EV Digest 4967
Topics covered in this issue include:
1) RE: Am I Killing Batteries?(+)
by "Roger Stockton" <[EMAIL PROTECTED]>
2) Sydney AEVA Meeting tonight
by "Mark Fowler" <[EMAIL PROTECTED]>
3) RE: A Dumb Old Laptop Can Be Pretty Slick Tool
by "Roger Stockton" <[EMAIL PROTECTED]>
4) Re: A Dumb Old Laptop Can Be Pretty Slick Tool
by Danny Miller <[EMAIL PROTECTED]>
5) RE: A Dumb Old Laptop Can Be Pretty Slick Tool
by "Harris, Lawrence" <[EMAIL PROTECTED]>
6) More on that NiCD Pack made from small cells
by [EMAIL PROTECTED]
7) RE: Connecting Muliple 12V battery chargers?
by "Stefan T. Peters" <[EMAIL PROTECTED]>
8) Re: Am I Killing Batteries?(+)
by "Roland Wiench" <[EMAIL PROTECTED]>
9) 1994 Other Makes : Electric Geo Metro Electric vehicle Item number:
4595363002
by [EMAIL PROTECTED]
10) RE: More on that NiCD Pack made from small cells
by "Mark Fowler" <[EMAIL PROTECTED]>
11) RE: More on that NiCD Pack made from small cells
by "damon henry" <[EMAIL PROTECTED]>
12) RE: Am I Killing Batteries?(+)
by "Roger Stockton" <[EMAIL PROTECTED]>
13) RE: Am I Killing Batteries?(+)
by "Dewey, Jody R ATC (CVN75 IM3)" <[EMAIL PROTECTED]>
14) Re: conversion kits, an"' Stuff.
by Lee Hart <[EMAIL PROTECTED]>
15) Re: Am I Killing Batteries?(+)
by "Roland Wiench" <[EMAIL PROTECTED]>
16) Re: Am I Killing Batteries?(+)
by "Roland Wiench" <[EMAIL PROTECTED]>
--- Begin Message ---
Joe Smalley [mailto:[EMAIL PROTECTED] wrote:
> Wow, That is quite a testimony about the behavior of a smart
> charger and a PFC-50.
It certainly isn't anything I'd take to the bank ;^>
The fact that Roland can crank up his PFC-50 and *overcharge* his house
battery because he doesn't understand that a battery is charged based on
the temperature it is *at*, not at the temperature he might later use it
in, is really a good illustration of why smart chargers are a "good
thing" for those who don't understand batteries well.
Nowhere does he indicate what temperature the battery is actually at,
which is the only thing of interest to properly charging it. 15.53V is
about right for a battery at -5C (23F), but his battery is being charged
in a 74F ambient after being used for some amount of time in a 0F
ambient.
All I can really glean from his "testimonial" is that it sounds like he
is relying on a voltage-based SOC indicator, and that by mis-adjusting
his PFC-50 he can charge the battery such that it is most likely gassing
and heating up more than with the smart charger such that when he takes
it outside for his short test (battery has little time to significantly
change temperature) its voltage holds up better than the cooler battery.
Of course, a charger is not necessarily good just because it is "smart",
so it is possible that Roland's particular "smart" charger isn't
properly charging his battery either, and indeed may be erring on the
side of undercharging while Roland is manually erring on the side of
overcharging.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Hi all,
A quick reminder for people Sydney (Australia) interested in EVs.
The Sydney Chapter of the Australian Electric Vehicle Association is
having a meeting tonight
Date:Tue, 6th Dec
Time: 8:00pm
Place: Norwest McDonalds - Old Windsor Rd, Bella Vista
I think there will be some discussion of a field day in the near future.
Anyway, everyone is welcome.
See you there,
Mark
--- End Message ---
--- Begin Message ---
Danny Miller [mailto:[EMAIL PROTECTED] wrote:
> Sharing the serial bus through simple master/slave addressing would
> allow for many more nodes.
The limitation is a hardware one, not related to the protocol being
used.
Think of it like "fan-out" on a logic IC; it doesn't matter what data
you are transferring, or in what format, you can still only hook so many
devices to a single output before it stops working acceptably.
> Can't a std RS232 port do addressing like that?
You can certainly do any sort of addressing you wish with a standard
RS232 port. The issue is more what Peter Vanderwal pointed out: RS232
is not a multidrop bus, so you may need a bit of hardware to interface
between each RS232 port and the multidrop bus to allow multiple devices
to share a single bus.
> Can a Java terminal prog snoop the bus ok and sort out the
> packets and/or take over the mastering job?
Dunno, but pretty much anything is possible.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Roger Stockton wrote:
Danny Miller [mailto:[EMAIL PROTECTED] wrote:
Sharing the serial bus through simple master/slave addressing would
allow for many more nodes.
The limitation is a hardware one, not related to the protocol being
used.
