EV Digest 6705
Topics covered in this issue include:
1) Re: Light EV, controller/motor: Lynch motor
by "Peter VanDerWal" <[EMAIL PROTECTED]>
2) Re: Light EV, controller/motor: Lynch motor
by "Peter VanDerWal" <[EMAIL PROTECTED]>
3) Re: cheap batts for the very patient? :-0
by "Peter VanDerWal" <[EMAIL PROTECTED]>
4) Re: DOD question - new/old debate
by Danny Miller <[EMAIL PROTECTED]>
5) RE: Controller Schematics that are descent?
by "Simon Chambers" <[EMAIL PROTECTED]>
6) State of Charge Confusion
by Steve Powers <[EMAIL PROTECTED]>
7) Re: State of Charge Confusion
by "Peter VanDerWal" <[EMAIL PROTECTED]>
8) Re: DOD question - new/old debate
by Jeff Shanab <[EMAIL PROTECTED]>
9) RE: corvette conversion
by "Miller, John" <[EMAIL PROTECTED]>
10) Re: Motor, controller & battery recommendations?
by Jeff Shanab <[EMAIL PROTECTED]>
11) Power calculation, was: Re: [EV] RE: Issues involved in...
by James Massey <[EMAIL PROTECTED]>
12) Re: Motor, controller & battery recommendations?
by "Marty Hewes" <[EMAIL PROTECTED]>
13) Astrodyne DC-DC
by [EMAIL PROTECTED]
14) Re: LED headlight bulbs?Very OT
by murdoch <[EMAIL PROTECTED]>
15) Re: Minn Kota Chargers?
by Jeff Major <[EMAIL PROTECTED]>
16) Re: cheap batts for the very patient? :-0
by "Dmitri" <[EMAIL PROTECTED]>
17) Re: corvette conversion
by "Dmitri" <[EMAIL PROTECTED]>
18) RE: DOD question - new/old debate
by "Randy Burleson" <[EMAIL PROTECTED]>
19) Re: cheap batts for the very patient? :-0
by Danny Miller <[EMAIL PROTECTED]>
20) Re: LED headlight bulbs?Very OT
by Danny Miller <[EMAIL PROTECTED]>
21) Re: DC-DC converter
by Lee Hart <[EMAIL PROTECTED]>
22) Re: Catapillar Drive? WAS Re: Kind OT: homemade disk motors
by Lee Hart <[EMAIL PROTECTED]>
23) Re: DOD question - new/old debate
by Lee Hart <[EMAIL PROTECTED]>
24) Re: cheap batts for the very patient? :-0
by Lee Hart <[EMAIL PROTECTED]>
25) Re: State of Charge Confusion
by Lee Hart <[EMAIL PROTECTED]>
26) Re: LED headlight bulbs?Very OT
by Lee Hart <[EMAIL PROTECTED]>
27) Re: DOD question - new/old debate
by Lee Hart <[EMAIL PROTECTED]>
--- Begin Message ---
ANd I'll bet they are more expensive too.
Considering that you'd need at least three of them for this
application....probably not the most economical choice.
> Apologies if someone has already mentioned this, I haven't read the rest
> of the thread;
>
> The newer versions of the Lynch motor have a higher power
>
> http://www.agnimotors.com/
> http://www.agnimotors.com/home/index.php?option=com_content&task=view&id=5&Itemid=36
>
>
>
> Peter VanDerWal wrote:
>>
>>
>> I disagree.
>>
>> The Lemco/Lynch motors are nice, but not powerfull enough for this
>> application. At least not a single motor.
>>
>> The continuous power is only about 6hp, which is probably not enough to
>> maintain 60-70 mph on a vehicle with no doors (i.e. poor aerodynamics),
>> even with doors it would be questionable.
>> Secondly, the ammount of time it can produce the max power (16hp?) is
>> measured in seconds.
>> Try climbing a long hill at any speed and poof goes the motor. With
>> single speed ratio's the amount of current needed for hills is virtually
>> the same at 5mph as it is at 30 mph, so tying to climb slower doesn't
>> help.
>>
>>
>
>
--
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--- Begin Message ---
Oops, sorry about that last post, I was confusing my threads and though I
was talking about the Jeep conversion.
> Apologies if someone has already mentioned this, I haven't read the rest
> of the thread;
>
> The newer versions of the Lynch motor have a higher power
>
> http://www.agnimotors.com/
> http://www.agnimotors.com/home/index.php?option=com_content&task=view&id=5&Itemid=36
>
>
>
> Peter VanDerWal wrote:
>>
>>
>> I disagree.
