EV Digest 5651
Topics covered in this issue include:
1) Re: BMS poll
by Christopher Zach <[EMAIL PROTECTED]>
2) An Early Retirement For The Hydrogen Fuel Cell
by "jmygann" <[EMAIL PROTECTED]>
3) Mostly OT was (RE: "Who Killed the Electric Car" radio blurb......)
by Mike Willmon <[EMAIL PROTECTED]>
4) Re: BMS poll
by Nick Viera <[EMAIL PROTECTED]>
5) Re: BMS poll
by Nick Viera <[EMAIL PROTECTED]>
6) Re: BMS poll
by "Death to All Spammers" <[EMAIL PROTECTED]>
7) RE: BMS poll
by Mike Willmon <[EMAIL PROTECTED]>
8) Re: Trying to understand shunt regs
by Danny Miller <[EMAIL PROTECTED]>
9) Re: BMS poll
by "Mike Phillips" <[EMAIL PROTECTED]>
10) A BMS definition (Re: BMS poll)
by Victor Tikhonov <[EMAIL PROTECTED]>
11) Re: BMS poll
by "Philippe Borges" <[EMAIL PROTECTED]>
12) Re: Battery Charger Testing
by "Philippe Borges" <[EMAIL PROTECTED]>
13) RE: A BMS definition (Re: BMS poll)
by Mike Willmon <[EMAIL PROTECTED]>
14) Re: who's reviving the electric car?
by "Jorg Brown" <[EMAIL PROTECTED]>
15) RE: who's reviving the electric car?
by Mike Willmon <[EMAIL PROTECTED]>
16) Re: AC output to rectifier
by James Massey <[EMAIL PROTECTED]>
17) RE: BMS poll
by "Bill Dennis" <[EMAIL PROTECTED]>
18) Re: BMS
by Matthew Milliron <[EMAIL PROTECTED]>
19) RE: BMS poll
by Mike Chancey <[EMAIL PROTECTED]>
--- Begin Message ---
Roger Stockton wrote:
You are not asking about a BMS, you are specifically polling to see how
many people are doing *something* to their batteries individually during
charge.
I think you're picking at the details a bit hard here. What Mike is
asking is how many people use some sort of active devices to manage the
charging of batteries in strings.
Some people use neat battery shufflers, some use a sensor system on each
battery talking to a central charger, some use clampers that go to a
certain voltage then cut in an outside load, and some of us use $1.00
Lee Zener regs.
If you're going to charge batteries in a string then you will either
have to equalize/vent to make sure all catch up, or have some sort of
active frob to regulate the batteries.
I've tried it the other way with a really smart charger and temp
sensors; it doesn't work on AGMs. It does however work fine on flooded
Pb and flooded NiCD batteries.
I think it is a pretty meaningful poll: Before Lee described his system
I was resigned to either doing nothing or spending about $5,000 on a set
of Rudman regs. Which are nice, but have had problems as well in the
sparrows I have seen. And which still would not have worked on the Prizm
without a lot of re-engineering to put 100+ wires out of the pack where
the regs could dump heat.
The suggestions that the US_Electricars are "junk", "bad design" and all
that are not helpful either.
The Lee zeners aren't perfect, but they are way way way better than
nothing. How much better remains to be seen but if I'm driving around
next year on this pack and still pulling 20+ miles on a charge then it
will be quite interesting.
Chris
--- End Message ---
--- Begin Message ---
Maybe this will help .....
http://www.thewatt.com/article-1210-nested-1-0.html
--- In [EMAIL PROTECTED], "Mike Phillips" <[EMAIL PROTECTED]>
wrote:
>
> That was awesome. The problem is that the hydrogen economy could be
> sustained with preidential initiative and cash, sadly.
>
> Do you have a link to the original post perhaps?
>
> Mike
>
>
>
> --- In [EMAIL PROTECTED], "jmygann" <ev@> wrote:
> >
> > An Early Retirement For The Hydrogen Fuel Cell
> >
> >
> >
> > Announcement Lucerne Fuel Cell Forum
> > 2-6 July 2007,
> > Lucerne / Switzerland
> >
> > Fuel cells are energy converters, not energy sources. They will
be
> > part of
> > a sustainable energy solution only if they can compete with other
> > conversion technologies. This includes system parameters, fuels
and
> > applications. Time has come for a critical assessment.
> >
> > We need fuel cells for available fuels, not synthetic fuels for
new
> > fuel
> > cells. Natural gas and oil-derived liquid hydrocarbons will be
> > around for
> > many years. However, their use will be restricted by costs,
> > environmental
> > concerns or even political reasons. Sustainable hydrocarbons like
> > bio-methane, bio-ethanol and bio-methanol from organic waste,
wood or
> > farming are already replacing fuels of fossil origin.
Hydrocarbon
> > fuels
> > will be important forever and so will fuel cells capable of
directly
> > converting these fuels into electricity.
> >
> > The impressive performance of phosphoric acid, molten carbonate
and
> > solid
> > oxide fuel cells clearly indicates that these fuel cell families
can
> > meet
> > the challenges of a sustainable future. Some of these fuel cells
have
> > reached 65,000 hours of operation with the first stack and
natural
> > gas or
> > bio-methane.
