can you tell us how many AH per charger? Would you say a 64ah pack
at
28vdc might be practical now? Something for a scooter. I can make a 17
ah
pack from lead acid BB batteries using 2 17 ah batteries at 24v. If I
could
fit 64ah at 24vdc into a Rad to Go it would be sweet. Can it be
practically
done? The Rad to Go uses two 17 ah batteries on their sides. There is
plenty of room in a scooter like the Rad to GO or the GoPed, plus the
battery compartment could be spacered up a bit if needed. With this
battery
we could approach a 30 mile range using the stock configuration.
Lawrence
Rhodes.....
----- Original Message -----
From: "Rich Rudman" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, February 11, 2006 11:25 AM
Subject: Re: Jesse James & Monster Garage Go Lithium!!!
> The Lions packs are from Millwaukee Tools.
> The Cells are from Molicell in BC.
> John did not tell me were they came from, I had to guess and haggle it
out
> of him, and on dissassembly it was obvious.
> I have great respect for these cells and the efforts that Millwaukee
tool
> had to go through to get a system that works with them. There is a LOT
of
> brains in the Cell pack and in the charger. If you look at the photo
from
> Philille Borges post you will see a potted black blob that has a LOT of
> brains in it.
> My Guess....Is it has the Texas Instruments LION protection chip set
> and
> the gas gage chip. I might learn more later.. but this is getting close
to
> betraying a Good Team memebers confidence. I won't be publishing any
> circuits schematics for sure. All the rest of the information is left
> up
> to
> the Lister to find from the TI site and the Molicell site.
>
> Lion has to be protected from shorts, over charging and thermal abuse.
> Without this.. you will kill them. And maybe get hurt also. So....the
> level
> if BMS and the depth that you have to go to have a good support of each
> cell
> is close to a sensor per cell. That's a LOT of equipment when you have
> 2,688
> Cells to monitor. As the Mg car did.
> We had to total tear down the battery pack and charge every module
> in
> it's seprate charger.. and we had 210 chargers. This makes this kind of
> pack
> and the service of it totally unpratical for a Street EV. You need at
> least
> 3 guys and 4 hours to pull a charge cycle off. We did it once and
> there
> were no cameras on us when we did it for Real.
>
> In the next coulpe of years I expect as a Charger and now also a BMS
> designer... I will get Very good at doing all the above foot work....in
> designing my own version that can be Series charged with a single very
> high
> power charger.
>
> Madman
>
> ----- Original Message -----
> From: "Hacker Joel-QA6240" <[EMAIL PROTECTED]>
> To: <[email protected]>
> Sent: Friday, February 10, 2006 12:08 PM
> Subject: RE: Jesse James & Monster Garage Go Lithium!!!
>
>
>> Okay Rich,
>>
>> Could you please tell us all just for curiosity (and bookmarking sake)
>> Where you got the Lions and what the cons are against them or
>> Why you said,
>> "Lion is going to be a heart ache.. Lots to be gained...much effort
>> needed."
>>
>> -----Original Message-----
>> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
>> On
>> Behalf Of Rich Rudman
>> Sent: Friday, February 10, 2006 12:34 PM
>> To: [email protected]
>> Subject: Re: Jesse James & Monster Garage Go Lithium!!!
>>
>> I could bring one of my V28 lions.. should you wish to play with 28
>> volts and 100 amps.
>>
>> I have 4, 2 came with my Combi Kit... and two followed me home.
>> 2 came home with scorch marks on them. One has been diassected... I
>> learned a LOT...
>>
>> Lion is going to be a heart ache.. Lots to be gained...much effort
>> needed.
>>
>> Rich Rudman
>> Madman
>>
>
--- End Message ---
--- Begin Message ---
For your information,
if you are ready to order your batteries:
My supplier told me that they will raise their prices by
at least 8% for all batteries due to peaking metal (lead)
prices and increased fuel (transport) costs.
Lead has recently jumped from $400 to over $1400 per
metric ton.
They will take orders for the old prices until March 1st,
so inquire with your dealer/supplier how much time you
have before new prices set in.