Well, it's both hardware and protocol. Hardware can be modified to
drive more current if necessary (of course this would mean it draws more
current as well). Or use a repeater node. But the way time slicing is
being laid out in the protocol prohibits more than 32 transmitters on a
bus, though more "listen only" nodes would be possible if the hardware
drove more current. There aren't all that many devices that would be
useful in "listen only" mode though.
Can't a std RS232 port do addressing like that?
You can certainly do any sort of addressing you wish with a standard
RS232 port. The issue is more what Peter Vanderwal pointed out: RS232
is not a multidrop bus, so you may need a bit of hardware to interface
between each RS232 port and the multidrop bus to allow multiple devices
to share a single bus.
It would probably use the exact same hardware we're already discussing.
No change there.
Danny
--- End Message ---
--- Begin Message ---
Let's not get too mired in details. The evil bus has a purpose to attach
safely simple (relatively speaking) data monitors usually near the batteries
and in areas of high noise. To do this it is limited in data rate to allow
it to work with very low cost hardware. As soon as you (yes you) are
willing to pay the cost you can raise the data rate, raise the complexity
etc. Beyond that the physical bus is already laid down and most of the
protocol has been agreed to and the command set almost agreed to over on the
evtech mailing list. So all that is left is 'how' do we use it and if
necessary how do we work around it's limitation with respect to our specific
needs.
For example if you have a system that is so complex as to need more than 32
nodes and/or more bandwidth then there is nothing to stop you from running
two or more separate busses and either attaching them to two serial ports on
your computer or better building a simple data concentrator that would
monitor multiple evil bus's and report in any format you like or maybe
report out at 38,400 baud to your laptop (4 bus's at 9600 baud is 38,400
baud).
Lawrence
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Danny Miller
Sent: Monday, December 05, 2005 1:15 PM
To: [email protected]
Subject: Re: A Dumb Old Laptop Can Be Pretty Slick Tool
I'm still wondering if 32 nodes is a good limit for the future. If one
wanted to expand the use of the bus into future purposes- monitoring a
hybrid generator, GPS, atmospheric condition sensors, an inclination
sensor- or you just want power door locks- that may become a problem.
Sharing the serial bus through simple master/slave addressing would
allow for many more nodes.
Can't a std RS232 port do addressing like that? Can a Java terminal
prog snoop the bus ok and sort out the packets and/or take over the
mastering job?
Danny
Roger Stockton wrote:
>Cor van de Water [mailto:[EMAIL PROTECTED] wrote:
>
>
>
>>Even if the speed would be limited to 9600 and there are 32
>>batteries or other devices on the bus, each could send up to
>>300 bits per second, while the typical amount of data of a
>>single voltage measurement takes 1/10 of that number of bits.
>>So there still is an order of magnitude more bandwidth than
>>the application needs. What was the problem again?
>>
>>
>
>300 bits/device per second is the theoretical maximum; in practice some
>of the available bandwidth is lost to allow dead time between messsages
>from different devices (to avoid collisions), etc. In this particular
>communication scheme there each device can transmit a maximum of 240
>bits/second, or 24 ASCII characters.
>
>A single voltage reading sent in ASCII format looks like "12.23", which
>is 50 bits or 21% of the bandwidth available to the device. To this
>needs to be added the packet header and trailer. By the time all is
>said and done, 50% of the device's bandwidth is consumed sending a
>single voltage reading.
>
>As to the 32 devices, no one says that each device only reports
>voltages, nor that each device only monitors a single object (battery,
>etc.). Consider Lee's E-Meter example: this sort of device would report
>pack voltage, pack current, kWh, Ah, and could report pack temperature,
>SOC, and a couple other less useful values that appear in an E-Meter's
>data output.
>
>The 32 device limitation is a hardware one; the bus only supports
>connection of about 32 devices, however, if one has a pack of NiCds or
>LiIon (or ?) cells, they may have a hundred or more individual module
>voltages being reported by some number of devices each monitoring
>several cells. There is not enough bandwidth to do this in ASCII and
>receive voltage updates every second.
>
>The nature of the particular communications scheme/bus being used is
>that the limited bandwidth means that in some cases reports may not be
>generated for a few seconds after the condition has occurred. The real
>problem here is that we don't have a good feel for how much delay is
>acceptable (or more accurately, there is disagreement about that).
>There is just an uneasy feeling amongst some that this is really too
>small a bandwidth channel to afford the luxury of ASCII format packets
>because it is relatively easy to come up with scenarios where the delay
>between something happening and being reported gets into the few second
>range.
>
>I really didn't want to provide so much information that we start repeat
>here of the discussion that has been taking place on the EVTech list. I
>mentioned the limited bandwidth bus and the fact that it was being
>shared between several devices only to provide a bit of context so
>people didn't assume the question was "what format should data from a
>device that connects directly to your PC like an E-Meter be in?".
>
>Cheers,
>
>Roger.
>
>
>
>
>
--- End Message ---
--- Begin Message ---
A little more info.