> >
> > It is highly uncertain that synthetic hydrogen can ever be
> > established as a
> > universal energy carries. Electricity from renewable sources
will be
> > the
> > source energy in a sustainably organized future. The direct
> > distribution of
> > electricity to the consumer is three to four times more
efficient
> > than its
> > conversion to hydrogen by electrolysis of water, packaging and
> > transport of
> > synthetic energy carrier to the consumer and its conversion back
to
> > electricity with efficient fuel cells. By laws of physics,
hydrogen
> > economy
> > can never compete with an "electron economy".
> >
> > But the laws of physics cannot be changed with further research,
> > investments or political decisions. A sustainable future energy
> > harvested
> > from renewable sources (nuclear energy is not sustainable!) must
be
> > distributed and used with the highest efficiency. A wasteful
hydrogen
> > economy does not meet the criteria of sustainability. As a
result, a
> > viable
> > free-market hydrogen infrastructure will never be established
and
> > fuel
> > cells for hydrogen may not be needed. For all applications
> > electricity from
> > hydrogen fuel cells have to compete with the source electricity
used
> > to
> > make hydrogen.
> >
> > The European Fuel Cell Forum is committed to the establishment
of a
> > safe
> > energy future. Therefore, it will continue to promote fuel cells
for
> > sustainable fuels, but discontinue supporting the development of
> > fuel cells
> > for hypothetical fuel supplies. Time has come for decisions.
Keeping
> > all
> > options open is not an adequate response to mounting energy
problems.
> >
> > Therefore, the schedule of the European SOFC Forum will be
continued
> > in
> > 2008 with an extended conference every second year. Beginning
2007
> > (July 2
> > to 6) sustainable energy topics will be emphasized in odd years.
> > Despite
> > earlier announcements the European PEFC Forum series will not be
> > continued.
> >
> > I would like to thank all who have contributed to establish the
> > European
> > PEFC Forum. You and your colleagues have developed a magnificent
> > technology, but the fuel needed to make it work is not offered
by
> > nature.
> > We cannot solve the energy problem by wasting energy. The laws
of
> > physics
> > speak against a hydrogen economy. Physics cannot be replaced by
> > wishful
> > thinking, or changed by presidential initiatives, research
programs
> > and
> > venture capital.
> >
> > Solutions must be implemented soon as long as resources are
> > available for
> > this most challenging task. I sincerely hope that this
announcement
> > will be
> > accepted as a constructive contribution to the ongoing energy
debate.
> >
> > Ulf Bossel, Ph.D.
> >
> >
> > Ithaca, NY 14853
> >
> >
> >
> > --- In [EMAIL PROTECTED], "Mike Phillips" <ev@>
> > wrote:
> > >
> > > Great source, thanks. Got any more?
> > >
> > > I wonder if there are any papers out there that have a
conclusion
> > > leaning towards fuel cells? I'd just like to see someones data
on
> > a
> > > viewpoint that does not support my own.
> > >
> > > Mike
> > >
> > >
> > >
> > > --- In [EMAIL PROTECTED], "Adrian DeLeon" <ev@>
> > > wrote:
> > > >
> > > > On Wed, 12 Jul 2006 17:48:11 -0700, "Mike Phillips"
> > > > <mikep_95133@> wrote:
> > > >
> > > > > Do you guys know of a reliable web source about the energy
it
> > > takes to
> > > > > make hydrogen?
> > > >
> > > >
> > > > Here's a good scientific type of paper -
> > > > http://www.modenergy.com/BEVs%20vs%20FCVs%20EavesEaves%
> > 20120603.pdf
> > > >
> > > > It makes a case for BEVs vs FCVs using (theoretical) 135 HP,
300
> > > mile
> > > > range vehicles. Done by a university prof.
> > > >
> > > > Adrian
> > > >
> > >
> >
>
--- End Message ---
--- Begin Message ---
Several have asked about some resources to read about Alternative Energy
Analysis. This report by the Arlington Institute while
not direstly quoting the figures does a fairly through analysis of the
alternatives. There are lots of references which you can
look up the studies. If possible its better to print this 264 page .pdf
document. Perusing from the computer may be tedious.
Interesting to note in the Hydrogen section in Appendix G starting on page 150
are several articles blasting the "Hydrogen
Economy". "GM's Billion Dollar Bet" on page 161. Electric vehicles are not
handled much except to say in several sections that
electricity generation and transportation systems are already fairly efficient
and infrastructure exists.
Also Bill Dennis asked about
***> 1) 30% of the energy in the US is used by vehicles***
The 2002 chart below indicates ALL of transportation fuel is imported and
comprises 26.5% of the US Energy use. Of that amount,
21.2% of the total energy used, by Transportation, is wasted as heat and only
5.3% gets us to work EVery day. :-(
These are interesting charts.
US Energy Flow Trends 1973 - 2002 http://eed.llnl.gov/flow/
2002 http://eed.llnl.gov/flow/pdf/USEnFlow02-quads.pdf
2001 http://eed.llnl.gov/flow/pdf/USEnFlow01-quads.pdf
2000 http://eed.llnl.gov/flow/pdf/USEnFlow00-quads.pdf
2004 is the newest chart I've seen but I can't remember where and I can't seem
to Google it...will keep looking though. It was
probably in print as these are published around 2 years later. So the 2004
chart is most likely newly out there, somewhere...
