Pulse charging physically possible?

[Alex Weedy]

I've been looking at a Turnigy Accucel 6 or 8 when I discovered this project. This is very interesting.

I have question related to NiCd/NiMh and Pb charging. Are these Imax clones capable of pulsing the charge current? How fast can they be pulsed?
In the case of NiCd/NiMh, my favourite charger (bc10000/iq328) uses a 25% duty cycle. IE: the 1A setting is 4A for 0.25 second, then zero for the next 0.75 seconds until deltaV- or 1.55v. http://imgur.com/zY8xgYb

With Pb charging if we can pulse the voltage high enough we could add desulfation to the feature list. But that needs 2x the battery voltage.
For example, small SLAs. 100-150mA pulse at 24-30v cycled around 1KHz. For car batteries 750mA and higher.
The same setting could be used (for short periods of time, under 5 minutes) on NiCd if they have been abused to extend there lifetime some what. (You can google people reviving cordless tool packs with welders and such).

Bonus: You mentioned you could not find a reliable source for Pb curves. Here is my take.
A Pb will charge when given more then 2.15 volts per cell (12.9v for a 12v, 6 cell battery). It will finish charging when it gets to 2.4 volts per cell (14.4v for a 12v).
So assuming you have a larger SLA or car battery STAGE 1(constant current) would dump the maximum amperage your charger can output until you reach 2.4 volts per cell (maybe 2.35v to be safe). Now you switch to STAGE 2(constant voltage) and start lowering the current to maintain 2.4 volts per cell.
Once the current tapers off to under 1amp I would switch to STAGE 3(maintenance) and keep the batteries at 2.30 volts per cell.
http://www.batteryuniversity.com/_img/content/clead1.jpg
Now assuming pulsing is possible I can imagine cycles where parts of either stage2 or stage3 are replaced with high voltage desulfation spikes.
Note: everything I just said assumes 20-25C room/starting battery temp. https://dl.dropboxusercontent.com/u/54767697/Screenshot%20from%202013-12-29%2006%3A07%3A11.png

Thank you for your hard work Paweł.

[Paweł Si]

2013/12/29 Alex Weedy <weed...@gmail.com>

I've been looking at a Turnigy Accucel 6 or 8 when I discovered this project. This is very interesting.

I have question related to NiCd/NiMh and Pb charging. Are these Imax clones capable of pulsing the charge current? How fast can they be pulsed?

I don't know but I'm sure it's fast enough,

The output current is controlled by the CPU (switching buck/boost converter) with a frequency of 31kHz

so the only limit is the output filter (capacitor).

In fact the original imaxB6 firmware charges NiCd/NiMh batteries with pulses,

unfortunately this is currently not implemented in cheali-charger, as for version 0.32 the NiCd/NiMh are charged with constant current, this may change in the (far) future.

 

In the case of NiCd/NiMh, my favourite charger (bc10000/iq328) uses a 25% duty cycle. IE: the 1A setting is 4A for 0.25 second, then zero for the next 0.75 seconds until deltaV- or 1.55v. http://imgur.com/zY8xgYb

With Pb charging if we can pulse the voltage high enough we could add desulfation to the feature list. But that needs 2x the battery voltage.
For example, small SLAs. 100-150mA pulse at 24-30v cycled around 1KHz. For car batteries 750mA and higher.
The same setting could be used (for short periods of time, under 5 minutes) on NiCd if they have been abused to extend there lifetime some what. (You can google people reviving cordless tool packs with welders and such).

Interesting idea, I understand it so that in the battery there formed small "needles" which shortened the battery plates,

and a very high current evaporates the "needles" (and also a part of the battery),

but I'm not sure it's the same as desulfation.

Nevertheless the maximum output voltage is ~25.2V but I'm pretty sure that

what really matters for desulfation is the maximum output current.

Bonus: You mentioned you could not find a reliable source for Pb curves. Here is my take.

Thanks for the bonus, as for cheali-charger-0.32 the Pb charge is implemented based on:

http://www.battery-usa.com/Catalog/NPAppManual%28Rev0500%29.pdf

site 11,

and: http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery

(the "stage3" is currently not implemented),

with a end voltage of 2.45V/cell and a current limit of 0.25C (changeable).

 

A Pb will charge when given more then 2.15 volts per cell (12.9v for a 12v, 6 cell battery). It will finish charging when it gets to 2.4 volts per cell (14.4v for a 12v).
So assuming you have a larger SLA or car battery STAGE 1(constant current) would dump the maximum amperage your charger can output until you reach 2.4 volts per cell (maybe 2.35v to be safe). Now you switch to STAGE 2(constant voltage) and start lowering the current to maintain 2.4 volts per cell.
Once the current tapers off to under 1amp I would switch to STAGE 3(maintenance) and keep the batteries at 2.30 volts per cell.
http://www.batteryuniversity.com/_img/content/clead1.jpg
Now assuming pulsing is possible I can imagine cycles where parts of either stage2 or stage3 are replaced with high voltage desulfation spikes.
Note: everything I just said assumes 20-25C room/starting battery temp. https://dl.dropboxusercontent.com/u/54767697/Screenshot%20from%202013-12-29%2006%3A07%3A11.png

Thank you for your hard work Paweł.