Regards,
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
--- End Message ---
--- Begin Message ---
> Do you have a URL on them because I am having a hard time Googling
> them....
It's on John's sponsors page:
http://www.plasmaboyracing.com/sponsors.php
--- End Message ---
--- Begin Message ---
Capstone Microturbine is the most practical solution, but it still seems
to be a similar efficiency to a Otto cycle piston engine. It quotes
remarkable-sounding numbers but they are actually assuming you want to
recover the waste heat so they count captured heat as a product (and
turning fuel into heat is basically 100% efficient!). It's nice that it
can burn basically anything that can burn and is fairly quiet.
The key here is that the "sweet spot" of an engine is not dramatically
more efficient than most of the mid-range. Now the full throttle and
idle ends of the range are notably worse for efficiency, those are
worthwhile to avoid for long periods.
The generator concept usually completely defeats the point of an EV.
While "inverter generator" technology like Honda's EU1000i, EU2000i,
etc is leaps and bounds over old gens for efficiency, noise, and
emissions, it's still plain awful compared to modern auto engines. At
least I'm pretty sure the efficiency (hp-hr per lb fuel) is worse, I
don't know for sure though. But the emissions are way off for sure.
It's got no catalytic converter and no EFI system controlling the
mixture and timing. Emissions per hp-hr has got to be order(s) of
magnitude worse than an average modern mid-priced sedan. Now there's a
theory that being able to extend your range with a gen on 5% of your
driving would enable you to use your EV 100% of the time thus not need a
second IC vehicle, there's some justification to that idea in theory but
probably not in reality.
I believe the Prius is often misunderstood. Its mpg gains didn't come
from adding batteries and a motor. It came from using an Atkinson cycle
piston engine (never before used in an automobile I believe) that was
probably highly tuned over an impractically small RPM range. The hybrid
motor picks up the slack making the Atkinson cycle practical for the
general public. Also it is made very light and has an exceptionally
good drag coefficient (these features would benefit a non-hybrid equally
well) and regerative braking.
Simply having a smaller motor and banking the power in batteries alone
would probably not make any gains. The loss in converting shaft hp to
electrical energy, loss in the charge/discharge cycle, and loss in the
controller/motor is fairly substantial. Hard to say but that's
something like 20%-50% lost, right? The engine would have to be much
more efficient to make up for that loss.
Danny
Hacker Joel-QA6240 wrote:
Maybe I need to be slapped upside the head for such an idea,
But the number one problem that I've notice with EV's is a
Range limited to somewhere less than 100 miles (on a very good
Day).
Here's a solution that crosses my mind...what's the most
Efficient way possible to convert gas/ethanol/biodiesel/natural gas
(fossil fuels) to electrical power.
Since all engines are based on heat differential, the most efficient
Would be a turbine, but that causes problems with noise, heat, and
Safety (possibly).
Does anyone know of successful tests/trials/attempts to make this work?
Also, the second best option would be to get a gennie that is run from
Fossil fuels and run it set at its most efficient RPM (for gas engines,
Somewhere around ~3K rpm, for diesel engines, somewhere around ~2K rpm).
That way, you would never have to stop for recharges, or would never
Have to depend upon a charging station to back you up...
Here's why I ask...Not that I am trying to turn this group into a Hybrid
Power group, but I live in Chicagoland and would like to own just one
Car and not have to own two (a gas model just for distance driving), and
Keep thinking to myself, what are the options for driving an EV car, but
Still having portable power to charge, even if it is a Honda 1000 Watt
Generator that I leave running in the trunk for 4-6 hours just to top
off
The battery pack...
Any ideas out there, has this thought ever run across anyone else's'
mind?
Do they make a gas/diesel turbine generator yet that is a reasonable
size?
Thanks,
Joel
--- End Message ---
--- Begin Message ---
The 14 inch tires will still require 14 inch wheels though,
like the EV1 tires. My car has 13 inch wheels.
What I'd like even more to get ahold of is the Goodyear
Invicta GLR, size 175/70R13. Haven't been able to find them,
either.