I don't mean to discuss all this stuff as it is for the most part OT. But I
throw it out as FYI.
Mike,
Anchorage,AK.
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Behalf Of Bill Dennis
> Sent: Friday, July 14, 2006 11:17 AM
> To: [email protected]
> Subject: RE: "Who Killed the Electric Car" radio blurb tomorrow (Friday)
> morning on CBC Radio One at 8:36am Central.
>
>
> I've never taken a statistics course, so someone more knowledgeable correct
> me if I'm off-base here, but Montis' counter-claim seems a bit out of whack.
> According to Montis:
>
> 1) 30% of the energy in the US is used by vehicles
> 2) Art Spinella says that it takes 10x energy to build vs. to run a vehicle
> 3) Therefore it would take 300% of US energy each year to build our vehicles
>
> Wouldn't that be true only if 100% of the vehicles on the road were built
> new every year? I don't know what the average life of a vehicle is, but
> let's say 8 years just for argument's sake. That would mean that each year,
> about 1/8 of the vehicles in the US are built. If Art Spinella is correct
> (which I doubt), then wouldn't the real yearly energy for building vehicles
> be:
>
> 30% * 10 * .125 = 37.5%
>
> instead of 300%?
>
> Thanks.
>
> Bill Dennis
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
> Behalf Of Mike Ellis
> Sent: Friday, July 14, 2006 7:05 AM
> To: [email protected]
> Subject: Re: "Who Killed the Electric Car" radio blurb tomorrow (Friday)
> morning on CBC Radio One at 8:36am Central.
>
> Rebroadcast available within a day at
> http://www.cbc.ca/thecurrent/logs2006.html .
>
> 25 minutes of interviews.
>
> Interviews with Chris Paine, GM public relations guy, Art Spinella,
> Montis Walker-something.
>
> Chris summarizes the history of the EV1.
>
> GM denies they wanted to kill the project. Blaims not enough interest.
>
> Art Spinella claims the total energy cost of a hybrid is higher than a
> Hummer.
>
> Montis Walker-somthing says using Art's figures, if true, would mean
> that America's car industry would use three times the total energy
> output of the States.
>
> Comments (could be played on air): (416) 205-7878
>
> -Mike
>
>
--- End Message ---
--- Begin Message ---
Hi all,
Roger Stockton wrote:
I think the use of the term "BMS" in the context of this rather
focused poll is misleading at best. -snip- I would suggest that a
*BMS* refers to a system that looks after the batteries on both
charge *and* discharge, not just on charge, and does *not* have to
specifically involve some sort of bypass regulation.
I agree with Roger here... polling for how many users use a "BMS"
without first defining "BMS" and without getting other basic yet
pertinent information about the batteries the "BMS" is used on is going
to result in almost meaningless data.
I'd also agree that a true "Battery Management System" is a system that
takes care of the batteries at *all* times. Shunt regulators by
themselves are not a "BMS", they're just a single component providing a
couple of the features of a full blown "BMS". This is because they do
nothing to protect batteries during discharge, and some don't even fully
protect the batteries during charging.
While the results of the poll may be interesting, I think they are
not particularly meaningful without having people also indicate if
they are running lead-acid packs or not, and if their lead-acid packs
are VRLA (gel or AGM) or not.
The chemistry and sub-type of the batteries is definitely information
worth knowing for such a poll. I also think it'd be good to know the
voltage of the batteries used. The reason being that if you use a
per-battery BMS on 6-Volt batteries, you're managing groups of 3 cells.
If you use 12-Volt batteries, you've now got double the number of cells
being managed in a group, which gives you less control of whats going on
on a cell-to-cell basis.
My 0.333 kWh,
--
-Nick
1988 Jeep Cherokee 4x4 EV
http://go.DriveEV.com/
http://www.ACEAA.org/
--------------------------
--- End Message ---
--- Begin Message ---
Hi all,
Roger Stockton wrote:
I think the use of the term "BMS" in the context of this rather
focused poll is misleading at best. -snip- I would suggest that a
*BMS* refers to a system that looks after the batteries on both
charge *and* discharge, not just on charge, and does *not* have to
specifically involve some sort of bypass regulation.
I agree with Roger here... polling for how many users use a "BMS"
without first defining "BMS" and without getting other basic yet
pertinent information about the batteries the "BMS" is used on is going
to result in almost meaningless data.
I'd also agree that a true "Battery Management System" is a system that
takes care of the batteries at *all* times. Shunt regulators by
themselves are not a "BMS", they're just a single component providing a
couple of the features of a full blown "BMS". This is because they do
nothing to protect batteries during discharge, and some don't even fully
protect the batteries during charging.
While the results of the poll may be interesting, I think they are
not particularly meaningful without having people also indicate if
they are running lead-acid packs or not, and if their lead-acid packs
are VRLA (gel or AGM) or not.
The chemistry and sub-type of the batteries is definitely information
worth knowing for such a poll. I also think it'd be good to know the
voltage of the batteries used. The reason being that if you use a
per-battery BMS on 6-Volt batteries, you're managing groups of 3 cells.
