# [EVDL] Li-Ion w/o BMS



## EVDL List (Jul 27, 2007)

Let me come out right and say that using a Li-Ion pack without a BMS is
downright foolish.

Yet, I realize that many hobbyists will do so anyway, out of financial
constraints or limitations in technical understanding.

I could just scoff and move on. Instead, I would like to use my
understanding of Li-Ion packs and Li-Ion BMSs to try to answer the question:
what's the least risky way of implementing a BMS-less Li-Ion pack?

Here is my answer.

1) Top balance the cells
- Connect all the cells in parallel (including any spares you may have)
- Set a regulated supply for the max cell voltage (the bigger the supply,
the faster the balancing)
- 3.6 V for LiFePO4
- 4.0 V for Thundersky
- 4.2 V for standard LiPo, standard Cobalt
- Connect the regulated supply to the cells in parallel, through an DVM set
as an ammeter 
- Let sit for a few days, until the ammeter shows a current of less than 10
mA
- Now all the cells are at 100 % SOC: they are top balanced

2) Build the pack
- Disconnect the cells, install them in battery boxes, connect them in
series

3) Use a CCCV charger
- Set the charger for the max pack voltage = number of cells in series *
max cell voltage (see above)
- For most chargers: place a voltmeter on its output (disconnected from
pack) and adjust the voltage
- For Manzanita: connect to pack, when voltage is at max, reduce setting
until the current goes to 0
- For Zivan and ElCon: specify the max voltage when ordering charger

4) Find least capacity cell
- Place a DVM on any cell, to measure Volts
- Drive around, nice and easy, until the cell voltage (at rest) reaches a
low level
- 3.15 V for LiFePO4 and Thundersky
- 3.55 V for standard LiPo, standard Cobalt
- Measure each cell voltage, find the few cells with the lowest voltage
- Place the DVM on one of those cells
- Drive around, really nice and easy, until the cell voltage (at rest)
reaches a low level
- 2.9 V for LiFePO4 and Thundersky
- 3.3 V for standard LiPo, standard Cobalt
- Measure each cell voltage, find the cell with the lowest voltage: the
lowest capacity cell

5) Add voltmeter on least capacity cell
- Install a voltmeter on the dashboard, measuring the voltage of the lowest
capacity cell
- (If you're clever, use a comparator IC to flash a light and ring a bell)

6) Use the EV:
- When driving, keep an eye on the low cell voltmeter, and do not let it
dip below:
- LiFePO4 and Thundersky: 3.0 V at rest, 2.2 V during short bursts
- standard LiPo, standard Cobalt: 3.4 V at rest, 3.0 V during short
bursts
- Charge the pack fully, regularly
- Every 3 months, manually top-balance the pack
- Fully charge the pack
- Turn off the charger and allow the cell voltages to settle for 15
minutes
- Measure each cell voltage
- Either use a small supply to bring up the voltage of the few cells that
are still low (safe),
- or use a power resistor to take some charge away from the cell that are
too high (risky)
- 2 Ohm, 10 W resistor -> ~ 2 A balance current -> ~ 30 min / cell
- 0.2 Ohm, 100 W resistor -> ~ 20 A balance current -> ~ 3 min / cell
- After all the cells are at the same voltage, charge fully

However, I'll say it again: using a Li-Ion pack without a BMS is downright
foolish.

-----
Davide Andrea
http://liionbms.com/php/index.php Elithion 
-- 
View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Li-Ion-w-o-BMS-tp2339874p2339874.html
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## EVDL List (Jul 27, 2007)

PS. Quick and dirty trick:
Make the pack with a single, lower capacity cell (e.g.: a 90 AH cell in a
100 AH pack). Then you know a priory that that is the lowest cell, so that's
the one you wire your voltmeter to. Place this cell so that it easy to
replace, as this is your sacrificial cell should you push the SOC too low.

-----
Davide Andrea
http://liionbms.com/php/index.php Elithion 
-- 
View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Li-Ion-w-o-BMS-tp2339874p2339906.html
Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.

