# [EVDL] Batteries, Can't quite make a choice



## EVDL List (Jul 27, 2007)

Buddy,

If I were you I would look at lithium. By the time you load up a 
tercel with about 1000 lbs of batteries the AC24 will give very anemic 
performance. Also, I assume you want to go AC to take advantage of 
the regen capabilities. If that be the case lithium will take the 
regen charge better than an AGM.

Hypothetically, if you purchased 15 - 65Ah 12 V AGM batteries you get 
at best about 30 usable Ah out of them after figuring in Peukert's and 
the fact that you don't want to over discharge them or suffer the 
consequences of short battery life. So your left with about 5.4 kWh 
usable energy storage. Then the batteries are going to last about 
300-500 cycles if you lucky.

With Lithium you could get 2000-3000 cycles at 80% discharge. You 
would need 60 - 40 Ah cells to give you the same usable energy, but 
now your vehicle is over 600 lbs lighter, so your range and 
acceleration are way better on that same amount of energy.

The going price is about $1.50/Ah/cell so this pack will set you back 
about $3,600 + BMS. So, its kind of within your budget.

Roger



> Buddy Mills @ Cox.net wrote:
> 
> > First I would like to thank the listserv. I has been most helpful
> > to get this hobby going. A little confusing at times, but helpful.
> ...


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## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> > If I were you I would look at lithium. By the time you load up a
> > tercel with about 1000 lbs of batteries the AC24 will give very anemic
> > performance. Also, I assume you want to go AC to take advantage of
> ...


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## EVDL List (Jul 27, 2007)

> Buddy Mills @ Cox.net wrote:
> > I have determined that I want AGM
> > at a weight of ~ 40LB - 70LB. I am looking for 180 volts (12 volts X
> > 15 batteries, 5 per box/location). And I am converting a Toyota
> ...


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## EVDL List (Jul 27, 2007)

When looking at 40-60AH lithiums I find that they will not supply the
currnet, 400A+, I need for my direct drive system. 65AH AGMs provide
this with no problem. me



> Lee Hart <[email protected]> wrote:
> > Buddy Mills @ Cox.net wrote:
> >> I have determined that I want AGM
> >> at a weight of ~ 40LB - 70LB. I am looking for 180 volts (12 volts X
> ...


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## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> > With Lithium you could get 2000-3000 cycles at 80% discharge. You
> > would need 60 - 40 Ah cells to give you the same usable energy, but
> > now your vehicle is over 600 lbs lighter, so your range and
> ...


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> 
> > Roger Heuckeroth wrote:
> >> If I were you I would look at lithium. By the time you load up a
> ...


----------



## EVDL List (Jul 27, 2007)

400amps is motor current. Battery current is proportional to power, not
torque, so at startup if you have a high enough voltage, current will be
low.





> Rick Beebe <[email protected]> wrote:
> > Steve West wrote:
> >> On 19/02/2009, at 10:31 AM, Mark Eidson wrote:
> >>
> ...


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## EVDL List (Jul 27, 2007)

Motor current is only equal to battery current just before going out
of current limit.

Motor current starts at the controller limit (400 amps) and stays at
400 amps until
the motor sees full battery voltage. After that, it drops while the
voltage stays full.
(of course assuming no peukert/resistive drop)

Motor voltage starts very low and goes up until it reaches battery
voltage just before
getting out of current limit. Then stays the same.

So, if you have enough volts, you may never reach full batt amps. All
controllers
do that.





> Mike Bachand <[email protected]> wrote:
> > Steve,
> >
> > Remember that not all controllers are able to separate a lower battery current from the peak current needed for adequate performance from the motor. In the case of my Curtis, battery current = motor current which peaks at 400 amps. I measured this while driving. For brief periods my AGMs (YTs) actually see 400 amps (direct drive). Just swapping Lithiums in to this abusive environment would be a bad plan.
> ...


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## EVDL List (Jul 27, 2007)

> So, if you have enough volts, you may never reach full batt amps. All
> controllers
> do that.
>

Depending on how good the filter caps in the controller are. If they are
weak, or have too high of ESR, I suspet tah the batteries could be called
upon to supply some of the ripple current.

Z
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## EVDL List (Jul 27, 2007)

The Lithiums (LiFEPO4 to be more specific) that go for the $1.50/Ah 
price are normally rated at 3C continuous and 5-10C Max. I was 
responding to the post about the Azure Dynamics AC24LS which does not 
pull that many amps.



> Mark Eidson wrote:
> 
> > When looking at 40-60AH lithiums I find that they will not supply the
> > currnet, 400A+, I need for my direct drive system. 65AH AGMs provide
> ...


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## EVDL List (Jul 27, 2007)

Rick,

I'm working with a Chinese company (not Thundersky) about their packs 
that come fully integrated with BMS energy balancing systems. If you 
want me to get a price for you, tell me what you looking for. The 
deal their giving me is for a 20kWh pack with BMS for under $10K.

I'm not interested in buying and selling these products, but will 
happily facilitate.

Roger



> Rick Beebe wrote:
> 
> > Roger Heuckeroth wrote:
> >> With Lithium you could get 2000-3000 cycles at 80% discharge. You
> ...


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## EVDL List (Jul 27, 2007)

Agreed, however the AC24LS doesn't draw a lot of current.
60 x 60AH TS cells (192v nom, 180v under 1C load when pack is 15-20 deg C)
will do 30kw peak (more when above 30 deg C) which is around the peak of
the AC24LS does in delta at that voltage.
It would cost more ($US7-8k), but the usable energy in that pack is 7.77 kwh
in 330lb.

As stated earlier, your budget probably isnt high enough for lithium (unless
you could live with 20kw peak, and the same range, in which case you could
afford it)

Matt

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Mark Eidson
Sent: Thursday, 19 February 2009 6:31 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Batteries, Can't quite make a choice

When looking at 40-60AH lithiums I find that they will not supply the
currnet, 400A+, I need for my direct drive system. 65AH AGMs provide this
with no problem. me



> Lee Hart <[email protected]> wrote:
> > Buddy Mills @ Cox.net wrote:
> >> I have determined that I want AGM
> >> at a weight of ~ 40LB - 70LB. I am looking for 180 volts (12 volts X
> ...


