EV Digest 3950
Topics covered in this issue include:
1) Re: zap-wavecrest-electrocharger
by Ken Trough <[EMAIL PROTECTED]>
2) RE: Boost Pack Circuit
by "Bill Dennis" <[EMAIL PROTECTED]>
3) Re: Boost Pack Circuit
by Victor Tikhonov <[EMAIL PROTECTED]>
4) Re: Boost Pack Circuit
by "Doug Hartley" <[EMAIL PROTECTED]>
5) 3.6V for calculations, Re: Boost Pack Circuit
by "Doug Hartley" <[EMAIL PROTECTED]>
6) Mystery Machine
by James D Thompson <[EMAIL PROTECTED]>
7) RE: Boost Pack Circuit
by "Bill Dennis" <[EMAIL PROTECTED]>
8) Re: Mystery Machine
by "Mr23" <[EMAIL PROTECTED]>
9) Re: Boost Pack Circuit
by "Doug Hartley" <[EMAIL PROTECTED]>
10) Re: Interesting URL
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
11) Re: Relative of the Fiamp?
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
12) emergency cutoff using anderson connector.
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
13) Re: Mystery Machine
by "Joe Smalley" <[EMAIL PROTECTED]>
14) A89 vs. ETEK
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
15) Re: A89 vs. ETEK
by richard ball <[EMAIL PROTECTED]>
--- Begin Message ---
Just wondering if Wavecrest is an all hype no substance company
Wavecrest is real. They have products for sale in the mass market and a
significant amount of money backing the company.
Beyond their well known high tech electric bicycle (that is currently
both being sold in Costco, and being used/evaluated by U.S. special
forces), Wavecrest has a number of real products and technology in the
pipeline:
Wavecrest has developed a high amperage spiral wound NiMH cell that
solves the weak interconnect problem with a VERY novel approach. The
cells actually screw together and the interconnects consist of a
significant portion of the cell external structure making for a truly
massive current path for high performance applications and very fast
charging. Last I heard, these cells were slated for imminent release.
Wavecrest has also developed a self contained powered bicycle wheel that
contains both a direct drive, brushless hub motor and battery pack
within a single wheel. They combine this with wireless controls and
wireless dash readout. Just replace the front wheel on your bicycle of
choice with this one and you have a high tech electric bicycle with a
super clean looking install with no unsightly batteries clamped to the
frame and no unsightly wiring running all over the place. Last I heard,
this product was also slated for imminent release.
Wavecrest has built also proof-of-concept working prototype of an
all-wheel drive, wheel motor powered Euro sports car. This product is
not intended for production, but rather to show the possibilities of
their motor design in order to attract possible automotive manufacturing
partners as an OEM.
Zap on the other hand has NOTHING of substance. They purchase a couple
of units of cheap EV product from Asia, slap a Zap sticker on it, then
tout it as their own "revolutionary" new designs. They attach themselves
to anything they think they can hype to boost what remains of their
stock price. They even had the audacity to try to hype the Moller Air
Car as something that Zap would be developing/marketing.
I don't expect Zap to be developing anything, much less anything as
significant as prototyping a new car concept. Zap is an empty husk of a
company with no significant money, no significant products, no
significant engineering talent, no significant resources, and no
significant future.
Just an opinion.
-Ken Trough
Admin - V is for Voltage Megasite
http://visforvoltage.com
AIM - ktrough
FAX - 801-749-7807
message - 866-872-8901
--- End Message ---
--- Begin Message ---
Hi, Victor. What's the status of the BMS that you've been developing?
Thanks.
Bill
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Victor Tikhonov
Sent: Thursday, December 09, 2004 3:28 PM
To: [EMAIL PROTECTED]
Subject: Re: Boost Pack Circuit
Doug (and Bill),
Your suggested setup will work OK. 2 concerns:
- With temp change, LiIon pack getting softer
drastically quicker than PbA pack, so at about 0'C
freshly charged LiIon pack will sag to the point that
PbA one will take over right away.
- You certainly can shunt diode between packs to allow
charging current to flow in reverse, but the charging
requirements (profile) are different for two, so it may
be better idea to charge both packs separately.
Since variable current seems to be preferred way for LiIons
and PbA don't care, one can use variable current for
both battery types, and then indeed total charging can be
done in one pass. However,
LiIon pack NEEDS A BMS supervising individual cells and
controlling the charger based on that supervision info.
That will impact charging of PbA as well. If one pack is full
but the other is not and this repeats cycle after cycle,
you're going to ruin one of the two unless separate
the chemistries for individual charging.
I know, everyone wants to get away cheaply, but this setup
is more complicated that may seem, and if not done right,
unavoidable trouble will cost you more in the long run.
Victor
'91 ACRX - something different
Bill Dennis wrote:
>Hi, Doug. Quick question for your advice on something. I might have the
>possibility of getting 35 200Ah TS cells. If I went with your hybrid
>system, the voltages would be as follows:
>
>Starting TS: 35 * 3.6 = 126 Ending TS: 35 * 3 = 105
>Starting PbA: 9 * 13.2 = 118.8 Ending PbA: 9 * 11 = 99
>
>Do you think these numbers are close enough to work? The other possibility
>would be to drop down to using only 33 of the TS cells. Then the numbers
>work out identically to each, but I'd be giving up some capacity:
>
>Starting TS: 33 * 3.6 = 118.8 Ending TS: 33 * 3 = 99
>Starting PbA: 9 * 13.2 = 118.8 Ending PbA: 9 * 11 = 99
>
>Which method do you think is better? Thanks.
