Lithium or not, that is the question

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Lithium or not, that is the question

Buddy Mills @ Cox.net
I have come to a dilemma that I hope the list serve can help with because
many of you have already then in my place.  I have read many emails on here
about increase mileage with the switch over from lead to lithium.
Presently I have 15 Deka 831Gel (180 volts, 100AH -18KW), four in place of
the radiator, 4 in place of the gas tank and 7 in place of the rear seat.
The weight is about 1080 lbs total.  If I go to Lithium I could lose about
420 lbs storing them in place of the gas tank and rear seat.   At present I
get a good 30 miles per charge and if I push it have gone 37.  I have the
Azure DMOC and AC motor with regen and it is set to pull max of 200amps.
Personal observation shows that I have taken it down to 75% DOD but mostly
around 50%.  I have noticed a lot of sag with these Dekas.  At present I
cannot drive to work, 42 miles one way. 30 miles interstate.   I would like
anyone to weigh in on  the following questions/concerns before I talk to
sales type person.  

1.       What is a reasonable amount of miles increase would I expect if I
stayed at the same voltage and AH?

2.       Will the decrease in weight really make a noticeable difference?

3.       How much sag can I expect.

4.       Does anyone know if the Azure 24 will hold up to daily use, one
hour twice a  day?

5.       Does Lithium play well with regen?

6.       Will I need to turn regen off when at the top of the charge or will
the BMS take care of it.?

Any other advice before I invest $10K to $15K

 

Thanks in advance.

 

Buddy Mills

 <mailto:[hidden email]> [hidden email]

 

Look mom, no gas.  <http://www.evalbum.com/2887> http://www.evalbum.com/2887

 

Disclaimer:  No animals were harmed or killed in the process of writing this
email.  Any stories to the contrary are, for the most part, either fictional
or greatly exaggerated.

 

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Re: Lithium or not, that is the question

Peter C. Thompson-2
Hi Buddy,

I have put 2000 miles on a DMOC445 and AC24.  I did like the motor, but
I have a mid-engine car that is notorious for bad airflow - not a good
idea for really hot areas like San Diego.  Once I got the controller
dialed in, I was satisfied with it.  I've never been very satisfied with
the power - I can do freeway speeds, but there is no acceleration left
at 70 mph - again, not a good idea for San Diego (they drive rather
aggressively here).

Short version:  keep your AC24 where there is good airflow, and you are
going to ok.

(I'm replacing it with an 80kw BLDC motor that is liquid cooled and 2x
power).

More below.

Cheers,
     Peter

On 3/4/12 9:45 AM, Buddy Mills wrote:

> I have come to a dilemma that I hope the list serve can help with because
> many of you have already then in my place.  I have read many emails on here
> about increase mileage with the switch over from lead to lithium.
> Presently I have 15 Deka 831Gel (180 volts, 100AH -18KW), four in place of
> the radiator, 4 in place of the gas tank and 7 in place of the rear seat.
> The weight is about 1080 lbs total.  If I go to Lithium I could lose about
> 420 lbs storing them in place of the gas tank and rear seat.   At present I
> get a good 30 miles per charge and if I push it have gone 37.  I have the
> Azure DMOC and AC motor with regen and it is set to pull max of 200amps.
> Personal observation shows that I have taken it down to 75% DOD but mostly
> around 50%.  I have noticed a lot of sag with these Dekas.  At present I
> cannot drive to work, 42 miles one way. 30 miles interstate.   I would like
> anyone to weigh in on  the following questions/concerns before I talk to
> sales type person.
>
> 1.       What is a reasonable amount of miles increase would I expect if I
> stayed at the same voltage and AH?
This is difficult to say, but dropping 420 pounds would help a little on
your energy usage.  I don't know how much tho - I'll let the experts
weigh in on this.  :)
>
> 2.       Will the decrease in weight really make a noticeable difference?
Yes.  Your acceleration will be faster.  Your energy usage will drop a
little.
>
> 3.       How much sag can I expect.
I have a 370v, 60Ah pack, and the sag I get is from 370v to 330 or
340v.  This is pulling 150a.
>
> 4.       Does anyone know if the Azure 24 will hold up to daily use, one
> hour twice a  day?
Yes, no question there.
>
> 5.       Does Lithium play well with regen?
Yes.  I have CALB 60Ah batteries - no issues from the 2000 miles so far.
>
> 6.       Will I need to turn regen off when at the top of the charge or will
> the BMS take care of it.?
The controller will do that.  Set the max voltage, and you are good.  
Even better if your BMS can work with the controller.
>
> Any other advice before I invest $10K to $15K
Why stay with 100Ah batteries?  Why not go for 180Ah or 200Ah?  That
will easily take care of your range problem.  :)

However, do the math - find out what your Wh/mile are for worst case,
find out your worst case daily drive situation, and that will tell you
how Wh you need from your pack.  If you can keep your pack to 70% DOD,
you will get about 3000 cycles out of them (according to CALB).

