siingle cell capacity tester

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siingle cell capacity tester

Peakfoto Digital Photo Still n Video
 Is there an atuomatic  siingle cell LFP cycling capacity tester ? out there ..

Like  an RC hobby gadget that would work with even a 40ah  to  150 ah cell, $100 or less, maybe 5 - 20 amps, so it could work, maybe  2 to 24 hours, and would digitally tell you, your AH capacity ?

Itd be nice to how the cells are doing in our pack.

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Re: siingle cell capacity tester

Michael Ross
Doubtful you can buy it, but you can make one.  I am in the process myself.
 Sure you want to do this at home?  This much power is non-trivial.  Be
wary.

You can see Jack Rickard doing a high C discharge in a video from  last
fall, 1000Amps. (EVTV Motor Verks
http://www.evtv.me.s3-website-us-east-1.amazonaws.com/vidarch.html)
 He used a 20 foot reebar bent in half.  You can turn them red.  Sorry I
don't remember which video.  I think I saw a guy doing it with a reebar on
his sandy driveway on you tube, and someone else suggest a roll of welded
wire in a trash can full of water.  That is the sort of resistor you need
to do it fast.  You can buy big wirewound resistors too. For example
http://snipurl.com/28uh1bm but bigger.
Some people run their batteries down with their EV - jack it up and let it
spin.

You will want a big contactor for closing and opening the circuit, a bunch
of fat wire.  A JLD 404 with a shunt is very handy for measuring the Ah you
are passing in and out of the cells.  It has relay control outputs that are
very handy.  JLD 612 is a temperature controller that is good as a thermal
safety.

You need to be handy with the arithmetic - Ohms Law and all that.
 Seriously, if you don't size things right you can get hurt or burn
something up or down.


On Fri, Apr 25, 2014 at 2:35 AM, Peakfoto Digital Photo Still n Video <
[hidden email]> wrote:

>  Is there an atuomatic  siingle cell LFP cycling capacity tester ? out
> there ..
>
> Like  an RC hobby gadget that would work with even a 40ah  to  150 ah
> cell, $100 or less, maybe 5 - 20 amps, so it could work, maybe  2 to 24
> hours, and would digitally tell you, your AH capacity ?
>
> Itd be nice to how the cells are doing in our pack.
>
> _______________________________________________
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>
>


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(919) 550-2430 Land
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Re: siingle cell capacity tester

Adrian DeLeon
In reply to this post by Peakfoto Digital Photo Still n Video
Have a look at the iCharger units made for RC packs. The
charge/discharge/cycle modes show elapsed time, charge current, and
total mAHr. The iCharge 206B that I have is $112 at www.hobbyking.com

Note: all iChargers require an EXTERNAL DC POWER SUPPLY, and the power
supply voltage may limit the maximum charge/discharge current of the unit.

iCharger 206B specs:

Requires 10-28V DC power supply
Will charge up to 6S Li, 17S NiMH/NiCad, or 2-24V Pb

20A (300W max) charge
20A (20W max) discharge - 300W with external load
Internal resistance measurement (haven't tried this one)
Temperature probe/compensation
Programmable settings
36 Hour data logging - transfer via USB


There is also a "regenerative discharge" feature that discharges packs
by feeding power back into the power supply. I couldn't find any
information on the max cell capacity cell it will handle. Maximum
capacity is not listed in the manual and examples in the literature only
show data for 5 AHr or smaller packs. The iCharger website is
www.icharger.co.nz

HTH,

Adrian

On 04/24/2014 11:35 PM, Peakfoto Digital Photo Still n Video wrote:

>   Is there an atuomatic  siingle cell LFP cycling capacity tester ? out there ..
>
> Like  an RC hobby gadget that would work with even a 40ah  to  150 ah cell, $100 or less, maybe 5 - 20 amps, so it could work, maybe  2 to 24 hours, and would digitally tell you, your AH capacity ?
>
> Itd be nice to how the cells are doing in our pack.
>
> _______________________________________________
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>

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Re: siingle cell capacity tester

Lee Hart
In reply to this post by Peakfoto Digital Photo Still n Video
Peakfoto Digital Photo Still n Video wrote:
>   Is there an atuomatic  siingle cell LFP cycling capacity tester ? out there ..
>
> Like  an RC hobby gadget that would work with even a 40ah  to  150 ah cell, $100 or less, maybe 5 - 20 amps, so it could work, maybe  2 to 24 hours, and would digitally tell you, your AH capacity ?
>
> Itd be nice to how the cells are doing in our pack.

