EV Digest 3412
Topics covered in this issue include:
1) Quick newbie charging question
by "Jamie Marshall \(GAMES\)" <[EMAIL PROTECTED]>
2) Re: Newbie Questions About Traction Battery Pack Design
by Victor Tikhonov <[EMAIL PROTECTED]>
3) RE: exide orbitals
by "Ryan Bohm" <[EMAIL PROTECTED]>
4) Re: Newbie Questions About Traction Battery Pack Design
by Seth <[EMAIL PROTECTED]>
5) Re: Newbie Questions About Traction Battery Pack Design
by "Mark Thomasson" <[EMAIL PROTECTED]>
6) Re: Newbie Questions About Traction Battery Pack Design
by Sam Uzi <[EMAIL PROTECTED]>
7) high-performance EV sports
by Sam Uzi <[EMAIL PROTECTED]>
8) Re: Electrical connectors: was Motor shaft temperature
by Doug Weathers <[EMAIL PROTECTED]>
9) OT-SVR Battery Sale-OT
by "David Chapman" <[EMAIL PROTECTED]>
10) Re: Newbie Questions About Traction Battery Pack Design
by Victor Tikhonov <[EMAIL PROTECTED]>
11) How do you use a variac for charging?
by Jude Anthony <[EMAIL PROTECTED]>
12) Re: Newbie Questions About Traction Battery Pack Design
by Rich Rudman <[EMAIL PROTECTED]>
13) Re: Quick newbie charging question
by Rich Rudman <[EMAIL PROTECTED]>
14) Re: Newbie Questions About Traction Battery Pack Design
by "David Chapman" <[EMAIL PROTECTED]>
15) Re: How do you use a variac for charging?
by "David Chapman" <[EMAIL PROTECTED]>
16) Re: Quick newbie charging question
by "David Chapman" <[EMAIL PROTECTED]>
17) Re: Electrical connectors: was Motor shaft temperature
by Rod Hower <[EMAIL PROTECTED]>
18) Hydrogen Hokum
by [EMAIL PROTECTED]
19) Re: Quick newbie charging question
by Rich Rudman <[EMAIL PROTECTED]>
20) Re: Newbie Questions About Traction Battery Pack Design
by Lee Hart <[EMAIL PROTECTED]>
21) Re: Newbie Questions About Traction Battery Pack Design
by Lee Hart <[EMAIL PROTECTED]>
22) Re: Newbie Questions About Traction Battery Pack Design
by Lee Hart <[EMAIL PROTECTED]>
23) Re: Newbie Questions About Traction Battery Pack Design
by Lee Hart <[EMAIL PROTECTED]>
24) Re: Newbie Questions About Traction Battery Pack Design
by Lee Hart <[EMAIL PROTECTED]>
25) Re: Quick newbie charging question
by Lee Hart <[EMAIL PROTECTED]>
26) Re: How do you use a variac for charging?
by Lee Hart <[EMAIL PROTECTED]>
--- Begin Message ---
I've been thinking about how my to charge my sparrow, and maintain more
balance on my optima yellow-tops.
I know there is some debate about ideal charging sequences, but is there
any agreement about what a single optima would want? What would happen
if I just float charged each battery up to 14 volts? This would
probably take a while, but my car is plugged in if I'm not driving.
Would a 14 volt constant charge put 17 amphours (my commute) into the
battery in 8 hours?
What about equalization. I guess there needs to be an intra-battery
equalization, but isn't that a once in a while need?
What I'd really like is if someone can point me to a nice resource so I
can RTFM.
Thanks in advance,
-Jamie
--- End Message ---
--- Begin Message ---
enu wrote:
Ok, I get it!!!
I will send plain text when I send a post !!!
So sorry to all for the inconvenience - - -
No problem, no problem.
Victor, thanks for the battery lesson - I really need it so that I don't
blow up my garage!!!
I'm not in the position to give lessons, I just offer my experience
and opinion (not guaranteed to be always valid). You choose to listen,
or to ignore it.
If I keep both packs in parallel, what makes the steady drive condition only
using the Li-ion pack?
If the voltage on the pack is about constant, no current flows in
or out of the caps stack (they are at the same voltage), so it's like
caps are not there. The only times you notice them when the voltage
changes.
In other words, how does the inverter/controller only pull from the Ultra
capacitor pack when the Li-ions are delivering less than needed?
To explain simply - the most of the current comes out of the
source with less internal resistance. And the caps have
at least 10 times less than my LiIons. (Yours may be different).
Imagine two 12V batteries in parallel, but one has 10 Ohm resistor
in series with it (representing high internal resistance).
OCV voltages are identical. You load both with 12V bulb.
Which battery is going to supply most of the current?
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
While I haven't yet bought Orbitals from them,
http://www.autosupplyusa.com/exor34exdeep.html appeals to me. Their prices
are what most places charge ($98), but they offer discounts for cash
purchases and have will-call pickup if you live in So. Cal. I don't know if
anyone beats that.
I don't have any real affiliation with this place - just a free banner on my
site.