----------



## EVDL List (Jul 27, 2007)

I was just talking to our local battery supplier looking for some used
8v floodies. He told me he is replacing batteries in 200 golf carts
for a country club. He saved me a couple of the better ones for $30
each. Sounds like this is the time of year to pick up a decent starter
pack at reasonable cost.



> Lee Hart <[email protected]> wrote:
> > Buddy Mills @ Cox.net wrote:
> >> I have determined that I want AGM
> >> at a weight of ~ 40LB - 70LB. I am looking for 180 volts (12 volts X
> ...


----------



## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> > I'm working with a Chinese company (not Thundersky) about their packs
> > that come fully integrated with BMS energy balancing systems. If you
> > want me to get a price for you, tell me what you looking for. The
> ...


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## EVDL List (Jul 27, 2007)

Well said as usual Lee.
I haven't been on this list long and haven't even gotten started good with 
my project but I have done a LOT of reading and headscratching. Although I 
haven't vocalized it, this is the exact reason and thinking that has me 
directed to AGM's.

Thanks for your insight and willingness to post down to earth answers to 
this list. Because of this I've actually been just searching your name and 
reading your posts in the archives.

Stub






> Lee Hart wrote:
> > The best predictor of the future is the past. So, we need to look at
> > EVs that already *have* lithium battery packs, and see how they
> > turned out. Most of them are highly specialized, one-of-a-kind,
> ...


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## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> > According to information I have read Lithiums are better at absorbing
> > short bursts of energy (typical of regen braking) than SLA, NiCd or
> > NiMh batteries. I have read this on several occasions.
> ...


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## EVDL List (Jul 27, 2007)

Lee wrote -
> There are only a few examples of EVs with lithium batteries that are
> real, drive-every-day vehicles that have accumulated enough miles so we
> can guess at their cost and life. Most are tiny vehicles, like R/C toys
> or electric bikes or scooters.
>
> The few full size vehicles I know of were built by highly talented
> experts. They put a lot of time and money into the project, and have
> generously shared information on how it turned out. Examples include
> Cedric Lynch's feet-forward motorcycle, and cars built by Victor
> Tikhonov and Jukka Jarvinen.


One of our members converted an S-10 and put Lithium batteries in it. He got 
them from http://foxxpower.com/

FoxxCel 50
3.2v x 50a
Weight 4.75 lbs Dimension 8"H x 6"W x 1.75"Thick
96 of them.

He has them split into 2 seperate packs since Fox decieded to send him 50 
amp cells instead of the 100 amp he ordered.

He has 2 strings with 48 cells in each string, 48 x 3.2v = 153 volts, with 
50 amps in each string for a total of 100 amps, 153v x 100 amps = 15300 
watts

Here are some pics of the inside of his BMS/Charger
http://teva2.com/lithium.html

He hasn't really found out what distance they will do. He drives about 10 
miles a day, errands in Tucson, never above 40 mph. He was going to get an 
Emeter, but since he has to charge each string sperately, it made no sense. 
So he relies on the LED's of the charger to determine when the charge is 
complete.

Rush
Tucson AZ 

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## EVDL List (Jul 27, 2007)

DeWalt's Warranty for their DC9360 36V Lithium pack is for 2,000 cycles.


> I'm not aware of any 
> lithium pack that has achieved a 1000 cycle life, outside
> of the 
> laboratory or special case applications.





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## EVDL List (Jul 27, 2007)

That is only true if the acceleration in both gears is the same.
The lower gear is a slower acceleration and the lower motor amps and 
higher motor rpm means a higher motor and controller motor effiency 
which will result in less battery amps, sometimes this combines to 
become 50% less.

> 400amps is motor current. Battery current is proportional to power, not
> torque, so at startup if you have a high enough voltage, current will be
> low.
>
>
>
>


> Rick Beebe <[email protected]> wrote:
> >
> >> > Steve West wrote:
> >>
> ...


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## EVDL List (Jul 27, 2007)

> Rush wrote:
> > One of our members converted an S-10 and put Lithium batteries in it. He got
> > them from http://foxxpower.com/
> 
> ...


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## EVDL List (Jul 27, 2007)

>DeWalt's Warranty for their DC9360 36V Lithium pack is for 2,000 cycles.

So at $134 and 85wh, the cost is still upwards of 1.5$/wh.
When that cost drops to half that amount, the cycle life might start to
justify the cost for more of us.
Hard to convince when a T-105 with 1.11kwh (5hr rate) at $160 or less, or
0.15$/wh.
Even 200 cycles on the floodies justifies.
One bad cycle on the lithium destroys its investment.
I once landed my lithium powered RC glider on the top of a tall shrub and
lost it overnight.
With no onboard BMS to turn the system off before the 2S2P pack discharged
too low, the batteries were below the 2.5v/cell when I found the glider the
next day.
The cells never recovered.
I probably got 30 cycles on these, max.

-Myles Twete, Portland, OR.

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## EVDL List (Jul 27, 2007)

> Steven Ciciora wrote:
> > DeWalt's Warranty for their DC9360 36V Lithium pack is for 2,000 cycles.
> 
> That's encouraging. I believe they use A123 cells in them. But, I don't
> ...


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> 
> > Roger Heuckeroth wrote:
> >> According to information I have read Lithiums are better at absorbing
> ...


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## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> Lee Hart wrote:
> > I remember one source was from a group developing a lithium pack for a
> > Prius plug-in conversion. They tested the lithium packs recharge
> ...