I have an MRC-89 Superbrain battery tester. It is built for R/C cells
and batteries up to 20aH. These sell for about $100. It can test
higher-capacity cells, but its amphour counter will "roll over" from
199.99ah to 0 so you have you have to add the excess beyond this.

It is limited to a charge/discharge current of about 5 amps. They claim
more; but it will overheat if you do and shut down before the test is
complete.

I built my own tester for higher currents. It goes to 100 amps. If you
like building things, I could supply the PC board for it.

--
Any intelligent fool can make things bigger, more complex, and more
violent. It takes a touch of genius, and a lot of courage, to move
in the opposite direction. -- Albert Einstein
--
Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.htm
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Re: siingle cell capacity tester

Jeff Major
In reply to this post by Michael Ross
westmountainradio.com


CBA IV  Works well.  I have one.  Fairly automatic, I guess.  Holds constant current and shuts off at LVC. 
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Re: siingle cell capacity tester

Adrian DeLeon
In reply to this post by Adrian DeLeon

On 04/25/2014 07:54 AM, Adrian DeLeon wrote:
> Have a look at the iCharger units made for RC packs.

Just noticed in the manual that a "forming charge" for NiCad/NiMH is
limited to 9.9 AHr, and the portion of the display for measuring mAHr is
5 digits, implying a 99,999 mAHr limit before something "unknown"
happens. I sent an inquiry to the manufacturer for clarification. I'll
forward any responses.

-Adrian
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Re: siingle cell capacity tester

Lee Hart
In reply to this post by Michael Ross
Michael Ross wrote:
> Doubtful you can buy it, but you can make one. I am in the process myself.
> Sure you want to do this at home? This much power is non-trivial. Be
> wary.

A single cell isn't too bad. Doing a whole pack gets into high power
territory.

Power = volts x amps. For power under 1000 watts, you can make or buy
power resistors. 3.6v at 100a is only 360 watts. This will be smaller
than your fist. It will get hot, so a good airflow around it is needed
(like a fan). Up to 1000 watts or so, you can re-purpose a small ceramic
heater. Replace its heating element with your load resistors, and use
its fan to cool it.

For high current and high voltage at the same time, the power gets
pretty high. Commercial multi-kilowatt power resistors are as big as
your arm, and can be found for $20 and up. These need to be cooled with
a big fan, or immersed in water.

Jury-rigged resistors can be made out of almost anything, if you're
knowledgeable. The resistance is unpredictable, and will change with
temperature and how well you connect the wires to it.

For the pack as a whole, you can use your car's motor controller as an
adjustable resistor. It can drive a resistive load just as well as an
inductive load (the motor). Disconnect the motor, and connect your load
resistor in its place. Use the throttle to control the battery current.
This has the advantage that your contactors, fuses, and meters are all
in the circuit.

--
Any intelligent fool can make things bigger, more complex, and more
violent. It takes a touch of genius, and a lot of courage, to move
in the opposite direction. -- Albert Einstein
--
Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.htm
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Re: siingle cell capacity tester

Peakfoto Digital Photo Still n Video
In reply to this post by Peakfoto Digital Photo Still n Video
 

For the pack as a whole, you can use your car's motor controller as an
adjustable resistor. It can drive a resistive load just as well as an
inductive load (the motor). Disconnect the motor, and connect your load
resistor in its place. Use the throttle to control the battery current.
This has the advantage that your contactors, fuses, and meters are all
in the circuit.
 

> what about a resitor /s for an ac motor controlling circut?
you'd have to have 3 ?

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Re: siingle cell capacity tester

Lee Hart
In reply to this post by Lee Hart
Lee Hart wrote:
> I have an MRC-89 Superbrain battery tester. It is built for R/C cells
> and batteries up to 20aH. These sell for about $100. It can test
> higher-capacity cells, but its amphour counter will "roll over" from
> 199.99ah to 0 so you have you have to add the excess beyond this.

Correction: It's an MRC Superbrain 989 (not 89). And the amphour counter
rolls over at 19.99ah (not 199.99ah).