>
>Bill Dennis
>
>-----Original Message-----
>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
>Behalf Of Doug Hartley
>Sent: Wednesday, June 16, 2004 8:14 PM
>To: [EMAIL PROTECTED]
>Subject: Re: Boost Pack Circuit
>
>Bill, it can be easier and simpler than that:
>
>Use an AGM lead acid pack, connected to the TS Li Ion pack with a large
>diode, as the support. As more current is drawn and the Li Ion pack
voltage
>drops under load, the AGM pack starts supplying current.
>
>Here are some more details on one way to do it:
>Plan a pack of small AGM batteries (such as Interstate DCS-33) having a
>total pack charged resting voltage a little lower than the nominal voltage
>of the TS Li Ion pack. In my case, 7 12V AGMs are used to support a 26
cell
>300 A-Hour TS pack (made up of 26 200 and 26 100 A-hr cells).
> So, for this real life example: 7 x 13V = 91V for the AGM pack, which is
>a little less than 26 X 3.6V = 93.6V for the Li Ion pack.
> As a second quick check calculation, verify that the reasonable minimum
>voltage for the AGM pack is about the same as for the Li Ion pack. At
about
>11V per AGM battery and 3V per Li Ion cell, both packs are down to about
>77V when discharged and under load. That checks out, so they should both
>work well together "to the end".
>
> Connect one polarity (say negative) of both packs directly together.
>Connect the positive of the AGM pack (through a 200A DC rated circuit
>breaker for protection and disconnect), to the anode of a large diode rated
>to carry more than this current (ideally something like a low drop Schottky
>300A diode on a suitable heat sink). Note that these current ratings are
>for a low voltage high current EV, and can be reduced proportionately for a
>higher voltage EV. Connect the cathode end of the diode to the Li Ion pack
>positive. Connect a charging circuit across this diode to pass a limited
>current in the other direction. I used a 12V 1 Amp. automotive light bulb
>in series with a 10V 40W zener diode array (4 of the 5V, 5W zeners in
>series/parallel) as a quick and dirty method for now.
>
>How it works:
>When the Li Ion pack is near full charge and under light load, the AGM pack
>supplies no current as its voltage is lower than the Li Ion pack. Under
>heavy acceleration/load when the Li Ion pack voltage is drawn down below
>the AGM pack voltage, the diode conducts and the AGM pack supplies part of
>the current. The more it is needed, as the Li Ion pack is discharged
>further and/or loading increases, the more the AGM pack supplies current.
>As I brake, regen raises the Li Ion pack voltage and the AGM pack charges a
>little. When put on charge, the AGM pack starts charging once the Li Ion
>pack voltage comes up. With a more sophisticated charging circuit, the AGM
>pack can also absorb a lot of the regen current and allow for stronger
regen
>plus get partially recharged to help more. (applies to EVs with
>regenerative braking capabilities).
>
>If you want any further information or a drawing, let me know.
>
>Best Regards,
>
>Doug
>
>
>----- Original Message -----
>From: "Bill Dennis" <[EMAIL PROTECTED]>
>To: <[EMAIL PROTECTED]>
>Sent: Wednesday, June 16, 2004 5:04 PM
>Subject: Boost Pack Circuit
>
>
>
>
>>In preparation for my EV conversion, I'm still in the early stages of
>>
>>
>trying
>
>
>>to teach myself some electronics, so I apologize in advance if this is an
>>unworkable configuration dreamed up by a novice. I'm wondering if a
>>
>>
>circuit
>
>
>>something like the one below could be designed to work for a boost pack.
>>The "Nifty Current Following Circuit" would do the following: When the
>>controller called for 140A or less (.7C), all current would flow from the
>>
>>
>TS
>
>
>>Traction Pack. For Amperages above 140A, the Nifty Circuit would pull
>>
>>
>some
>
>
>>proportional number of amps from the DC-DC along with the amps from the TS
>>Traction Pack.
>>
>>
>
>Snip
>
> > Bill Dennis
>
>
>
>
>
--- End Message ---
--- Begin Message ---
Well, individual modules have been done and currently
in pilot production - they look like this (without heat sinks):
http://www.metricmind.com/images/can1.jpg. I'll be also
testing them on real cells once I get the cells to experiment
with. The modules have ability to drain or boost individual
cells as needed.
These are not really intended for sale as loose parts.
The main controller hardware is done too. The software is
being written (not by me), and will be tested with these
early next year, hopefully in January.
Some specs you can see here:
http://www.metricmind.com/bms.htm
Sorry, at this point I'm not at liberty to tell you more
than this, but in short complete propulsion solution
(battery pack, BMS, contactors, fuses, charger and other
optional hardware in one enclosure, as well as user
interface small display or large touch screen one)
will be offered, so a user won't mess with individual
cells and interconnecting/wiring. The BMS will have ability
to talk to a propulsion controller/inverter to prevent the
pack abuse, so to work as one integrated system.