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## EVDL List (Jul 27, 2007)

<<< My understanding is that full equalization charges are recommended on
SLAs, also. Am I mistaken? If that be the case the top 80-100% SOC
on a lead battery is a constant inefficiency each time you charge.
You loose that extra energy by nature of the technology, not just when
your batteries are out of balance. Correct me if I'm wrong. >>>

You seem to be asking questions (and making blanket statements) that 
others experienced in EVs would not - maybe go to Battery U., i.e. 
peruse the archives, especially what Lee has posted? Equalization on 
lead packs is done as a maintenance procedure (not daily or even 
weekly), because a series string is always at risk for imbalances 
along the chain, but lead can handle small amounts of 
overcharge/overvoltage to an extent that lithium (and nimh) can't, and 
these chemistries have to rely on a dependable BMS.

It is generally accepted that lead-acid in the 20-80% SOC range are 
basically 100% efficient in charging.

Even lithium would be useless for regen at 100% SOC (look back a few 
years and you'll see several posts about charging at the top of a 
hill!) - the BMS would have to handle high current if the system tried 
to feed the amps into the pack. OEM EVs deal with this by turning off 
regen capabilities until SOC is low enough to not stress the BMS.


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> 
> >>
> >> To get the range I want from my vehicle I would need over 2000 lbs
> ...


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## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> > Starting with a 3,200 lb sedan that normally gets about 25-30 mpg, how
> > many lbs of lead do you think it would take to get a 60 mile to 20%
> > SOC range?
> ...


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## EVDL List (Jul 27, 2007)

> Willie McKemie wrote:
> 
> > On Thu, Feb 19, 2009 at 01:06:28PM -0500, Roger Heuckeroth wrote:
> >> Starting with a 3,200 lb sedan that normally gets about 25-30 mpg,
> ...


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## EVDL List (Jul 27, 2007)

My perspective as a non-engineer hobbyist is that lithium batteries have a 
lot of potential, but I can't even consider them right now. I want a bolt-
in, black-box solution that WORKS, one that will protect the huge investment 
I make in such a battery. The only such product I know if is the Valence U-
charge system, and it's WAY out of my budget.

Lithium batteries have taken off in mobile phones and laptops because people 
demand large energy storage capacity and are willing to pay for it. Because 
they're so energy-hungry, there really isn't any practical alternative 
energy source for those devices.

However, vehicles still can use petroleum, which has far higher specific 
energy than even lithium batteries. And although some builders have 
experiemented with using mass-market laptop batteries to power EVs, IMO the 
jury is still out on the viability of these thousands-of-connections 
monstrosities. 

Golf car batteries and to some extent UPS type AGMs are commodity items. 
That's why they can approach being cost-competitive with petroleum for day 
to day transportation. (Actually, many of the components we use in 
conversions are only available and affordable because they're modified 
versions of parts used in near-mass-market applications such as golf cars, 
forklifts, and burden carriers.)

Lithium laptop cells are now also pretty much commodity items. But AFAIK, 
for the present, lithium cells of a useful (or at least easily-applied) size 
for a small-car size road EV are quite some way from achieving that status.

Thus, when you look at the cost and complexity of lithium systems suited to 
4-wheel road EVs (including charger, bms, etc), you realize that gasoline is 
going to have to get VERY expensive before lithium can compete with it for 
that application. Only if legislation or government incentives create a 
massive shift in the market is there any real chance for short-circuiting 
this natural inertia.

Where lithium does appear useful and competitive for EVs right now is in 
small, light personal vehicles, such as scooters and bikes. I suspect that 
most of them can use those commodity laptop cells -- fortunately, not in the 
thousands. 

If someone can somehow manage to attain economy of scale in 4-wheel road EV-
size lithium cells, things might change. But it's the classic "chicken and 
egg" problem. High cost means low demand and low demand means high cost.

If some automaker were to design a true (plug-in) hybrid and it really took 
off in popularity, as the Prius did, then its battery might be able to 
eventually achieve something close to commodity status. You'll know that's 
happened when 3 or 4 manufacturers are offering generic spares, and Autozone 
is competing with NAPA for the lowest price. As a wild, irresponsible 
guess, I'd estimate that would take between 10 and 15 years from the date of 
the vehicle's introduction. (But the automaker might also decide to change 
the battery every year or two, in order to prevent this and maintain a 
monopoly in the spares market!)

For the present, I think that lithium is only practical for the EV hobbyist 
who has lots of spare cash and is willing to spend it, or for the engineer 
who has lots of spare time and is willing to spend it. I would love to have 
that proven wrong, however.

David Roden - Akron, Ohio, USA
EVDL Administrator

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## EVDL List (Jul 27, 2007)

Roger,

Of course you have put a thumb on the scale
by comparing the recommendation of a very conservative
and real-world sub-perfect things-that-work calculator
with a good safety margin against the optimistic
assumption that you can use all of the energy in the
Lithium pack and need almost no reserve.

Let me make it clear by calculating the two packs:
Lead: 180V x 260Ah = 46.8 kWh
Lithium: 100Ah x 205V = 20.5 kWh 

Estimated energy needed for a moderately efficient
family car at 60 miles range:
300Wh/mi x 60mi = 18 kWh

For the usable energy in the lead pack the common
wisdom is that you take half the 20h capacity as a
conservative amount that you maximum can take out of
the pack routinely without killing it, so to say an
80% discharge on daily bases taking into account the
Peukert effect and possibly some colder weather, though
real cold weather will cut the capacity significantly more.
So, in reality in not too cold climates or with an insulated
battery box in cold climates we can use about 50% of the
20h capacity of 46.8, so a little more than 23 kWh.

Now the Lithium pack: it is not wise to expect more
than 80% of the specified capacity of Lithium and even
that can leave you stranded after a couple months of
daily drivinng when the max capacity of your pack is 
not longer the same as it started with.
But just to follow your optimism, let's say that you
can routinely remove 80% of the specified capacity 
of 20.5 which equals 16.4 kWh.

See how the Lithium battery does not stack up to the
lead solution you proposed? There is about 7 kWh between
the two in usable energy. The weight of a vehicle will
slightly impact the efficiency, but it should not change
so much as to require this difference unless your vehicle
has other problems.

Please also note that the available capacity in Lithium
is not sufficient to give you the range you specified.