If you use 12-Volt batteries, you've now got double the number of cells
being managed in a group, which gives you less control of whats going on
on a cell-to-cell basis.
My 0.333 kWh,
--
-Nick
1988 Jeep Cherokee 4x4 EV
http://go.DriveEV.com/
http://www.ACEAA.org/
--------------------------
--- End Message ---
--- Begin Message ---
> It's easy enough to find out from the list admin how many people are on
> this list. So I thought a poll is appropriate to see how many have
> something attached to each battery that is active in managing the
> battery pack. One charger per battery counts. Having a fancy charger
> alone does not count.
>
> So how many folks on this last have bms on their battery pack?
>
> Mike
2000 Ranger EV - (p.s.- every other OEM EV Ranger or RAV4 on the list
has a BMS)
1993 Kewet (not running) - no BMS because it's got a flooded NiCd pack
(does any use a BMS on NiCds?), but there is an emeter to watch
amp-hours in and out.
--- End Message ---
--- Begin Message ---
Roger is right. BMS is only vaguely defined. This will no doubt cause many and
varied conclusions. However if we refer to Mike
Phillips original claim that:
**"I've watched this list to see who has BMS in <ANY> form. 3% is being
generous. I could be wrong ;)"**
Mike Willmon however, supports the arguement:
**"that more than 3% of the people driving EV's on this list have at least a 2
stage charger, a charge timer or Regs/Balancers of
some sort. If not then they at least are aware to check the battery voltage
and temperature EVery so often while charging and
turn them off when full. This is the most basic form of Battery Management
which if performed dilligently can be effective."**
For example read Roland Wiench's post with this subject: "I have none, after 5
years, 30 of my T-145's are still in with 0.02
volts of each other with over 20 in the 0.01 volt range..."
But then again the poll does not distinguish between batteries that absolutely
need a BMS and ones that could merely benefit a
little, IF they are abused. I have no doubt Roland takes very good care of his
batteries. Human TLC is the best BMS you can
have, and the most costly if you want to buy it. I would argue that this
counts. Maybe a better poll with qualifiers would ask
the type of battery, if they have "active/automatic" charge control/discharge
control, if they all stay within 20mV, 50mv, 1V etc.
and if the person even checks individual voltages.
I wonder if Mike Chancey could work a Poll section onto the EVAlbum front page?
Or make use of the database now built into the
EVAlbum listings?
Mike
Anchorage, Ak.
> Christopher Zach wrote:
> I think you're picking at the details a bit hard here.
> Roger Stockton wrote:
> > You are not asking about a BMS, you are specifically polling to see how
> > many people are doing *something* to their batteries individually during
> > charge.
--- End Message ---
--- Begin Message ---
Whoops, missed Roger's sarcastic element on the first read.... ok
explaining the basic lead-acid charging algorithm to a guy who builds
them wasn't really called for.
That's the algorithm you'll see in like 100 pages on charging
flooded/gel/VRLA batteries anyways.
Danny
Danny Miller wrote:
The prescribed 3-step charging method is
1. a constant current until a voltage set point is reached,
2. a fixed voltage for either a fixed time period and/or until current
drops below a set point
3. a lower current/voltage float
That's typical for 6v-24v at least, all types. However strings with
more cells and/or unusual construction may have different
recommendations. For one, there are greater cell imbalance issues.
The presence of shunt regs will fix a lot of that, but these will
themselves need to be taken into consideration. For example, if you
have a very powerful charger, it would be advisable to lower the
current once one of the shunts turn on or it could blow it right there.
The float stage is likely unnecessary, since the vehicle will not be
sitting for long periods. With this long of a string and without a
BMS, I would suspect more emphasis should be placed on making a
current which will finish the charge off in the more deeply discharged
cells but not so much that it is overcharging the more full cells at
too high a rate. With a BMS, it would be wise to focus on detecting
when all the shunt regs have turned on indicating all batteries have
reached the top voltage.
Danny
Roger Stockton wrote:
This is a very interesting statement ;^>
Where might one find this "ideal" PbA algorithm documented? Is it
"ideal" for all PbA, or just flooded, or just VRLA or just AGM or just
gel types?
You see, I do charge algorithm development as part of my day job, and it
would greatly simplify my life if there really were an ideal PbA
algorithm I could hand to each customer and battery manufacturer I work
with. Unfortunately, I don't recall *any* of the battery manufacturers
I have worked has ever recommending an IU algorithm of this sort.
In fact, one of the points that most of the battery manufacturers have
been in agreement on is that they do *not* want their batteries float
charged. Universally the preference is to fully charge the batteries
and then turn the charger off and restart to top the batteries up
periodically as required.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
I was plain the first time. But for those with doubts, let me clarify.
If you have a Zreg BMS or better it qualifies as a BMS for this pole.
This thread is not for debate or definition of a BMS. It's strictly
for a head count.
If folks want to debate what a BMS is, please start your own thread.
Mike
--- In [EMAIL PROTECTED], "Roger Stockton" <[EMAIL PROTECTED]> wrote:
>
> Mike Phillips wrote:
>
> > I thought a poll is appropriate to see how many have
> > something attached to each battery that is active in
> > managing the battery pack. One charger per battery
> > counts. Having a fancy charger alone does not count.