-Ryan
--------- Original Message --------
From: [EMAIL PROTECTED]
To: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
Subject: RE: exide orbitals
Date: 19/03/04 22:48
>
> At 04:15 PM 19/03/04 -0600, David Brandt wrote:
> >By the way, I can't seem to get anywhere trying to locate orbitals.
And
> >Exide doesn't list distributors on their website. They do list
stores, but
> >all that comes up in my area is Wal-Mart, which doesn't know an
orbital from
> >a parakeet (they don't sell those either), and won't order anything
special
> >for you. Where has everyone else gotten theirs? I'd like to get 4
for the
> >go-cart I'm building.
>
> Hi David.
>
> Assuming you are in the USA, I can't directly help you (I drove 5 miles to
> the Exide state distribution warehouse...).
>
> However, If you let the List know where you are, there may be someone near
> you who can help.
>
> James Massey,
> Launceston, Tasmania, Australia
>
>
>
>
>
>
__________________________________
www.evsource.com - 100% Electric!
--- End Message ---
--- Begin Message ---
http://www.nesscap.com/prod/articles.htm
the ones from G Wight and EVermont are probably what you are referring
to...
Seth
On Mar 19, 2004, at 5:47 PM, David Roden wrote:
On 19 Mar 2004 at 13:07, Lee Hart wrote:
The end result is that adding the DC/DC converter drasticlaly reduces
the number of ultracapacitors needed.
This is the method Solectria used in their tests a few years back,
IIRC.
They found that using ultracaps to level the peak current demands from
the
pack helped the range quite a bit, though I don't recall what the
percentage
figure was any more. I'm pretty sure they issued a press release
about it
at the time, but now I can't find it on their website. Sorry to be so
vauge; maybe someone else remembers more about those tests.
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Want to unsubscribe, stop the EV list mail while you're on vacation, or
switch to digest mode? See http://www.evdl.org/help/
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
David Roden - Akron, Ohio, USA
1991 Solectria Force 144vac
1991 Ford Escort Green/EV 128vdc
1970 GE Elec-trak E15 36vdc
1974 Avco New Idea rider 36vdc
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Cutting the space budget really restores my faith in humanity. It
eliminates dreams, goals, and ideals and lets us get straight to the
business of hate, debauchery, and self-annihilation.
-- Johnny Hart
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
--- End Message ---
--- Begin Message ---
My text book shows E = 1/2 x C x V^2. At 4v, capacitors store E = 1/2 x 1f
x 4v^2 = 8 wattseconds per farad. At 3v, the capacitors still hold E = 1/2 x
1f x 3v^2 = 4.5 wattseconds per farad. So, you used (8-4.5)/8 = 44% of the
ultracapacitor's energy storage capability.
Taking them from 4v to 1v per cell will give you (8-0.5)/8 = 94% of their
stored energy.
If your ultracapacitors can go up to 5.5v, stored energy goes from 8
wattsec/farad to 15 wattsec/farad.
Let me know if I made a mistake. These changes add more strength to your
conclusions. Mark T.
>
> But the voltage of a capacitor changes drastically; 0 volts at 0% SOC,
> and peak voltage at 100% SOC. The equation is E = 1/2 x C x V where E is
> the energy stored in the capacitor in watt-seconds, C is its capacitance
> in farads, and V is the voltage on it.
>
> If you directly parallel the LiIons and Ultracapacitors, then you only
> utilize a small fraction of the energy storage capability of the
> Ultracapacitors. At 4v, capacitors store E = 1/2 x 1f x 4v = 2
> wattseconds per farad. At 3v, the capacitors still hold E = 1/2 x 1f x
> 3v = 1.5 wattseconds per farad. So, you only used (2-1.5)/2 = 25% of the
> ultracapacitor's energy storage capability.
>
> So, a much better way is to connect the ultracapacitors thru a DC/DC
> converter. When you need power from the ultracapacitors, run them down
> to as low a voltage as the DC/DC will allow. For example, taking them
> from 4v to 1v per cell will give you (2-0.5)/2 = 75% of their stored
> energy. When recharging the ultracapacitors, the DC/DC also lets you
> charge them right up to their maximum voltage, not just that of the
> LiIons. For example, if your ultracapacitors can go up to 5.5v, stored
> energy goes from 2 wattsec/farad to 2.75 wattsec/farad.
>
> The end result is that adding the DC/DC converter drasticlaly reduces
> the number of ultracapacitors needed.
> ........................
--- End Message ---
--- Begin Message ---
re: supercaps
> Just as for any cap, you can let it go to 0V, no problem.
as with batteries, I presume the caps have power and energy curves (eg: how
many watts can be pulled as the cap is drained, etc) that vary with various
chemistry and design choices...
how significant are those differences with supercaps in general (as compared
to how significant it is with batteries), and with those you have experience
with specifically?