>>
>> The Lemco/Lynch motors are nice, but not powerfull enough for this
>> application. At least not a single motor.
>>
>> The continuous power is only about 6hp, which is probably not enough to
>> maintain 60-70 mph on a vehicle with no doors (i.e. poor aerodynamics),
>> even with doors it would be questionable.
>> Secondly, the ammount of time it can produce the max power (16hp?) is
>> measured in seconds.
>> Try climbing a long hill at any speed and poof goes the motor. With
>> single speed ratio's the amount of current needed for hills is virtually
>> the same at 5mph as it is at 30 mph, so tying to climb slower doesn't
>> help.
>>
>>
>
>
--
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--- Begin Message ---
> 2x18650 LiIon cells in qualcomm packs (used) $0.89 ea, 13,500 in stock
> 1200mAh @7.2V
*Used* LiIon cells? Aren't those similar to used lottery tickets?
>
> 8x1.7Ah NiMh cells in HP laptop packs (new) $0.69 ea, 5600 in stock
> 1700mA @ 9.6V
>
> 1.2Ah Duracell/Toshiba NiMh AAs (new 95-97 vintage) $0.25 ea, 25k in stock
>
> Anyone ever dealt with these guys? Does radio shack carry a 6000 AA
> carrier sled? :-)
>
> Rob
>
>
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--- Begin Message ---
Possible, but really coloubmetry- measuring amp-hrs used- and just
voltage will tell you SOC fairly accurately, especially if you can take
voltage when the pack is at rest at a stoplight.
The SOC is not so much the issue, we can measure that with decent
accuracy. The issue is Peukert's reduces is the amount of usable
capacity depending on how many amps you need. If you want to crawl at
30 amps there is more capacity available than if you need 100 amps. Do
you need to go uphill? Well, maybe the batt could take you up that now
and then do a 15 mi level stretch with the remaining capacity, but not
the exact same thing in the reverse order.
Also, another factor- which is a bit different than Peukert's- is a
pack's voltage will sag when you draw high current. A consequence of
this is the controller will have to increase the duty cycle to produce
the same power as when the pack was fresh. This increases the current
needed to produce that power level. So you kinda get bit twice- the
voltage sag means you need more current as the remaining capacity gets
lower and Peukert's will reduce the remaining capacity when higher
currents are involved.
Danny
Rob&Amy Smith wrote:
I would agree as well. Your ICE gas gauge doesn't tell you how far
you can go, just what's left in the tank. It seems like trip
computers that try to estimate DTE based on previous driving
conditions have the same trouble, and bounce around depending on how
you are driving. Seems like best you can do is a rolling average
with an adjustable averaging window. If there was a way to just more
directly estimate remaining Ah's it seems like thats what you really
want to know.
SO, how about this :-) Has anyone ever tried monitoring electrolyte
pH in real time? I would assume that as it progresses from acid ->
water from full charge to empty that the pH would track this fairly
quickly & smoothly? Seems like how much energy you have left should
be a direct function of how many ions you have left in the
electrolyte. There are plenty of pH meters out there, but I have no
idea if there is any sort of cheap bulk sensor that you could deploy
across the pack in an economical way so as to have an average picture
of pack state of charge. Would be really cool if you could monitor
each cell independently in real time :-)
Rob
--- End Message ---
--- Begin Message ---
http://www.robotpower.com/osmc_info/
This is designed for battle robots (e.g. robotwars, etc), hence it's a
fairly good design with plenty of overload protection. Only rated to 36v if
you run it off lead acid, but a little work modifying the circuit could
easily make it run off higher voltage. Rather nice starting point if you're
thinking of designing your own controller, and also there's plenty of good
documentation explaining why every single major component does and is there
for.
Regards,
Si
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
> Behalf Of Chris
> Sent: 26 April 2007 1:09 PM
> To: ev@listproc.sjsu.edu
> Subject: Controller Schematics that are descent?
>
> Does anybody have Controller schematics that are descent? Or schematics
> for a inverter for AC motors??
>
> Thanx Chris
>
>
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>
> This message was checked by NOD32 antivirus system.
> http://www.eset.com
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--- Begin Message ---
I was trying to determing my state of charge / DOD,
and I'm confused.
Batteries are 80 AH. Pack now consists of 7 Deka
Group 24 AGM and 2 Johnson Controls Flooded. I put in
the two flooded batts because I found I had some weak
batteries, and I didn't want to replace the whole pack
yet.