Invest in a good BMS at the same time.  Please note this is a bit of a
religious issue, and some people don't believe in them.  As you might
guess, I DO believe in them.

>
>
>
> Thanks in advance.
>
>
>
> Buddy Mills
>
>   <mailto:[hidden email]>  [hidden email]
>
>
>
> Look mom, no gas.<http://www.evalbum.com/2887>  http://www.evalbum.com/2887
>
>
>
> Disclaimer:  No animals were harmed or killed in the process of writing this
> email.  Any stories to the contrary are, for the most part, either fictional
> or greatly exaggerated.
>
>
>
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Re: Lithium or not, that is the question

Willie2
In reply to this post by Buddy Mills @ Cox.net
On Sun, Mar 04, 2012 at 12:45:29PM -0500, Buddy Mills wrote:

> 1.       What is a reasonable amount of miles increase would I expect if I
> stayed at the same voltage and AH?

With the same weight, you should expect about three times the range
with lithium.  Rather than trying to match your lead pack in capacity,
I recommend increasing your range.  With the wide range of available
lithium cell sizes, you can easily tailor your pack to desired capacity
and voltage.

> 3.       How much sag can I expect.

"Cheap" LFPs should give you more than 2C without noticeable sag (in
warm weather).  Match the cell size to your current need.  If you need
only 200 amps, any cell 100ah or larger should do it.  Again, I
recommend the largest cell you can afford and fit in.  I can pull more
than 600 amps from 260ah cells.  I never need that much; I could get
by with maybe as little as 300 amps; that would indicate cells as small
as 160ah but probably not 100ah.

Maximum lithium life is supposed to be achieved by keeping discharges
above 30% SOC.  Going down to 20% regularly still is supposed to give
you far more life than lead.  As long as single cells are kept above
about 3v, discharges to 0% SOC are not fatal.  A new lithium pack is
highly likely to have about 110% of rated capacity.

--
Willie, ONWARD!  Through the fog!
http://counter.li.org Linux registered user #228836 since 1995
Debian3.1/GNU/Linux system uptime  39 days  7 hours 43 minutes

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Re: Lithium or not, that is the question

fred ungewitter
My experiences with my rather-lightweight Gizmo is just as Willie suggests. I've easily tripled my range, although I did increase pack capacity from 48v x 196 ah (lead) to 60v x 180 ah. Despite the increase in capacity, 300 pounds of "ballast" is no longer aboard, which has improved acceleration and braking as well. The lead pack would not provide 48v to 196ah, as the voltage drop is excessive compared to LiFePO4, and the practical safe depth of discharge is much higher. I rarely pulled more than 50 percent from the lead pack.


I'm using CALB cells, which are purported to be able to handle 3C and better, but I'll never put that much of a load on the pack. I may drag the SOC to 20 percent now and then, but even at that level, I probably won't be on the planet long enough to put the cycles into the pack. I might drive the Gizmo one to two times a week, 3-10 miles (currently) as I'm a velomobile driver (human powered vehicle), but I went with the massive capacity and massive capability, as I will likely not be able to pedal 200 miles a week in my sunset years and the Gizmo is a perfect sunset vehicle for me.

I don't regret for a moment having spent the big bucks on LiFePO4.



________________________________
 From: Willie McKemie <[hidden email]>
To: Electric Vehicle Discussion List <[hidden email]>
Sent: Sunday, March 4, 2012 3:15 PM
Subject: Re: [EVDL] Lithium or not, that is the question
 
On Sun, Mar 04, 2012 at 12:45:29PM -0500, Buddy Mills wrote:

> 1.       What is a reasonable amount of miles increase would I expect if I
> stayed at the same voltage and AH?

With the same weight, you should expect about three times the range
with lithium.  Rather than trying to match your lead pack in capacity,
I recommend increasing your range.  With the wide range of available
lithium cell sizes, you can easily tailor your pack to desired capacity
and voltage.

> 3.       How much sag can I expect.