> >
> > So how many folks on this last have bms on their battery pack?
>
> I think the use of the term "BMS" in the context of this rather focused
> poll is misleading at best.
>
> You are not asking about a BMS, you are specifically polling to see how
> many people are doing *something* to their batteries individually during
> charge.
>
> I would suggest that a *BMS* refers to a system that looks after the
> batteries on both charge *and* discharge, not just on charge, and does
> *not* have to specifically involve some sort of bypass regulation.
>
> In this context, examples of systems that might be considered BMS's
> include the Zivan Smoother and Lee Hart Balancer, and perhaps the
> Powercheqs. Examples of systems that would not count as BMS's include
> Lee's Zener regs, Rudman regs, or the use of individual chargers.
>
> I think that unless the question is rephrased, the results of this poll
> would most accurately be interpreted as revealing how many on the list
> treat individual batteries differently during charge, or perhaps more
> generously, how many are using some sort of *charge* management system
> that treats individual batteries differently (as opposed to smart
> chargers that may be just as effective (or more), but do not treat
> individual batteries differently).
>
> While the results of the poll may be interesting, I think they are not
> particularly meaningful without having people also indicate if they are
> running lead-acid packs or not, and if their lead-acid packs are VRLA
> (gel or AGM) or not. It is fairly well recognised that flooded lead
> acid batteries are fairly tolerant of abuse and can deliver rated life
> without any BMS simply by not abusing them overly on charge or discharge
> and providing regular maintenance. I would suggest that the vast
> majority of those on this list are using flooded lead acid, and so a
> poll whose results indicated that only 5% of the list considers
> individual batteries while charging doesn't paint an accurate picture if
> 75% of the list are using batteries which don't actually benefit
> significantly from such treatment.
>
> Cheers,
>
> Roger.
>
--- End Message ---
--- Begin Message ---
Mike Willmon wrote:
> Roger is right. BMS is only vaguely defined. This will no doubt
cause many and varied conclusions.
Let me try to fill the void here.
Suggested definition of a BMS (battery management system)
The main functions of a BMS are:
- To keep the battery (individual cells/batteries and so the
whole pack) going outside predefined limits (integration with
the charging hardware is mandatory)
- To keep individual cells/batteries at the same (or close)
SOC at all times, e.g. continuously "manage" them.
- To disconnect the pack from the charger or from the load
if preset alarm/pre-alarm conditions are met. (This can be
done gradually, in stages, etc. Point is such a function must
exist).
/side note
Clampers/shunt regulators which are active only at the end
of charge do not qualify because:
a) they are typically only active at the end of charge
to prevent exceeding max voltage on a cell/battery
while allowing cells/batteries with lower voltage still
being charged. This is very useful feature, but different
class of hardware. Shunt type regulators:
b) Have no idea about SOC of each cell/battery
c) Never have chance to work if cells/batteries are
purposely cycled in the middle of capacity range and for whatever reason
never fully charged. This is not good for lead but allowed for
Lithium based battery. I use to cycle my pack between about
40% and 80% SOC. Any shunt type regulators/clampers in this case
would be useless.
/end of side note
Nice to have but strictly speaking not necessary features are:
a) Detailed visual feed back to the driver ("OK" idiot light may
be sufficient as long as the battery is being treated all right)
b) Control of the drive system
c) Data collection (for off line analysis) facility
'Course far from exhaustive list - there is no limit for
nice-to-have stuff. This won't impact the basic definition
of "management" though.
Since balancing SOC is primary goal (however SOC is defined),
the SOC of each cell/battery has to be known at any time.
This pretty much mandates some sort of polling each cell/battery
by a central controller which then decides on the local activity.
If, for simplicity, cell/battery voltage is substituted for SOC,
simpler devices can be used to equalize voltages (flying capacitor,
powercheq type or hardware and Lee's balancer) - one may get away
even without communication bus if only adjacent voltages are compared
and acted upon.
These devices still qualify for a BMS as long as voltages are being
compared and acted upon continuously (this disqualifies any type of
clampers) *AND* total pack voltage is held within limits (this last
requirement disqualifies powercheqs and flying caps schemes which
try to maintain the voltage delta between adjacent battery close to
zero while ignoring absolute value.
Battery monitoring systems are qualifying as long as they include
a person observing data as a part of the system to act upon conditions.
Since this is not guaranteed "management", such systems should
not really qualify for a real BMS. It is similar as trying to qualify
a variac charger + fluke meter as fine and flexible charger because
a person can keep observing and adjusting it to follow very
sophisticated profiles. Consistently. In reality this does not happen.
Hopefully this clarifies common definition of a BMS.
I'm sure there will be some improvements or fine point debate,
but this is basic info for comparison purposes.