I was planning to use about 3000+ (depending on how many are available) Sub C
(or even high capacity - high performance AA) cells. I was thinking cells in
the range of 1.6 - 2 AH each. It would take a minimum of 3000 of them in an
array of 60 in series by 50 + in parallel to even give the performance I am
looking at. By the way, there are much larger cells, but high cap AA and sub C
are less expensive because of the production volumes. You can get high
performance D and F cells that are upward of 10 AH each (I think), but they are
extremely expensive, and not available to the average consumer.
Why?
1. These type of cells are very much out of favor in the industry and can be
bought surplus very cheap. But, probably not as cheap as some other options.
This pack would probably be about the same cost as an equivalent pack made of
Optimas (same voltage / capacity, but less weight and I think maybe more
cycles. These types of NICDs if treated well can go over 2000 cycles (I
think).)
2. They can tolerate very high charge / discharge rates. Think about
cordless screwdrivers. I believe a 80 AH pack would tolerate 700 A peak / 160
- 200
A continuous discharge without destroying itself. But, don't quote me on that.
3. Charging is easier with the NICD than NIMH.
By the way, I do have extensive experience building batteries with these
types of cells, but never one this large. Maybe 30 cells, but not 3000.
Disadvantages:
1. I'm really not looking forward to figuring out how to hook up a minimum of
3000 cells in a 60 x 50 grid and keeping all the connections good.
2. Troubleshooting a bad cell could be a major pain. But, if they were built
into say blocks of 30 cells each (7.2 V), you would only need 100 such packs
and they could be more easily managed and monitored.
It will be a major project if I decide to do this, but I think the result
would be a very decent battery pack. I seem to recall many years ago that
someone powered an EV with 9 V's. I remember seeing pictures of thousands and
thousands of 9 V's in some car years back. The article was in Popular Science,
maybe in the mid to late 80's.
--- End Message ---
--- Begin Message ---
> Using one 12V battery charger per 12V module will work provided the
chargers have isolated outputs like the transformer style chargers. If
the chargers have the same shut off voltage it can be a good way to
balanced the battery bank. Making sure the chargers are all on is
something to watch like Steve mentioned, another problem is the charge
rate or time of the cheaper Sam's Club chargers. If the charge rate is
high (15A to 25A setting) the cheap charger will reach the shut off
voltage and shut off before the battery is fully charged. If you use the
low setting (2A to 6A) the charger will give a full charge but it will
take a long time. Sometimes an old battery will not reach the shut off
voltage when the charger is on the high setting and can put the battery
into thermal runaway. This system requires a lot of monitoring.
Would the SONEIL 1214S charger be a good one for this application (I was
thinking of mounting the status LEDs in an array on the dash)?
http://soneil.com/12v_chargers.htm
Spec Sheet:
http://soneil.com/Completesets/SPEC1214S(Rev01).042904.pdf
--
Stefan T. Peters
--- End Message ---
--- Begin Message ---
Roger, I understand that the battery that the battery is charged at the
temperature it is at. I have complete graphs on charging vs ambient
temperature. For my main battery pack of 90 cells, it is about 0.5 volt
increase of charging voltage per 1 degree rise of ambient temperature, which is
close to what you have stated.
This is a new charger that does not seem to charge like my old charger made by
the same company, which is just a standard taper type charger that took the
battery voltage to 15 volts no matter what the temperature is and than the
current taper off to below 5 amps.
I ran this old charger for 30 years with no problems and had one 12 volt
battery last me 12 years from 1991 to 1993. The EV would start up no matter if
it was 45 below or 105 above.
I just did another charging test on this battery. Leaving the EV outside in
the 0 degrees which was cold soaking for two hours. The Battery % indicator
show it was 51 percent while only drawing 5 amps out of it for 8 minutes. I
than charge it outside with the Auto Smart Charger, this time instead of 15
minutes charging inside at 72 degrees, it took about 44 minutes to get to 100
percent.
Drove the EV again drawing 5 amps for 8 minutes and letting set for 60 minutes
in 0 degree ambient temperature. This time the battery % indicator still read
100 percent.
Ran the EV drawing 50 amps for 8 minutes and letting set for another 60 minutes
in 0 degree temperature, the battery % indicator read 83 percent.
I than charge it again inside at 70 degrees with a standard charger which took
it to 15 volts and than the ampere taper to 5 amps. The battery temperature at
end of charger was only 66 degrees. There was very little gassing. The battery
% indicator reads 100 percent
The Smart charger must receiving the ambient temperature directly to the
charger, not reading the battery temperature. To test this out, I will charge
the battery leaving it outside, while having the charger inside. We will see
what happens. Could be a bad charger. I contacted the battery charger company
about this to see what they say.
Roland
----- Original Message -----
From: Roger Stockton<mailto:[EMAIL PROTECTED]>
To: [email protected]<mailto:[email protected]>
Sent: Monday, December 05, 2005 2:09 PM
Subject: RE: Am I Killing Batteries?(+)
Joe Smalley [mailto:[EMAIL PROTECTED] wrote:
> Wow, That is quite a testimony about the behavior of a smart
> charger and a PFC-50.