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## EVDL List (Jul 27, 2007)

> Date: Thu, 26 Aug 2010 07:58:19 -0700
> From: [email protected]
> To: [email protected]
> Subject: [EVDL] Li-Ion w/o BMS
> 
> 
> Let me come out right and say that using a Li-Ion pack without a BMS is
> downright foolish.
> 

For me the foolishness is directly proportional to the investment. As Li-Ion packs come down in price the need for a BMS becomes less mandatory. Of course, I mean an automated BMS. Many of us are used to being our own BMS  As an extreme example... If my primary concern was budget, and I could get 100ah cells for $1 each, I probably would not bother spending money on a BMS, I would just buy extra cells. I would do my best to charge and discharge within their limits and occasionally manually balance them, then replace any cells that I ruin along the way with my cheap $1 extras. We are a long way from that extreme, but being someone who is still dreamin of lithium, the lower the price the more tempted I am to buy some and be my own BMS.

damon 
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## EVDL List (Jul 27, 2007)

But with 100Ah cells costing $130+ and MiniBMS costing $12 per cell, isn't
that really cheap insurance?

Mike

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of damon henry
Sent: Thursday, August 26, 2010 11:47 AM
To: EV List
Subject: Re: [EVDL] Li-Ion w/o BMS





> Date: Thu, 26 Aug 2010 07:58:19 -0700
> From: [email protected]
> To: [email protected]
> Subject: [EVDL] Li-Ion w/o BMS
> 
> 
> Let me come out right and say that using a Li-Ion pack without a BMS 
> is downright foolish.
> 

For me the foolishness is directly proportional to the investment. As
Li-Ion packs come down in price the need for a BMS becomes less mandatory.
Of course, I mean an automated BMS. Many of us are used to being our own
BMS  As an extreme example... If my primary concern was budget, and I
could get 100ah cells for $1 each, I probably would not bother spending
money on a BMS, I would just buy extra cells. I would do my best to charge
and discharge within their limits and occasionally manually balance them,
then replace any cells that I ruin along the way with my cheap $1 extras.
We are a long way from that extreme, but being someone who is still dreamin
of lithium, the lower the price the more tempted I am to buy some and be my
own BMS.

damon 
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## EVDL List (Jul 27, 2007)

It depends, even at those prices going without a BMS is tempting. I'm not sure what the miniBMS buys you, or what risks it exposes your cells to (poorly designed BMS modules can fail in a way that ruins the cell it is supposed to protect), but you are paying a 10% premium. You could buy 10% more cells and possibly come out ahead depending on how good you are to your batteries. 

Personally, when/if I do do something with lithium, I will likely do it like almost everything I have done with my EV's. I will find a way to start out small with limited financial risk while gaining valuable experience. For instance, right now I could easily put 4 100 ahr lithium cells in series with my current pack of flooded Nicads in my truck. I could try using them without a BMS and see how I like it. After gaining some experience I would know how important a BMS is to me personally as well as what features of a BMS really want the most. Then, I could try buying just 4 BMS modules and see how I like those etc...

damon

> From: [email protected]
> To: [email protected]
> Date: Thu, 26 Aug 2010 21:17:22 -0600
> Subject: Re: [EVDL] Li-Ion w/o BMS
> 
> But with 100Ah cells costing $130+ and MiniBMS costing $12 per cell, isn't
> that really cheap insurance?
> 
> Mike
> 
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf
> Of damon henry
> Sent: Thursday, August 26, 2010 11:47 AM
> To: EV List
> Subject: Re: [EVDL] Li-Ion w/o BMS
> 
> 
> 
> 
> 
> > Date: Thu, 26 Aug 2010 07:58:19 -0700
> > From: [email protected]
> > To: [email protected]
> > Subject: [EVDL] Li-Ion w/o BMS
> > 
> > 
> > Let me come out right and say that using a Li-Ion pack without a BMS 
> > is downright foolish.
> > 
> 
> For me the foolishness is directly proportional to the investment. As
> Li-Ion packs come down in price the need for a BMS becomes less mandatory.
> Of course, I mean an automated BMS. Many of us are used to being our own
> BMS  As an extreme example... If my primary concern was budget, and I
> could get 100ah cells for $1 each, I probably would not bother spending
> money on a BMS, I would just buy extra cells. I would do my best to charge
> and discharge within their limits and occasionally manually balance them,
> then replace any cells that I ruin along the way with my cheap $1 extras.
> We are a long way from that extreme, but being someone who is still dreamin
> of lithium, the lower the price the more tempted I am to buy some and be my
> own BMS.
> 
> damon 
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## EVDL List (Jul 27, 2007)

> damon henry wrote:
> >
> > It depends, even at those prices going without a BMS is tempting. I'm not
> > sure what the miniBMS buys you, or what risks it exposes your cells to
> ...