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[Weedy]

On 3 Jan 2014 09:38, "Paweł Si" <sta...@gmail.com> wrote:
> 2013/12/29 Alex Weedy <weed...@gmail.com>
>>
>> I've been looking at a Turnigy Accucel 6 or 8 when I discovered this project. This is very interesting.
>>
>> I have question related to NiCd/NiMh and Pb charging. Are these Imax clones capable of pulsing the charge current? How fast can they be pulsed?
>
>
> I don't know but I'm sure it's fast enough,
> The output current is controlled by the CPU (switching buck/boost converter) with a frequency of 31kHz
> so the only limit is the output filter (capacitor).
> In fact the original imaxB6 firmware charges NiCd/NiMh batteries with pulses,
> unfortunately this is currently not implemented in cheali-charger, as for version 0.32 the NiCd/NiMh are charged with constant current, this may change in the (far) future.

This is good news. Hardware is hard(er) to modify. Software only needs time.

>>
>> In the case of NiCd/NiMh, my favourite charger (bc10000/iq328) uses a 25% duty cycle. IE: the 1A setting is 4A for 0.25 second, then zero for the next 0.75 seconds until deltaV- or 1.55v. http://imgur.com/zY8xgYb
>>
>> With Pb charging if we can pulse the voltage high enough we could add desulfation to the feature list. But that needs 2x the battery voltage.
>> For example, small SLAs. 100-150mA pulse at 24-30v cycled around 1KHz. For car batteries 750mA and higher.
>> The same setting could be used (for short periods of time, under 5 minutes) on NiCd if they have been abused to extend there lifetime some what. (You can google people reviving cordless tool packs with welders and such).
>
>
> Interesting idea, I understand it so that in the battery there formed small "needles" which shortened the battery plates,
> and a very high current evaporates the "needles" (and also a part of the battery),
> but I'm not sure it's the same as desulfation.
>
> Nevertheless the maximum output voltage is ~25.2V but I'm pretty sure that
> what really matters for desulfation is the maximum output current.

Voltage please.
The crystals can be broken up with either. But high voltage low amperage spikes "vibrate" or "crumble" the crystals. High amperage would "crush" or "explode" them. This doesn't matter if the battery is abused and very sulfated. But if the battery is in decent condition with thin inconsistent layers of sulfate on the plates we would clean the plates quickly and start destroying them soon after.

Imagine breaking a wine glass with a pellet gun vs. 9mm bullet.
Both will break the glass, but the 9mm will be much more likely to keep going and hit the wall behind.

>>
>> Bonus: You mentioned you could not find a reliable source for Pb curves. Here is my take.
>
>
> Thanks for the bonus, as for cheali-charger-0.32 the Pb charge is implemented based on:
> http://www.battery-usa.com/Catalog/NPAppManual%28Rev0500%29.pdf
> site 11,
> and: http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery
> (the "stage3" is currently not implemented),
> with a end voltage of 2.45V/cell and a current limit of 0.25C (changeable).

Ignoring the missing maintenance charge those curves are fine.
That said I dislike 2.45 for standard Pb batteries at room temperature. Fine for AGM, but I would prefer 2.40 since we can't use a temp probe.

On the other hand imaxB6 only puts out 5amps so it's probably fine...

[Simone Fabris]

>
> Voltage please.

I have a desulfator, I can measure short peaks in excess of 50 V with an oscilloscope.

So, I don't think this peaks are reproducible with our lipo chargers.

BTW, I have a turnigy 400W charger. I did not flash anything on it as it seems to be properly calibrated, but I will certainly try out cheali charger in the next weeks.

Simone

--

[Weedy]

On 3 Jan 2014 17:14, "Simone Fabris" <simone...@gmail.com> wrote:
>
>
> >
> > Voltage please.
>
> I have a desulfator, I can measure short peaks in excess of 50 V with an oscilloscope.

Considering our chargers are 5 amp you wouldn't use them on car sized batteries.

25v might be enough for SLA scooter or UPS batteries. I've seen Chinese desulfators on eBay advertising 30v.
Better then nothing?

[Nagy Jozsef]

Hi all

one info:

The 'tricke charge mode menu' is not available an stock 50W chargers, only 200W,400W.

[Paweł Si]

2014/1/4 Weedy <weed...@gmail.com>

On 3 Jan 2014 17:14, "Simone Fabris" <simone...@gmail.com> wrote:
>
>
> >
> > Voltage please.
>
> I have a desulfator, I can measure short peaks in excess of 50 V with an oscilloscope.