I have indivual 6 A chargers on each battery - which
are now finally working OK. The "Smart Chargers" are
supposed to charge the pask "fast".
Deka's website says:
12.8 V - full
12.6 V = 80%
12.4 V = 60%
12.2 V = 40%
12.0 V = 20%
Under what conditions though????
So yesterday, I took readings of the resting voltage
and I drove, took more readings, drove, took more
readings, etc. And, finally "ran out of electric
fuel." Much to my surprise I got stranded 1 mile from
my house. I was able to let it rest a few hours and
limped home at 25 MPH.
I checked all the resting voltages again, and clearly
the new batts were OK. The oldedr ones were a little
lower, but not really that much.
Then, I checked them under a light load. I spun the
motor in neutral. The new ones were reading 12.25
under load. The old ones were 12 - 12.2 V. But, one
was 10.5 V. Obviously that was the problem.
So, I put each on a 6 A charge. This morning, after
9-10 hours on the charger, they still aren't fully
charged. The old ones are close. The new ones in the
front are not. Not even 80%. But, 9 hrs x 6 A = 54
AH and they are only 80 AH to begin with.
So, what happened. I can't believe I took out that
much energy driving only 8 miles. If I did, that is
very high Watt Hours / mile.
Can anyone explain what is going on?
Thanks,
Steve
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--- Begin Message ---
> Deka's website says:
> 12.8 V - full
> 12.6 V = 80%
> 12.4 V = 60%
> 12.2 V = 40%
> 12.0 V = 20%
>
> Under what conditions though????
I believe that would be resting charge with nothing connected to the
battery for 24 hrs, and the battery at 80 degrees F.
>
> So yesterday, I took readings of the resting voltage
> and I drove, took more readings, drove, took more
> readings, etc. And, finally "ran out of electric
> fuel." Much to my surprise I got stranded 1 mile from
> my house. I was able to let it rest a few hours and
> limped home at 25 MPH.
Don't do this too often, it will shorten the life of your batteries.
> Then, I checked them under a light load. I spun the
> motor in neutral. The new ones were reading 12.25
> under load. The old ones were 12 - 12.2 V. But, one
> was 10.5 V. Obviously that was the problem.
10.5V under load indicates that the battery is at 100% DoD at that load.
Under heavy loads you'll reach this point sooner than at light loads.
Since this was a very light load, this indicates that the battery was
completely empty.
> So, I put each on a 6 A charge. This morning, after
> 9-10 hours on the charger, they still aren't fully
> charged. The old ones are close. The new ones in the
> front are not. Not even 80%. But, 9 hrs x 6 A = 54
> AH and they are only 80 AH to begin with.
How full were they to start with? Also, I'm guessing that you are just
assuming that the chargers are putting out the full 6A? Have you measured
them? What is the voltage that the chargers turn off at? Perhaps they
have NEVER fully charged your batteries.
--
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 ---
I am gonna suggest that the gauge be calibrated and offset E to F is 20%
to 100% at the 1hr rate.(or whatever is decided) During driveing it
always goes down, never up.
Then a second "range at current usage" (with selectable
current/Average/5minAverage settings) display is allowed to bounce around.
So if you are on it hard the e-f guage moves faster and the miles to go
readout reads less. If you suddenly slow down the miles to go jumps up
but the E-F guage stays the same and just slows it's decent.
--- End Message ---
--- Begin Message ---
Who needs another lead-sled pickup truck?
I'd love one
--- End Message ---
--- Begin Message ---
I remember many episodes with a turbo 350 when vacuum wasn't present or
the modulator had died.
it won't shift out of first unless you manually shift it or rev and
backoff to cause the govener to shift it.
Think of it this way: The governer gave it a reading on speed and vacuum
gave it a reading on demand. The two are used to define the point where
the vacuum can pull the spool to cause an upshift.
The full electronic units that shift up based on a 5V signal may
actually be more adaptable to EV's.
Although...you probably have a vacuum pump for the brakes and if you use
a throttle body for your pot, you could probably rig up something to the
ported vacuum in the throttle body.