"Cheap" LFPs should give you more than 2C without noticeable sag (in
warm weather).  Match the cell size to your current need.  If you need
only 200 amps, any cell 100ah or larger should do it.  Again, I
recommend the largest cell you can afford and fit in.  I can pull more
than 600 amps from 260ah cells.  I never need that much; I could get
by with maybe as little as 300 amps; that would indicate cells as small
as 160ah but probably not 100ah.

Maximum lithium life is supposed to be achieved by keeping discharges
above 30% SOC.  Going down to 20% regularly still is supposed to give
you far more life than lead.  As long as single cells are kept above
about 3v, discharges to 0% SOC are not fatal.  A new lithium pack is
highly likely to have about 110% of rated capacity.

--
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Re: Lithium or not, that is the question

matt lacey-2
In reply to this post by Buddy Mills @ Cox.net
Hi Buddy,

> Presently I have 15 Deka 831Gel (180 volts, 100AH -18KW), four in place of
> the radiator, 4 in place of the gas tank and 7 in place of the rear seat.
> The weight is about 1080 lbs total.  If I go to Lithium I could lose about
> 420 lbs storing them in place of the gas tank and rear seat.   At present
> I
> get a good 30 miles per charge and if I push it have gone 37.  I have the
> Azure DMOC and AC motor with regen and it is set to pull max of 200amps.

with the DMOC, I highly suggest going to 300V for more power.

200A is easy enough, just don't go any smaller than 60Ah cells.

with regen, just set the max voltage to 3.6v x number of cells

How many Ah does your present battery actually deliver now?

At interstate speeds, most of the energy is used pushing air out of the way,
so a decrease in weight doesn't reduce the energy requirement much.
What will improve your range is increasign usable capacity.

I wouldn't normally expect a 180V 100Ah lead pack to deliver more than 9kwh,
but it rather depends upon how you are measuring DOD
If you don't already have an Ah counter, I highly recommend installing
something like a cycle analyst to get a handle on your present Wh/mile (and
battery capacity)

A 90 cell 288V 60Ah pack can deliver 14kwh of usable capacity for $6500 +
$500 charger (Elcon 1500W) + $1200 in BMS

You can of course go larger, $10K can get you 288V 70Ah (16 kwh) , $15K can
get you 288V 130Ah (29 kwh)

You could bottom balance the cells intially and install the BMS at a later
date.
The cell matching process the major LiFePO4 manuacturers use result in cells
that are matched to within 2% of capacity


Matt

----- Original Message -----
From: "Buddy Mills" <[hidden email]>
To: <[hidden email]>
Sent: Monday, March 05, 2012 1:45 AM
Subject: [EVDL] Lithium or not, that is the question


>I have come to a dilemma that I hope the list serve can help with because
> many of you have already then in my place.  I have read many emails on
> here
> about increase mileage with the switch over from lead to lithium.
> Presently I have 15 Deka 831Gel (180 volts, 100AH -18KW), four in place of
> the radiator, 4 in place of the gas tank and 7 in place of the rear seat.
> The weight is about 1080 lbs total.  If I go to Lithium I could lose about
> 420 lbs storing them in place of the gas tank and rear seat.   At present
> I
> get a good 30 miles per charge and if I push it have gone 37.  I have the
> Azure DMOC and AC motor with regen and it is set to pull max of 200amps.
> Personal observation shows that I have taken it down to 75% DOD but mostly
> around 50%.  I have noticed a lot of sag with these Dekas.  At present I
> cannot drive to work, 42 miles one way. 30 miles interstate.   I would
> like
> anyone to weigh in on  the following questions/concerns before I talk to
> sales type person.
>
> 1.       What is a reasonable amount of miles increase would I expect if I
> stayed at the same voltage and AH?
>
> 2.       Will the decrease in weight really make a noticeable difference?
>
> 3.       How much sag can I expect.
>
> 4.       Does anyone know if the Azure 24 will hold up to daily use, one
> hour twice a  day?
>
> 5.       Does Lithium play well with regen?
>
> 6.       Will I need to turn regen off when at the top of the charge or
> will
> the BMS take care of it.?
>
> Any other advice before I invest $10K to $15K
>
>
>
> Thanks in advance.
>
>
>
> Buddy Mills
>
> <mailto:[hidden email]> [hidden email]
>
>
>
> Look mom, no gas.  <http://www.evalbum.com/2887>
> http://www.evalbum.com/2887
>
>
>
> Disclaimer:  No animals were harmed or killed in the process of writing
> this
> email.  Any stories to the contrary are, for the most part, either
> fictional
> or greatly exaggerated.
>
>
>
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> | Please take those discussions elsewhere.  Thanks.
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> | REPLYING: address your message to [hidden email] only.
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Re: Lithium or not, that is the question

martinwinlow
In reply to this post by Buddy Mills @ Cox.net

On 4 Mar 2012, at 17:45, Buddy Mills wrote:

> I have come to a dilemma that I hope the list serve can help with because
> many of you have already then in my place.  I have read many emails on here
> about increase mileage with the switch over from lead to lithium.
> Presently I have 15 Deka 831Gel (180 volts, 100AH -18KW), four in place of
> the radiator, 4 in place of the gas tank and 7 in place of the rear seat.
> The weight is about 1080 lbs total.  If I go to Lithium I could lose about
> 420 lbs storing them in place of the gas tank and rear seat.   At present I
> get a good 30 miles per charge and if I push it have gone 37.  I have the
> Azure DMOC and AC motor with regen and it is set to pull max of 200amps.
> Personal observation shows that I have taken it down to 75% DOD but mostly
> around 50%.  I have noticed a lot of sag with these Dekas.  At present I
> cannot drive to work, 42 miles one way. 30 miles interstate.   I would like
> anyone to weigh in on  the following questions/concerns before I talk to
> sales type person.  
>
> 1.       What is a reasonable amount of miles increase would I expect if I
> stayed at the same voltage and AH?
> 2.       Will the decrease in weight really make a noticeable difference?
> 3.       How much sag can I expect.
> 4.       Does anyone know if the Azure 24 will hold up to daily use, one
> hour twice a  day?
> 5.       Does Lithium play well with regen?
> 6.       Will I need to turn regen off when at the top of the charge or will
> the BMS take care of it.?
> Any other advice before I invest $10K to $15K
> Thanks in advance.
> Buddy Mills
> <mailto:[hidden email]> [hidden email] Look mom, no gas.  <http://www.evalbum.com/2887> http://www.evalbum.com/2887

Buddy,

1. As others have said you will double to tripple your range.  Your Wh/mile is pretty poor, even if you could still do 30 miles. That equates to 600Wh/m for your 18kWh pack.  That is probably the worst one I have seen.  Are you sure you haven't got a sticking brake or something?

2.  If you imgagine driving your original truck (before it was converted) with 5 really fat guys (330lbs each) in the truck with you (I am assuming you are a svelte, lithe, athletic chap, much like myself) you will get some idea of how much difference reducing your pack weight from 3k lbs of Pb-A to 400 lbs of LiFePO4 (56 x 100Ah at 7lbs each).

3.  Sag depends on how much current you are pulling and battery temperature.  In the fisrt case it is much less with Li - perhaps only 10% of PB-A - in the second I have no idea but probaly much the same - so if you live somewhere cold in winter, heat your pack(s).  My favourite method is a battery box  insulated with bubble wrap-type insulation, which is very thin and heated with a domestic electric blanket.  Having small Li cells like the 100Ah ones may give you heating problems due to the relatively high C draw.  So, be mindful that you may need to cool (ventilate) the cells as well as heat them.  If you want to be really cunning, you coulld use 2 small (cot) ones designed for 110VAC and wire them so that when the car is plugged into the mains they use mains power and when disconnected they use pack power - tho your pack volts may be a little high...

4. Can't help you here.

5.  Ditto but I would have thought the controler (if that is what is controlling the regen) will have a max regen volts setting to limit how much juice goes back into the cells.

6.  See 5.

10k would be more than enough if you do use 100Ah cells - $8k (inc BMS).  My preference would be 160Ah cells which give much greater flexibility on the C rating - for both discharge and charge/regen - particularly for a relatively large vehicle, will allow for an upgrade in controller power (if needed one day) and of course will improve your range and reduce the aging rate on your pack overall.  But can you afford $11k?

Best of luck whatever route you choose.

Regards, Martin Winlow
Herts, UK
http://www.evalbum.com/2092
www.winlow.co.uk




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Re: Lithium or not, that is the question

Lee Hart
This is indeed a complicated question. It's easy to get off-the-cuff
answers that "lithium will triple your range"; but that's only going to
be true under certain circumstances. There could also be cases where you
get *less* range.

Cost is also a major factor. Your battery cost per mile can also go up
significantly with lithium if you're not careful.