Victor
'91 ACRX - something different
Bill Dennis wrote:
Hi, Victor. What's the status of the BMS that you've been developing?
Thanks.
Bill
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Victor Tikhonov
Sent: Thursday, December 09, 2004 3:28 PM
To: [EMAIL PROTECTED]
Subject: Re: Boost Pack Circuit
Doug (and Bill),
Your suggested setup will work OK. 2 concerns:
- With temp change, LiIon pack getting softer
drastically quicker than PbA pack, so at about 0'C
freshly charged LiIon pack will sag to the point that
PbA one will take over right away.
- You certainly can shunt diode between packs to allow
charging current to flow in reverse, but the charging
requirements (profile) are different for two, so it may
be better idea to charge both packs separately.
Since variable current seems to be preferred way for LiIons
and PbA don't care, one can use variable current for
both battery types, and then indeed total charging can be
done in one pass. However,
LiIon pack NEEDS A BMS supervising individual cells and
controlling the charger based on that supervision info.
That will impact charging of PbA as well. If one pack is full
but the other is not and this repeats cycle after cycle,
you're going to ruin one of the two unless separate
the chemistries for individual charging.
I know, everyone wants to get away cheaply, but this setup
is more complicated that may seem, and if not done right,
unavoidable trouble will cost you more in the long run.
Victor
'91 ACRX - something different
Bill Dennis wrote:
Hi, Doug. Quick question for your advice on something. I might have the
possibility of getting 35 200Ah TS cells. If I went with your hybrid
system, the voltages would be as follows:
Starting TS: 35 * 3.6 = 126 Ending TS: 35 * 3 = 105
Starting PbA: 9 * 13.2 = 118.8 Ending PbA: 9 * 11 = 99
Do you think these numbers are close enough to work? The other possibility
would be to drop down to using only 33 of the TS cells. Then the numbers
work out identically to each, but I'd be giving up some capacity:
Starting TS: 33 * 3.6 = 118.8 Ending TS: 33 * 3 = 99
Starting PbA: 9 * 13.2 = 118.8 Ending PbA: 9 * 11 = 99
Which method do you think is better? Thanks.
Bill Dennis
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Doug Hartley
Sent: Wednesday, June 16, 2004 8:14 PM
To: [EMAIL PROTECTED]
Subject: Re: Boost Pack Circuit
Bill, it can be easier and simpler than that:
Use an AGM lead acid pack, connected to the TS Li Ion pack with a large
diode, as the support. As more current is drawn and the Li Ion pack
voltage
drops under load, the AGM pack starts supplying current.
Here are some more details on one way to do it:
Plan a pack of small AGM batteries (such as Interstate DCS-33) having a
total pack charged resting voltage a little lower than the nominal voltage
of the TS Li Ion pack. In my case, 7 12V AGMs are used to support a 26
cell
300 A-Hour TS pack (made up of 26 200 and 26 100 A-hr cells).
So, for this real life example: 7 x 13V = 91V for the AGM pack, which is
a little less than 26 X 3.6V = 93.6V for the Li Ion pack.
As a second quick check calculation, verify that the reasonable minimum
voltage for the AGM pack is about the same as for the Li Ion pack. At
about
11V per AGM battery and 3V per Li Ion cell, both packs are down to about
77V when discharged and under load. That checks out, so they should both
work well together "to the end".
Connect one polarity (say negative) of both packs directly together.
Connect the positive of the AGM pack (through a 200A DC rated circuit
breaker for protection and disconnect), to the anode of a large diode rated
to carry more than this current (ideally something like a low drop Schottky
300A diode on a suitable heat sink). Note that these current ratings are
for a low voltage high current EV, and can be reduced proportionately for a
higher voltage EV. Connect the cathode end of the diode to the Li Ion pack
positive. Connect a charging circuit across this diode to pass a limited
current in the other direction. I used a 12V 1 Amp. automotive light bulb
in series with a 10V 40W zener diode array (4 of the 5V, 5W zeners in
series/parallel) as a quick and dirty method for now.
How it works:
When the Li Ion pack is near full charge and under light load, the AGM pack
supplies no current as its voltage is lower than the Li Ion pack. Under
heavy acceleration/load when the Li Ion pack voltage is drawn down below
the AGM pack voltage, the diode conducts and the AGM pack supplies part of
the current. The more it is needed, as the Li Ion pack is discharged
further and/or loading increases, the more the AGM pack supplies current.
As I brake, regen raises the Li Ion pack voltage and the AGM pack charges a
little. When put on charge, the AGM pack starts charging once the Li Ion
pack voltage comes up. With a more sophisticated charging circuit, the AGM
pack can also absorb a lot of the regen current and allow for stronger
regen
plus get partially recharged to help more. (applies to EVs with
regenerative braking capabilities).
If you want any further information or a drawing, let me know.