It certainly isn't anything I'd take to the bank ;^>
The fact that Roland can crank up his PFC-50 and *overcharge* his house
battery because he doesn't understand that a battery is charged based on
the temperature it is *at*, not at the temperature he might later use it
in, is really a good illustration of why smart chargers are a "good
thing" for those who don't understand batteries well.
Nowhere does he indicate what temperature the battery is actually at,
which is the only thing of interest to properly charging it. 15.53V is
about right for a battery at -5C (23F), but his battery is being charged
in a 74F ambient after being used for some amount of time in a 0F
ambient.
All I can really glean from his "testimonial" is that it sounds like he
is relying on a voltage-based SOC indicator, and that by mis-adjusting
his PFC-50 he can charge the battery such that it is most likely gassing
and heating up more than with the smart charger such that when he takes
it outside for his short test (battery has little time to significantly
change temperature) its voltage holds up better than the cooler battery.
Of course, a charger is not necessarily good just because it is "smart",
so it is possible that Roland's particular "smart" charger isn't
properly charging his battery either, and indeed may be erring on the
side of undercharging while Roland is manually erring on the side of
overcharging.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
1994 Other Makes : Electric Geo Metro Electric vehicle Item number:
4595363002
I thought this was interesting, although too expensive considering it needs a
complete battery pack replacement and a charger. The automatic transmission
is interesting. Do you suppose it has a custom gear box, or the standard
automatic transmission? I think this may be another 1 of a kind, unlike the
Solectria.
To get something like this on the road, I figure you would need at least
$1700 for batteries and a basic charger. Better batteries and better charger
could run twice that. The more and more I reaserch, it seems that "it's all
about
the charger." You need one that can charge the batteries fast enough for you
to get back on the road promptly (4 hours would be great, but maximum 10
hours would be acceptable). And, the charger performance can really affect
bettery life. That is one of those hidden costs you don't think about until
you
kill your batteries and have to spend $1200 on a new set. I still like
individual chargers that are individually monitored just because I think they
give
better control, but they also have more failure points and can do a lot of
damage
if you let one cell in the pack go bad. Just my opinion, and I know most
people on the list disagree about the multiple chargers. I could build an
array
of twelve 12 A chargers (the kind you can buy at Wal Mart for $60 or $18 - 20
on E-bay, and charge a 144 V pack overnight. And, those chargers are supposed
to be safe for AGM batteries. It is a lot of connections and monitoring, and
each one would have to be set-up each time you charge (a lot of button
pushing), but $240 for a 12 A charger that can charge a 144 V AGM battery pack,
seems
like a pretty good deal to me. If you wanted a 25 A charge rate, it would
cost more like $450 to build the array of chargers. Just my thoughts. Since I
haven't done this and had the nuisence of hooking it up, maybe it just looks
good on paper, but it impractical in the real world.
Just FYI.
Steve
--- End Message ---
--- Begin Message ---
A good plan here is to buy a cheap electric scooter and try powering it
with some small cells.
This will let you sort out your interconnects, battery robustness and so
on without spending megabucks.
Mark
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of
> [EMAIL PROTECTED]
> Sent: Tuesday, 6 December 2005 9:07 AM
> To: [email protected]
> Subject: More on that NiCD Pack made from small cells
>
>
> A little more info.
>
> I was planning to use about 3000+ (depending on how many are
> available) Sub C
> (or even high capacity - high performance AA) cells. I was
> thinking cells in
> the range of 1.6 - 2 AH each. It would take a minimum of
> 3000 of them in an
> array of 60 in series by 50 + in parallel to even give the
> performance I am
> looking at. By the way, there are much larger cells, but
> high cap AA and sub C
> are less expensive because of the production volumes. You
> can get high
> performance D and F cells that are upward of 10 AH each (I
> think), but they are
> extremely expensive, and not available to the average consumer.
>
> Why?
> 1. These type of cells are very much out of favor in the
> industry and can be
> bought surplus very cheap. But, probably not as cheap as
> some other options.
> This pack would probably be about the same cost as an
> equivalent pack made of
> Optimas (same voltage / capacity, but less weight and I think
> maybe more
> cycles. These types of NICDs if treated well can go over
> 2000 cycles (I think).)
> 2. They can tolerate very high charge / discharge rates. Think about
> cordless screwdrivers. I believe a 80 AH pack would tolerate
> 700 A peak / 160 - 200
> A continuous discharge without destroying itself. But, don't
> quote me on that.
> 3. Charging is easier with the NICD than NIMH.
> By the way, I do have extensive experience building batteries
> with these
> types of cells, but never one this large. Maybe 30 cells,
> but not 3000.
>
>
> Disadvantages:
> 1. I'm really not looking forward to figuring out how to hook
> up a minimum of
> 3000 cells in a 60 x 50 grid and keeping all the connections good.