Ricky Suiter wrote:
>As far as the EV1 tires, he said he got them a few
>years ago, basically right at the end of any EV1
>support. He got them at a Saturn dealership. I
>specifically asked Michelin once about a year ago if
>any of those tires were still available, and they said
>I'd have to check with local stores if there might be
>any in warehouses.
>Actually if you want the ultimate in extreme
>efficiency tire you might try the
>Insight tire, Bridgestone Potenza RE92 in 165/65R14. I
>recall reading about an Insight owner getting a set of
>Proxima's a few years ago and it actually cost a
>few mpg due to the 10mm extra width.
--- End Message ---
--- Begin Message ---
Myles Twete wrote:
>> With 2700 cells, you could have a 100S27P config for nom. 370v.
>> Configured as 100 series sets of 27 buddies, you'd need [100]
>> monitors. And that ain' so many monitors after all is it?
What happens if a cell shorts? Aren't its 99 paralleled buddies going to
dump a truly awesome amount of current into it? This could lead to fires
or other dramatic events.
So, you at least need a fuse in series with every parallelled cell.
If it's just a fuse, what happens when one blows? If the fuse blew as
the result of a high current load (drag racing, etc.), the other 99 have
to carry slightly more current. Another one blows. And another. This
could lead to a popcorn failure. That means the last fuse to go has to
safely open at 100x normal current. And when it's open, it has to be
able to clear the full 370v pack voltage. Fuses that can do that are
larger and more expensive than the cells themselves!
So, I think this leads to some kind of battery management system that
can monitor the voltage *and* current of every cell, and take
appropriate action to prevent this kind of runaway worst-case situation.
I don't know what it will be -- but it ain't gonna be cheap or simple!
--
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 ---
Well, this is a possible future idea. Right now with 2 year old batteries the
range is down to about 40 miles according to Greg (which is still pretty dang
good). This is a thought for the future when it is time for him to get a new
pack for the car.
I'm also considering maybe one time trailering my Saturn down there as well.
Does that defeat the purpose?
Later,
Ricky
Rush <[EMAIL PROTECTED]> wrote:
Ricky and Greg -
It was great having you both down here. We got lots of new input and can't wait
to see Greg's VW again when you use your double charging idea at Casa Grande.
John and I are putting in a 220 v outlet at his house so we can do some fast
charging, so next month think about bringing down Greg's VW.
Rush
Tucson AZ
www.ironandwood.org
---------------------------------
Yahoo! Mail
Use Photomail to share photos without annoying attachments.
--- End Message ---
--- Begin Message ---
Lee Hart said:
>> A ceramic heating element shouldn't exceed 200-250 deg.C. even
>> if the airflow is blocked.
Chris Robison wrote:
> This is a **LOT** higher than I'd been planning on -- 250C is 482F,
> I'd been told I could expect around 180F, similar to an automotive
> core.
180 deg.F is the *normal* self-regulating temperature if they are
working right, i.e. sufficient airflow and not too much voltage. 482
deg.F is the worst-case hot-spot *fault* temperature, if something goes
wrong. Any hotter than this and it melts the solder and disassembles
itself.
Examples of things that can go wrong:
- Something stops the fan or blocks the airflow. If there aren't
any other faults, the element just heats up to 200 def.F or so.
But if there are other factors (too much voltage, etc.) this
can be the causative factor for a more serious problem.
- Your control circuit fails, leaving the elements powered all
the time, even with no fan. Same as above.
- Water, leaves, bugs, or dirt get sucked into the air intake and
bridge the heating elements. The space between + and - is very
small, barely 1/16" so it doesn't take much.
- An element cracks or breaks, due to age, shock, vibration,
mounting stress, or manufacuring defects.
- One element of a series pair shorts, doubling the voltage on the
other element.
- Something strikes an arc across an element (it only takes a tiny
bit of metal, as the spacing is so small). Once a DC arc is
it won't extinguish itself until a considerable amount of the
heater is burned away.
> I searched for hours trying to find a website that would actually
> provide the terminal temperature for a 120V PTC wafer at a given
> voltage assuming no airflow, and my search turned up nothing.