Best Regards,
Doug
----- Original Message -----
From: "Bill Dennis" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, June 16, 2004 5:04 PM
Subject: Boost Pack Circuit
In preparation for my EV conversion, I'm still in the early stages of
trying
to teach myself some electronics, so I apologize in advance if this is an
unworkable configuration dreamed up by a novice. I'm wondering if a
circuit
something like the one below could be designed to work for a boost pack.
The "Nifty Current Following Circuit" would do the following: When the
controller called for 140A or less (.7C), all current would flow from the
TS
Traction Pack. For Amperages above 140A, the Nifty Circuit would pull
some
proportional number of amps from the DC-DC along with the amps from the TS
Traction Pack.
Snip
Bill Dennis
--- End Message ---
--- Begin Message ---
Hi Bill et all,
The 35 200 AH TS to 9 AGM is a little higher ratio than what I used but I
would prefer that one over 33 cells. With 35 cells, the AGM will do less or
nothing at full charge and at modest acceleration, (which is fine, your
voltage is still high enough) but will be well matched to help more at lower
temperatures and when the TS pack is more discharged, when needed most. The
higher voltage TS pack would also be better able to part recharge the AGM
pack (if you set-up for this) during pauses and braking. And as you
indicated, you have more capacity.
One thing you have to consider is the full charged voltage of the TS pack
and how your motor controller will like it. You will be near 150V. If your
controller is designed to work with 120V nominal lead-acid or higher voltage
pack, you should be fine. (If a only a 120V max controller, you might have
to turn on the heater for a few seconds if driving right after a full charge
in cold weather, to let the controller start.)
Victor's points about temperature and charging are worth noting, and taking
proper care of these factors is required for best results:
Temperature: Around 25 deg. C will give the best results for both battery
chemistries. For lead acid they suffer from reduced AH capacity and
somewhat from reduced voltage when cold. For TS Li Ion, the voltage drops
noticeably as the cells get colder, requiring more current drain from them,
using more AH, to get the same power to your motor controller. So the range
is effectively lowered, and top speed also. You should keep your packs
heated and insulated under cold conditions for these reasons. If you don't,
as Victor indicated, there will also be a shift in the balance between the 2
packs of the load sharing. The TS pack voltage will drop down quickly and
the AGM pack will sooner supply more of the current. Since cars with TS Li
Ion typically have long range (unless you are pushing the envelope "too far"
towards cheap like I am doing with the hatchback and 28 only 100 AH cells)
and are likely used mostly for short trips and only part (the "top" part) of
this range, this may not be a problem in practice - the car will get you
there and back before the AGM batteries are being discharged too much. As
you drive, the TS cells will self heat and their temperature and voltage
will improve somewhat. You have to consider that the maximum range is a lot
less if you let your batteries get cold. True also with plain lead-acid,
except the lead acid range will quickly get too short. Whereas with a
properly sized TS - AGM hybrid pack, you can afford to lose a bigger
percentage of the range and still make the same trip, such as 20 miles. You
have to consider how you are using the vehicle and understand how the
battery packs will behave and work together. The short and simple
recommendation is to heat, insulate, and monitor temperature of both packs
to keep them at the best temperature range in cold weather.
Charging:
Can vary from simple to more complex, but no method can violate battery
limits, or not for long. More complex will give some advantages.
Here are some suggestions (partial repeat of previous posted methods). All
of them work from the premise that you charge directly on the TS Li Ion pack
(with cell BMS), as it has the highest charging voltage, and have a voltage
dropping, current limiting path to the AGM pack at one polarity (e.g.
positive) and a direct connection on the other side (e.g. negative) with
circuit breaker disconnect/protection:
1) Simplest: Join with a "fixed" voltage dropping circuit (big Zener
diodes) in series with a current limiting, Positive Temperature Coefficient,
self indicating, resistance (i.e. a 12V 1Amp. light bulb!) to keep charging
current low, like 1A or less. In your case of 35 200 AH TS to 9 AGM , you
need to drop about 20V. You could do the "fixed" voltage dropping circuit
part with 2 parallel strings of 4 of the 5V 5W Zener diodes in series.
(like joining 2 strings of batteries not buddy paired) Disadvantage: Slow
to recharge the AGM pack. If you drive a significant part of your range one
day and happen to want to part charge for just a short while and drive
again - the AGM pack will not get recharged. Works OK if you fully charge
and let sit before next use.
2) Add this to 1) A contactor with electronic control which joins the packs
when the AGM voltage is less than say 108V (12V per battery) and releases
(opens) when the AGM pack is above 124V (13.8V/battery). This will get the
AGM pack mostly charged first, ideal for overcoming the disadvantage
mentionned above. Ideally, this contactor's electronic control is tied to
Mk2 Regs, or similar on the AGM batteries, to switch off in the
should-be-rare case if one battery gets full early.
3) voltage, current and time controlled buck regulator to allow the AGM pack
to be charged at a higher current when its voltage is low, and the current
will be tapered off after the bulk charging, to a finishing
current/voltage. Same comment as above on the Reg controlled throttle back.
HTH.