Kind regards,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Roger Heuckeroth
Sent: Thursday, February 19, 2009 11:36 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Batteries, Can't quite make a choice




> Lee Hart wrote:
> 
> >>
> >> To get the range I want from my vehicle I would need over 2000 lbs
> ...


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## EVDL List (Jul 27, 2007)

> EVDL Administrator wrote:
> 
> > Thus, when you look at the cost and complexity of lithium systems
> > suited to
> ...


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## EVDL List (Jul 27, 2007)

> Cor van de Water wrote:
> >
> >
> > Of course you have put a thumb on the scale
> ...


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## EVDL List (Jul 27, 2007)

That is 3 kWh difference at max, not the 7 kWh
that you suggested and I have seen very little
effect from carrying a lot of weight around if
you drive your EV like an EV.

But the best way is to build it, use it, measure
how well it does and let us know please, so we can
all learn if Lithium does what it promises.

Success,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Roger Heuckeroth
Sent: Friday, February 20, 2009 1:20 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Batteries, Can't quite make a choice




> Cor van de Water wrote:
> >
> >
> > Of course you have put a thumb on the scale
> ...


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## EVDL List (Jul 27, 2007)

> Cor van de Water wrote:
> 
> > That is 3 kWh difference at max, not the 7 kWh
> > that you suggested and I have seen very little
> ...


----------



## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> >
> > Once you are rolling at constant speed the extra weight makes only a
> > bit of difference in adding a bit of rolling resistance, but climbing
> ...


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## EVDL List (Jul 27, 2007)

> Willie McKemie wrote:
> 
> > On Thu, Feb 19, 2009 at 03:30:30PM -0500, Roger Heuckeroth wrote:
> >>
> ...


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## EVDL List (Jul 27, 2007)

Isn't half the 20-hr. rate high? I thought general wisdom with floodies was that the higher discharge currents used by EV's resulted in 55-60% energy availability compared to the 20-hr. rate. Using half that (50% DOD) means about one quarter of the 20-hr rate is available. Or am I just confused again?

thanks,
Frank


________________________________
From: Cor van de Water <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Thursday, February 19, 2009 2:08:25 PM
Subject: Re: [EVDL] Batteries, Can't quite make a choice

<snip>
For the usable energy in the lead pack the common
wisdom is that you take half the 20h capacity as a
conservative amount that you maximum can take out of
the pack routinely without killing it, so to say an
80% discharge on daily bases taking into account the
Peukert effect and possibly some colder weather, though
real cold weather will cut the capacity significantly more.
So, in reality in not too cold climates or with an insulated
battery box in cold climates we can use about 50% of the
20h capacity of 46.8, so a little more than 23 kWh.



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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> >> Has anyone actually *achieved* 2000 cycles from [a lithium pack],
> >> at some known current or depth of discharge?
> 
> ...


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## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> >
> > Willie, are you trying to say that weight doesn't mater due to
> > conservation of energy theory?
> ...


----------



## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> > Starting with a 3,200 lb sedan that normally gets about 25-30 mpg, how
> > many lbs of lead do you think it would take to get a 60 mile to 20%
> > SOC range?
> ...


----------



## EVDL List (Jul 27, 2007)

Actual battery capacity decreases as discharge current increases. A battery 
rated at 100 ampere-hours which can deliver 5 amperes for 20 hours, may 
deliver 20 amperes for 4 hours.

The battery reserved capacity is measure of how long a battery can deliver a 
certain amount of current.

If you look at the different deep cycle battery data charts that list the 
Reserve [email protected] 25 amps, Ampere Hour @ 20 hrs and Reserve [email protected] 75 minutes, 
your will see numbers of minutes list for each ampere.

For example, the T-145 6 volt battery is listed at 145 reserve minutes at 75 
amp load which would be completely discharge in 145 minutes.

The T-145 is listed at 260 AH at a 20 hour rated which would be 260/20= 13 
amps per hour. Actually you would only want to go about 6.5 hours at this 
rated which would be about 50% SOC.

Now if you drove at 75 amps with the T-145's the estimate amount of 
ampere-hour use will be about:

145 minutes / 60 = 2.416 hours

2.416 x 75 amps = 181.25 ampere-hour to full discharge.

181.25/2 = 90.6 usable ampere hour to 50% SOC.

Therefore the estimate range for me on one drive that range from speeds of 
15 mph starting up hill and 80 mph on some of the down hills while the 
battery ampere was ranging from 125 amps to 0 amps.

145 min./2 = 72.5 min

Then (72.5 x 30)/60 = 36.25 miles.

I actual drove 39.5 miles to 50% SOC driving on roller coaster hills that 
allow my EV to make about 75% of the next hill and at times have a down hill 
roll out for over 2 miles.

Roland




----- Original Message ----- 
From: "Frank John" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Thursday, February 19, 2009 1:49 PM
Subject: Re: [EVDL] Batteries, Can't quite make a choice


> Isn't half the 20-hr. rate high? I thought general wisdom with floodies 
> was that the higher discharge currents used by EV's resulted in 55-60% 
> energy availability compared to the 20-hr. rate. Using half that (50% 
> DOD) means about one quarter of the 20-hr rate is available. Or am I just 
> confused again?
>
> thanks,
> Frank
>
>
> ________________________________
> From: Cor van de Water <[email protected]>
> To: Electric Vehicle Discussion List <[email protected]>
> Sent: Thursday, February 19, 2009 2:08:25 PM
> Subject: Re: [EVDL] Batteries, Can't quite make a choice
>
> <snip>
> For the usable energy in the lead pack the common
> wisdom is that you take half the 20h capacity as a
> conservative amount that you maximum can take out of
> the pack routinely without killing it, so to say an
> 80% discharge on daily bases taking into account the
> Peukert effect and possibly some colder weather, though
> real cold weather will cut the capacity significantly more.
> So, in reality in not too cold climates or with an insulated
> battery box in cold climates we can use about 50% of the
> 20h capacity of 46.8, so a little more than 23 kWh.
>
>
>
> _______________________________________________
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>
> 

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## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> > Good point. I live in the Northeast US. Upstate NY. It gets cold
> > here. Another plus for lithium.
> 
> ...