It's not the sort of information a manufacturer will post on the web. It
falls under the category of "things we don't want someone's lawyer to
know". You'd find it in the UL test report for one of these heaters, and
you can buy copies of these reports. UL does some amazingly stupid
tests, just to see what happens (wrap it in cheesecloth :-) But they
wouldn't have tested it on DC unless someone paid them to.
>> Each element is *NOT* a resistor! They tend to self-stabilize
>> at a particular temperature, regardless of the applied voltage.
>> Thus, series and parallel switching or PWM modulation is not
>> effective for controlling the amount of heat.
> Even at extremely low duty cycle, you disagree that PWM would
> effectively reduce output?
PWM works, but not very well. For example, suppose your PWM is 100% on;
the heater is at 180 deg.F and drawing 10 amps. You change the PWM to
50% on, hoping to get half the heat. The heater cools off to 170 deg.F,
which makes its resistance drop almost 2:1. Now it's drawing 19 amps
during the PWM on-time, and 0 amps during the off-time. You've barely
decreased your heat, and made the switching current twice as high.
You're better off turning off some of the elements completely to limit
heat. Or, control heat production via fan speed.
--
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 ---
PWM works fine for heater coils. They do increase in resistance (thus
lowering the current) with higher temps. That only means that for a 50%
duty cycle you get somewhat more than 50% of the heat. Incandescent
light bulb filaments have a similar feature in their V/I curve, actually
I think they're a lot steeper, and they dim well enough. You want to
choose a PWM freq that is rapid enough to prevent the element's temp
from oscillating but that's a pretty low freq.
Danny
Chris Robison wrote:
Each element is *NOT* a resistor! Changing the voltage has relatively
little effect on the heat produced. More voltage just makes it heat up a
little, which causes its resistance to go up a lot. This cuts back the
power a lot. Thus, they tend to self-stabilize at a particular
temperature, regardless of the applied voltage. Thus, series and
parallel switching or PWM modulation is not effective for controlling
the amount of heat.
Even at extremely low duty cycle, you disagree that PWM would effectively
reduce output? Or is it just that at very low temperatures, the elements
would draw unrealistically high currents during the "on" periods? I'd
wanted to control output via PWM; I may have to drop that plan as well.
--chris
--- End Message ---
--- Begin Message ---
I haven't anything about Gone Postal for ages. What's happening with
it?
--- End Message ---
--- Begin Message ---
Well - it is nitpicking, but usually the notation is either
number C, like 5C to indicate that the current is 5 times
the normalised Capacity of the battery.
(For a 100Ah capacity this means discharging it at 500A);
or the indication is C/number (divided by number) as you are
using a fraction of the capacity in current per hour,
resulting in a longer duration at the lower current.
Most batteries are specified at C/20, which means the current to
discharge them in 20 hours time.
For example 100Ah batteries will supply 5Amp for 20 hours.
NOTE that these batteries will not supply 500A for 12 minutes,
even though that would still amount to 100Ah, as the higher
current causes higher losses - you may not be able to run 5 min
at a constant 500A draw.
Often bettery specs have a series of graphs for discharge times
at different discharge rates.
The 100Ah (at C/20) battery may sustain 70A when discharged
in 1 hour, resulting in a reduced 70Ah capacity at this current.
Hope this clarifies,
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 Peter VanDerWal
Sent: Monday, February 13, 2006 12:52 PM
To: [email protected]
Subject: Re: C?
It's a sorta fuzzy term, but basically:
C or 1C means to drain the entire capacity of the battery in one hour.
10C is ten times the 1C current i.e. draining the battery in about 5-6
minutes.
C5 (notice number AFTER the letter) means to drain the capacity in 5
hours, or a current roughly 1/5 of C
The fuzzy bit comes in because batteries don't have the same total AHr
capacity at 10C as they do at C10. So does C mean 220 Amps if you have a
220 AHr battery (rated at the 20 hour rate) or does it mean the maximum
current you can actually get out of it continuously for one hour, perhaps
145 amps?
I've seen people use it both ways.
So to recap:
'number' before C means a current that equals that number times the AHr
capacity of the battery.
'number' after C means a current that equals the AHr capacity divided
by that number. I.e. draining the battery over 'number' hours.