--
Any intelligent fool can make things bigger, more complex, and more
violent. It takes a touch of genius, and a lot of courage, to move
in the opposite direction. -- Albert Einstein
--
Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.htm
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Re: siingle cell capacity tester

Lee Hart
In reply to this post by Peakfoto Digital Photo Still n Video
Peakfoto Digital Photo Still n Video wrote:

>
>
> For the pack as a whole, you can use your car's motor controller as an
> adjustable resistor. It can drive a resistive load just as well as an
> inductive load (the motor). Disconnect the motor, and connect your load
> resistor in its place. Use the throttle to control the battery current.
> This has the advantage that your contactors, fuses, and meters are all
> in the circuit.
>
>
>> what about a resitor /s for an ac motor controlling circut?
> you'd have to have 3 ?

Yes, for a 3-phase AC motor controller you'd need 3 load resistors.

Note that DC motor controllers are pretty "laid back" about the load
they will drive. You can put any motor on any controller, and it won't
care (beyond its normal current and voltage limits).

An EV AC motor controller is typically matched to its motor. It will
probably complain and refuse to work with a resistive load. However,
industrial 3-phase AC motor controllers don't care. I've tested them
before with resistive loads when a motor wasn't handy.

--
Any intelligent fool can make things bigger, more complex, and more
violent. It takes a touch of genius, and a lot of courage, to move
in the opposite direction. -- Albert Einstein
--
Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.htm
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Re: siingle cell capacity tester

EVDL Administrator
In reply to this post by Lee Hart
On 25 Apr 2014 at 10:25, Lee Hart wrote:

> For the pack as a whole, you can use your car's motor controller as an
> adjustable resistor. It can drive a resistive load just as well as an
> inductive load (the motor).

Don't you need inductance in the load for a DC controller's current limit to
function?  If so, you'd have to manually monitor the current carefully, no?

David Roden - Akron, Ohio, USA
EVDL Administrator

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Re: siingle cell capacity tester

John Lussmyer
On Fri Apr 25 10:36:58 PDT 2014 [hidden email] said:
>On 25 Apr 2014 at 10:25, Lee Hart wrote:
>
>> For the pack as a whole, you can use your car's motor controller as an
>> adjustable resistor. It can drive a resistive load just as well as an
>> inductive load (the motor).
>
>Don't you need inductance in the load for a DC controller's current limit to
>function?  If so, you'd have to manually monitor the current carefully, no?

A big Honkin Resistor will limit the current quite well.
Unless you decide to use 2 feet of 4/0 cable as your resistor.
I doubt that you will want your "load" to be drawing 1000A.  So you choose a resistor that will limit current to what you want. (likely well below the controllers current limit.)


--

Bobcats and Cougars, oh my!  http://john.casadelgato.com/Pets
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Re: siingle cell capacity tester

EcoReality
In reply to this post by Peakfoto Digital Photo Still n Video
> From: Lee Hart <[hidden email]>
>
> Michael Ross wrote:
>> Doubtful you can buy it, but you can make one. I am in the process myself.
>> Sure you want to do this at home? This much power is non-trivial. Be
>> wary.
>
> A single cell isn't too bad. Doing a whole pack gets into high power
> territory.

Depending on your pack voltage, you might consider electric baseboard heaters for a load. They are designed to dissipate heat! And they are fairly cheap, even if new. When people re-model, they are often free.

I put an ad on our local Craigslist for a bunch of these, and bartered ten of them for some canned farm goods. I strip the heating element out and mount it to the bottom of our greenhouse tables for early spring seedling heat. (Seed mats designed for the purpose cost hundreds of dollars!)

A 6' baseboard dissipates 5kW at 240 volts, or 1.25kW at 120 volts. You can parallel or series various units to come up with just about any multi-kilowatt power dissipation you want.

Do this in the winter and save on your gas or wood heating bill. (Do it in the summer, and add to your air-conditioning bill. :-)

:::: Wouldn’t it be something to live in an era when every town and village has its own honored food farmers as well as its own revered artists, artisans, musicians, writers, restaurateurs and educators? -- Gene Logsdon
:::: Jan Steinman, EcoReality Co-op ::::

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Re: siingle cell capacity tester

h.godavari
Your local Freecycle.org is another source for the heaters. Totally free for the asking :-)

hg
----- Original Message -----
From: Jan Steinman <[hidden email]>
To: [hidden email]
Sent: Fri, 25 Apr 2014 12:02:00 -0600 (MDT)
Subject: Re: [EVDL] siingle cell capacity tester

> From: Lee Hart <[hidden email]>
>
> Michael Ross wrote:
>> Doubtful you can buy it, but you can make one. I am in the process myself.
>> Sure you want to do this at home? This much power is non-trivial. Be
>> wary.
>
> A single cell isn't too bad. Doing a whole pack gets into high power
> territory.