--- End Message ---
--- Begin Message ---
At 08:01 PM 26/04/07 -0400, Jack wrote:
I would like to thank the people for helping me with how things work , you
really helped clear things up on how it works . Sorry I did not answer
sooner but I just got a job out of town & did not have internet connecton
were I was , got firerd today now have more time but no money to convert
my truck to ele. Does any body know how many amps 400watts 12v are, & how
many watts there are in 130 amps . am working on a new project with wind
power to help recharge batts. I am sure one of you will know . Thanks
again Jack
G'day Jack, All
DC Power is volts x amps (AC there is a "funny" where the amps is usually
not in synch with the volts, so the term VA is used, or watts or kilo-watts
when properly compensated for the non-synch (power factor correction and
harmonic distortion correction)).
So in an EV, or any other DC system:
Watts = Volts x amps
Watts divided by volts = amps
Watts divided by amps = volts.
In answer to your question, 400 watts divided by 12 is 33.3 amps, but is
your 12V system 12V? 400W divided by 13.8V = 29 amps.
Then you ask how many watts in 130 amps, but you don't give a voltage, at
12V (130 x 12) = 1560 watts, at 14.4 volts (fast charging volts for a 12V
system) is 1870 watts.
Bummer about the job.
Hope this helps
Regards
[Technik] James
--- End Message ---
--- Begin Message ---
Hi Jeff,
I appreciate the help. In an ICE wide open throttle condition, I thought
there is no vacuum, and it shifts up before redline anyway, which might
still be too low for an electric. How is that different from having no
vacuum to the modulator at all, did they use a vacuum source that never went
to zero? Also, do you know what the cable from the throttle linkage to the
trans does? I still haven't found that one in the book, but maybe the two
interact. No vacuum but the cable indicating less than full throttle might
cause an ambiguous state.
Also, the governer is driven from the driveshaft end, not the input shaft,
right? It seems to be positioned to read road speed. I've got to get my
mind around what it could know about motor RPM since what it sees is altered
depending on what gear you're in. I wouldn't think it would be spinning
much during a 1-2 shift. Maybe that's why I hear they have 2 sets of
weights. The heavy ones to influence 1-2, the light ones to influence 2-3,
based on the normal gear ratios being present.
I've been toying with the idea of supplying varied vacuum to the modulator
to adjust shift firmness, I was contemplating vacuum operated heater control
or EGR control valves, a throttle body sounds like a good idea if it doesn't
bleed too much vacuum. I've never messed with vacuum lines on an injected
engine. I don't think getting shift points or firmness at full acceleration
will be too tough, the hot rodders have all kinds of ways of tweaking that.
What might take ingenuity is softening the shifts during normal driving
without messing up the full throttle shifts. I suspect having no converter
mass and way less rotating mass in the motor than the ICE would have, will
reduce the shift shock somewhat, but I don't know what the effect will be of
having no fluid coupling.
Thanks,
Marty
----- Original Message -----
From: "Jeff Shanab" <[EMAIL PROTECTED]>
To: "Electric Vehicle Discussion List" <ev@listproc.sjsu.edu>
Sent: Friday, April 27, 2007 7:02 AM
Subject: Re: Motor, controller & battery recommendations?
I remember many episodes with a turbo 350 when vacuum wasn't present or
the modulator had died.
it won't shift out of first unless you manually shift it or rev and
backoff to cause the govener to shift it.
Think of it this way: The governer gave it a reading on speed and vacuum
gave it a reading on demand. The two are used to define the point where
the vacuum can pull the spool to cause an upshift.
The full electronic units that shift up based on a 5V signal may
actually be more adaptable to EV's.
Although...you probably have a vacuum pump for the brakes and if you use
a throttle body for your pot, you could probably rig up something to the
ported vacuum in the throttle body.
--- End Message ---
--- Begin Message ---
All,
Does anyone have experience with the Astrodyne SD-150D-12 DC/DC
converter (spec http://datasheet.astrodyne.com/SD150.pdf)?
I'm considering using it for my conversion. Any input is appreciated.
Rob
RAVolt.com / EVAlbum 995
--- End Message ---
--- Begin Message ---
You seem knowledgeable about lighting and efficiency. I'm not
understanding some things here.
In my home, I have CFCs and they save energy over incandescents, and I
have bought and tested one $40 LED bulb and verified their extreme
energy savings (though their color and brightness leave a lot to be
desired, at first glance).
I don't understand though where conventional Halogen fits into this.
My impression from looking at the wattage and lumens at the store is
that even though Halogen bulbs seem very bright, they seem also to use
a lot of energy and so, purely from an energy-savings standpoint, I am
not saving any power, per lumen.
>From what you're telling us, I should also look into HID as a separate
matter, to understand its properties.