--- End Message ---
--- Begin Message ---
> Besides, tandem seating, with all its advantages, has some attitudinal
> baggage. In most people's minds, the back seat is for kids and persons
> being conveyed by a hired driver (taxicabs, limos). That association is
> going to present a challenge for the Tango and other tandems, I think.
yeah... structurally, the in-line design allows the vehicle body to be slung
fron the frame in a way that can take excellent advantage of its narrow
balance trim profile to naturally "lean" into sharp turns, etc... ie:
super-high performance racing vehicles...
very fast, very maneuvaerable, small, and silent...
can you imagine the on-board feeds from a pack of those puppies running an
open-road rally?
like a bike-race, only with high-speed EV bumper cars
!gnioz
(and, for kicks, let's say the entire concept of "high-speed EV bumper cars"
is protected under a gnu copyleft, so the sport can retain an amatuer
status... people can still profit from promotion of the sport - to their
best ability, of course, as an open market allows, etc - but no one can
claim any sort of exclusivity to the rights of the sport)
--- End Message ---
--- Begin Message ---
On Friday, March 19, 2004, at 06:52 AM, Ryan Bohm wrote:
Does anyone know where you can buy automotive style/quality electrical
connectors? Google usually has the answers, but I'm not having much
success on this one.
I got a free sample of a Deutsch connector from a company rep after I
posted an info request on the US distributor's web site.
http://www.laddinc.com/
I was specifically looking for a connector to mate up with the
triangular connector coming off of the tach sensor on my Sparrow motor.
These are very nice connectors, with rubber seals to keep out the
moisture.
Thanks,
Ryan
--
Doug Weathers
Bend, OR, USA
http://learn-something.blogsite.org
--- End Message ---
--- Begin Message ---
I have decided to run a different type battery on my project so I am putting
my SVRs up for sale. I have both SVR-14s and a few SVR-30s. They are
currently on E-bay at a special price. You may view them
@http://members.ebay.com/aboutme/fine-junque/ . Just cut and paste
everything after the @ into your browser. This will get you to my main E-bay
page and just scroll down to the the batteries. If someone buys a quantity I
will be glad to arrange truck freight. Questions offlist please.
TIA for looking, David Chapman.
--- End Message ---
--- Begin Message ---
Mark Thomasson wrote:
My text book shows E = 1/2 x C x V^2.
I vent by the formula Lee provided. But if it is V^2, even better
for me!
If your ultracapacitors can go up to 5.5v, stored energy goes from 8
wattsec/farad to 15 wattsec/farad.
Mine can be charged to 2.5V max. I use 160 of them in series.
Let me know if I made a mistake. These changes add more strength to your
conclusions. Mark T.
I can look up tomorrow on the web for this formula.
But, it will work in my case regargless. I just cannot attach the
number to the degree of improvement.
Victor
--- End Message ---
--- Begin Message ---
I just ordered a PFC-20 from evparts.com; until it arrives, Nathan's
stuck with what I assume is a variac "bad boy" charger. All I know for
sure is that there's a big cylinder with a dial on top; I assume it has
the transformer and rectifier bridge as well.
So how does one charge with a variac? Dial it up to the proper voltage,
then let it sit until pack voltage is high enough? If he forgets to
turn it off, does this work as a equalization charge, or is it just
boiling off electrolyte?
This is a 144v pack of flooded batteries.
--- End Message ---
--- Begin Message ---
Mark Thomasson wrote:
>
> >
> > The end result is that adding the DC/DC converter drasticlaly reduces
> > the number of ultracapacitors needed.
> > ........................
Uhhh Huh!
And just where are you going to find a 25 to 150 Kw Dc/Dc converter,
that is also Bidirectional??
Or at the very least for DC drives single direction, from the pack to
the caps?
Joe says it can be done with a PFC50 power stage, and about 400 amp
modules.
David Chapman, Got one of those 600 amp inductors from Dennis B????
That's about what it would take. Oh and liquid cooled power stage.
Somebody got about $10K for me to play with????
It would be a Kick Butt project that's for sure.
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
--- End Message ---
--- Begin Message ---
Jamie Marshall (GAMES) wrote:
>
> I've been thinking about how my to charge my sparrow, and maintain more
> balance on my optima yellow-tops.
>
> I know there is some debate about ideal charging sequences, but is there
> any agreement about what a single optima would want? What would happen
> if I just float charged each battery up to 14 volts? This would
> probably take a while, but my car is plugged in if I'm not driving.
> Would a 14 volt constant charge put 17 amphours (my commute) into the
> battery in 8 hours?
>
> What about equalization. I guess there needs to be an intra-battery
> equalization, but isn't that a once in a while need?
>
> What I'd really like is if someone can point me to a nice resource so I
> can RTFM.
>
> Thanks in advance,
> -Jamie
Jamie, some of us are in the process of doing just that, but What the
Battery boys say works just fine in the lab doesn't work very well out
here in Ev land.
14.00 volts won't get your Yts charged very fast. You want 14.8 peak,
and you want to hold it on all the batteries until the amps comes down
to below 2 amps. I usueally let them set there for 15 minutes, and it
tapers to less than 1,4 amps. I have 5 year old Yts Blems... ya know the
first batch made??? well some still live in Goldie.