Depending on your pack voltage, you might consider electric baseboard heaters for a load. They are designed to dissipate heat! And they are fairly cheap, even if new. When people re-model, they are often free.

I put an ad on our local Craigslist for a bunch of these, and bartered ten of them for some canned farm goods. I strip the heating element out and mount it to the bottom of our greenhouse tables for early spring seedling heat. (Seed mats designed for the purpose cost hundreds of dollars!)

A 6' baseboard dissipates 5kW at 240 volts, or 1.25kW at 120 volts. You can parallel or series various units to come up with just about any multi-kilowatt power dissipation you want.

Do this in the winter and save on your gas or wood heating bill. (Do it in the summer, and add to your air-conditioning bill. :-)

:::: Wouldn’t it be something to live in an era when every town and village has its own honored food farmers as well as its own revered artists, artisans, musicians, writers, restaurateurs and educators? -- Gene Logsdon
:::: Jan Steinman, EcoReality Co-op ::::

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Re: siingle cell capacity tester

Lee Hart
In reply to this post by EVDL Administrator
EVDL Administrator wrote:
>  Don't you need inductance in the load for a DC controller's current
limit to
> function?  If so, you'd have to manually monitor the current carefully, no?

As long as your load has enough resistance to limit the current to
something under the controller's current limit, the controller will be fine.

Plus, you will have inductance in the load whether you like it or not.
If it's a wire-wound resistor, it will be inductive. The connecting
wires add a little more inductance as well.

I just know that it works. :-) Note that the Curtis controller manual
even shows testing the controller with light bulbs as a simulated motor
load. Light bulbs are almost purely resistive.
--
Any intelligent fool can make things bigger, more complex, and more
violent. It takes a touch of genius, and a lot of courage, to move
in the opposite direction. -- Albert Einstein
--
Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.htm
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Re: siingle cell capacity tester

EV professor
In reply to this post by EVDL Administrator
The circuit of the motor controller makes a difference. The old SCR
controllers needed the inductive CEMF kick to assure switching, Modern
IGFET power transistors do not.  so they can act as battery chargers.

*Dennis Lee Miles *

*Director   **E.V.T.I. Inc.*

*E-Mail:*  *[hidden email]* <[hidden email]>

   *Phone #* *(863) 944-9913*

Dade City, Florida 33523

 USA




On Fri, Apr 25, 2014 at 1:36 PM, EVDL Administrator <[hidden email]> wrote:

> On 25 Apr 2014 at 10:25, Lee Hart wrote:
>
> > For the pack as a whole, you can use your car's motor controller as an
> > adjustable resistor. It can drive a resistive load just as well as an
> > inductive load (the motor).
>
> Don't you need inductance in the load for a DC controller's current limit
> to
> function?  If so, you'd have to manually monitor the current carefully, no?
>
> David Roden - Akron, Ohio, USA
> EVDL Administrator
>
> = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
> EVDL Information: http://www.evdl.org/help/
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> reach me.  To send a private message, please obtain my
> email address from the webpage http://www.evdl.org/help/ .
> = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
>
>
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>
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Re: siingle cell capacity tester

Lee Hart
Dennis Miles wrote:
> The circuit of the motor controller makes a difference. The old SCR
> controllers needed the inductive CEMF kick to assure switching, Modern
> IGFET power transistors do not.  so they can act as battery chargers.

I've actually observed just the opposite with the controllers I've tried
this with. The old GE EV-1 SCR controller has its own internal
inductors, and worked fine with a resistor or battery as a load.

Solid state controllers with IGBTs or MOSFETs can drive a resistive
load, as long as the peak current doesn't exceed their current limit.
But they cannot drive a battery as load; the battery's resistance is too
low.