Regards,
Doug
----- Original Message -----
From: "Bill Dennis" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, December 09, 2004 11:24 AM
Subject: RE: Boost Pack Circuit
Hi, Doug. Quick question for your advice on something. I might have the
possibility of getting 35 200Ah TS cells. If I went with your hybrid
system, the voltages would be as follows:
Starting TS: 35 * 3.6 = 126 Ending TS: 35 * 3 = 105
Starting PbA: 9 * 13.2 = 118.8 Ending PbA: 9 * 11 = 99
Do you think these numbers are close enough to work? The other
possibility
would be to drop down to using only 33 of the TS cells. Then the numbers
work out identically to each, but I'd be giving up some capacity:
Starting TS: 33 * 3.6 = 118.8 Ending TS: 33 * 3 = 99
Starting PbA: 9 * 13.2 = 118.8 Ending PbA: 9 * 11 = 99
Which method do you think is better? Thanks.
Bill Dennis
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Doug Hartley
Sent: Wednesday, June 16, 2004 8:14 PM
To: [EMAIL PROTECTED]
Subject: Re: Boost Pack Circuit
Bill, it can be easier and simpler than that:
Use an AGM lead acid pack, connected to the TS Li Ion pack with a large
diode, as the support. As more current is drawn and the Li Ion pack
voltage
drops under load, the AGM pack starts supplying current.
Here are some more details on one way to do it:
Plan a pack of small AGM batteries (such as Interstate DCS-33) having a
total pack charged resting voltage a little lower than the nominal voltage
of the TS Li Ion pack. In my case, 7 12V AGMs are used to support a 26
cell
300 A-Hour TS pack (made up of 26 200 and 26 100 A-hr cells).
So, for this real life example: 7 x 13V = 91V for the AGM pack, which is
a little less than 26 X 3.6V = 93.6V for the Li Ion pack.
As a second quick check calculation, verify that the reasonable minimum
voltage for the AGM pack is about the same as for the Li Ion pack. At
about
11V per AGM battery and 3V per Li Ion cell, both packs are down to about
77V when discharged and under load. That checks out, so they should both
work well together "to the end".
Connect one polarity (say negative) of both packs directly together.
Connect the positive of the AGM pack (through a 200A DC rated circuit
breaker for protection and disconnect), to the anode of a large diode
rated
to carry more than this current (ideally something like a low drop
Schottky
300A diode on a suitable heat sink). Note that these current ratings are
for a low voltage high current EV, and can be reduced proportionately for
a
higher voltage EV. Connect the cathode end of the diode to the Li Ion
pack
positive. Connect a charging circuit across this diode to pass a limited
current in the other direction. I used a 12V 1 Amp. automotive light bulb
in series with a 10V 40W zener diode array (4 of the 5V, 5W zeners in
series/parallel) as a quick and dirty method for now.
How it works:
When the Li Ion pack is near full charge and under light load, the AGM
pack
supplies no current as its voltage is lower than the Li Ion pack. Under
heavy acceleration/load when the Li Ion pack voltage is drawn down below
the AGM pack voltage, the diode conducts and the AGM pack supplies part of
the current. The more it is needed, as the Li Ion pack is discharged
further and/or loading increases, the more the AGM pack supplies current.
As I brake, regen raises the Li Ion pack voltage and the AGM pack charges
a
little. When put on charge, the AGM pack starts charging once the Li Ion
pack voltage comes up. With a more sophisticated charging circuit, the
AGM
pack can also absorb a lot of the regen current and allow for stronger
regen
plus get partially recharged to help more. (applies to EVs with
regenerative braking capabilities).
If you want any further information or a drawing, let me know.
Best Regards,
Doug
----- Original Message -----
From: "Bill Dennis" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, June 16, 2004 5:04 PM
Subject: Boost Pack Circuit
In preparation for my EV conversion, I'm still in the early stages of
trying
to teach myself some electronics, so I apologize in advance if this is an
unworkable configuration dreamed up by a novice. I'm wondering if a
circuit
something like the one below could be designed to work for a boost pack.
The "Nifty Current Following Circuit" would do the following: When the
controller called for 140A or less (.7C), all current would flow from the
TS
Traction Pack. For Amperages above 140A, the Nifty Circuit would pull
some
proportional number of amps from the DC-DC along with the amps from the
TS
Traction Pack.
Snip
> Bill Dennis
--- End Message ---
--- Begin Message ---
The cells will quickly drop to this voltage IF they are used at high current
for accelerating. Otherwise the voltage may not drop this much for average
current drains until later in the discharge, and the help from the AGM pack
is not needed, when the TS cells are fairly well charged.
When the battery temperature is colder (I am not always able to follow my
own advise! in case of heater failure or because of design for only 3-season
use heating and winter storage) I will lock the 2 packs together with the
contactor sooner in the trip. This is done since the TS pack voltage gets
lower sooner at colder temperatures, and the AGM pack can benefit from the
voltage rise during pauses (coasting) and regen braking recharging to get
their strength back during the drive, to be able to help more and longer.
Regards,
Doug
----- Original Message -----
From: "Bill Dennis" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, December 09, 2004 4:20 PM
Subject: RE: Boost Pack Circuit
In the note that Doug posted here a couple of months ago, he used 3.6V for
his calculations. This is probably because that's the nominal voltage for
the cells, and they quickly drop to this level as soon as they're used.
Doug can verify this if he responds.