----------



## EVDL List (Jul 27, 2007)

The MiniBMS does two things: If the 12V system is off, it assumes you are
charging. Each cell monitor watches for the high threshold voltage. When
that is triggered, it can either alert or turn off the charger. Most people
have it turn off the charger.

When the 12V system is off, it assumes you are discharging. Each cell
monitor then watches for the low threshold voltage. When that is triggered,
it alerts the driver with a buzzer. You could do something more drastic,
but generally, you just want to back off and stop driving very soon.

In addition, the cell monitors can be ordered with shunts that dissipate
power as a cell reaches the threshold. This is supposed to allow time for
the cells with lower capacity to reach a fuller charge.

The car I bought arrived with them so it wasn't an issue for me. Also, I'm
only driving 1/2 capacity on the batteries, so I really don't expect to
reach the low threshold. Still, a pretty slick system and I know that no
cells are going to be overcharged. I'm not convinced the shunting operates
long enough to keep the tops balanced, though. I plan to check cell
voltages this weekend and see how things are going after a month of driving.

Mike

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of damon henry
Sent: Thursday, August 26, 2010 9:53 PM
To: EV List
Subject: Re: [EVDL] Li-Ion w/o BMS


It depends, even at those prices going without a BMS is tempting. I'm not
sure what the miniBMS buys you, or what risks it exposes your cells to
(poorly designed BMS modules can fail in a way that ruins the cell it is
supposed to protect), but you are paying a 10% premium. You could buy 10%
more cells and possibly come out ahead depending on how good you are to your
batteries. 

Personally, when/if I do do something with lithium, I will likely do it like
almost everything I have done with my EV's. I will find a way to start out
small with limited financial risk while gaining valuable experience. For
instance, right now I could easily put 4 100 ahr lithium cells in series
with my current pack of flooded Nicads in my truck. I could try using them
without a BMS and see how I like it. After gaining some experience I would
know how important a BMS is to me personally as well as what features of a
BMS really want the most. Then, I could try buying just 4 BMS modules and
see how I like those etc...

damon

> From: [email protected]
> To: [email protected]
> Date: Thu, 26 Aug 2010 21:17:22 -0600
> Subject: Re: [EVDL] Li-Ion w/o BMS
> 
> But with 100Ah cells costing $130+ and MiniBMS costing $12 per cell, 
> isn't that really cheap insurance?
> 
> Mike
> 
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On 
> Behalf Of damon henry
> Sent: Thursday, August 26, 2010 11:47 AM
> To: EV List
> Subject: Re: [EVDL] Li-Ion w/o BMS
> 
> 
> 
> 
> 
> > Date: Thu, 26 Aug 2010 07:58:19 -0700
> > From: [email protected]
> > To: [email protected]
> > Subject: [EVDL] Li-Ion w/o BMS
> > 
> > 
> > Let me come out right and say that using a Li-Ion pack without a BMS 
> > is downright foolish.
> > 
> 
> For me the foolishness is directly proportional to the investment. As 
> Li-Ion packs come down in price the need for a BMS becomes less mandatory.
> Of course, I mean an automated BMS. Many of us are used to being our 
> own BMS  As an extreme example... If my primary concern was budget, 
> and I could get 100ah cells for $1 each, I probably would not bother 
> spending money on a BMS, I would just buy extra cells. I would do my 
> best to charge and discharge within their limits and occasionally 
> manually balance them, then replace any cells that I ruin along the way
with my cheap $1 extras.
> We are a long way from that extreme, but being someone who is still 
> dreamin of lithium, the lower the price the more tempted I am to buy 
> some and be my own BMS.
> 
> damon
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## EVDL List (Jul 27, 2007)

> Date: Fri, 27 Aug 2010 04:06:23 -0700
> From: [email protected]
> To: [email protected]
> Subject: Re: [EVDL] Li-Ion w/o BMS
> 
> 
> 


> > damon henry wrote:
> > >
> > > It depends, even at those prices going without a BMS is tempting. I'm not
> > > sure what the miniBMS buys you, or what risks it exposes your cells to
> ...