----------



## EVDL List (Jul 27, 2007)

> According to information I have read Lithiums are better at absorbing 
> short bursts of energy (typical of regen braking) than SLA, NiCd or 
> NiMh batteries. I have read this on several occasions. I didn't keep 
> track of where I read this. They say don't believe everything you 
> hear, but I have read the same conclusion from multiple sources. I 
> also read that Lithiums in general have a more efficient charge cycle, 
> in that they return about 90-95% of the energy that is supplied to 
> charge them, where lead acid is more like 80% efficient.
> 
Thundersky Li-Ion charge mostly from 3.5V to 4.2V, while discharging 
approximately linearly from 3.5V to 3.0V. That's about 3.25/3.85 or 85%, 
at rates below 1C, going off ideal numbers.

Cory

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## EVDL List (Jul 27, 2007)

Lee, I thought that using the full ~1087 W-h would drop voltage (by definition) to 1.75 vpc i.e. fully discharged. For 20% SOC wouldn't that mean there's about 800 W-h/battery available and therefore 22-24 batteries would be needed? I realize these numbers are approximate but it looks to me like discharging 16 batteries in this manner would put a lot of stress on them.




________________________________
From: Lee Hart <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Thursday, February 19, 2009 5:50:25 PM
Subject: Re: [EVDL] Batteries, Can't quite make a choice

<Well, let's see. Let's say you use 300 watthours per mile. 60 miles than 
requires 60 x 300 = 18,000 watthours. A T-145 delivers 75a x 6v for 145 
minutes = 1087 watthours. So you need 18,000 / 1087 = 16 T-145's (not 
30) to do this range.

This isn't using the batteries to 0% SOC, either. The T-145 actually 
holds 244ah, and we are only using 75a x 145m = 181ah; about 75% DOD (so 
they'd end at about 25% SOC). The rated life at this depth of discharge 
is 625 cycles.>



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## EVDL List (Jul 27, 2007)

> Willie McKemie <[email protected]> wrote:
> 
> > On Thu, Feb 19, 2009 at 04:37:58PM -0500, Roger Heuckeroth wrote:
> >>
> ...


----------



## EVDL List (Jul 27, 2007)

> EVDL Administrator wrote:
> > My perspective as a non-engineer hobbyist is that lithium batteries have a
> > lot of potential, but I can't even consider them right now. I want a bolt-
> > in, black-box solution that WORKS, one that will protect the huge investment
> ...


----------



## EVDL List (Jul 27, 2007)

I think part of the problem is, if these cells really do get 2000 cycles to
80%dod, it will be quite some time before someone kills them by natural
causes.

The 40AH cells in my scooter that gets 35km range to 80%dod have done
16'000km to date.
Back when new, I used to get 40km to 80%dod.
So ive lost 15% or so in capacity.
So im up to equivalent 400 cycles to 80%dod.
Though in truth its been more like 800 cycles to 40%dod

My pack consists of 19 40AH cells for 60.8v nominal.
Ive crashed the scooter twice
Ive knocked it over a few times
Ive overdischarged the cells 8 times (enough that no load voltage on every
cell was less than 2.3v)
I discarge at 50A continuous, 120A for several seconds on acceleration (at
120A I still get 2.8vpc)
My suspension doesn't work, so the vibration is constant (one of the
terminal bolts I have to re-tighten every couple of months)
It only has 10" wheels, yet I do 40mph *all* the time

When this pack eventually does die, ill let the list know how many real
world cycles you can expect out of these cells in the real world.
At least then ew'd have a data point.

Matt

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Lee Hart
Sent: Friday, 20 February 2009 8:01 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Batteries, Can't quite make a choice



> Lee Hart wrote:
> >> Has anyone actually *achieved* 2000 cycles from [a lithium pack], at
> >> some known current or depth of discharge?
> 
> ...


----------



## EVDL List (Jul 27, 2007)

Probably the only truthful answer you will get with
a varying mix of environments is: it depends.
Just like lead-acid batteries - some murder them
in short order, others get 18,000 miles out of
an unlikely pack of 8V floodeds.

Time will tell and YMMV.

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Lee Hart
Sent: Friday, February 20, 2009 4:31 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Batteries, Can't quite make a choice



> Lee Hart wrote:
> >> Has anyone actually *achieved* 2000 cycles from [a lithium pack],
> >> at some known current or depth of discharge?
> 
> ...


----------



## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> 
> > Roger Heuckeroth wrote:
> >> Starting with a 3,200 lb sedan that normally gets about 25-30 mpg,
> ...


----------



## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> 
> > Roger Heuckeroth wrote:
> >> Good point. I live in the Northeast US. Upstate NY. It gets cold
> ...


----------



## EVDL List (Jul 27, 2007)

Blower is a good idea but your
batteries may be unhappy the other (cold)
half of the year.
Build it and let us know how well it does.

Success,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Roger Heuckeroth
Sent: Friday, February 20, 2009 7:34 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Batteries, Can't quite make a choice




> Lee Hart wrote:
> 
> > Roger Heuckeroth wrote:
> >> Good point. I live in the Northeast US. Upstate NY. It gets cold
> ...


----------



## EVDL List (Jul 27, 2007)

> matt wrote:
> 
> > I think part of the problem is, if these cells really do get 2000
> > cycles to
> ...


----------



## EVDL List (Jul 27, 2007)

Which brand/chemistry of Lithium?
How many cycles were they "rated" for?

Thanks,
Thor


-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of matt
Sent: Friday, February 20, 2009 5:31 AM
To: 'Electric Vehicle Discussion List'
Subject: Re: [EVDL] Batteries, Can't quite make a choice

I think part of the problem is, if these cells really do get 2000 cycles
to
80%dod, it will be quite some time before someone kills them by natural
causes.