Assuming that for a given task I was willing to size the bulb for the
appropriate amount of brightness, are halogen or HID competitive in
energy efficiency with CFC and LEDs?
I know, this is not EV-specific or auto-specific, though surely it can
be applied to EVs. It is a matter, I suppose, of granting that
different lighting solutions are appropriate to different uses. If we
wish to conserve EV battery energy, we would choose an
energy-conserving bulb, but also need it to satisfy the color,
brightness and other requirements of legal autos.
Still, it seems worthwhile, if possible, to get a sense of the basic
energy-efficiency pecking order, along with the other basics
(durability, longevity, color, best uses, environmental drawbacks such
as Mercury in CFCs, etc.).
On Mon, 23 Apr 2007 22:08:36 -0500, Danny Miller
<[EMAIL PROTECTED]> wrote:
>"xenon" does not mean HID.
>Xenon is a halogen element on the periodic table, it is often used in
>halogen bulbs and thus the term may be used for ordinary halogen bulbs
>and headlights.
>
>HID is a xenon-filled capsule that forms an arc between two electrodes,
>much like a xenon strobe or camera flash but continuous.
>HID is extremely efficient, more so than halogen bulbs, LEDs, and even
>flourescent tubes.
>
>HID headlights are extremely bright but generally legal since the law
>specified the electrical power the headlights consume, not the output.
>HIDs cannot be started and stopped at will like a halogen bulb, it must
>go through a starting cycle that takes a minute or so, even if it's
>still warm from being run only moments ago. This prevents it from being
>switched on and off like a normal high beam.
>
>Some aftermarket modifications that put a HID capsule in place of a
>replaceable conventional bulb have been accused of having a bad spread
>that exposes oncoming drivers to too much stray light. They might be right.
>
>Danny
>
>> w" <[EMAIL PROTECTED]>
>> To: <ev@listproc.sjsu.edu>
>> Sent: Monday, April 23, 2007 6:44 AM
>> Subject: RE: LED headlight bulbs?
>>
>>
>>> Michael,
>>>
>>> You might consider HID (High Intensity Discharge) headlamp bulb
>>> replacement
>>> kits (AKA 'Xenon'). They cut the power used by the headlights in
>>> half and
>>> produce a much better (brighter and more suited to human eyes) lighting
>>> effect.
>>
>>
>> Who says that??!!! I HATE them, because they half-blind me! Maybe they
>> are just mis-aligned, but I wish they would be BANNED!
>>
>> Joseph H. Strubhar
>>
>> Web: www.gremcoinc.com
>>
>> E-mail: [EMAIL PROTECTED]
>>
>>>
>>>
>>
>
--- End Message ---
--- Begin Message ---
Hi Rob,
I have used the MK440 on my 48 volt IUVs (Industrial
Utility Vehicle). With a number of different
lead-acid battery types. It works great. I like it
because I pull 12 volt accessories off one of the four
batteries. Also have used the MK220. A pair of them
because the 440 would not fit the battery tray. They
all are isolated on each output and temp compensated
and fused on each output. Made for boat installation,
so seem to be rugged weather tight units. I like
them. See no reason they won't work for higher
voltage packs. My installation is not tight, that is
somewhat ventilated, no fan and I do not have any heat
issues. They seem pretty efficient, but I have never
measured the VA in and Watts out. If you can live
with 10 amp (or 15) charge rate, I'd go for it.
I did have one issue where a guy left the lights on
and discharged the one battery completely. Then the
Minn Kotta would not charge that one battery because
it was down to 6 volts. I simply disconnected the
series connection and jumpered that battery to a
charged one for 15 minutes, got the voltage up to 10
or 11 V and then the charger took over. O.K. now.
These chargers are also nice because they have LEDs
for each output, so you can tell which one of the
batteries is bad.
Jeff
--- [EMAIL PROTECTED] wrote:
> Anyone ever look at using Minn Kota chargers for a
> parallel charging setup?
>
> As I recall the biggest issue folks had been having
> with Soleil's and the like seemed to be related to
> vibration and environment induced failures. Is that
> still the case? These are probably heavier, but
> claim to be AGM friendly and
> vibration/shock/weather/salt resistant as they're
> meant for onboard marine use.