Goldie has always had Regulators of some kind, She is the test bead for
Rudman Regs. And Manzaita chargers.... and DCP Raptore, and T-Rexes, and
Well just about anything I make gets tested in Her.
So once you get the 14.8 on every battery, No more no less, then you
realize that a Adjustable voltage regualted charger, and adjustable per
battery voltage limits...
The it becomes clear What is lacking in the Sparrow battery system. The
Sparrow Zivan takes the whole string to 2 amps NO limit on EVERY cycle.
Just exactly what my regs keep from happening. There are some Sparrow
folks that claim a brand new pack will have noticable damage in as few
as 50 cycles. If they just didn't add the "equalization" stage, The
packs would have lasted about 3 times as long.
The long series string is what messes up the 2 amp to infinity, Yea it
works, but while one may be just right others are headed out to 17 and
18 volt land and that just about garenties that you gas them hard enough
to vent them. Just try to take charge a Yt at 2 amps for 30 minutes, You
will be surprised how high a voltage they get to. Now put 13 in a row,
and let the Juice fly, and then measure the results. About 1/2 are going
to be venting in about 20 minutes.
I rather be gental to the Yts, and not let them get really spanked
with voltage. Now Current when they are empty and hungry... Bring on the
Amps!!!
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
--- End Message ---
--- Begin Message ---
Rich, yep I got all the inductors you could need. A couple of these are at
least 600 amps ea. Around 125 lbs+ ea. I now have inductors in stock from
about 3 lbs to these huge ones. I just wish I knew how to calculate values
for these things. David Chapman.
----- Original Message -----
From: "Rich Rudman" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Friday, March 19, 2004 10:52 PM
Subject: Re: Newbie Questions About Traction Battery Pack Design
> > > the number of ultracapacitors needed.
<Snipped>
> Joe says it can be done with a PFC50 power stage, and about 400 amp
> modules.
>
> David Chapman, Got one of those 600 amp inductors from Dennis B????
> That's about what it would take. Oh and liquid cooled power stage.
> Somebody got about $10K for me to play with????
> It would be a Kick Butt project that's for sure.
>
>
> --
> Rich Rudman
> Manzanita Micro
> www.manzanitamicro.com
> 1-360-297-7383,Cell 1-360-620-6266
>
--- End Message ---
--- Begin Message ---
Better verify that it has a Rectifier bridge built in. Most Variacs I see
don't. Just check for DC output, if it doesn't then a suitable bridge
rectifier can be purchased cheap from surplus outlets on the net. One of the
more qualified listers can suggest values. David Chapman.
----- Original Message -----
From: "Jude Anthony" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Friday, March 19, 2004 10:47 PM
Subject: How do you use a variac for charging?
> I just ordered a PFC-20 from evparts.com; until it arrives, Nathan's
> stuck with what I assume is a variac "bad boy" charger. All I know for
> sure is that there's a big cylinder with a dial on top; I assume it has
> the transformer and rectifier bridge as well.
>
> So how does one charge with a variac? Dial it up to the proper voltage,
> then let it sit until pack voltage is high enough? If he forgets to
> turn it off, does this work as a equalization charge, or is it just
> boiling off electrolyte?
>
> This is a 144v pack of flooded batteries.
>
--- End Message ---
--- Begin Message ---
Rich, I got a bunch of YTs with a big "P" on them. They have been sitting at
almost 0 SOC for years. Think there is any chance? If I can get them to
start taking juice what do you think the charged voltage should look like?
And is that 14.8 a good figure for all 12V nominal SLAs or just the YTs? I
was charging my Delphis at 14.4 and vented one. Man, I sure need some big
Ni-cad modules. David Chapman.
----- Original Message -----
From: "Rich Rudman" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Friday, March 19, 2004 11:11 PM
Subject: Re: Quick newbie charging question
> Jamie Marshall (GAMES) wrote:
> >
> > I've been thinking about how my to charge my sparrow, and maintain more
> > balance on my optima yellow-tops.
> >
> > I know there is some debate about ideal charging sequences, but is there
> > any agreement about what a single optima would want? What would happen
> > if I just float charged each battery up to 14 volts? This would
> > probably take a while, but my car is plugged in if I'm not driving.
> > Would a 14 volt constant charge put 17 amphours (my commute) into the
> > battery in 8 hours?
> >
> > What about equalization. I guess there needs to be an intra-battery
> > equalization, but isn't that a once in a while need?
> >
> > What I'd really like is if someone can point me to a nice resource so I
> > can RTFM.
> >
> > Thanks in advance,
> > -Jamie
>
> Jamie, some of us are in the process of doing just that, but What the
> Battery boys say works just fine in the lab doesn't work very well out
> here in Ev land.
> 14.00 volts won't get your Yts charged very fast. You want 14.8 peak,
> and you want to hold it on all the batteries until the amps comes down
> to below 2 amps. I usueally let them set there for 15 minutes, and it
> tapers to less than 1,4 amps. I have 5 year old Yts Blems... ya know the
> first batch made??? well some still live in Goldie.