> Hi all,
>
> Here's a noob sort of question, but I don't know much about batteries...
>
> What does the C rating mean? For example, 30C or 100C for the A123's?
>
> Thanks,
>
> Mike
>
>
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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 ---
Lee Hart [mailto:[EMAIL PROTECTED] wrote:
> What happens if a cell shorts? Aren't its 99 paralleled
> buddies going to dump a truly awesome amount of current into
> it?
27 buddies; Lawrence was suggesting 100 series blocks of 27 paralleled
cells each.
Still, the possibility of 2600A+ being dunped into that shorted cell
still seems to justify your concern. ;^>
I think that a possible answer is that such a massively paralleled pack
really only makes sense for racing (where its 2700A+ discharge current
could be exploited), and so the possibility of a spectacular failure
might be an acceptable risk.
Another is that if the interconnects between individual cells are sized
appropriately for normal discharge rates (~100A), then in the event of a
cell failing shorted, the 26x normal current would simply blow the
interconnect. Although the interconnects would be acting as fuses, they
would never have to interrupt full pack voltage since that would require
all paralleled cells in a block to short, and then the voltage monitor
for that block would obviously sense the undervoltage condition and
force the system to shutdown. In such an unlikely catastrophic failure,
the last interconnect might indeed open with full pack voltage across
it, but since the fault can now be sensed by the BMS, the controller can
be shut down and/or main contactor(s) dropped out to interrupt the fault
current even if the interconnect was unable to clear the fault.
For applications other than racing (where the unusually high discharge
rates of these cells (~35C) is an advantage), it probably makes far more
sense to use a single string of much larger capacity cells, such as the
Kokams with their 20C discharge capability.
Another possible way to sidestep this issue is to use paralleled strings
of single cells. Although one would now require some sort of BMS per
cell, the BMS could end up being sufficiently simpler (e.g. under/over
voltage and temperature per cell rather than per block plus current per
cell) and cheaper to be justifiable.
Cheers,
Roger.
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--- Begin Message ---
Well, if a cell has a failure that creates a 3.6mOhm short, you'd
probably blow it up just from the charge remaining in that cell alone,
but if not, that would draw 100 amps off all the other cells (limited by
the resistance of the short) which is more than enough to blow it up
without exceeding the normal current rating.
It's pointless to speculate how low ohm a shorted battery could be from
unfamiliar technology, but if I were going to wildly speculate, it seems
less likely to have shorts down into the microohm range (thus could be
protected by a fuse or fusible link interconnect). Again, not knowing
anything about the technology it's wild speculation, but an internal
short of hundreds of amps might melt the shorted region leaving a less
conductive mass meaning a mild short could be a more likely sustained
condition.
Danny
Roger Stockton wrote:
27 buddies; Lawrence was suggesting 100 series blocks of 27 paralleled
cells each.
Still, the possibility of 2600A+ being dunped into that shorted cell
still seems to justify your concern. ;^>
I think that a possible answer is that such a massively paralleled pack
really only makes sense for racing (where its 2700A+ discharge current
could be exploited), and so the possibility of a spectacular failure
might be an acceptable risk.
Another is that if the interconnects between individual cells are sized
appropriately for normal discharge rates (~100A), then in the event of a
cell failing shorted, the 26x normal current would simply blow the
interconnect. Although the interconnects would be acting as fuses, they
would never have to interrupt full pack voltage since that would require
all paralleled cells in a block to short, and then the voltage monitor
for that block would obviously sense the undervoltage condition and
force the system to shutdown. In such an unlikely catastrophic failure,
the last interconnect might indeed open with full pack voltage across
it, but since the fault can now be sensed by the BMS, the controller can
be shut down and/or main contactor(s) dropped out to interrupt the fault
current even if the interconnect was unable to clear the fault.
For applications other than racing (where the unusually high discharge
rates of these cells (~35C) is an advantage), it probably makes far more
sense to use a single string of much larger capacity cells, such as the
Kokams with their 20C discharge capability.
Another possible way to sidestep this issue is to use paralleled strings
of single cells. Although one would now require some sort of BMS per
cell, the BMS could end up being sufficiently simpler (e.g. under/over
voltage and temperature per cell rather than per block plus current per
cell) and cheaper to be justifiable.