>
> In particular I was looking at the MK 440, which has
> 4 independent banks at 10A each, 3 stage charging
> and temperature compensation. They seem to indicate
> its ok to hook these up to series connected
> batteries, so I assume each bank is isolated but
> there's not much tech info. After the rebate and
> shipping, it seems like you can find these for about
> $250. For a 144V pack it works out to about 67.6
> lbs and $750. Not too bad seems like. There is
> also a 15A per bank version which would put it up to
> ~$1150 and 93 lbs.
>
> Any thoughts?
>
> Thanks,
> Rob
>
>
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--- Begin Message ---
Haha, yes.
----- Original Message -----
From: "Peter VanDerWal" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Friday, April 27, 2007 5:49 AM
Subject: Re: cheap batts for the very patient? :-0
2x18650 LiIon cells in qualcomm packs (used) $0.89 ea, 13,500 in stock
1200mAh @7.2V
*Used* LiIon cells? Aren't those similar to used lottery tickets?
--- End Message ---
--- Begin Message ---
Don't forget www.metricmind.com
----- Original Message -----
From: "Jack Murray" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Thursday, April 26, 2007 8:25 PM
Subject: Re: corvette conversion
Hi Steve, as you know I think the vette is a good choice although my
choice would be the C4. The AC55 looks like a good motor. It doesn't
have the best power/weight, but not many other options for AC.
The lack of feedback means you are likely a trail blazer here, which is
a good thing, who needs another lead-sled pickup truck :)
Not to discount the value added of electroauto but it's a pricey package.
If you want to get it done quickly, that is probably the best option.
I'm certainly interested in seeing the progress, but sure to get a
wepage going for it.
Cheers,
Jack
Steve wrote:
Hi,
Just put down a deposit on a 1981 donor corvette, so now I need to
get busy. I didn't receive any feedback on the questions concerning
the Solectria AC55 motor/controller, or electroauto.com.
Any/all comments appreciated, either via the list, or by private
email. I would like to place an order within a week or 2 at most.
---
tia,
Steve
[EMAIL PROTECTED]
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--- Begin Message ---
I know that interface wasn't part of the original question, but...
Can you show length of relative sample AND make it adjustable through
UI? If the driver wants more detailed prediction, he could lengthen or
shorten the sample against which mileage is predicted... this would make
the driver more responsible for accuracy (with all the benefits and
weaknesses that this might bring).
Randii
--- End Message ---
--- Begin Message ---
Yes, same problem. However NiCds DO come in large-cell formats and as
such it's possible to make a pack with only one series string. This
avoids the problems associated with paralleling strings. They are also
wet cells that you can add water to. If I understand this correctly
this helps with keeping the series string balanced since the loss of
water due to overcharging can be replaced. So getting the cells which
are slightly low back up by overcharging the cells which are already
full is not a critical problem. I'm not sure though, ask the guys who
run NiCd cells. Several people here have.
Danny
Rob&Amy Smith wrote:
Similar problems with NiCad's, or no?
On Apr 26, 2007, at 7:09 PM, Danny Miller wrote:
NiMH cannot be put in parallel without a charge controller. They
can't be charged directly in parallel nor can they even be connected
in parallel after being charged.
Large series strings also come with serious balance issues. They're
not very tolerant of overcharge so it's a bad idea to bring all the
cells up to full by overcharging the cells which start with a higher
SOC.
These two issues pretty make it difficult to use many small, cheap
cells as a NiMH pack. Well, Prius did but they had a great design
and don't use nearly as much capacity. IIRC there were some people
trying to build with "D" NiMH which is up to 9AH. There are other
issues- the cheap ones don't survive high discharges for long.
NiMH shouldn't be soldered, the button area has some kind of heat-
sensitive plastic underneath it. It's bad news for the batt. They
need to be connected with welded tabs.
Danny
[EMAIL PROTECTED] wrote:
Anyone every been crazy enough to build an EV pack out of AA sized
cells? I assume pack construction would drive you insane :-)
Maybe the scooter/bike guys then?
These guys seem to have some ridiculously cheap deals ($100 min
order though I think) on surplus small cells:
http://www.73.com/a/0658.shtml
Sanyo KR-1700E NiCad $0.23 ea, ~14k in stock
1700mAh 4/3A, discharge curves up to 8C, charge curves up to 1.5C
http://www.73.com/specs/th720.pdf
50 strings of 120 would yield 89Ah @ 144V, Imax ~680A, Rint
~17mOhm, 555 lbs plus pack construction for $1380 plus materials.