> Goldie has always had Regulators of some kind, She is the test bead for
> Rudman Regs. And Manzaita chargers.... and DCP Raptore, and T-Rexes, and
> Well just about anything I make gets tested in Her.
> So once you get the 14.8 on every battery, No more no less, then you
> realize that a Adjustable voltage regualted charger, and adjustable per
> battery voltage limits...
> The it becomes clear What is lacking in the Sparrow battery system. The
> Sparrow Zivan takes the whole string to 2 amps NO limit on EVERY cycle.
> Just exactly what my regs keep from happening. There are some Sparrow
> folks that claim a brand new pack will have noticable damage in as few
> as 50 cycles. If they just didn't add the "equalization" stage, The
> packs would have lasted about 3 times as long.
> The long series string is what messes up the 2 amp to infinity, Yea it
> works, but while one may be just right others are headed out to 17 and
> 18 volt land and that just about garenties that you gas them hard enough
> to vent them. Just try to take charge a Yt at 2 amps for 30 minutes, You
> will be surprised how high a voltage they get to. Now put 13 in a row,
> and let the Juice fly, and then measure the results. About 1/2 are going
> to be venting in about 20 minutes.
> I rather be gental to the Yts, and not let them get really spanked
> with voltage. Now Current when they are empty and hungry... Bring on the
> Amps!!!
>
>
> --
> Rich Rudman
> Manzanita Micro
> www.manzanitamicro.com
> 1-360-297-7383,Cell 1-360-620-6266
>
--- End Message ---
--- Begin Message ---
These are excellent connectors for automotive
environments. We used them on all of the Caterpillar
wire harnesses back in 1991. I still have a nice
collection of these parts and bought a crimper at
the Dayton Hamfest for $5 (they cost several hundred
dollars new).
Rod
--- Doug Weathers <[EMAIL PROTECTED]> wrote:
>
> On Friday, March 19, 2004, at 06:52 AM, Ryan Bohm
> wrote:
>
> > Does anyone know where you can buy automotive
> style/quality electrical
> > connectors? Google usually has the answers, but
> I'm not having much
> > success on this one.
>
> I got a free sample of a Deutsch connector from a
> company rep after I
> posted an info request on the US distributor's web
> site.
>
> http://www.laddinc.com/
>
> I was specifically looking for a connector to mate
> up with the
> triangular connector coming off of the tach sensor
> on my Sparrow motor.
> These are very nice connectors, with rubber seals
> to keep out the
> moisture.
>
> >
> > Thanks,
> >
> > Ryan
> >
> --
> Doug Weathers
> Bend, OR, USA
> http://learn-something.blogsite.org
>
--- End Message ---
--- Begin Message ---
There is a very interesting article in the MIT Alumni Association
website about the potential of electrified guideway cars, subtitled
"Hydrogen Hokum", which points out that serious automobile and
aerospace engineers do not believe that fuel cells and on-board
hydrogen storage is a viable or energy efficient concept.
See <http://alum.mit.edu/ne/whatmatters/200403/index.html>.
Don McGrath
--- End Message ---
--- Begin Message ---
David Chapman wrote:
>
> Rich, I got a bunch of YTs with a big "P" on them. They have been sitting at
> almost 0 SOC for years. Think there is any chance? If I can get them to
> start taking juice what do you think the charged voltage should look like?
> And is that 14.8 a good figure for all 12V nominal SLAs or just the YTs? I
> was charging my Delphis at 14.4 and vented one. Man, I sure need some big
> Ni-cad modules. David Chapman.
> ----- Original Message -----
> From: "Rich Rudman" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Friday, March 19, 2004 11:11 PM
> Subject: Re: Quick newbie charging question
>
> > Jamie Marshall (GAMES) wrote:
> > >
> > > I've been thinking about how my to charge my sparrow, and maintain more
> > > balance on my optima yellow-tops.
> > >
> > > I know there is some debate about ideal charging sequences, but is there
> > > any agreement about what a single optima would want? What would happen
> > > if I just float charged each battery up to 14 volts? This would
> > > probably take a while, but my car is plugged in if I'm not driving.
> > > Would a 14 volt constant charge put 17 amphours (my commute) into the
> > > battery in 8 hours?
> > >
> > > What about equalization. I guess there needs to be an intra-battery
> > > equalization, but isn't that a once in a while need?
> > >
> > > What I'd really like is if someone can point me to a nice resource so I
> > > can RTFM.
> > >
> > > Thanks in advance,
> > > -Jamie
> >
> > Jamie, some of us are in the process of doing just that, but What the
> > Battery boys say works just fine in the lab doesn't work very well out
> > here in Ev land.
> > 14.00 volts won't get your Yts charged very fast. You want 14.8 peak,
> > and you want to hold it on all the batteries until the amps comes down
> > to below 2 amps. I usueally let them set there for 15 minutes, and it
> > tapers to less than 1,4 amps. I have 5 year old Yts Blems... ya know the
> > first batch made??? well some still live in Goldie.