Cheers,
Roger.
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--- Begin Message ---
I still say get ahold of Bob Batson ev-america.com. He has a get that has
hinges and brackets with gas lift struts like on a tail gate of an suv to help
lift the box manually.
Thank you. I dropped him a line, and it sounds like he has what I am
looking for. A bolt in kit for $150 will work perfectly.
Chris
--- End Message ---
--- Begin Message ---
On Mon, 13 Feb 2006 14:24:42 -0800, you wrote:
>For your information,
>if you are ready to order your batteries:
>My supplier told me that they will raise their prices by
>at least 8% for all batteries due to peaking metal (lead)
>prices and increased fuel (transport) costs.
>
>Lead has recently jumped from $400 to over $1400 per
>metric ton.
>They will take orders for the old prices until March 1st,
>so inquire with your dealer/supplier how much time you
>have before new prices set
Great, hope the tax refund check gets here in time.
Matt Milliron [EMAIL PROTECTED]
1981 Jet Electrica, Ford Escort
My daughter named it, "Pikachu".
It's yellow and black, electric and
contains Japanese parts, so I went with it.
--- End Message ---
--- Begin Message ---
The front motor is down at Jim's High Torque Electric getting some new mods
done that I had an idea about and he is pulling it off. He will do a lot of
his own magic as well. At the moment I do not know if I will race it this
year. If we do run it will be at Bremerton Raceway with Madman and friends,
Father Time, Tom True, and possibly Steve Kiser. Maybe we could even get
John and Tim to come up from Portland and bring Jim and crew and his car of
course. That would be like the old days when EV racing was fun. We will let
you know in case you want to join us. I am going to put money in the "Maniac
Mazda" this year but I may not race it ever again in this country.
Roderick Wilde
"Suck Amps EV Racing"
www.suckamps.com
----- Original Message -----
From: "Tom Shay" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Monday, February 13, 2006 4:36 PM
Subject: Gone Postal Van
I haven't anything about Gone Postal for ages. What's happening with
it?
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--- End Message ---
--- Begin Message ---
That's funny Lee, how come I didn't see such a response when
we were discussing ceramic vs water heaters a while back?
I'm sure John Wayland (ceramic heater fan) would love to see it :-)
Everyone was thrilled about $15 wall-mart heaters and couldn't
figure out why anyone in their right mind would spend $500 for a
normal EV heater designed for the job then...
Victor
Lee Hart wrote:
Examples of things that can go wrong:
- Something stops the fan or blocks the airflow. If there aren't
any other faults, the element just heats up to 200 def.F or so.
But if there are other factors (too much voltage, etc.) this
can be the causative factor for a more serious problem.
- Your control circuit fails, leaving the elements powered all
the time, even with no fan. Same as above.
- Water, leaves, bugs, or dirt get sucked into the air intake and
bridge the heating elements. The space between + and - is very
small, barely 1/16" so it doesn't take much.
- An element cracks or breaks, due to age, shock, vibration,
mounting stress, or manufacuring defects.
- One element of a series pair shorts, doubling the voltage on the
other element.
- Something strikes an arc across an element (it only takes a tiny
bit of metal, as the spacing is so small). Once a DC arc is
it won't extinguish itself until a considerable amount of the
heater is burned away.
--- End Message ---
--- Begin Message ---
Danny Miller wrote:
> PWM works fine for heater coils.
It works fine for nichrome (resistive) heating elements. Their
resistance is stable with temperature, so they behave just as you'd
expect with PWM (50% duty cycle gives you 50% heat).
> That only means that for a 50% duty cycle you get somewhat more than
> 50% of the heat.
Correct. 50% duty cycle gives you 80-90% of the heat. The reduction in
on-time due to PWM is accompanied by an increase in peak current. This
forces you to use much larger transistors to handle the peak. That's
what I mean by it being rather ineffective.
> Incandescent light bulb filaments have a similar feature in their V/I
> curve, actually I think they're a lot steeper, and they dim well enough.