> 2. Troubleshooting a bad cell could be a major pain. But, if
> they were built
> into say blocks of 30 cells each (7.2 V), you would only need
> 100 such packs
> and they could be more easily managed and monitored.
>
> It will be a major project if I decide to do this, but I
> think the result
> would be a very decent battery pack. I seem to recall many
> years ago that
> someone powered an EV with 9 V's. I remember seeing pictures
> of thousands and
> thousands of 9 V's in some car years back. The article was
> in Popular Science,
> maybe in the mid to late 80's.
>
>
--- End Message ---
--- Begin Message ---
Before you get too far into this consider the fact that at $10 a cell plus
$3 for interconnects a 72 v pack of BB600 Nicads would cost about $800.
Most of us are getting between 35 and 40 ahrs out of these cells. They are
flooded Nicads which has both it's advantages and disadvantages. That
should make for a good price point to comapre against.
damon
A little more info.
I was planning to use about 3000+ (depending on how many are available) Sub
C
(or even high capacity - high performance AA) cells. I was thinking cells
in
the range of 1.6 - 2 AH each. It would take a minimum of 3000 of them in
an
array of 60 in series by 50 + in parallel to even give the performance I am
looking at. By the way, there are much larger cells, but high cap AA and
sub C
are less expensive because of the production volumes. You can get high
performance D and F cells that are upward of 10 AH each (I think), but they
are
extremely expensive, and not available to the average consumer.
Why?
1. These type of cells are very much out of favor in the industry and can
be
bought surplus very cheap. But, probably not as cheap as some other
options.
This pack would probably be about the same cost as an equivalent pack made
of
Optimas (same voltage / capacity, but less weight and I think maybe more
cycles. These types of NICDs if treated well can go over 2000 cycles (I
think).)
2. They can tolerate very high charge / discharge rates. Think about
cordless screwdrivers. I believe a 80 AH pack would tolerate 700 A peak /
160 - 200
A continuous discharge without destroying itself. But, don't quote me on
that.
3. Charging is easier with the NICD than NIMH.
By the way, I do have extensive experience building batteries with these
types of cells, but never one this large. Maybe 30 cells, but not 3000.
Disadvantages:
1. I'm really not looking forward to figuring out how to hook up a minimum
of
3000 cells in a 60 x 50 grid and keeping all the connections good.
2. Troubleshooting a bad cell could be a major pain. But, if they were
built
into say blocks of 30 cells each (7.2 V), you would only need 100 such
packs
and they could be more easily managed and monitored.
It will be a major project if I decide to do this, but I think the result
would be a very decent battery pack. I seem to recall many years ago that
someone powered an EV with 9 V's. I remember seeing pictures of thousands
and
thousands of 9 V's in some car years back. The article was in Popular
Science,
maybe in the mid to late 80's.
--- End Message ---
--- Begin Message ---
Roland Wiench [mailto:[EMAIL PROTECTED] wrote:
> Roger, I understand that the battery that the battery is
> charged at the temperature it is at.
OK; it is just that what you seemed to be suggesting is that the charger
needs to know what the *outside* temperature is so that it can charge
the battery properly for use in that temperature, even though the
battery is sitting in a heated garage while being charged.
This, of course, is not at all what you want to do when charging a
battery. If temperature the charger senses is cooler than that of the
battery, it will overcharge the battery; if the temperature sensed is
higher than that of the battery, it will undercharge it. If the charger
has temperature compensation, it needs to sense the actual battery
temperature, and ideally, this means the electrolyte temperature, not
just the temperature of the case.
> I just did another charging test on this battery. Leaving
> the EV outside in the 0 degrees which was cold soaking for
> two hours. The Battery % indicator show it was 51 percent
> while only drawing 5 amps out of it for 8 minutes.
If I recall correctly, you are using a fairly large 12V battery. What
was its temperature and voltage after 2 hours?
I think the main problem you have is that you are placing way too much
faith in this battery % indicator. It sounds like the %indicator is
voltage-based, and it also sounded like it is built into the new
charger. A % indicator built into a charger almost certainly is not
meant to indicate accurately while you are drawing any current from the
battery, and will read low depending on how much voltage sag the load
results in. The voltage sag will increase as the battery becomes
cooler, so anything you do that warms the battery will make the %
indicator read higher when a load is applied.
This is a flooded battery, isn't it? Check the s.g. after charging in
the heated garage (I'm not going so suggest you do this outside in 0F!
;^). The battery is either fully charged, or it isn't; the % indicator
may lie, but s.g. won't.
Even 50A for 8 minutes isn't taking enough out of the battery (6.7Ah)
for it to read significantly below 100% SOC unless it is either a very
small battery or nearly shot (i.e. much less than nameplate capacity
even fully charged).
Get the battery fully charged inside the heated garage and verify the
s.g. indicates it is fully charged, then park the car outside for a few
hours. If the % indicator indicates significantly less than 100% at no
load or with some load on the battery when you check after the cold
soak, then you know the indicator is lying. It simply doesn't handle
temperature properly, and/or doesn't indicate properly while a load is
applied to the battery.