Bill
--- End Message ---
--- Begin Message ---
Whose buggy is this?
http://www.megawattmotorworks.com/photos//woodburn%202000/slides/12.htm
http://www.megawattmotorworks.com/photos//woodburn%202000/slides/13.htm
David Thompson
--- End Message ---
--- Begin Message ---
Thanks, Doug. I've got a Curtis 1231C, which handles up to a nominal 144V.
With 12 PbA batteries, that would have given 13.2 * 12 = 158.4V. With 35 TS
cells, that will be 4.25 * 35 = 148.75, so I think I'll be okay.
Bill Dennis
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Doug Hartley
Sent: Thursday, December 09, 2004 8:54 PM
To: [EMAIL PROTECTED]
Subject: Re: Boost Pack Circuit
Hi Bill et all,
The 35 200 AH TS to 9 AGM is a little higher ratio than what I used but I
would prefer that one over 33 cells. With 35 cells, the AGM will do less or
nothing at full charge and at modest acceleration, (which is fine, your
voltage is still high enough) but will be well matched to help more at lower
temperatures and when the TS pack is more discharged, when needed most. The
higher voltage TS pack would also be better able to part recharge the AGM
pack (if you set-up for this) during pauses and braking. And as you
indicated, you have more capacity.
One thing you have to consider is the full charged voltage of the TS pack
and how your motor controller will like it. You will be near 150V. If your
controller is designed to work with 120V nominal lead-acid or higher voltage
pack, you should be fine. (If a only a 120V max controller, you might have
to turn on the heater for a few seconds if driving right after a full charge
in cold weather, to let the controller start.)
Victor's points about temperature and charging are worth noting, and taking
proper care of these factors is required for best results:
Temperature: Around 25 deg. C will give the best results for both battery
chemistries. For lead acid they suffer from reduced AH capacity and
somewhat from reduced voltage when cold. For TS Li Ion, the voltage drops
noticeably as the cells get colder, requiring more current drain from them,
using more AH, to get the same power to your motor controller. So the range
is effectively lowered, and top speed also. You should keep your packs
heated and insulated under cold conditions for these reasons. If you don't,
as Victor indicated, there will also be a shift in the balance between the 2
packs of the load sharing. The TS pack voltage will drop down quickly and
the AGM pack will sooner supply more of the current. Since cars with TS Li
Ion typically have long range (unless you are pushing the envelope "too far"
towards cheap like I am doing with the hatchback and 28 only 100 AH cells)
and are likely used mostly for short trips and only part (the "top" part) of
this range, this may not be a problem in practice - the car will get you
there and back before the AGM batteries are being discharged too much. As
you drive, the TS cells will self heat and their temperature and voltage
will improve somewhat. You have to consider that the maximum range is a lot
less if you let your batteries get cold. True also with plain lead-acid,
except the lead acid range will quickly get too short. Whereas with a
properly sized TS - AGM hybrid pack, you can afford to lose a bigger
percentage of the range and still make the same trip, such as 20 miles. You
have to consider how you are using the vehicle and understand how the
battery packs will behave and work together. The short and simple
recommendation is to heat, insulate, and monitor temperature of both packs
to keep them at the best temperature range in cold weather.
Charging:
Can vary from simple to more complex, but no method can violate battery
limits, or not for long. More complex will give some advantages.
Here are some suggestions (partial repeat of previous posted methods). All
of them work from the premise that you charge directly on the TS Li Ion pack
(with cell BMS), as it has the highest charging voltage, and have a voltage
dropping, current limiting path to the AGM pack at one polarity (e.g.
positive) and a direct connection on the other side (e.g. negative) with
circuit breaker disconnect/protection:
1) Simplest: Join with a "fixed" voltage dropping circuit (big Zener
diodes) in series with a current limiting, Positive Temperature Coefficient,
self indicating, resistance (i.e. a 12V 1Amp. light bulb!) to keep charging
current low, like 1A or less. In your case of 35 200 AH TS to 9 AGM , you
need to drop about 20V. You could do the "fixed" voltage dropping circuit
part with 2 parallel strings of 4 of the 5V 5W Zener diodes in series.
(like joining 2 strings of batteries not buddy paired) Disadvantage: Slow
to recharge the AGM pack. If you drive a significant part of your range one
day and happen to want to part charge for just a short while and drive
again - the AGM pack will not get recharged. Works OK if you fully charge
and let sit before next use.
2) Add this to 1) A contactor with electronic control which joins the packs
when the AGM voltage is less than say 108V (12V per battery) and releases
(opens) when the AGM pack is above 124V (13.8V/battery). This will get the
AGM pack mostly charged first, ideal for overcoming the disadvantage
mentionned above. Ideally, this contactor's electronic control is tied to
Mk2 Regs, or similar on the AGM batteries, to switch off in the
should-be-rare case if one battery gets full early.
3) voltage, current and time controlled buck regulator to allow the AGM pack
to be charged at a higher current when its voltage is low, and the current
will be tapered off after the bulk charging, to a finishing
current/voltage. Same comment as above on the Reg controlled throttle back.
HTH.