Only 12000 solder points ;-)
2x18650 LiIon cells in qualcomm packs (used) $0.89 ea, 13,500 in stock
1200mAh @7.2V
8x1.7Ah NiMh cells in HP laptop packs (new) $0.69 ea, 5600 in stock
1700mA @ 9.6V
1.2Ah Duracell/Toshiba NiMh AAs (new 95-97 vintage) $0.25 ea, 25k
in stock
Anyone ever dealt with these guys? Does radio shack carry a 6000
AA carrier sled? :-)
Rob
Amy Smith
[EMAIL PROTECTED]
Birth Doula
Childbirth Educator
602-277-1572
602-405-3744
"Education is not the filling of a pail, but the lighting of a fire" -
Yeats
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There is no significant energy savings on LED over CFL on a per lumen
basis. LEDs are slightly less efficient, at least they were a few years
ago. I know there have been significant advances in LED emitters but
nothing which totally changed the game on efficiency. Nowadays, they're
probably a bit more efficient IF you were to build the
latest-and-greatest emitters into a product (typically bulb sellers use
far cheaper devices designed 5+ years ago). However, with a frequently
worse Color Rendering Index than CFL and astronomically higher price, a
few % of efficiency one way or the other is irrelevant.
Now if you need a reading lamp, a CFL projects light over an
omnidirectional 360 deg. Only perhaps 10% may hit your book. LEDs can
have 20 deg or even less divergence, and thus illuminate the book on far
less power. This advantage does not exist in room lighting. In fact
the directionality of the emitter is often an undesirable feature and
requires some rethinking of how to use lighting. In some cases the
directionality can be an advantage. Also an issue, LEDs emit light from
a much smaller area than CFL. This is desirable for some reasons- they
can be focused with smaller optics- but for room lighting they can blind
you due to the high light density. Additional light diffusers will help
but eat up the efficiency.
Danny
murdoch wrote:
You seem knowledgeable about lighting and efficiency. I'm not
understanding some things here.
In my home, I have CFCs and they save energy over incandescents, and I
have bought and tested one $40 LED bulb and verified their extreme
energy savings (though their color and brightness leave a lot to be
desired, at first glance).
I don't understand though where conventional Halogen fits into this.
My impression from looking at the wattage and lumens at the store is
that even though Halogen bulbs seem very bright, they seem also to use
a lot of energy and so, purely from an energy-savings standpoint, I am
not saving any power, per lumen.
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Dave Cover wrote:
Speaking of blowing things up, I just got a nice switch mode power
supply for my DC-DC... rated for 115-230 VAC, 300 VDC. My pack is
nominally around 212v.
That's an unfortunate combination. The 240vac line is bridge rectified,
or the 120vac line voltage doubled to produce 320vdc. 212vdc is
considerably below this 320vdc that the power supply is designed for.
Watch out for overheating, or reduced output due to undervoltage protection.
Do I just hook up my pack to L1 and L2?
Yes. It doesn't matter which is positive.
Do I want to ground the unit to the chassis?
Yes. You ground it for safety and noise considerations.
Also, is there a problem with using a relay to power the DC-DC only
when running?
No; though you will see considerable arcing on that relay's contacts
when it closes, due to the huge inrush current to charge the power
supply's input capacitors. It's a hard application for a relay or switch.
It's the same problem as controller precharge, with the same solution;
add a precharge circuit. Only here, the precharge parts are much
smaller, due to the smaller size of the problem.
--
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
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Bob Rice wrote:
Then we COULD have a "caterpiller Drive" as depicted in "Hunt For Red
October, movie? I think THAT was the sub movie where the Russian sub
stole away silently on caterpiller power, a way to blast water out
the pipe in the stern of the sub. No prop or noisy reduction gear!
Or is this still in the Flux Capaciter realm?
No, it's a real concept. The problem (as I mentioned) is that you are
building a fairly inefficient motor, due to the high resistance of its
rotor "windings" (i.e. the seawater). But that's no problem on a ship
with a nuclear power plant for power.
--
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
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Victor Tikhonov wrote:
No matter how you slice it, gadget will never show how far you
can drive, one reading or ten readings. Best it will do is show
how much you've spent and how much remains *if* you keep spending
at the same rate which you generally may not. That's the source
of the problem.
The problem is you're either forced to drive the same way if you
want to believe the readout, or accept the fact that it may be way
off if you drive differently.
No regular car has this sort of perfectly-accurate "miles to go"
indicator, either. The few luxury cars that have such an indicator have
exactly the same problem. They don't know how fast you are planning to
drive, or if there is stop-and-go traffic, or mountains in the way.