> The Smart charger must receiving the ambient temperature
> directly to the charger, not reading the battery temperature.
This is certainly possible. If the charger is to sense the battery
temperature, it must have a sensor that attatches to the battery. This
could be a separate wire from the charger, or the sensor might be
incorporated into one of the charger's output leads (which would
typically require that the charger's output cord include at least 3
wires).
The cheap/simple approach is for the charger to use a sensor that is
inside the charger's box, however, this means that at best it can sense
ambient temperature, and at worst, it will sense the charger's own
temperature, which can be quite a bit warmer than ambient while it is
operating! One charger I've seen compromises and has the temperature
sensor in a little rubber stalk that sticks out of the charger case
about 1-2". This keeps the charger's self-heating from affecting the
reading so much, but still relies on the assumption that the batteries
will be near ambient temperature.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Does anyone make a temp sensor that sits IN the electrolyte? I would think
that would be the best way to read the temperature of the battery.
-----Original Message-----
From: Roger Stockton [mailto:[EMAIL PROTECTED]
Sent: Monday, December 05, 2005 6:01 PM
To: [email protected]
Subject: RE: Am I Killing Batteries?(+)
Roland Wiench [mailto:[EMAIL PROTECTED] wrote:
> Roger, I understand that the battery that the battery is
> charged at the temperature it is at.
OK; it is just that what you seemed to be suggesting is that the charger
needs to know what the *outside* temperature is so that it can charge
the battery properly for use in that temperature, even though the
battery is sitting in a heated garage while being charged.
This, of course, is not at all what you want to do when charging a
battery. If temperature the charger senses is cooler than that of the
battery, it will overcharge the battery; if the temperature sensed is
higher than that of the battery, it will undercharge it. If the charger
has temperature compensation, it needs to sense the actual battery
temperature, and ideally, this means the electrolyte temperature, not
just the temperature of the case.
> I just did another charging test on this battery. Leaving
> the EV outside in the 0 degrees which was cold soaking for
> two hours. The Battery % indicator show it was 51 percent
> while only drawing 5 amps out of it for 8 minutes.
If I recall correctly, you are using a fairly large 12V battery. What
was its temperature and voltage after 2 hours?
I think the main problem you have is that you are placing way too much
faith in this battery % indicator. It sounds like the %indicator is
voltage-based, and it also sounded like it is built into the new
charger. A % indicator built into a charger almost certainly is not
meant to indicate accurately while you are drawing any current from the
battery, and will read low depending on how much voltage sag the load
results in. The voltage sag will increase as the battery becomes
cooler, so anything you do that warms the battery will make the %
indicator read higher when a load is applied.
This is a flooded battery, isn't it? Check the s.g. after charging in
the heated garage (I'm not going so suggest you do this outside in 0F!
;^). The battery is either fully charged, or it isn't; the % indicator
may lie, but s.g. won't.
Even 50A for 8 minutes isn't taking enough out of the battery (6.7Ah)
for it to read significantly below 100% SOC unless it is either a very
small battery or nearly shot (i.e. much less than nameplate capacity
even fully charged).
Get the battery fully charged inside the heated garage and verify the
s.g. indicates it is fully charged, then park the car outside for a few
hours. If the % indicator indicates significantly less than 100% at no
load or with some load on the battery when you check after the cold
soak, then you know the indicator is lying. It simply doesn't handle
temperature properly, and/or doesn't indicate properly while a load is
applied to the battery.
> The Smart charger must receiving the ambient temperature
> directly to the charger, not reading the battery temperature.
This is certainly possible. If the charger is to sense the battery
temperature, it must have a sensor that attatches to the battery. This
could be a separate wire from the charger, or the sensor might be
incorporated into one of the charger's output leads (which would
typically require that the charger's output cord include at least 3
wires).
The cheap/simple approach is for the charger to use a sensor that is
inside the charger's box, however, this means that at best it can sense
ambient temperature, and at worst, it will sense the charger's own
temperature, which can be quite a bit warmer than ambient while it is
operating! One charger I've seen compromises and has the temperature
sensor in a little rubber stalk that sticks out of the charger case
about 1-2". This keeps the charger's self-heating from affecting the
reading so much, but still relies on the assumption that the batteries
will be near ambient temperature.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Bob Rice wrote:
>> Our early customers will be out test pilots, telling us what to fix,
>> NOW! Get it right in the first few production models.
David Roden wrote:
> I hope they're getting their cars free in return for their help! ...
> I'm afraid the era when a manufacturer can use his customers as
> testers is over; consumers have high expectations these days.
I disagree. *ALL* manufacturers use their customers to do their testing. If
anything, they're doing it more than ever!
First, because in the mad rush to get things to market quickly, they eliminate
as much testing as possible. They depend more heavily on simulations and
quick-and-dirty tests.