Buddy Mills wrote:
> 1. What is a reasonable amount of miles increase would I expect if I
>    stayed at the same voltage and AH?

If the voltage and amphour capacity is the same *at the current loads
you normally draw*, then changing the type of battery won't change the
range.

But amphour capacity changes with load current. Your present "100ah"
batteries are probably only 100ah at the 20-hour rate (5 amps), and you
aren't using them at anything even close to this. Look up or measure its
actual capacity at the currents you normally draw.

For example, if it's a Deka "Dominator" 8G31, it is rated at
        97.6ah at the 20-hour rate (4.88 amps for 20 hours)
        64.5ah at the 1-hour rate (64.5 amps for 1 hour)
If your range is 37 miles at best, it's likely that you're drawing more
like 100 amps average, which means your pack is only good for perhaps 50
amphours.

This fall-off in amphour capacity versus current is called the Peukert
effect. It's presesnt in all types of batteries, but most noticeable in
lead-acids because their internal resistance rises as they run discharge.

If the proposed lithium pack provided 100ah *at 100 amps*, then you
would indeed get double the range. But not triple.

Note that the lithiums will also have a reduction in capacity as the
load current increases. You'll need data or curves for the actual cells
you'd use; "rules of thumb" will be a waste of time.

> 2. Will the decrease in weight really make a noticeable difference?

Weight usually doesn't make much difference. There are three factors
that determine the power your EV needs to move; friction, rolling
resistance, and aerodynamic drag. Aerodynamic drag is usually the
largest of these, and it isn't affected by weight.

Rolling resistance is about 1/3th of the total, and is proportional to
weight; but it's the percent change in the entire vehicle's weight that
matters. For example, say your EV's total weight is 3000 lbs including
1000 lbs of batteries. You change it to 50 lbs of lithiums, so it now
weighs 2500 lbs total. The weight is reduced 2500/3000 = 83% (17% less).
1/3rd of that is 5.5%; so the weight loss gives you about 5.5% more range.

This will be more if you drive at very low speeds so wind resistance
doesn't matter, or if you have lots of hills or like jackrabbit starts.
(Though your controller does have regen; this helps reduce the effects
of hills and fast starts).

> 3. How much sag can I expect.

That depends dramatically on the particular battery!

The gels you have are particularly bad. They have a higher internal
resistance than flooded or AGM lead-acid batteries. You are also
apparently using a marine/RV type, which is also bad for EV use. So I
would expect your voltage sag to be quite severe at high currents.

Lithiums will be all over the map as well. Some types have extremely low
internal resistance; and some are just as high as your gels. You really
have to know what you're getting! Don't be swayed by marketing claims or
anecdotal evidence!

> 4. Does anyone know if the Azure 24 will hold up to daily use, one
>    hour twice a  day?

I have no direct experience, but they seem to be reasonably well made
controllers.

> 5. Does Lithium play well with regen?

Yes. However, you will need a BMS to be sure you never overvoltage the
cells!

> 6. Will I need to turn regen off when at the top of the charge or will
>    the BMS take care of it.?

The BMS had *better* take care of it. Otherwise, you have the risk of a
fire!

--
Opportunity is missed by most people because it is dressed in overalls
and looks like work. -- Thomas A. Edison
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart at earthlink.net

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Re: Lithium or not, that is the question

David Nelson-5
On Mon, Mar 5, 2012 at 1:16 PM, Lee Hart <[hidden email]> wrote:
> Note that the lithiums will also have a reduction in capacity as the
> load current increases. You'll need data or curves for the actual cells
> you'd use; "rules of thumb" will be a waste of time.

Unless you over size your pack a little then the variation in the
"rules of thumb" from reality will be lost in the "noise".

>> 2. Will the decrease in weight really make a noticeable difference?
>
> Weight usually doesn't make much difference. There are three factors
[snip]
> 1/3rd of that is 5.5%; so the weight loss gives you about 5.5% more range.

My _one_ test with a weight increase of 18% resulted in only an 11%
increase in energy usage for hills and stop and go driving. Tested
with my LiFePO4 pack.

>> 3. How much sag can I expect.
>
> That depends dramatically on the particular battery!

Including brand, formulation, and Ah size.

>
> Lithiums will be all over the map as well. Some types have extremely low
> internal resistance; and some are just as high as your gels. You really
> have to know what you're getting! Don't be swayed by marketing claims or
> anecdotal evidence!