----------



## EVDL List (Jul 27, 2007)

> damon henry wrote:
> > even at those prices going without a BMS is tempting. I'm not sure what the miniBMS buys you, or what risks it exposes your cells to (poorly designed BMS modules can fail in a way that ruins the cell it is supposed to protect), but you are paying a 10% premium.
> Lithiums burn, and one of their failure modes is to start a fire. So one
> of the risks of going without a BMS is that one catches fire and
> ...


----------



## EVDL List (Jul 27, 2007)

Has a LiFePO4 cell ever burned from being overcharged or over discharged in a
vehicle without a BMS?




> Lee Hart wrote:
> >
> >
> > Lithiums burn, and one of their failure modes is to start a fire.
> ...


----------



## EVDL List (Jul 27, 2007)

> AMPhibian wrote:
> > Has a LiFePO4 cell ever burned from being overcharged or over discharged in a
> > vehicle without a BMS?
> >
> ...


----------



## EVDL List (Jul 27, 2007)

> Mike Nickerson wrote:
> 
> > (The MiniBMS is) ... "a pretty slick system and I know that no cells are
> > going to be overcharged. I'm not convinced the shunting operates long
> ...


----------



## EVDL List (Jul 27, 2007)

> Lock Hughes wrote:
> > Lee... I'm assembling a pack of Headway LiFePO4 in a "motorcycle" (really just a powered kick scooter in my opinion, but using lame legal definitions here) so this concerns me... Truth. Was it the cells themselves that caught fire or surrounding wiring/packaging etc that got overheated? Name names pls?
> The person that it happened to is on the list. I'd rather leave it to
> him to provide more details if he's so inclined. But the essence of it
> ...


----------



## EVDL List (Jul 27, 2007)

On Fri, Aug 27, 2010 at 7:32 PM, Charles Whalen <[email protected]> wro=
te:


> > Mike Nickerson wrote:
> >
> >> (The MiniBMS is) ... "a pretty slick system and I know that no cells are
> >> going to be overcharged. I'm not convinced the shunting operates long
> ...


----------



## EVDL List (Jul 27, 2007)

There was a plug in prius that burned not too long ago. A123 cells
combined with poor pack construction and insufficient monitoring =
fire. From the pictures it looks like the lithium burned in some
cells.





> AMPhibian <[email protected]> wrote:
> >
> > Has a LiFePO4 cell ever burned from being overcharged or over discharged in a
> > vehicle without a BMS?
> ...


----------



## EVDL List (Jul 27, 2007)

http://endless-sphere.com/forums/viewtopic.php?f=14&t=18577&start=0

http://www.batteryvehiclesociety.org.uk/forums/viewtopic.php?t=1825

-Osmo



Peter Gabrielsson kirjoitti 28.8.2010 kello 7.08:

> There was a plug in prius that burned not too long ago. A123 cells
> combined with poor pack construction and insufficient monitoring =
> fire. From the pictures it looks like the lithium burned in some
> cells.
>
>
>
> On Fri, Aug 27, 2010 at 3:18 PM, AMPhibian <[email protected]> 


> > wrote:
> >>
> >> Has a LiFePO4 cell ever burned from being overcharged or over
> >> discharged in a
> ...


----------



## EVDL List (Jul 27, 2007)

I have had several possibilities to investigate burned EVs and other
battery systems. And there are too many of those if you ask me.

At some cases the BMS has recorded effects of loose connection
(voltage loss and heat generation) on the pack and prevented the fire.
Users have been able to get away with just tightening bolts etc.

Molten charger control relay that never stopped the charger from
overcharging. After added features and redundancy problem was solved.
But it was a close call.

I know few of these Prius upgrades that have burned down due wrong
connection method with the cables (very similar cases that was
reported here). If the BMS would have been measuring the temperature
on every cell those cars could still be on the roads. Now they are
recycled metal. LiFePO4 cells do burn just like any other Lithium
cells. They just need more heat.

Fully working BMS with limited capabilities can prevent most of the
failure modes. But every now and then there are situations that would
require more. Commercial solutions cannot be designed to be
"half-safe".

If the user cannot understand how the battery works they should not be
allowed to even touch the internal parts of the system. Welded IP68
casing and no possibility for user to tinker. But before we can go
there BMS has to work flawlessly at least 10 years. It's a challenge
to tackle.

No BMS is no-go even with LiFePO4. It just takes considerably longer
time to see the effects of systematic cell murder.