Second, they depend heavily on part vendors to do all the testing. Many
companies receive parts from their vendors, put them directly into their
products, and ship them to customers with no testing whatsoever. It is common
to get products that never worked, and never COULD have worked due to missing
parts, incorrect assembly, etc.
Third, manufacturers routinely set up barriers to isolate themselves from
customer returns and warranty service. "Don't return it to us; return it to
the store where you bought it." And the store simply discards it; they are
under contract not to return anything. The store has to eat the cost of
giving you a replacement or your money back.
Fourth, customers are being trained NOT to return products, or complain when
things don't work. Customer service is offloaded to people who have nothing
to do with the company or product.
The result is that customers frequently *are* doing the final QC testing.
> Or perhaps I'm misunderstanding the comment?
Yes, I think you are. What I understand Bob and Jerry to be saying is that
they will build their EVs the best they know how; but that they know they
aren't perfect and so will miss things. So, they will keep the communication
channels open to the customers, so they will a) *design* their EV so it is
practical to fix and update it, b) *hear* about it when there are problems,
and c) take prompt to action to *fix* the problems.
That is a far cry better than most carmakers do!
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 [EMAIL PROTECTED]
--- End Message ---
--- Begin Message ---
Hello Roger,
I think the ambient temperature between the battery and the charger is what
making it error.
I had charge the battery to 100 percent and just move the EV outside for about
a two hours, but had to move it in. There is a white out blizzard condition
with blowing snow, and I did not want to open the compartments to charge the
battery outside.
So I move it in, took the battery temperature which was a 55 degrees, the
outside ambient temperature is 5 degrees.
The temperature in the garage to 70 degrees. I than using the smart charger,
the battery % read 62 percent. A drop in 38 percent while not using it. I
than charge it at 40 amps which finish charging the battery in 5 minutes and 22
seconds which show battery % of 100 percent! This is telling me that the
battery is not discharge that much, because it takes a lot longer to charge a
battery from 62 percent to 100 percent.
The battery was still cold at 62 degrees, did not gas or hardly bubble. The
battery is a Trojan 225S 12V deep cycle 130 AH.
The battery charger is a Schumacher Model No WM 1000A. It only has a Battery %
and a Voltage indicator.
Ampere selection is from 2 to 40 amps with Gel, AGM, and Deep Cycle selections.
There is no other adjustments to make.
My next test is to lower the garage temperature to 65 degrees and let the
battery set in that temperature for 16 hours before I charge it to see what
happens.
Roland
----- Original Message -----
From: Roger Stockton<mailto:[EMAIL PROTECTED]>
To: [email protected]<mailto:[email protected]>
Sent: Monday, December 05, 2005 4:00 PM
Subject: RE: Am I Killing Batteries?(+)
Roland Wiench [mailto:[EMAIL PROTECTED] wrote:
> Roger, I understand that the battery that the battery is
> charged at the temperature it is at.
OK; it is just that what you seemed to be suggesting is that the charger
needs to know what the *outside* temperature is so that it can charge
the battery properly for use in that temperature, even though the
battery is sitting in a heated garage while being charged.
This, of course, is not at all what you want to do when charging a
battery. If temperature the charger senses is cooler than that of the
battery, it will overcharge the battery; if the temperature sensed is
higher than that of the battery, it will undercharge it. If the charger
has temperature compensation, it needs to sense the actual battery
temperature, and ideally, this means the electrolyte temperature, not
just the temperature of the case.
> I just did another charging test on this battery. Leaving
> the EV outside in the 0 degrees which was cold soaking for
> two hours. The Battery % indicator show it was 51 percent
> while only drawing 5 amps out of it for 8 minutes.
If I recall correctly, you are using a fairly large 12V battery. What
was its temperature and voltage after 2 hours?
I think the main problem you have is that you are placing way too much
faith in this battery % indicator. It sounds like the %indicator is
voltage-based, and it also sounded like it is built into the new
charger. A % indicator built into a charger almost certainly is not
meant to indicate accurately while you are drawing any current from the
battery, and will read low depending on how much voltage sag the load
results in. The voltage sag will increase as the battery becomes
cooler, so anything you do that warms the battery will make the %
indicator read higher when a load is applied.
This is a flooded battery, isn't it? Check the s.g. after charging in
the heated garage (I'm not going so suggest you do this outside in 0F!
;^). The battery is either fully charged, or it isn't; the % indicator
may lie, but s.g. won't.
Even 50A for 8 minutes isn't taking enough out of the battery (6.7Ah)
for it to read significantly below 100% SOC unless it is either a very
small battery or nearly shot (i.e. much less than nameplate capacity
even fully charged).
Get the battery fully charged inside the heated garage and verify the
s.g. indicates it is fully charged, then park the car outside for a few
hours. If the % indicator indicates significantly less than 100% at no
load or with some load on the battery when you check after the cold
soak, then you know the indicator is lying. It simply doesn't handle
temperature properly, and/or doesn't indicate properly while a load is
applied to the battery.