--
Any intelligent fool can make things bigger, more complex, and more
violent. It takes a touch of genius, and a lot of courage, to move
in the opposite direction. -- Albert Einstein
--
Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.htm
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Re: siingle cell capacity tester

Willie2
On 04/25/2014 04:34 PM, Lee Hart wrote:

> Dennis Miles wrote:
>> The circuit of the motor controller makes a difference. The old SCR
>> controllers needed the inductive CEMF kick to assure switching, Modern
>> IGFET power transistors do not.  so they can act as battery chargers.
>
> I've actually observed just the opposite with the controllers I've
> tried this with. The old GE EV-1 SCR controller has its own internal
> inductors, and worked fine with a resistor or battery as a load.
>
> Solid state controllers with IGBTs or MOSFETs can drive a resistive
> load, as long as the peak current doesn't exceed their current limit.
> But they cannot drive a battery as load; the battery's resistance is
> too low.
>
I've read/heard that the Synkromotive controller can function as a
charger.  Does anyone know anything about that?  Were that true, it
seems like a lotta folks would be doing it and saving $500+ for a charger.

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Re: siingle cell capacity tester

EV professor
Lee Hart, I have great respect for you and your opinion.
 I would admonish anyone not to go and try using a motor controller for a
battery charger without ascertaining the exact design parameters it is
capable of. Every model is usually different and some are capable of
battery charging right off of the shelf, and others will require current
limiting, to prevent excessive current flow, or other circuit enhancements.
Technical Expertise, is why some can modify or repurpose equipment and
others who haven't the knowledge can not...

*Dennis Lee Miles *

*Director   **E.V.T.I. Inc.*

*E-Mail:*  *[hidden email]* <[hidden email]>

   *Phone #* *(863) 944-9913*

Dade City, Florida 33523

 USA




On Fri, Apr 25, 2014 at 6:10 PM, Willie2 <[hidden email]> wrote:

> On 04/25/2014 04:34 PM, Lee Hart wrote:
>
>> Dennis Miles wrote:
>>
>>> The circuit of the motor controller makes a difference. The old SCR
>>> controllers needed the inductive CEMF kick to assure switching, Modern
>>> IGFET power transistors do not.  so they can act as battery chargers.
>>>
>>
>> I've actually observed just the opposite with the controllers I've tried
>> this with. The old GE EV-1 SCR controller has its own internal inductors,
>> and worked fine with a resistor or battery as a load.
>>
>> Solid state controllers with IGBTs or MOSFETs can drive a resistive load,
>> as long as the peak current doesn't exceed their current limit. But they
>> cannot drive a battery as load; the battery's resistance is too low.
>>
>>  I've read/heard that the Synkromotive controller can function as a
> charger.  Does anyone know anything about that?  Were that true, it seems
> like a lotta folks would be doing it and saving $500+ for a charger.
>
>
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Re: siingle cell capacity tester

Lee Hart
Dennis Miles wrote:
> Lee Hart, I have great respect for you and your opinion.
>   I would admonish anyone not to go and try using a motor controller for a
> battery charger without ascertaining the exact design parameters it is
> capable of. Every model is usually different and some are capable of
> battery charging right off of the shelf, and others will require current
> limiting, to prevent excessive current flow, or other circuit enhancements.
> Technical Expertise, is why some can modify or repurpose equipment and
> others who haven't the knowledge can not...

You're right, Dennis. You don't want to fool with this stuff unless you
know what you're doing. One mistake, and you can blow an expensive or
motor controller!

That said... Figure out what current your resistive load would draw if
you connected it straight to the battery. If that's less than your motor
controller's rated current, it's pretty much a safe bet that you won't
hurt anything powering that resistor with the motor controller. The
motor controller will just work like a giant rheostat. It lets you
'throttle' power to the resistor just like it would do for a motor.

At worst, a microcomputer in the controller might shut down and say,
"Hey, that ain't no motor! I ain't gonna power it!"

As for using a motor controller as a battery charger: That is a much
trickier proposition. A battery has very low resistance, and can deliver
awesome peak currents! Few motor controllers are going to like powering
a battery directly. To do it, they would need a substantial output
inductor. The GE EV-1 happens to have such an inductor; but many
controllers won't!
--
Any intelligent fool can make things bigger, more complex, and more
violent. It takes a touch of genius, and a lot of courage, to move
in the opposite direction. -- Albert Einstein
--
Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.htm
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