> > Goldie has always had Regulators of some kind, She is the test bead for
> > Rudman Regs. And Manzaita chargers.... and DCP Raptore, and T-Rexes, and
> > Well just about anything I make gets tested in Her.
> > So once you get the 14.8 on every battery, No more no less, then you
> > realize that a Adjustable voltage regualted charger, and adjustable per
> > battery voltage limits...
> > The it becomes clear What is lacking in the Sparrow battery system. The
> > Sparrow Zivan takes the whole string to 2 amps NO limit on EVERY cycle.
> > Just exactly what my regs keep from happening. There are some Sparrow
> > folks that claim a brand new pack will have noticable damage in as few
> > as 50 cycles. If they just didn't add the "equalization" stage, The
> > packs would have lasted about 3 times as long.
> > The long series string is what messes up the 2 amp to infinity, Yea it
> > works, but while one may be just right others are headed out to 17 and
> > 18 volt land and that just about garenties that you gas them hard enough
> > to vent them. Just try to take charge a Yt at 2 amps for 30 minutes, You
> > will be surprised how high a voltage they get to. Now put 13 in a row,
> > and let the Juice fly, and then measure the results. About 1/2 are going
> > to be venting in about 20 minutes.
> > I rather be gental to the Yts, and not let them get really spanked
> > with voltage. Now Current when they are empty and hungry... Bring on the
> > Amps!!!
> >
> >
> > --
> > Rich Rudman
> > Manzanita Micro
> > www.manzanitamicro.com
> > 1-360-297-7383,Cell 1-360-620-6266
> >
I would use 14.8 of just about any AGM PbLa battery. Until I found out
otherwise. So far that has not been challenged. It works.
Years at 0 volts on Proto types, They are high quality Lead ore...
suitable for recycle purposes...
I have bunches that won't take a charge, and or only have a amphour or
two in them. Thier days are over. I just need to shovel them out of
here, they are getting in the way.
Most of the dead are from Sparrows, and the Fiero that never had Regs.
Joe and Lee are going to have to develop a method of measuring the
inductace of unknown inductors. Something like a scope and a 100 amp
switch, and measure the rise time and fall time of a known pulse
duration and current. I don't have a formula and method.
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
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>> The end result is that adding the DC/DC converter drastically
>> reduces the number of ultracapacitors needed.
Rich Rudman wrote:
> Uhhh Huh! And just where are you going to find a 25 to 150 Kw DC/DC
> converter, that is also Bidirectional?
Assume an EV with an ordinary series motor and PWM controller. Add the
ultracapacitors and a *second* PWM controller. Batteries charge
ultracapacitors thru controller#1 (with series inductor in its output to
simulate the motor field inductance). Ultracapacitors power motor thru
controller#2. Now you can both charge and discharge the ultracapacitors
at the full current limit of the controllers.
Controller#1 can probably be much smaller than controller#2, since it
mainly has to handle the average current, not the peak (that's what the
ultracapacitors are for).
This system doesn't do regen, but that's a consequence of the series
motor at controller#2. You could pick an appropriate motor and
controller here that did regen. For example, use one of Victor's Siemens
AC drives for the motor and controller#2 and you would have regen.
--
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Diana Trevino wrote:
> Has anyone ever tried hydraulic energy storage during braking?
Yes, it's been done, in everything from garden tractors to diesel
locomotives, to giant earthmovers. Prof. Ernie Parker and his students
at Hennepin Community Collegen in Minneapolis MN built a whole series of
cars with hydraulic accumulators
> Or end cells for acceleration?
This has also been tried. (In fact, given that electric cars have been
around much longer than gasoline cars, and that some of the greatest
engineering minds in history have applied themselves to the problem,
just about everything imaginable has been tried at one time or another!)
Adding end cells to temporarily boost pack voltage for accelleration is
a good 'quick and dirty' trick. It's been used in CitiCars, for example,
by wiring the 12v accessory battery in series with the 48v propulsion
pack for a littl more 'oomph'. But it tends to unbalance the batteries,
and create other odd problems (like the headlights dim when you 'floor'
the accellerator).
--
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Sam Uzi wrote:
> as with batteries, I presume the caps have power and energy curves
> (eg: how many watts can be pulled as the cap is drained, etc.) that
> vary with various chemistry and design choices.
Yes. Like batteries, capacitors are available with a wide range of
characteristics. Parts with low energy storage but very high peak power;
parts with high energy storage but low peak power; and everything
between. Like batteries, they generally have to trade off one to get the
other.
> How significant are those differences with supercaps in general
> (as compared to how significant it is with batteries), and with
> those you have experience with specifically?
At one extreme, we have conventional aluminum electrolytics; low energy
storage (1000 times worse than batteries), but high peak energy
capability (easily 1/1000th the internal resistance). That's why we use
them in controllers; a pop-can-sized capacitor can supply the
thousand-amp peak currents that a half ton of batteries cannot.