Incandescent light bulbs have much *less* change in resistance with
temperature. But their light output varies drastically with temperature;
so much so that PWM works to control brightness, even though it doesn't
work well to control power. For example, 60% PWM reduces a lamps
brightness by 5:1, reduces average current by 25%, and INCREASES peak
current to 1.5 times its full-on value.
--
Lee A. Hart
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--- Begin Message ---
Lee Hart wrote:
So, you at least need a fuse in series with every parallelled cell.
If it's just a fuse, what happens when one blows? If the fuse blew as
the result of a high current load (drag racing, etc.), the other 99 have
to carry slightly more current.
??
If I understand you correctly, I think each will carry exactly
just 1% more in this case.
100 cells supply 100A so each cell supplies 1A.
One fuse blows, so 99cells now supply 100A so
each supplies 100/99=1.01A.
This will certainly go totally unnoticeable.
Victor
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--- Begin Message ---
Due to a lucky dumpster dive I am the proud owner of 48 GE
capacitors. I would like to make a cap pack. My math tells me that I
should be able to get a little more than 8 Farads out of these. The
only information I can cross check with is on the MetricMind site. I
also want to run them in parrallel not series. I know that I am only
looking at maybe 2 to 5 seconds of power, but heck they were free.
What do yall think.
DIELEKTROL
GE Capacitor
61L378
30uF
660VAC 60HZ
PROTECTED P854
D1000AFC
Matt Milliron [EMAIL PROTECTED]
1981 Jet Electrica, Ford Escort
My daughter named it, "Pikachu".
It's yellow and black, electric and
contains Japanese parts, so I went with it.
--- End Message ---
--- Begin Message ---
uF is microFarard, or:
1 Farad / 1,000,000
Also, it looks like you got ahold of non-polarized
AC Motor Capacitors (for correcting Inductive Loading
In Motors)...they won't store DC too well being
Non-polarized and rated at 600V.
Better luck is to raid computer power supplies
And other industrial rectifier circuits (before
They went to switching power).
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Matt Milliron
Sent: Monday, February 13, 2006 9:54 PM
To: [email protected]
Subject: capacitor packs
Due to a lucky dumpster dive I am the proud owner of 48 GE capacitors.
I would like to make a cap pack. My math tells me that I should be able
to get a little more than 8 Farads out of these. The only information I
can cross check with is on the MetricMind site. I also want to run them
in parrallel not series. I know that I am only looking at maybe 2 to 5
seconds of power, but heck they were free.
What do yall think.
DIELEKTROL
GE Capacitor
61L378
30uF
660VAC 60HZ
PROTECTED P854
D1000AFC
Matt Milliron [EMAIL PROTECTED]
1981 Jet Electrica, Ford Escort
My daughter named it, "Pikachu".
It's yellow and black, electric and
contains Japanese parts, so I went with it.
--- End Message ---
--- Begin Message ---
Victor Tikhonov wrote:
> That's funny Lee, how come I didn't see such a response when
> we were discussing ceramic vs water heaters a while back?
> I'm sure John Wayland (ceramic heater fan) would love to see it :-)
I believe I and others have posted these failure modes before. I'm sure
John knows about all of them, and has taken them into consideration when
he did the ceramic heaters in his EVs. (Right, John? :-)
> Everyone was thrilled about $15 wall-mart heaters and couldn't
> figure out why anyone in their right mind would spend $500 for a
> normal EV heater designed for the job then...
There is "inexpensive", and there is "cheap". They're not the same thing
at all!
An "inexpensive" solution is when you find a good price on the right
parts to do a job. Maybe you buy them at a discount, or used, or
surplus, or something built for another purpose but which fully meets
the requirements of the application. Or, you might get something
substandard, but spend a lot of time modifying it so it does fully meet
the requirements (when you have a lot more time than money).
A "cheap" solution is when you cut corners to save a buck. Leave things
out as a calculated risk, or because you don't know any better. "We don'
need no steenkin fuses!" "This will never overheat!" "That oughta be
strong enough."
You can use a $15 ceramic heater as part of either a cheap or an
inexpensive solution. But you'll get what you pay for!
--
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 ---