> The Smart charger must receiving the ambient temperature
> directly to the charger, not reading the battery temperature.
This is certainly possible. If the charger is to sense the battery
temperature, it must have a sensor that attatches to the battery. This
could be a separate wire from the charger, or the sensor might be
incorporated into one of the charger's output leads (which would
typically require that the charger's output cord include at least 3
wires).
The cheap/simple approach is for the charger to use a sensor that is
inside the charger's box, however, this means that at best it can sense
ambient temperature, and at worst, it will sense the charger's own
temperature, which can be quite a bit warmer than ambient while it is
operating! One charger I've seen compromises and has the temperature
sensor in a little rubber stalk that sticks out of the charger case
about 1-2". This keeps the charger's self-heating from affecting the
reading so much, but still relies on the assumption that the batteries
will be near ambient temperature.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
The temperature sensor I am using is a sensor that attaches to the lead post,
like the Emeter uses. I also check it against a remote bulb sensor that plugs
into my multimeter. I also have a Stewart Temperature Meter on the dash that
reads from 0 to 600 degrees using the same type of bolt on sensor.
Roland
----- Original Message -----
From: Dewey, Jody R ATC (CVN75 IM3)<mailto:[EMAIL PROTECTED]>
To: '[email protected]'<mailto:'[email protected]'>
Sent: Monday, December 05, 2005 4:11 PM
Subject: RE: Am I Killing Batteries?(+)
Does anyone make a temp sensor that sits IN the electrolyte? I would think
that would be the best way to read the temperature of the battery.
-----Original Message-----
From: Roger Stockton [mailto:[EMAIL PROTECTED]
Sent: Monday, December 05, 2005 6:01 PM
To: [email protected]<mailto:[email protected]>
Subject: RE: Am I Killing Batteries?(+)
Roland Wiench [mailto:[EMAIL PROTECTED] wrote:
> Roger, I understand that the battery that the battery is
> charged at the temperature it is at.
OK; it is just that what you seemed to be suggesting is that the charger
needs to know what the *outside* temperature is so that it can charge
the battery properly for use in that temperature, even though the
battery is sitting in a heated garage while being charged.
This, of course, is not at all what you want to do when charging a
battery. If temperature the charger senses is cooler than that of the
battery, it will overcharge the battery; if the temperature sensed is
higher than that of the battery, it will undercharge it. If the charger
has temperature compensation, it needs to sense the actual battery
temperature, and ideally, this means the electrolyte temperature, not
just the temperature of the case.
> I just did another charging test on this battery. Leaving
> the EV outside in the 0 degrees which was cold soaking for
> two hours. The Battery % indicator show it was 51 percent
> while only drawing 5 amps out of it for 8 minutes.
If I recall correctly, you are using a fairly large 12V battery. What
was its temperature and voltage after 2 hours?
I think the main problem you have is that you are placing way too much
faith in this battery % indicator. It sounds like the %indicator is
voltage-based, and it also sounded like it is built into the new
charger. A % indicator built into a charger almost certainly is not
meant to indicate accurately while you are drawing any current from the
battery, and will read low depending on how much voltage sag the load
results in. The voltage sag will increase as the battery becomes
cooler, so anything you do that warms the battery will make the %
indicator read higher when a load is applied.
This is a flooded battery, isn't it? Check the s.g. after charging in
the heated garage (I'm not going so suggest you do this outside in 0F!
;^). The battery is either fully charged, or it isn't; the % indicator
may lie, but s.g. won't.
Even 50A for 8 minutes isn't taking enough out of the battery (6.7Ah)
for it to read significantly below 100% SOC unless it is either a very
small battery or nearly shot (i.e. much less than nameplate capacity
even fully charged).
Get the battery fully charged inside the heated garage and verify the
s.g. indicates it is fully charged, then park the car outside for a few
hours. If the % indicator indicates significantly less than 100% at no
load or with some load on the battery when you check after the cold
soak, then you know the indicator is lying. It simply doesn't handle
temperature properly, and/or doesn't indicate properly while a load is
applied to the battery.
> The Smart charger must receiving the ambient temperature
> directly to the charger, not reading the battery temperature.
This is certainly possible. If the charger is to sense the battery
temperature, it must have a sensor that attatches to the battery. This
could be a separate wire from the charger, or the sensor might be
incorporated into one of the charger's output leads (which would
typically require that the charger's output cord include at least 3
wires).
The cheap/simple approach is for the charger to use a sensor that is
inside the charger's box, however, this means that at best it can sense
ambient temperature, and at worst, it will sense the charger's own
temperature, which can be quite a bit warmer than ambient while it is
operating! One charger I've seen compromises and has the temperature
sensor in a little rubber stalk that sticks out of the charger case
about 1-2". This keeps the charger's self-heating from affecting the
reading so much, but still relies on the assumption that the batteries
will be near ambient temperature.
Cheers,
Roger.
--- End Message ---