At the other extreme, we have the dual-layer carbon
"super-ultra-capacitors"; high energy storage (only 10 times worse than
batteries), but with lower peak energy capability (more internal
resistance than batteries). These parts are mainly attractive for
supplying tiny amounts of power over very long time periods; like backup
power for computer memories over many days.
(Note that terms like 'super-' and 'ultra-' are simply tacked onto
capacitor names by marketing people. They don't really mean anything.)
As for my personal experience, we tried using Panasonic supercapacitors
in a product to replace nicad batteries. The project was a failure --
the batteries were actually cheaper, more reliable, and lasted longer.
We had five 2.5v 100f supercapacitors in series, intended to function as
a 12v battery. One problem was that their actual capacitance varied
drastically between units, and over temperature and age. So the voltage
didn't divide equally between them. We tried resistors, but then had to
put individual 2.4v zeners across each one to keep them balanced (so no
cell went overvoltage on charge, or went excessively negative during
discharge). The voltage dropped so much during use that they had to be
drastically oversized (10f would have been enough if we'd had been able
to afford a DC/DC converter to boost the voltage).
The final blow was that like most electrolytic capacitors, their actual
reliability and life were poor, especially at high temperatures.
Now, this was all 6 years ago; maybe parts have improved. But I'm a
skeptic. I want to *see* a real application; how they work in the real
world, in a real power application, with life and reliability data --
not some manufacturer's rosy predictions designed to lure investors
rather than customers.
--
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Mark Thomasson wrote:
> My text book shows E = 1/2 x C x V^2.
Absolutely right! Thanks to Mark (and Philip Marino and others) for
catching my mistake. I mixed up the formula for charge Q=CV and the
formula for energy E=1/2 C V^2.
> At 4v, capacitors store E = 1/2 x 1f x 4v^2 = 8 wattsec/farad.
> At 3v, capacitors store E = 1/2 x 1f x 3v^2 = 4.5 wattsec/farad.
> So you used (8-4.5)/8 = 44% of the ultracapacitor's energy storage
> capability.
>
> Taking them from 4v to 1v gives (8-0.5)/8 = 94% of the stored energy.
Right. Allowing the larger voltage swing doubles the energy you can get.
You need half as many capacitors for the same energy.
> If your ultracapacitors can go up to 5.5v, stored energy goes from 8
> wattsec/farad to 15 wattsec/farad.
This improves the situation even more. If your DC/DC lets the capacitors
go from 1v to 5.5v, they can deliver 15.125 - 0.5 = 14.625 wattsec/f. If
the capacitors only go from 4v to 3v, they deliver 8 - 4.5 = 3.5
wattsec/f. Thus, you need 3.5/14.625 = one fourth as many capacitors.
It becomes an economic tradeoff. What do you pay for capacitors? What do
you pay for the DC/DC converter? Balance them to get the best overall
compromise.
--
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Lee Hart wrote:
>> you can simply parallel the Li-Ion and Ultracapacitor packs, but
>> this would result in a higher cost and poorer performance than
>> other systems.
Victor Tikhonov wrote:
> What other systems do you have in mind?
For example, the one I described in my answer to Rich Rudman on this
thread.
> This actually depends on many variables -- primarily type of
> LiIons and type of capacitors. And, for mortals, their cost.
Exactly. It's a tradeoff. If you get cheap capacitors, you can avoid the
DC/DC. If you have a cheap DC/DC, you can avoid using as many
capacitors.
I was assuming that both capacitors and DC/DC are expensive, so the
'best' solution would likely be a DC/DC with only a modest voltage
range, (maybe 2:1) which cuts the number of capacitors roughly in half
compared to wiring them straight across each cell with no DC/DC.
> Cost/size/efficiency of such a DC-DC *may* make you worse off
> than just using bunch of extra underutilized caps. I analyzed
> my circumstances, and this was the case, not to mention I could
> not find affordable DC-DC.
Yes. But an ordinary PWM DC motor controller is a pretty cheap
high-power DC/DC. Could you wire all your capacitors in series to the
input of your AC motor controller, and then charge these capacitors with
a small PWM motor controller (and series inductor)?
>> Ultracapacitors have exactly the problem of LiIons. You must watch
>> the voltage of very single cell, and not let it go too low or too
>> high.
> Sorry, no. Just as for any cap, you can let it go to 0V, no problem.
0v is not the problem. The problem is that the voltage will go
*negative*, and that is a BIG problem! It destroys the capacitor.
The voltage on one cell in a string of capacitors can go negative for
the same reason it does in a string of battery cell. One cell has less
capacity than the others, and so goes dead first. The other cells keep
forcing a high current to flow thru the dead cell, so it goes negative.
You wind up needing the same kind of individual cell monitoring and
balancing as for LiIon cells. That's one advantage of just wiring the
capacitors directly in parallel with the LiIon cells; one balancing
system works for both.
> For 18650 cells I'm not sure, but I haven't seen a spec stating
> it's OK to charge LiIons with the same rate you discharge them.
> Not to mention, individual control is not possible.