-Jukka



2010/8/28 Osmo S <[email protected]>:
> http://endless-sphere.com/forums/viewtopic.php?f=14&t=18577&start=0
>
> http://www.batteryvehiclesociety.org.uk/forums/viewtopic.php?t=1825
>
> -Osmo
>
>
>
> Peter Gabrielsson kirjoitti 28.8.2010 kello 7.08:
>
>> There was a plug in prius that burned not too long ago. A123 cells
>> combined with poor pack construction and insufficient monitoring =
>> fire. From the pictures it looks like the lithium burned in some
>> cells.
>>
>>
>>
>> On Fri, Aug 27, 2010 at 3:18 PM, AMPhibian <[email protected]>


> >> wrote:
> >>>
> >>> Has a LiFePO4 cell ever burned from being overcharged or over
> >>> discharged in a
> ...


----------



## EVDL List (Jul 27, 2007)

Peter Gabrielsson wrote:
> 
>


> AMPhibian <[email protected]> wrote:
> >> Has a LiFePO4 cell ever burned from being overcharged or over discharged
> >> in a
> >> vehicle without a BMS?
> ...


----------



## EVDL List (Jul 27, 2007)

You're right, missing hardware was the cause of the heat and
overcharging/discharging had nothing to do with it. However, with
sufficient temperature monitoring of each cell, the discharge could
have been stopped long before the thermal event. Max operating temp
for the cell is 60C and they went around 105C.

>From the investigation report:
"The temperature sensors used to monitor the temperature across the
parallel groups in a
battery were likely very slow to respond to this internal cell heat.
The fact that they were
not in contact with any cell and that each cell is somewhat thermally
insulated via the
cardboard sleeve means that heat conduction into the temperature
sensor would be a slow
process, lagging greatly behind the actual temperature of the cells. "

http://wikileaks.org/wiki/Toyota_Prius_A123_car_fire_investigation_report_2008



> Elithion <[email protected]> wrote:
> >
> >
> > Peter Gabrielsson wrote:
> ...


----------



## EVDL List (Jul 27, 2007)

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----------



## EVDL List (Jul 27, 2007)

A small capacity high power motorcycle pack is certainly one place I'd expect
to see a good BMS. The smaller ah capacity means there is going to be less
leeway in the amount of charge going in and out. A 100ah or larger EV pack
has a lot more room for error, so to speak. Not saying problems can't
arise, but the system has more cushion. The only prismatic LiFePO4 cell
fire I'm aware of is a single cell that Jack Rickard left on a 10 amp power
supply for hours, and forgot about.
As Tom has pointed out a BMS in and of itself does not guarantee a perfect
result every time. A fair number of people have lost cells because of
faulty BMS's. If fire is your main concern you might be better off with
temperature sensing circuits that can break a pack connection and shut down
a charger. Additionally since prismatic cells come with specs showing
tested internal resistance and capacity it would probably be worth paying a
small premium if necessary to get them all matched in capacity and
resistance, which would further minimize any need for a BMS.




> Lee Hart wrote:
> >
> > AMPhibian wrote:
> >> Has a LiFePO4 cell ever burned from being overcharged or over discharged
> ...


----------



## EVDL List (Jul 27, 2007)

It is also a place I'd expect to see a quality built battery pack vs some
hack tape job and expect it to perform properly. I'd love to see how the
connected his batteries. The burned pack shown in the photos goes to show
that it is very very very important to have a quality built pack too. If you
can't do it correctly yourself then have it done for you. I'd also expect
the person to use them within the safe limits of the pack. If you go outside
those limits or on the edge then you'd expect to see these kind of results. 

Pete 




-----
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## EVDL List (Jul 27, 2007)

Sounds like a rather bad idea to me. You will limit your potential range and
likely end up damaging that cell since it will always be charged and
discharged more than the others, plus run at a higher C rate. Your pack
will already come with a smallest cell, use that one as your trigger. When
you bottom balance your pack you'll know during your first charge which one
reaches full first, and is thus your smallest.




> Elithion wrote:
> >
> > PS. Quick and dirty trick:
> > Make the pack with a single, lower capacity cell (e.g.: a 90 AH cell in a
> ...


----------



## EVDL List (Jul 27, 2007)

If a BMS were not necessary for safe operation of a multi-cell 
battery pack, then the cell manufacturers would not require (or at 
least strongly recommend) a BMS. They would gladly let you charge 
them "to death" and then sell you replacements when you ruined them.