The 40AH cells in my scooter that gets 35km range to 80%dod have done
16'000km to date.
Back when new, I used to get 40km to 80%dod.
So ive lost 15% or so in capacity.
So im up to equivalent 400 cycles to 80%dod.
Though in truth its been more like 800 cycles to 40%dod

My pack consists of 19 40AH cells for 60.8v nominal.
Ive crashed the scooter twice
Ive knocked it over a few times
Ive overdischarged the cells 8 times (enough that no load voltage on
every
cell was less than 2.3v)
I discarge at 50A continuous, 120A for several seconds on acceleration
(at
120A I still get 2.8vpc)
My suspension doesn't work, so the vibration is constant (one of the
terminal bolts I have to re-tighten every couple of months)
It only has 10" wheels, yet I do 40mph *all* the time

When this pack eventually does die, ill let the list know how many real
world cycles you can expect out of these cells in the real world.
At least then ew'd have a data point.

Matt

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf
Of Lee Hart
Sent: Friday, 20 February 2009 8:01 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Batteries, Can't quite make a choice



> Lee Hart wrote:
> >> Has anyone actually *achieved* 2000 cycles from [a lithium pack], at
> >> some known current or depth of discharge?
> 
> ...


----------



## EVDL List (Jul 27, 2007)

LiFePO4 and 2000 cycles to 80%.



> Thor Johnson wrote:
> 
> > Which brand/chemistry of Lithium?
> > How many cycles were they "rated" for?
> ...


----------



## EVDL List (Jul 27, 2007)

> My suspension doesn't work, so the vibration is constant (one of the
> terminal bolts I have to re-tighten every couple of months)
> It only has 10" wheels, yet I do 40mph *all* the time

Is Loctite a bad idea for battery connections like these? Does anyone 
know of an electrically conductive threadlocker?

-Thor


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## EVDL List (Jul 27, 2007)

> Cor van de Water wrote:
> > Probably the only truthful answer you will get with a varying mix of
> > environments is: it depends. Just like lead-acid batteries - some
> > murder them in short order, others get 18,000 miles out of an
> ...


----------



## EVDL List (Jul 27, 2007)

>>> Starting with a 3,200 lb sedan that normally gets about 25-30 mpg, 
>>> how many lbs of lead do you think it would take to get a 60 mile
>>> to 20% SOC range?



> Lee Hart wrote:
> >> Well, let's see. Let's say you use 300 watthours per mile. 60 miles
> >> then requires 60 x 300 = 18,000 watthours. A T-145 delivers 75a x 6v
> >> for 145 minutes = 1087 watthours. So you need 18,000 / 1087 = 16
> ...


----------



## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> 
> > I was going to put them in an aluminum box mounted in the floor of the
> > trunk (where the spare tire and fuel tank were). I was not planning
> ...


----------



## EVDL List (Jul 27, 2007)

> matt wrote:
> > I think part of the problem is, if these cells really do get 2000 cycles to
> > 80%dod, it will be quite some time before someone kills them by natural
> > causes.
> ...


----------



## EVDL List (Jul 27, 2007)

> Frank John wrote:
> > Lee, I thought that using the full ~1087 W-h would drop voltage (by
> > definition) to 1.75 vpc i.e. fully discharged. For 20% SOC wouldn't
> > that mean there's about 800 W-h/battery available and therefore 22-24
> ...


----------



## EVDL List (Jul 27, 2007)

Lee and All,
This reminded me of our last trip to the Western Slope of Colorado, going over the Interstate 70 passes from the Front Range. On more than one occasion I filled up the stock pack in the wife-unit's '04 High Bride Prius, and then had to engage the engine compression braking. So, in addition to to being able to plug-in, a larger pack in a PEHV would suck up all the regen power that our mountains could toss at it!
Suck Amps,
BB

>Date: Thu, 19 Feb 2009 11:20:05 -0600
>From: Lee Hart

<snippage>

>Another possibility is that the mountains were so large that the stock 
>nimh pack didn't have enough amphour capacity to hold all the regen 
>energy. Once the pack is full, the Prius dumps the excess braking energy 
>in the mechanical brakes or ICE engine braking, like every other car. 

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## EVDL List (Jul 27, 2007)

Roger and All,
I could get 60 miles with 24 T-145's in the extended cab S10 pickup along
the relatively flat Front Range of Colorado at speeds of around 55 MPH, and it was truly a barn-door lead-sled! Of course, this was using long-range EV driving techniques, the most robust 6V floodies, etc. I've posted about the S10 activities, so as always, I recommend the EVDL archives.
Suck Amps,
BB

>Date: Thu, 19 Feb 2009 13:06:28 -0500
>From: Roger Heuckeroth

<snippage>
>Starting with a 3,200 lb sedan that normally gets about 25-30 mpg, how 
>many lbs of lead do you think it would take to get a 60 mile to 20% 
>SOC range?
>
>Using the EV calculator figured it would take 30 Trojan T-145's at 72 
>lbs each (2160 lbs). I could not fit that many without giving up the 
>back seat which would not work considering this is a family car.

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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> 
> >>>> Starting with a 3,200 lb sedan that normally gets about 25-30 mpg,
> >>>> how many lbs of lead do you think it would take to get a 60 mile
> ...


----------



## EVDL List (Jul 27, 2007)

If I was doing a pickup, I would probably be going down that road, 
too. They lend themselves well to becoming lead sleds as far as room 
under the bed and weight handling capability. I got nothing against 
lead acid, just that it won't work for my current conversion. Won't 
fit, won't give me the range and won't give me the performance I'm 
after.

On Feb 20, 2009, at 4:12 PM, Dave (Battery Boy) Hawkins wrote:

> Roger and All,
> I could get 60 miles with 24 T-145's in the extended cab S10 pickup 
> along
> the relatively flat Front Range of Colorado at speeds of around 55 
> MPH, and it was truly a barn-door lead-sled! Of course, this was 
> using long-range EV driving techniques, the most robust 6V floodies, 
> etc. I've posted about the S10 activities, so as always, I recommend 
> the EVDL archives.
> Suck Amps,
> BB
>
>> Date: Thu, 19 Feb 2009 13:06:28 -0500
>> From: Roger Heuckeroth
>
> <snippage>
>> Starting with a 3,200 lb sedan that normally gets about 25-30 mpg, 
>> how
>> many lbs of lead do you think it would take to get a 60 mile to 20%
>> SOC range?
>>
>> Using the EV calculator figured it would take 30 Trojan T-145's at 
>> 72
>> lbs each (2160 lbs). I could not fit that many without giving up the
>> back seat which would not work considering this is a family car.
>
> _______________________________________________
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>

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----------



## EVDL List (Jul 27, 2007)

> Lee Hart <[email protected]> wrote:
> 
> > Roger Heuckeroth wrote:
> >
> ...