I have seen data up to 1C rates, and this is probably adequate for
normal braking. This probably covers 90% or more of your braking
requirements.
--
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Jamie Marshall (GAMES) wrote:
> I've been thinking about how my to charge my sparrow, and maintain
> more balance on my optima yellow-tops. I know there is some debate
> about ideal charging sequences, but is there any agreement about
> what a single optima would want?
Yes, that is the easiest case. It's what all the manufacturer's data
assumes. There is little disagreement on the basics: Charge at whatever
your charger can deliver until the battery reaches the gassing point
(14.2v, give or take 0.5v). Then hold the voltage constant until the
current falls to about 1-3% of the battery's amphour capacity (1-2 amps
for a 55ah Optima). Shut it off when the battery is 'full' (various
definitions used).
> What would happen if I just float charged each battery up to 14 volts?
14 volts is too high for a float voltage; the battery would overcharge
if you left it on too long. 13.2-13.8v is the proper range for float
(lower for hot or old batteries, higher for new or cold batteries).
But 14v is too low to reach full charge in a reasonable time. It would
take over 24 hours to reach full at this voltage, and it would never
equalize if there are differences in the state of charge between cells.
14.4-15v is the more usual range to reach full in under a day (again,
the precise voltage varies with temperature, age, and how much
equalization is needed).
> Would a 14 volt constant charge put 17 amphours (my commute) into the
> battery in 8 hours?
It would if the battery was run down deeper than this. But once the
battery gets over about 80% SOC, the remaining current flows in very
slowly.
> What about equalization. I guess there needs to be an intra-battery
> equalization, but isn't that a once in a while need?
Battery manufacturers try hard to put a matched set of cells in a
battery. Still, they are never identical, and they will drift farther
apart as they age, due to temperature differences between cells, etc. So
once in a while, you have to deliberately overcharge so that the lower
cells have time to get up to full charge. This overcharges and damages
the higher cells, but the overall result is beneficial (it helps the
weak ones more than it hurts the strong ones).
Since you can't measure individual cell voltages, there is no external
way to know when you need to equalize. Your only option is to do a deep
discharge, keep track of the amphours, do an mild equalization charge,
and discharge again to see if the amphour capacity improved. If it does,
you can equalize more/harder and try again.
Or, I just apply a high enough voltage to equalize (like 15 volts) thru
a resistor to limit the current to under 1 amp, and let it sit for a
couple days. I only do this once or so a year. This is enough to
equalize even the worst-case battery, but at a low enough charge rate so
it shouldn't gas or vent (an Optima can recombine the gas it produces at
about this rate).
--
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Jude Anthony wrote:
> how does one charge with a variac?
Very carefully! Control is totally manual. They can do a fine job, or
destroy you batteries in a single day.
First, you MUST have instrumentation so you know what you're doing. At
the very least, an accurate voltmeter and ammeter. Better still is an
E-meter, which measures amphours and can be set up to tell you when
you've reached full charge.
For your 144v pack of floodeds, here's the basics:
1. If the pack is under 144v (i.e. very dead), turn up the variac
to get a few amps of charging current. The voltage should rise
above 144v very quickly. If it is still under 144v after an hour,
check every battery voltage individually. You probably have a
reversed or shorted cell.
2. Once over 144v at a few amps, turn up the variac for as high a
current as your AC circuit or the charger can stand. Watch out
for cords or plugs overheating, or anything on the charger getting
too hot to touch. If these happen, back the variac down.
3. As the pack charges, its voltage rises. To keep charging at the
maximum current, you'll have to keep checking and turning up the
variac. Or, just let it taper off if you're in no hurry.
4. When the first battery reaches 2.5v per cell (15v per 12v battery,
7.5v per 6v battery, etc.), start turning down the variac to keep
this voltage from going any higher. Experimentally, you will find
which one tends to get there first. Once the pack is broken in and
well balanced, you can just go by the entire pack voltage; 180v.
5. You'll have to keep checking, and turning down the variac to keep
this voltage the same. The charging current will fall off as the
batteries approach full charge. When it falls to about 2% of your
battery's amphour capacity (like 2 amps for 100 amphour batteries)
you are done; turn the charger off.
6. Let the batteries sit overnight, then measure the individual
voltages. They should differ less than 0.05v for 12v batteries,
0.03v for 6v batteries. If so, then the pack is well equalized,
and you are done. If there *is* a larger difference, you can
either charge the low ones with a separate charger, or charge
the whole pack at low current (2% again) for another couple
hours and try again.
As you can see, this is all pretty tedious. That's why people buy
automatic battery chargers.
I would strongly suggest you add a timer (if it doesn't already have
one). I'd get one of the 12-hour timers you see for bathroom fans, etc.
Wire it so you have to turn the knob to a time to turn on the charger.
Sooner or later you will fail to check the variac, and it will burn up
your batteries. The timer is a fail-safe, to turn it off if you forget.
If you have an E-meter, life is much simpler. It can tell you when you
reach full charge. You can even order them with a switched output, to
automatically turn off the charger when the batteries reach 'full'.
--
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