Regards,
Doug
----- Original Message -----
From: "Bill Dennis" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, December 09, 2004 11:24 AM
Subject: RE: Boost Pack Circuit
> Hi, Doug. Quick question for your advice on something. I might have the
> possibility of getting 35 200Ah TS cells. If I went with your hybrid
> system, the voltages would be as follows:
>
> Starting TS: 35 * 3.6 = 126 Ending TS: 35 * 3 = 105
> Starting PbA: 9 * 13.2 = 118.8 Ending PbA: 9 * 11 = 99
>
> Do you think these numbers are close enough to work? The other
> possibility
> would be to drop down to using only 33 of the TS cells. Then the numbers
> work out identically to each, but I'd be giving up some capacity:
>
> Starting TS: 33 * 3.6 = 118.8 Ending TS: 33 * 3 = 99
> Starting PbA: 9 * 13.2 = 118.8 Ending PbA: 9 * 11 = 99
>
> Which method do you think is better? Thanks.
>
> Bill Dennis
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
> Behalf Of Doug Hartley
> Sent: Wednesday, June 16, 2004 8:14 PM
> To: [EMAIL PROTECTED]
> Subject: Re: Boost Pack Circuit
>
> Bill, it can be easier and simpler than that:
>
> Use an AGM lead acid pack, connected to the TS Li Ion pack with a large
> diode, as the support. As more current is drawn and the Li Ion pack
> voltage
> drops under load, the AGM pack starts supplying current.
>
> Here are some more details on one way to do it:
> Plan a pack of small AGM batteries (such as Interstate DCS-33) having a
> total pack charged resting voltage a little lower than the nominal voltage
> of the TS Li Ion pack. In my case, 7 12V AGMs are used to support a 26
> cell
> 300 A-Hour TS pack (made up of 26 200 and 26 100 A-hr cells).
> So, for this real life example: 7 x 13V = 91V for the AGM pack, which is
> a little less than 26 X 3.6V = 93.6V for the Li Ion pack.
> As a second quick check calculation, verify that the reasonable minimum
> voltage for the AGM pack is about the same as for the Li Ion pack. At
> about
> 11V per AGM battery and 3V per Li Ion cell, both packs are down to about
> 77V when discharged and under load. That checks out, so they should both
> work well together "to the end".
>
> Connect one polarity (say negative) of both packs directly together.
> Connect the positive of the AGM pack (through a 200A DC rated circuit
> breaker for protection and disconnect), to the anode of a large diode
> rated
> to carry more than this current (ideally something like a low drop
> Schottky
> 300A diode on a suitable heat sink). Note that these current ratings are
> for a low voltage high current EV, and can be reduced proportionately for
> a
> higher voltage EV. Connect the cathode end of the diode to the Li Ion
> pack
> positive. Connect a charging circuit across this diode to pass a limited
> current in the other direction. I used a 12V 1 Amp. automotive light bulb
> in series with a 10V 40W zener diode array (4 of the 5V, 5W zeners in
> series/parallel) as a quick and dirty method for now.
>
> How it works:
> When the Li Ion pack is near full charge and under light load, the AGM
> pack
> supplies no current as its voltage is lower than the Li Ion pack. Under
> heavy acceleration/load when the Li Ion pack voltage is drawn down below
> the AGM pack voltage, the diode conducts and the AGM pack supplies part of
> the current. The more it is needed, as the Li Ion pack is discharged
> further and/or loading increases, the more the AGM pack supplies current.
> As I brake, regen raises the Li Ion pack voltage and the AGM pack charges
> a
> little. When put on charge, the AGM pack starts charging once the Li Ion
> pack voltage comes up. With a more sophisticated charging circuit, the
> AGM
> pack can also absorb a lot of the regen current and allow for stronger
> regen
> plus get partially recharged to help more. (applies to EVs with
> regenerative braking capabilities).
>
> If you want any further information or a drawing, let me know.
>
> Best Regards,
>
> Doug
>
>
> ----- Original Message -----
> From: "Bill Dennis" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Wednesday, June 16, 2004 5:04 PM
> Subject: Boost Pack Circuit
>
>
>> In preparation for my EV conversion, I'm still in the early stages of
> trying
>> to teach myself some electronics, so I apologize in advance if this is an
>> unworkable configuration dreamed up by a novice. I'm wondering if a
> circuit
>> something like the one below could be designed to work for a boost pack.
>> The "Nifty Current Following Circuit" would do the following: When the
>> controller called for 140A or less (.7C), all current would flow from the
> TS
>> Traction Pack. For Amperages above 140A, the Nifty Circuit would pull
> some
>> proportional number of amps from the DC-DC along with the amps from the
>> TS
>> Traction Pack.
>
> Snip
>
> > Bill Dennis
>>
>
>
>
--- End Message ---
--- Begin Message ---
I recall a triple-motored Rx7? a few years back at Woodburn, but I can't
recall if it was Wilde or Father Time or ?