My pack sags significantly more when the batteries are below 10°C than
when above that but they sag significantly less than the flooded lead
acid pack I replaced. Understand, however, that I sized my pack at
200Ah, just over the 255Ah flooded pack at the 20hr rate, so my max
battery current of 4-500A is at most 2.5C which is well below the 3C
rating of my TS batteries. If you size your pack smaller than this you
will see more sag.

>> 5. Does Lithium play well with regen?
>
> Yes. However, you will need a BMS to be sure you never overvoltage the
> cells!

Most definitely! The resistance is so low that I don't see much
voltage rise during regen. Again I have a 200Ah pack an regen is at
most 200A on my rig but usually down around 100A or less. I also have
my controller programmed to not allow the terminal voltage to go above
3.6vpc. I also only charge to just below 3.5vpc. I have never had my
controller cutback regen due to pack voltage going high. I also have
not needed a BMS to protect the pack. I have a top balanced pack with
a variation to Lee Harts batt-bridge and have never seen the pack
voltage balance be off more than 0.05V under regen and 0.14V under
load at around 10%SOC. We will see in time if balance becomes an issue
but my 2.5 year old pack has yet to show any signs of getting out of
balance. Note again that I am only talking about LiFePO4 cells and not
any other type of cell. Also note that I do not have an undersized
pack.

>> 6. Will I need to turn regen off when at the top of the charge or will
>>    the BMS take care of it.?
>
> The BMS had *better* take care of it. Otherwise, you have the risk of a
> fire!

If you are talking about LiFePO4 that is properly sized you are very
unlikely to ever have to have regen turned off unless you live at the
top of a long hill and you have practically not driving power needed
to get started down the hill and have just charged your pack to the
very top.

To give you an idea of what is going on in my particular case my rig
uses ~2.5Ah/mile. If I were to drive for a mile and then coast down a
hill I could coast for 1.5 minutes at 100A of regen current before I
replenished that 2.5Ah. In my case that would have to be an extremely
steep hill to maintain that high of regen current. This would likely
represent at least 2000 feet of elevation drop, too.

Unless your controller has a regen inhibit input that the BMS can
signal you probably won't have the BMS take care of it. Just make sure
your controller is set to a max voltage of 3.6vpc or if you are
concerned about it lower that to 3.5vpc or even 3.4vpc. Unless you
have a grossly out of balance pack it will be just fine with no BMS
intervention.

--
David D. Nelson
http://evalbum.com/1328
http://2003gizmo.blogspot.com

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Re: Lithium or not, that is the question

tomw
This post was updated on .
In reply to this post by Buddy Mills @ Cox.net
1.       What is a reasonable amount of miles increase would I expect if I
stayed at the same voltage and AH?
>>  I haven't switched from lead to lithium, so others can answer that better.

2.       Will the decrease in weight really make a noticeable difference?
>> The drag force is equal to rolling resistance force at about 45 mph or so for a sedan, so decrease in weight will mainly affect performance at lower speeds, and is not a huge effect since as Lee said it is the percentage weight increase/decrease relative to weight of the entire car.

3.       How much sag can I expect.
>> At 3C discharge (540A from my 180Ah cells) my pack sags from around 117-119V to around 100-105V, when near full charge.  My pack is heated when the car is parked, so it is always above 50 F, usually above 60 F.  The above sag is for about 65 F.

4.       Does anyone know if the Azure 24 will hold up to daily use, one
hour twice a  day?
>>Jeez, I would hope so. Does the warranty state something like only good for < 1 hr/day? :^))

5.       Does Lithium play well with regen?
>> Yes.  My pack is top balanced, and I have the max regen pack voltage set in my controller software so that no cell will exceed 3.47V - as long as it doesn't become too imbalanced.  If I go down a hill near my house (after about 0.2 mile drive) with a full charge the car coasts freely when I get toward the bottom with regen limited by the controller.  Similarly, if I have driven only a few miles after a full charge and give full regen during a panic stop from around 50 mph or higher, the charger will limit regen because the current is so high it drives the pack V up to the limit voltage.   You can set the limit voltage to whatever you like.  My bms has no option for controlling regen.  A bottom balanced pack would require special attention, as you have to set the regen voltage limit to ensure your highest voltage cell will not be overcharged.
 