----------



## EVDL List (Jul 27, 2007)

Hi Lee,

The cells are Thundersky LFP-40AHA cells, manufacture date 2nd Oct 2007.
There were a few of us who did this mod around the same time, I know of one
other guy who has done as many km as I have.

These cells are standard equipment on most of the extreme scooters now.

I do note that another list member is running the cells in his car at 8C
(with huge voltage sag of course).
Since I originally bought the cells for destructive testing, I may increase
the current limit to 300A, to see if this accelerates cell degredation.
I think it will, but id like to see anyway (also id like more power, 6kw
just isnt enough for a moped )

Matt

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Lee Hart
Sent: Saturday, 21 February 2009 4:18 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Batteries, Can't quite make a choice



> matt wrote:
> > I think part of the problem is, if these cells really do get 2000
> > cycles to 80%dod, it will be quite some time before someone kills them
> > by natural causes.
> ...


----------



## EVDL List (Jul 27, 2007)

Hi Thor,

The cells are thundersky, and are rated for 2000 cycles at 80%dod, and 3000
cycles at 70%dod 
The definition of end of service life isnt clear, nor is what the drop off
in capacity curve looks like.
I bought the pack as a test (which is why I have such a low range, I wanted
to rack up the cycles fairly quickly)

Matt


-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Thor Johnson
Sent: Saturday, 21 February 2009 12:01 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Batteries, Can't quite make a choice

Which brand/chemistry of Lithium?
How many cycles were they "rated" for?

Thanks,
Thor


-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of matt
Sent: Friday, February 20, 2009 5:31 AM
To: 'Electric Vehicle Discussion List'
Subject: Re: [EVDL] Batteries, Can't quite make a choice

I think part of the problem is, if these cells really do get 2000 cycles to
80%dod, it will be quite some time before someone kills them by natural
causes.

The 40AH cells in my scooter that gets 35km range to 80%dod have done
16'000km to date.
Back when new, I used to get 40km to 80%dod.
So ive lost 15% or so in capacity.
So im up to equivalent 400 cycles to 80%dod.
Though in truth its been more like 800 cycles to 40%dod

My pack consists of 19 40AH cells for 60.8v nominal.
Ive crashed the scooter twice
Ive knocked it over a few times
Ive overdischarged the cells 8 times (enough that no load voltage on every
cell was less than 2.3v) I discarge at 50A continuous, 120A for several
seconds on acceleration (at 120A I still get 2.8vpc) My suspension doesn't
work, so the vibration is constant (one of the terminal bolts I have to
re-tighten every couple of months) It only has 10" wheels, yet I do 40mph
*all* the time

When this pack eventually does die, ill let the list know how many real
world cycles you can expect out of these cells in the real world.
At least then ew'd have a data point.

Matt

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Lee Hart
Sent: Friday, 20 February 2009 8:01 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Batteries, Can't quite make a choice



> Lee Hart wrote:
> >> Has anyone actually *achieved* 2000 cycles from [a lithium pack], at
> >> some known current or depth of discharge?
> 
> ...


----------



## EVDL List (Jul 27, 2007)

What confuses me is that the 244ah number is obtained at a certain discharge rate (between 5-20 hours per current T-145 specs.) I thought that increasing the discharge rate would diminish capacity and establish a new DOD at that rate. Should one therefore estimate ultimate capacity using the 20-hr. rate (probably the 100-hr rate isn't that much greater as the curve flattens out) and use that as the basis for all DOD calculations, even if that capacity is not available at higher discharge rates?




________________________________
From: Lee Hart <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Friday, February 20, 2009 2:25:35 PM
Subject: Re: [EVDL] Batteries, Can't quite make a choice


<The T-145 actually holds 6v x 244ah = 1464wh, so taking 1087wh out is 
only taking them down to about 74% DOD.>

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## EVDL List (Jul 27, 2007)

The 80%dod should be at the discharge rate you are using.
So if you are discharging at 75A, then you have [email protected] as per the
specs.
So 80% of this is your usable capacity at 80%dod = 145AH.

Matt 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Frank John
Sent: Saturday, 21 February 2009 10:29 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Batteries, Can't quite make a choice

What confuses me is that the 244ah number is obtained at a certain discharge
rate (between 5-20 hours per current T-145 specs.) I thought that
increasing the discharge rate would diminish capacity and establish a new
DOD at that rate. Should one therefore estimate ultimate capacity using the
20-hr. rate (probably the 100-hr rate isn't that much greater as the curve
flattens out) and use that as the basis for all DOD calculations, even if
that capacity is not available at higher discharge rates?




________________________________
From: Lee Hart <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Friday, February 20, 2009 2:25:35 PM
Subject: Re: [EVDL] Batteries, Can't quite make a choice


<The T-145 actually holds 6v x 244ah = 1464wh, so taking 1087wh out is only
taking them down to about 74% DOD.>

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## EVDL List (Jul 27, 2007)

> Frank John wrote:
> > Isn't half the 20-hr. rate high? I thought general wisdom with
> > floodies was that the higher discharge currents used by EV's resulted
> > in 55-60% energy availability compared to the 20-hr. rate. Using
> ...


----------



## EVDL List (Jul 27, 2007)

And here is a not so encouraging data point.

I have a 300zx that I put 24 exide orbitals. These are 50ah at C20. So 
they only have about 24ah at the 1hr rate.
So it is 1000 lbs of lead in a rather heavy car making a 4000 lb curb 
weight. this is only 25% of weight in lead.