Your best bet is to stop being an engineer, and go out and ask real
customers what they want. They'll say the darndest things! :-). No one
has ever seen such a "miles to go" display, so no one will ask for one.
You'll have to work out a compromise between what they (think) they
want, and what is actually practical to provide.
This is one of those situations where a digital display is not
justified. The number you present can't be accurate to 3 digits. That's
why guess gauges are only marked at 0, 1/4, 1/2, 3/4, and full.
I assume you're driving the display with a microcomputer. How about
using the segments as a bargraph? If the display with all segments lit
looks like this:
_ _ _
|_| |_| |_|
|_| |_| |_|
then use just the vertical bars to make two bar-graphs like this:
| | | <-- 3 bars range to go if you drive fast
| | | | | | <-- 6 bars range to go if you drive slow
--
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
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Rob&Amy Smith wrote:
Similar problems with NiCad's, or no?
Nicads are very forgiving of overcharging, so you can get by with longer
series strings and even cells in parallel without as many problems.
There are still limits; just not as restrictive.
--
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
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Steve Powers wrote:
Batteries are 80 AH. Pack now consists of 7 Deka
Group 24 AGM and 2 Johnson Controls Flooded. I put in
the two flooded batts because I found I had some weak
batteries, and I didn't want to replace the whole pack
yet.
I have indivual 6 A chargers on each battery - which
are now finally working OK. The "Smart Chargers" are
supposed to charge the pask "fast".
Deka's website says:
12.8 V - full
12.6 V = 80%
12.4 V = 60%
12.2 V = 40%
12.0 V = 20%
Under what conditions though????
These are the voltages after the battery has been sitting with no load
and no charging for at least 8 hours.
So yesterday, I took readings of the resting voltage and
I drove, took more readings, drove, took more readings, etc.
And, finally "ran out of electric fuel." Then, I checked
them under a light load. The new ones were reading 12.25v
under load. The old ones were 12-12.2 V. But, one was 10.5 V.
Obviously that was the problem.
Right! That one is dead; essentially 0% SOC since it sags to 10.5v even
when just spinning the unloaded motor.
So, I put each on a 6 A charge. This morning, after
9-10 hours on the charger, they still aren't fully
charged. The old ones are close. The new ones in the
front are not. Not even 80%. But, 9 hrs x 6 A = 54
AH and they are only 80 AH to begin with.
Measure the *actual* current that your charger delivers. Most advertised
specs are exaggerations. Your "6 amp" charger might only deliver 6 amps
for a few minutes into a totally dead battery, and then immediately
falls off to a lower current for most of the charging time.
--
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
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Danny Miller wrote:
Neat idea but...
Polarization works by blocking the light with the wrong polarization.
This will decrease the transmission of unpolarized light and will appear
as a significantly tinted windshield. This is a problem when trying to
see at night. The filter on the headlight will also reduce headlight
output.
The patent said the polarizing material only needs to block about 70% of
the cross-polarized light. This dims the approaching headlights to 30%
of their brightness, but doesn't blank them out. This material also lets
80% of the total light through (50% for one axis plus 30% for the
other), which isn't enough to notice in normal driving.
You wouldn't use a diagonal polarization. Glare, say headlights off a
wet road, is largely polarized in one direction. That's why polarized
sunglasses can eliminate it. You'd want to maintain that effect for sure.
Actually, 45 degree diagonal polarization is the only angle that works.
This is a *different* angle than what is used for polarized sunglasses.
So, you can't use both ideas at the same time.
The "natural" polarization you get from light reflecting off surfaces at
a sharp angle is of a relatively random orientation (because the
surfaces it is reflecting from are of all sorts of orientations).
Polaroid sunglasses (another invention of Edwin Land) work by being
oriented to block *some* of this reflected light.
Of course, you could wear "daytime" sunglasses for blocking glare, and
"nightime" driving glasses for blocking the glare of oncoming headlights.
The reduction in headlight brightness is no problem, because we can
easily make more light. If the polarizing film on the headlights takes
half the light away, use twice as bright a light to bring you right back
to where you started.
--
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
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Timothy Balcer wrote:
As an addendum, if it is reasonable to associate resting voltage with
SOC, you could have the unit reset itself after charging, and
initialize when the car is started. Is that reasonable?
Yes; the E-meter does that, and it is reasonably successful. However,
all it does is rest the amphour counter to zero. It does not use this
information to improve its estimation of capacity or Peukert values.
--
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
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