6.       Will I need to turn regen off when at the top of the charge or will
the BMS take care of it.?
>> See above.  The controller should do it.  However, I usually don't require a full charge, so many times I just charge to within 7 -10Ah of full so the controller doesn't need to limit regen. Also, you can always take it out of gear and coast if you have a transmission.
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Re: Lithium or not, that is the question

RightHand Engineering-2
In reply to this post by Buddy Mills @ Cox.net

I'll give you my experience in range increase.
My 2001 GMC Sonoma DC conversion originally used 24 T145 "260 Ahr" wet PbA golf cart batteries. The total vehicle weight was 5000 lb. On my best days (warm, batteries pretty new) I was able to get 40 miles out of them, but only by going to under 20% SOC. And on those 40 mile days I was creaping home (that prompted me to take the EV sticker off my vehicle because I didn't want to give EVs a bad name). During cold weather my range was often more like 25 miles, and this gradually reduced as my batteries aged.
 
Last year I converted to 48 Winston 180 Ahr LiFePO4 cells (roughtly the same 144V as my old pack). The vehicle weight was reduced by 1000 lb. Last week I pulled 75 miles on a charge. My Link-10/E-Meter showed I used up all 180 Ahrs, but I was still well above the low voltage limit of my cells and I had no noticable reduction in vehicle power. The battery temp was about 55F. When my Li batteries are in the 30F-40F temp range, I do notice some reduction in power/range, but not more than 20% reduction (if a dependable range is important to you, I agree with others that you should consider keeping your batteries heated while plugged in).
 
So my range increase is close to 2x of my best PbA days, and 3x of my worst PbA days.
 
When I bought the batteries from Manzanita, they did a capacity test on a group of 4 cells and these 180 Ahr batteries measured around 240 Ahrs. But for the sake of longevity, I still treat them batteries with a 180 Ahr usable capacity.
 
I attribute the range increase to reduced weight and the vastly improved power curve (power vs. SOC) of LiFePO4.
 
I have nothing to add to the other questions that others have answered.
 
Regards,
Randy Richmond
http://evalbum.com/1253
 

> From: [hidden email]
> To: [hidden email]
> Date: Sun, 4 Mar 2012 12:45:29 -0500
> Subject: [EVDL] Lithium or not, that is the question
>
> I have come to a dilemma that I hope the list serve can help with because
> many of you have already then in my place. I have read many emails on here
> about increase mileage with the switch over from lead to lithium.
> Presently I have 15 Deka 831Gel (180 volts, 100AH -18KW), four in place of
> the radiator, 4 in place of the gas tank and 7 in place of the rear seat.
> The weight is about 1080 lbs total. If I go to Lithium I could lose about
> 420 lbs storing them in place of the gas tank and rear seat. At present I
> get a good 30 miles per charge and if I push it have gone 37. I have the
> Azure DMOC and AC motor with regen and it is set to pull max of 200amps.
> Personal observation shows that I have taken it down to 75% DOD but mostly
> around 50%. I have noticed a lot of sag with these Dekas. At present I
> cannot drive to work, 42 miles one way. 30 miles interstate. I would like
> anyone to weigh in on the following questions/concerns before I talk to
> sales type person.
>
> 1. What is a reasonable amount of miles increase would I expect if I
> stayed at the same voltage and AH?
>
> 2. Will the decrease in weight really make a noticeable difference?
>
> 3. How much sag can I expect.
>
> 4. Does anyone know if the Azure 24 will hold up to daily use, one
> hour twice a day?
>
> 5. Does Lithium play well with regen?
>
> 6. Will I need to turn regen off when at the top of the charge or will
> the BMS take care of it.?
>
> Any other advice before I invest $10K to $15K
>
>
>
> Thanks in advance.
>
>
>
> Buddy Mills
>
> <mailto:[hidden email]> [hidden email]
>
>
>
> Look mom, no gas. <http://www.evalbum.com/2887> http://www.evalbum.com/2887
>
>
>
> Disclaimer: No animals were harmed or killed in the process of writing this
> email. Any stories to the contrary are, for the most part, either fictional
> or greatly exaggerated.
>
>
>
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> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere. Thanks.
> |
> | REPLYING: address your message to [hidden email] only.
> | Multiple-address or CCed messages may be rejected.
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|
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Re: Lithium or not, that is the question

tomw
Good data!  Do you mean CALB 180Ah cells (blue), or Winston 160Ah (yellow) - Winston doesn't make 180.
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Re: Lithium or not, that is the question

Pestka, Dennis J
In reply to this post by RightHand Engineering-2
Randy;

Thanks for the great information.