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
nothing on Saxo electric
nothing on 106 electric
nothing on EVolution Scooter
homemade shunt regulator on E-pocket bike
homemade lithium BMS on the bench
cordialement,
Philippe
Et si le pot d'échappement sortait au centre du volant ?
quel carburant choisiriez-vous ?
http://vehiculeselectriques.free.fr
Forum de discussion sur les véhicules électriques
http://vehiculeselectriques.free.fr/Forum/index.php
----- Original Message -----
From: "Mike Phillips" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, July 15, 2006 12:14 AM
Subject: BMS poll
> It's easy enough to find out from the list admin how many people are on
> this list. So I thought a poll is appropriate to see how many have
> something attached to each battery that is active in managing the
> battery pack. One charger per battery counts. Having a fancy charger
> alone does not count.
>
> So how many folks on this last have bms on their battery pack?
>
> Mike
>
>
>
> Here's to the crazy ones.
> The misfits.
> The rebels.
> The troublemakers.
> The round pegs in the square holes.
> The ones who see things differently
> The ones that change the world!!
>
> www.RotorDesign.com
>
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connecting during charge a:
-2 ways data logging system + 1 computer
-fluke 123
-2 X DVM with rs232 + 2 computers or 1 with 2 rs232 ports
-rc watt'up meter (no recording but you have max values of V, W, I ...)
-rc Medusa power analyser
-rc Feigao power analyser
...
...
cordialement,
Philippe
Et si le pot d'échappement sortait au centre du volant ?
quel carburant choisiriez-vous ?
http://vehiculeselectriques.free.fr
Forum de discussion sur les véhicules électriques
http://vehiculeselectriques.free.fr/Forum/index.php
----- Original Message -----
From: "David Sherritze" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, July 15, 2006 5:41 AM
Subject: Battery Charger Testing
> I have been using ACI Supercharger 1214CC for charging my EV lead acid
> batteries
> .
> I have had several go bad over the past few months. I have another
> that that I think is bad.
>
> How do you test a 12 volt charger that only had a red and green light.
> I can put a voltage meter to a battery and get a reference. How do I
> test the output of a charger for both volts and amps?
>
> Any ideas?
>
>
>
>
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OK, I'll bite first. I'll validate for the query on the last thread back who
wondered if BMS was Battery Management System, it
could also refer to Battery Monitoring System. The terms are vague enough as
they are and now they have the same
acronym....anyway...moving on...
If powercheqs and flybacks are disqualified because they do not regulate
absolute pack voltage how about in combination with a
2-Stage, IU, or "smart charger" that runs constant current up to the maximum
"Regulation" voltage and then hold there for a preset
time interval and then shuts off? That seems to qualify, except that if they
do not communicate with the charger they cannot
shut it off if one reg/balancer fails. This would seem to put Rich Rudman's
combination of PFC-xx charger and MKxRegs in the
"BMS" category, correct?
**sarcasm mode on - not to anyone in particular though-
I think I have to go back and change my answer to the Poll then :-O If these
are what we're defining as a Battery Management
System then I'm afraid I must not have one. I might even lose the argument
that more than 3% of EV drivers on this list have a
BMS. And I would then have no right to argue that Fuel Cell Vehicles are
woefully inefficient because it either takes 4X the
electricity to make clean hydrogen, or less of you make dirty hydrogen, because
hey, I'm not getting the most out of "managing" my
pack. I do know however that even without a BMS on my pack, I'm still
operating way more efficiently than the FCV's you see
driving all over town.
**sarcasm mode off
Mike,
Anchorage, Ak.
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Behalf Of Victor Tikhonov
> Sent: Friday, July 14, 2006 11:08 PM
> To: [email protected]
> Subject: A BMS definition (Re: BMS poll)
>
>
> Mike Willmon wrote:
> > Roger is right. BMS is only vaguely defined. This will no doubt
> cause many and varied conclusions.
>
> Let me try to fill the void here.
>
> Suggested definition of a BMS (battery management system)
>
> The main functions of a BMS are:
>
> - To keep the battery (individual cells/batteries and so the
> whole pack) going outside predefined limits (integration with
> the charging hardware is mandatory)
> - To keep individual cells/batteries at the same (or close)
> SOC at all times, e.g. continuously "manage" them.
> - To disconnect the pack from the charger or from the load
> if preset alarm/pre-alarm conditions are met. (This can be
> done gradually, in stages, etc. Point is such a function must
> exist).
>
> /side note
>
> Clampers/shunt regulators which are active only at the end
> of charge do not qualify because:
>
> a) they are typically only active at the end of charge
> to prevent exceeding max voltage on a cell/battery
> while allowing cells/batteries with lower voltage still
> being charged. This is very useful feature, but different
> class of hardware. Shunt type regulators:
>
> b) Have no idea about SOC of each cell/battery
> c) Never have chance to work if cells/batteries are
> purposely cycled in the middle of capacity range and for whatever reason
> never fully charged. This is not good for lead but allowed for
> Lithium based battery. I use to cycle my pack between about
> 40% and 80% SOC. Any shunt type regulators/clampers in this case
> would be useless.
>
> /end of side note
>
> Nice to have but strictly speaking not necessary features are:
>
> a) Detailed visual feed back to the driver ("OK" idiot light may
> be sufficient as long as the battery is being treated all right)
> b) Control of the drive system
> c) Data collection (for off line analysis) facility
>
> 'Course far from exhaustive list - there is no limit for
> nice-to-have stuff. This won't impact the basic definition
> of "management" though.