I say to the folks that recommend not using a BMS; put your money 
where your mouth is. Offer to pay for the ruined cells, and the fire 
damage, that will occur when folks foolishly follow your advice.

I have seen multiple pack fires on hybrid electric buses, using 
lead-acid batteries, exactly because they did not have a BMS. 
Lead-acid batteries are mighty difficult to set on fire, but they 
managed to do so because they would eventually get out of balance, 
and then the problem would run away quickly. These were "matched" 
packs, by the way. (Installation of a BMS solved the problem, by the way.)

The only reason I jump into these "no BMS needed" threads is because 
I don't want news stories about all the EV fires that are _certian_ 
to occur when folks forgo a BMS on a Li_Ion pack. The news media will 
attribute the fires to "EV technology", not to the moron that advised 
the EV owner to forgo a BMS.

Bill D. 

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----------



## EVDL List (Jul 27, 2007)

You don't run your ICE vehicle on the fence line do you? Hardly. So why would
you do so with your battery pack? Why does every one have to operate their
pack on the edge of disaster. If you have a system that limit charge or
discharge then by all means use some sort of BMS system. If you must charge
your pack to it's upper limits and discharge it to its lowest limits you'd
be foolish to run without a system in place. But on the other hand if you
never take it over the top or under the bottom you have an excellent chance
to have your pack give you many years of trouble free service. I see every
one that runs on the edge needing to constantly watch and monitor and
balance and rebalance all the time and hope they can keep their packs alive.
I can also say that there are plenty of folks doing just that and having
very good luck with out the expensive controversial BMS systems out there.
Heck which one do you recommend? Can you say? Would you be willing to bet my
pack against your recommendation? There are just too many to choose from to
know if your actually buying a GOOD one. Every one says their product is
what you need. Normal business. How does one proceed? So far I know one who
has over 15000 miles and almost 2 years so far and not a single out of
balance pack yet. And that is with the early TS packs. If my controller did
not allow me to limit pack voltage limits then I'd need some sort of system
to cut it back. If I did not have a charger that would limit my charge
voltage I'd need something to limit that. I don't need a charger to take it
to its utter most limits and shunt until all are balanced. That is way to
risky for my investment. Even with a BMS. That is way risky. Even with lead
acid it's risky. You can limit Lead batteries too. Works just as well. Sure
you don't get the utmost out of your pack but then again you'd plan for that
now wouldn't you. 




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----------



## EVDL List (Jul 27, 2007)

Im one of these morons that doesnt have BMS on my 90Ahr Liion pack. However 
I run it in parallel with a 50Ahr string of lead acids that provides the 
high accel currents. Also I do a manual equalise every few months using a 
4V 25A cell charger. So I suppose I do have BMS but it is a passive/manual 
one

--------------------------------------------------
From: "Bill Dube" <[email protected]>
Sent: Sunday, August 29, 2010 10:18 AM
To: "Electric Vehicle Discussion List" <[email protected]>
Subject: Re: [EVDL] Li-Ion w/o BMS

> If a BMS were not necessary for safe operation of a multi-cell
> battery pack, then the cell manufacturers would not require (or at
> least strongly recommend) a BMS. They would gladly let you charge
> them "to death" and then sell you replacements when you ruined them.
>
> I say to the folks that recommend not using a BMS; put your money
> where your mouth is. Offer to pay for the ruined cells, and the fire
> damage, that will occur when folks foolishly follow your advice.
>
> I have seen multiple pack fires on hybrid electric buses, using
> lead-acid batteries, exactly because they did not have a BMS.
> Lead-acid batteries are mighty difficult to set on fire, but they
> managed to do so because they would eventually get out of balance,
> and then the problem would run away quickly. These were "matched"
> packs, by the way. (Installation of a BMS solved the problem, by the way.)
>
> The only reason I jump into these "no BMS needed" threads is because
> I don't want news stories about all the EV fires that are _certian_
> to occur when folks forgo a BMS on a Li_Ion pack. The news media will
> attribute the fires to "EV technology", not to the moron that advised
> the EV owner to forgo a BMS.
>
> Bill D.
>
> _______________________________________________
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_______________________________________________
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| Multiple-address or CCed messages may be rejected.
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## EVDL List (Jul 27, 2007)

> Bill Dube wrote:
> >
> > I say to the folks that recommend not using a BMS; put your money
> > where your mouth is. Offer to pay for the ruined cells, and the fire
> ...


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