----- Original Message -----
From: "James D Thompson" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, December 09, 2004 10:36 PM
Subject: Mystery Machine
Whose buggy is this?
http://www.megawattmotorworks.com/photos//woodburn%202000/slides/12.htm
http://www.megawattmotorworks.com/photos//woodburn%202000/slides/13.htm
David Thompson
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--- Begin Message ---
A 144V Curtis will give you lots of margin at the top end, as it can handle
up to the charging voltage. Now check that it won't quit on you too soon
going down to (9 X 10.5)- wiring drop = about 94V at the end of capacity
under load, and you should be fine for the controller. If you run into
trouble at the low end, you could add another 12V AGM and maybe 3 more cells
and a cash cow, and you will be all set. I am assuming that your DC-DC
converter is good for this voltage range also?
Regards,
Doug
----- Original Message -----
From: "Bill Dennis" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Friday, December 10, 2004 12:10 AM
Subject: RE: Boost Pack Circuit
Thanks, Doug. I've got a Curtis 1231C, which handles up to a nominal
144V.
With 12 PbA batteries, that would have given 13.2 * 12 = 158.4V. With 35
TS
cells, that will be 4.25 * 35 = 148.75, so I think I'll be okay.
Bill Dennis
--- End Message ---
--- Begin Message ---
Yes some people made that comment but I think the half empty half full rule
applies. Lawrence Rhodes.
----- Original Message -----
From: "Electro Automotive" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, December 08, 2004 5:51 PM
Subject: Re: Interesting URL
At 11:47 AM 12/8/04 -0800, you wrote:
http://www.evmaster.com/evm/links.asp
This is like a graveyard of dead EV companies. Many of these links are to
outfits that are LONG gone.
Shari Prange
Electro Automotive POB 1113 Felton CA 95018-1113 Telephone 831-429-1989
http://www.electroauto.com [EMAIL PROTECTED]
Electric Car Conversion Kits * Components * Books * Videos * Since 1979
--- End Message ---
--- Begin Message ---
Hmmm this seems like a fair starting point. Seems a little bigger than a
600.. Seems like a lot of room for batteries. Very spartan. Maybe the
pro's from Portland aught to be involved in this one. It would make a very
economical car. Lawrence Rhodes.....
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: "EV Discussion List" <[EMAIL PROTECTED]>
Sent: Thursday, December 09, 2004 1:49 PM
Subject: Relative of the Fiamp?
Electrified Fiat 750 in the NW:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=4510387619
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I was at the local forklift supply and they had quite a supply of anderson
connectors. Seems the wire size I use was matched to about a 50 amp
anderson connector.(#4 or #6 wire) Even a hundred amp Anderson connector
seems too big to use as a quick disconnect. Basically the idea is to use
an anderson connector with a loop in one end to be pulled on in an
emergency. Also functions as a sort of a key. I have seen this done on
pocket bikes. I'd like to put one on my Lectra. I use 200 amps ocasionally
for some seconds. Never had an overheating problem. Could I get by with
one of the 50 amp Anderson connectors? My average amp drain cruising is 20
to 50amps on level ground. Lawrence Rhodes..........
--- End Message ---
--- Begin Message ---
240Z?
Tom True?
Related to Father Time?
Joe Smalley
Rural Kitsap County WA
Fiesta 48 volts
NEDRA 48 volt street conversion record holder
[EMAIL PROTECTED]
----- Original Message -----
From: "Mr23" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, December 09, 2004 9:38 PM
Subject: Re: Mystery Machine
> I recall a triple-motored Rx7? a few years back at Woodburn, but I can't
> recall if it was Wilde or Father Time or ?
>
> ----- Original Message -----
> From: "James D Thompson" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Thursday, December 09, 2004 10:36 PM
> Subject: Mystery Machine
>
>
> > Whose buggy is this?
> >
> > http://www.megawattmotorworks.com/photos//woodburn%202000/slides/12.htm
> > http://www.megawattmotorworks.com/photos//woodburn%202000/slides/13.htm
> >
> > David Thompson
> >
>
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--- Begin Message ---
It seems to me with my limited testing is the ETEK is better at 48v than the
A89. At 72v however the A89 would be a bit peppier than the ETEK is what I
am guessing. My test is a steep hill going to my house that I can just pull
at 25 with the A89 geared up the ETEK could pull in the middle of the hill
from 20mph and accelerate where the A89 would be stuck with no acceleration.
I am even feeling a bit of difference in the 30 pounds I lost from the
change of motors too. So more power. Very little modification. More
efficient. I also have the A89 for another project if I desire. Lawrence
Rhodes.......
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--- Begin Message ---
what vehicle are you using the etek in?
i have one and am building a emotorcycle with it
it's currently in a test rig
Lawrence Rhodes <[EMAIL PROTECTED]> wrote:
It seems to me with my limited testing is the ETEK is better at 48v than the
A89. At 72v however the A89 would be a bit peppier than the ETEK is what I
am guessing. My test is a steep hill going to my house that I can just pull
at 25 with the A89 geared up the ETEK could pull in the middle of the hill
from 20mph and accelerate where the A89 would be stuck with no acceleration.
I am even feeling a bit of difference in the 30 pounds I lost from the
change of motors too. So more power. Very little modification. More
efficient. I also have the A89 for another project if I desire. Lawrence
Rhodes.......
Regards
Richard
---------------------------------
Win a castle for NYE with your mates and Yahoo! Messenger
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