24ah * (240+300)/2 = 6480wh (so you can see 6480 * .8 / 370 is only 14 
miles to 80%)
But agm's do a little better on pukerts than floddies so I used to get 
5000wh out of the pack comfortably, now I get 3000wh.

But on my route with lots of stop and go, I get about 370wh/mile 

When the pack was new I once 27 miles, but on freeway, no stops. and 
that was pulling it way to low.
Then I did a year+ of 8 miles-charge-8miles-charge
Then I did a year+ of 7 miles, sit 10+ hours, 7 miles -charge.

When it got cold, I couldn't do that anymore
(I did not put my batteries in a box, it's sunny california!
I underestimated the effect of temperature on lead acid.)

Luckily work put in a plug for me and I can continue commuting, but I 
can't even run an errand after work nowadays.

The points are
1) that we have to consider the range after the pack ages a bit too. If 
you need the max range on the onset, you will have to get a new pack 
when only 10% of the life is used up. you will also be doing full cycles 
so the pack will be dead in a year.
2) You need more like 33% weight of vehicle in battery.

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## EVDL List (Jul 27, 2007)

Jeff,

I had the impression that you rpack was not so much old
as well that it had a few bad cells, likely from a couplle
times pulling it too low, which kills cells exactly that
way that they have a small capacity and high resistance
after that. Ask me how I know.

BTW, my data point:
1800 lbs of lead (26 x 110Ah 12V AGM) in an S10, empty weight
must have been just over 3000 as the vehicle was now just over
5000 lbs with driver (6'3" 185 lbs) 

Data sheet promised a max 80Ah at 1h discharge rate, giving
a max available 20.8kWh My vehicle was not very much optimized
as it had a bad aerodynamics and I did not do anything to it
beyond pumping the tires to 50 PSI and checking alignment by
pushing it back and forth.
Driving a mixed freeway/city traffic commute as daily practice
I put almost 10,000 miles on my AGMs but suffered from small
capacity of several cells (which also got warm after a drive)
towards the end. Likely this was due to my initial optimism
about the range and I took it on fast freeway trips (higher
than normal power use) on several occasions, driving more than
60 miles (63 miles to be exact). Since my guesstimated usage
must have been at least 350 Wh/mi, I have likely sucked all
available energy out of the batteries at those times, causing
a few cells to get "more than empty", be reversed and damaged 
early.

For a well setup sedan, you should not see such bad power
use, that is the consequence of running a truck.

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Jeff Shanab
Sent: Saturday, February 21, 2009 10:36 PM
To: [email protected]
Subject: Re: [EVDL] Batteries, Can't quite make a choice

And here is a not so encouraging data point.

I have a 300zx that I put 24 exide orbitals. These are 50ah at C20. So 
they only have about 24ah at the 1hr rate.
So it is 1000 lbs of lead in a rather heavy car making a 4000 lb curb 
weight. this is only 25% of weight in lead.


24ah * (240+300)/2 = 6480wh (so you can see 6480 * .8 / 370 is only 14 
miles to 80%)
But agm's do a little better on pukerts than floddies so I used to get 
5000wh out of the pack comfortably, now I get 3000wh.

But on my route with lots of stop and go, I get about 370wh/mile 

When the pack was new I once 27 miles, but on freeway, no stops. and 
that was pulling it way to low.
Then I did a year+ of 8 miles-charge-8miles-charge
Then I did a year+ of 7 miles, sit 10+ hours, 7 miles -charge.

When it got cold, I couldn't do that anymore
(I did not put my batteries in a box, it's sunny california!
I underestimated the effect of temperature on lead acid.)

Luckily work put in a plug for me and I can continue commuting, but I 
can't even run an errand after work nowadays.

The points are
1) that we have to consider the range after the pack ages a bit too. If 
you need the max range on the onset, you will have to get a new pack 
when only 10% of the life is used up. you will also be doing full cycles

so the pack will be dead in a year.
2) You need more like 33% weight of vehicle in battery.

_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
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_______________________________________________
General EVDL support: http://evdl.org/help/
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Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev


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## EVDL List (Jul 27, 2007)

> matt wrote:
> > Hi Lee,
> >
> > The cells are Thundersky LFP-40AHA cells, manufacture date 2nd Oct
> ...


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## EVDL List (Jul 27, 2007)

> Frank John wrote:
> > What confuses me is that the 244ah number is obtained at a certain
> > discharge rate. I thought that increasing the discharge rate would
> > diminish capacity and establish a new DOD at that rate.
> ...


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## EVDL List (Jul 27, 2007)

Lee and All,
It's interesting that your calculations match the 500pounds-of-lead=one-gallon-of-gas rule:
60(mile range)/25(MPG)=2.4x500=1200 pounds of floodies...
1200/72(pounds per T-145)=16.6 or 17 floodies!
Suck Amps,
BB

>Date: Thu, 19 Feb 2009 16:50:25 -0600
>From: Lee Hart
>


> >Roger Heuckeroth wrote:
> >> Starting with a 3,200 lb sedan that normally gets about 25-30 mpg, how
> >> many lbs of lead do you think it would take to get a 60 mile to 20%
> >> SOC range?
> ...


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## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> > Lee, now I think I understand the why there's such a difference
> > between what The EV calculator says (30 batteries) and what you said
> > (16 batteries).
> ...


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## EVDL List (Jul 27, 2007)

Lee-
I'm looking to buy a pack of 8VGC's in the next couple of months. Are the 8
volters you got from Sam's club the "Energizer" label?

And, have you been happy with them?

Thanks

Phil Marino
Rochester, NY



> Lee Hart <[email protected]> wrote:
> 
> > Roger Heuckeroth wrote:
> > > Lee, now I think I understand the why there's such a difference
> ...


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## EVDL List (Jul 27, 2007)

> Phil Marino wrote:
> > Lee-
> > I'm looking to buy a pack of 8VGC's in the next couple of months. Are the 8
> > volters you got from Sam's club the "Energizer" label?
> ...


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