I'm considering a very similar Lithium transplant for my 65 Datsun.
(48) of the 180aH CALBS to replace my (13) 70aH Odysseys.
I should be able to shed ~ 250#, so after completed it should weigh in the ~ 2800# range.
I use ~ 275 WH per mile now with ~ 20 mile range.
With the Lithiums', my range should be at least as good as yours.
70 miles would be fantastic, and would let me travel to all the places I'd like to now, but can't.
 
This real life data you provided is extremely helpful with the decision making process.
Just need to scrape up the $$

Dennis                                            
Elsberry, MO                              
http://www.evalbum.com/1366 
                                              





-----Original Message-----
From: RightHand Engineering [mailto:[hidden email]]
Sent: Tuesday, March 06, 2012 3:43 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Lithium or not, that is the question


I'll give you my experience in range increase.
My 2001 GMC Sonoma DC conversion originally used 24 T145 "260 Ahr" wet PbA golf cart batteries. The total vehicle weight was 5000 lb. On my best days (warm, batteries pretty new) I was able to get 40 miles out of them, but only by going to under 20% SOC. And on those 40 mile days I was creaping home (that prompted me to take the EV sticker off my vehicle because I didn't want to give EVs a bad name). During cold weather my range was often more like 25 miles, and this gradually reduced as my batteries aged.

 
Last year I converted to 48 Winston 180 Ahr LiFePO4 cells (roughtly the same 144V as my old pack). The vehicle weight was reduced by 1000 lb. Last week I pulled 75 miles on a charge. My Link-10/E-Meter showed I used up all 180 Ahrs, but I was still well above the low voltage limit of my cells and I had no noticable reduction in vehicle power. The battery temp was about 55F. When my Li batteries are in the 30F-40F temp range, I do notice some reduction in power/range, but not more than 20% reduction (if a dependable range is important to you, I agree with others that you should consider keeping your batteries heated while plugged in).
 
So my range increase is close to 2x of my best PbA days, and 3x of my worst PbA days.
 
When I bought the batteries from Manzanita, they did a capacity test on a group of 4 cells and these 180 Ahr batteries measured around 240 Ahrs. But for the sake of longevity, I still treat them batteries with a 180 Ahr usable capacity.
 
I attribute the range increase to reduced weight and the vastly improved power curve (power vs. SOC) of LiFePO4.
 
I have nothing to add to the other questions that others have answered.
 
Regards,
Randy Richmond
http://evalbum.com/1253
 

> From: [hidden email]
> To: [hidden email]
> Date: Sun, 4 Mar 2012 12:45:29 -0500
> Subject: [EVDL] Lithium or not, that is the question
>
> I have come to a dilemma that I hope the list serve can help with because
> many of you have already then in my place. I have read many emails on here
> about increase mileage with the switch over from lead to lithium.
> Presently I have 15 Deka 831Gel (180 volts, 100AH -18KW), four in place of
> the radiator, 4 in place of the gas tank and 7 in place of the rear seat.
> The weight is about 1080 lbs total. If I go to Lithium I could lose about
> 420 lbs storing them in place of the gas tank and rear seat. At present I
> get a good 30 miles per charge and if I push it have gone 37. I have the
> Azure DMOC and AC motor with regen and it is set to pull max of 200amps.
> Personal observation shows that I have taken it down to 75% DOD but mostly
> around 50%. I have noticed a lot of sag with these Dekas. At present I
> cannot drive to work, 42 miles one way. 30 miles interstate. I would like
> anyone to weigh in on the following questions/concerns before I talk to
> sales type person.
>
> 1. What is a reasonable amount of miles increase would I expect if I
> stayed at the same voltage and AH?
>
> 2. Will the decrease in weight really make a noticeable difference?
>
> 3. How much sag can I expect.
>
> 4. Does anyone know if the Azure 24 will hold up to daily use, one
> hour twice a day?
>
> 5. Does Lithium play well with regen?
>
> 6. Will I need to turn regen off when at the top of the charge or will
> the BMS take care of it.?
>
> Any other advice before I invest $10K to $15K
>
>
>
> Thanks in advance.
>
>
>
> Buddy Mills
>
> <mailto:[hidden email]> [hidden email]
>
>
>
> Look mom, no gas. <http://www.evalbum.com/2887> http://www.evalbum.com/2887
>
>
>
> Disclaimer: No animals were harmed or killed in the process of writing this
> email. Any stories to the contrary are, for the most part, either fictional
> or greatly exaggerated.
>
>
>
> -------------- next part --------------
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> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere. Thanks.
> |
> | REPLYING: address your message to [hidden email] only.
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