>
> Since balancing SOC is primary goal (however SOC is defined),
> the SOC of each cell/battery has to be known at any time.
> This pretty much mandates some sort of polling each cell/battery
> by a central controller which then decides on the local activity.
> If, for simplicity, cell/battery voltage is substituted for SOC,
> simpler devices can be used to equalize voltages (flying capacitor,
> powercheq type or hardware and Lee's balancer) - one may get away
> even without communication bus if only adjacent voltages are compared
> and acted upon.
>
> These devices still qualify for a BMS as long as voltages are being
> compared and acted upon continuously (this disqualifies any type of
> clampers) *AND* total pack voltage is held within limits (this last
> requirement disqualifies powercheqs and flying caps schemes which
> try to maintain the voltage delta between adjacent battery close to
> zero while ignoring absolute value.
>
> Battery monitoring systems are qualifying as long as they include
> a person observing data as a part of the system to act upon conditions.
> Since this is not guaranteed "management", such systems should
> not really qualify for a real BMS. It is similar as trying to qualify
> a variac charger + fluke meter as fine and flexible charger because
> a person can keep observing and adjusting it to follow very
> sophisticated profiles. Consistently. In reality this does not happen.
>
> Hopefully this clarifies common definition of a BMS.
>
> I'm sure there will be some improvements or fine point debate,
> but this is basic info for comparison purposes.
>
> --
> Victor
> '91 ACRX - something different
>
>
>
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On 7/12/06, Michaela Merz <[EMAIL PROTECTED]> wrote:
> Note, a PR campaign is not a silly idea. Remember,
> Firefox supporters raised enough money for a full (2-page)
> spread in a major newspaper.
I agree. But I don't know if we would have to start a new foundation or
just leave the task to the people at Electric Auto Association? All the
would need is funds (and some guidance ;). I have never understood why
there is so little PR given the fact that 'Social Advertising' is not
expensive. Maybe they need a professional panhandler (ups: they call that
'fundraiser' nowadays).
Putting together a marketing campaign - whether it's advertising, PR,
word-of-mouth, whatever, is foolish if there is no sales conversion
opportunity.
Yes, Firefox raised money for a full 2-page spread. As a result, they
distributed TENS OF MILLIONS of copies of their browser.
Let's say you raised money for a full 2-page spread about EVs. What
effect would it have? The only EVs currently available in large
quantity are scooters. The only electric cars that come close are
Chrysler's GEM cars.
I'm not against the idea, mind you. But I think it doesn't make sense
until there are a lot more electric cars to sell. Next year, when the
Xebra, the Tesla, possibly the back-from-the-dead Th!nk, and others
are on the market, is the earliest it even begins to make sense. 3 or
4 years down the road when Tesla's $50K car is out, with GM's (and
possibly Toyota's) plug-in hybrids out... that's when it really makes
sense to do a lot of PR.
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We just need to make sure people know they are for real AND that they are
coming (again), so the big manufacturers do not try to
do something silly like lease them to us... :-O
Thats what grassroots organizations like EAA are for. Advertising and
advocating. The sooner highway type BEV's are on the
market and the more they make, the cheaper the parts will be for those of us
who still want to roll their own. Why wait?
as Michaela Merz <misch at steyla dot com> wrote:
> I have never understood why there is so little PR given the fact that 'Social
> Advertising' is not expensive. Maybe they need a professional panhandler
> (ups: they call that 'fundraiser' nowadays).
>Jorg Brown wrote
> I'm not against the idea, mind you. But I think it doesn't make sense
> until there are a lot more electric cars to sell. Next year, when the
> Xebra, the Tesla, possibly the back-from-the-dead Th!nk, and others
> are on the market, is the earliest it even begins to make sense. 3 or
> 4 years down the road when Tesla's $50K car is out, with GM's (and
> possibly Toyota's) plug-in hybrids out... that's when it really makes
> sense to do a lot of PR.
>
>
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At 09:29 PM 14/07/06 -0700, Steve Condie wrote:
<snip> Because you're just skimming the top of the voltage curve, and the
power factor is horrible, you're putting a lot more stress on your
components than the amperage delivered would ordinarily take. All of my
components are rated for 20 amps, and I use a 20 amp outlet, but I have a
15 amp circuit breaker in my charger. The most current I set my dim boy
at is around 7 or 8 amps. At that amp draw I get about a 75% power
factor, and my Watt-a-meter says I'm pulling over 14 amps out of the
socket. At float the power factor drops into the 40's.
G'day all
Well Steve, there is something wrong with your meter descriptions. "pick
me, teacher" applies to me here, too, since this is something I've only
come to a good understanding of in the last few weeks due to a project we
are working on. "Bad-boy" chargers, in fact any device that just rectifies
the "mains" as the first thing it does (be it any form of charger, power
supply etc) has good power factor. What these devices have wrong is high
harmonic distortion. Power factor may be 0.97 but harmonic distortion may
exceed 40%.
What is the difference? well, power factor is a statement of leading or
lagging of the current being drawn relative to the voltage waveform.
Transformer chargers and motors draw current later than the voltage wave
that drives them, (and is why small generators have a "VA" rating as well
as a wattage rating).
Harmonic distortion is due to the current being drawn in spikes or pulses -
usually right on top of the voltage wave, so each voltage wave peak has a
current spike that is only limited by the voltage sag of the "mains". The
average current may be 10A, but the peaks may be 20A or more (I don't
actually have any firm figures as to the magnitude of the spikes). Matrix
filters are made that reduce the harmonic distortion to something below 8%,
but can cost a fair bit. A project we are looking at requires to have
harmonic filters added to variable-frequency drives, in order to meet the
electricity and backup generator suppliers' requirements.
The alternative to a matrix filter is an active 'front end' on the device,
to draw current in very small steps that closely follows the voltage wave.
Rich Rudmans' PFC series and other chargers that tout their "power factor
correction" feature are in fact not being technically correct in what it is
that makes their chargers better than a conventional switched-mode charger.
A conventional switched-mode charger should have good power factor - but
terrible harmonic distortion. Transformer chargers can have both bad power
factor and bad harmonic distortion. Rich Rudmans' PFC chargers are an
example that does both power factor correction AND greatly reduced harmonic
distortion due to the active 'front end'.
I don't know what your watt-a-meter is actually attempting to report to you.
I guess this will probably confuse, rather than help, but should stimulate
some discussion.
Regards
[Technik] James
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I agree, Victor, but they seem to be on par with many of the other
responses, so I thought I'd chime in with my setup anyway.
Bill Dennis
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Victor Tikhonov
Sent: Friday, July 14, 2006 6:25 PM
To: [email protected]
Subject: Re: BMS poll
I wish, but they don't qualify for a "BMS" in true meaning
of the term :-(
Speaking of that, the best is the enemy of the good - I DON'T have
any BMS in my vehicle, though in the lab it is running as well as
one done professionally for one of my customers. Priority
is to get EVision (e-meter replacement) out. The BMS will
follow for masses hopefully by the end of this year.
I know, promises promises...
Victor
Bill Dennis wrote:
> On my TS cells, I have Victor's shunt regulators.
>
> Bill Dennis
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
> Behalf Of Mike Phillips
> Sent: Friday, July 14, 2006 3:14 PM
> To: [email protected]
> Subject: BMS poll
>
> It's easy enough to find out from the list admin how many people are on
> this list. So I thought a poll is appropriate to see how many have
> something attached to each battery that is active in managing the
> battery pack. One charger per battery counts. Having a fancy charger
> alone does not count.
>
> So how many folks on this last have bms on their battery pack?
>
> Mike
>
>
>
> Here's to the crazy ones.
> The misfits.
> The rebels.
> The troublemakers.
> The round pegs in the square holes.
> The ones who see things differently
> The ones that change the world!!
>
> www.RotorDesign.com
>
>
>
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OK I will re-reply:
right now I have 8 flooded lead acid batteries. I have the powercheq
units but have not installed them. I have a gang charger consisting
of one Schumacher SpeedCharge unit per battery.
Matt Milliron
http://www.austinev.org/evalbum/702
My daughter named it, "Pikachu". It's yellow and black,
electric and contains Japanese parts, so I went with it.
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Okay, can we get a better handle on all this? What is the point of
this poll? What is the statical accuracy of the responses? The only
true know numbers are count of subscribers to the EVDL and the count
of responses to the poll. The number of subscribers has nothing to
do with the number of EVs owned by EVDL members, so that is of no
particular value. The number of responses only shows how many folks
feel like responding. The differences of opinion on what defines a
BMS further clouds the results. Add on most folks using flooded
batteries and not being concerned about having a BMS or even
answering the poll and what do you get? Statistically irrelevant numbers.
As far as I know nothing that fully fits the definition of a battery
management system is available as an off the shelf plug and play
product that could be fitted to most EVs. The only options are more
limited devices such as the Rudman Regs or PowerCheq
equalizers. Everything else is either handmade or part of an OEM
system. So, what options does that give us? If the point of the
discussion is most people aren't using a true BMS then I would have
to say of course not, they can't get one.
I would like to see such a product become available, but it would
have a major headache for whoever developed and marketed it. The
massive variation in component choices on most EV conversion is going
to make it difficult to build something that works for everybody or
even for most folks. Add to it the naturally frugal nature of many
of us and the unknown payback of adding such a device and the chances
of selling many seem even less likely. Such a system would have to
have an obvious and measurable long term savings just to get any
real interest. That is a pretty tall order.
I think a more valid poll might be something like this:
1. Do you have an EV?
2. What kind of batteries do you use?
3. What kind of charger do you use?
4. Do you use any kind of individual battery charge
monitoring, regulation, or balancing?
5. If so, what kind?
FWIW, I cannot setup the code for a poll on the Album myself. Jerry
might be able to, but he is not available at this time. I do suspect
that adding a field for battery management/regulation to the Album
entries might be of value.
Thanks,
Mike Chancey,
'88 Civic EV
Kansas City, Missouri
EV Photo Album at: http://evalbum.com
My Electric Car at: http://www.geocities.com/electric_honda
Mid-America EAA chapter at: http://maeaa.org
Join the EV List at: http://www.madkatz.com/ev/evlist.html
In medio stat virtus - Virtue is in the moderate, not the extreme
position. (Horace)
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