Considering our chargers are 5 amp you wouldn't use them on car sized batteries.

25v might be enough for SLA scooter or UPS batteries. I've seen Chinese desulfators on eBay advertising 30v.
Better then nothing?

The charger is just a simple buck/boost converter:

http://en.wikipedia.org/wiki/Boost_converter

I'm no sure but it might be possible to get more voltage from the charger

in a short boost, 25.2V is only the average voltage.

If you think this functionality is useful, I highly encourage you

to try to implement it by yourself,

Of course I'll help you.

I can't do this by myself because of lack of free time,

and I don't even own a PB battery ;) 

Best Regards,

Paweł

[Weedy]

I need to buy a charger first ;)

Does anyone in this thread have a suggestion on which charger I should buy?
 http://www.hobbyking.com/hobbyking/store/__7028__turnigy_accucel_6_50w_6a_balancer_charger_w_accessories.html

Should I bother with a higher power model?

[Paweł Si]

2014/1/9 Weedy <weed...@gmail.com>

I need to buy a charger first ;)

Does anyone in this thread have a suggestion on which charger I should buy?
 http://www.hobbyking.com/hobbyking/store/__7028__turnigy_accucel_6_50w_6a_balancer_charger_w_accessories.html

Should I bother with a higher power model?

The 50W chargers are probably better for your purpose,

The software is more complex, you have to switch on-off the boost/buck converters transistors

in the software but because of that you have more control over the charger.

on the 200W (and more) you only control a hardware "current source", 

which is relatively slow.

[jarno83]

Has someone tried to implement the pulse charging?

I got a new motorcycle Pb AGM 6Ah battery today and doing the first charge.

The charging is seams to be in state 2 and voltage is 14.7v - 2.45V per cell and amps are going down.

But reading this - http://batteryuniversity.com/learn/article/absorbent_glass_mat_agm, it seams that 2.45v is bit high and it seams

to needs to be even smaller when environment temp is higher.

https://dl.dropboxusercontent.com/u/54767697/Screenshot%20from%202013-12-29%2006%3A07%3A11.png

Or I'm getting it all wrong :) 

Thanks,

Jarno

[jarno83]

My old battery I charged with imax b6 (fake) offical firmware and I think charger baked it. So I'm looking the right and best way to charge it with cheali-charger :)

[jarno83]

Hi, 

For getting Pb charging voltage down I saw values in file:  ProgramData.cpp

// { VIdle, VCharge, VDischarge, VStorage, ValidEmpty};

/*Pb*/ { ANALOG_VOLT(2.000), ANALOG_VOLT(2.450), ANALOG_VOLT(1.750), ANALOG_VOLT(0.000), ANALOG_VOLT(1.900)},

I changed VCharge to 2.300 :

/*Pb*/ { ANALOG_VOLT(2.000), ANALOG_VOLT(2.300), ANALOG_VOLT(1.750), ANALOG_VOLT(0.000), ANALOG_VOLT(1.900)},

should make max charging voltage 2.3 x 6 cells = 13.8v

Do I need change something else?

Thanks,

Jarno

[Paweł Si]

no, it's enough

 

[jarno83]

Thanks, Paweł :)

I have one question more:

How hard is to implement "Stage 3" float charge to Pb charging program?

Thanks,

Jarno

[Paweł Si]

depends, If you  only would like to add a "stage 3" to the whole charging process

(the charging process ends after "stage 3") then it should be relative easy,

but (correct me is I'm wrong - I'm not sure about that) the battery is considered to be charged after the "stage 2",

and "stage 3" is only to maintain the battery at full charge (due to self-discharge).

In this case, you probably would like to inform the user that the battery is fully charged

and still "pump" some energy into the battery - this approach is much more difficult to implement.

[jarno83]

Like I have understand that then yes, battery is full after "stage 2" and "stage 3" is for battery maintain the battery and keep it 100% full.

I would like to use this on my motorcycle so I can leave the charger connected for long period when I'm not riding and I keeps battery in good shape.

http://all-about-lead-acid-batteries.capnfatz.com

In the bottom of that page there is 2 versions how the "stage 3" can happen, 

What do you think?

[Paweł Si]

2015-04-01 18:01 GMT+02:00 jarno83 <jarnoo...@gmail.com>:

Like I have understand that then yes, battery is full after "stage 2" and "stage 3" is for battery maintain the battery and keep it 100% full.

I would like to use this on my motorcycle so I can leave the charger connected for long period when I'm not riding and I keeps battery in good shape.

http://all-about-lead-acid-batteries.capnfatz.com

In the bottom of that page there is 2 versions how the "stage 3" can happen, 

What do you think?

both methods are fine,

unfortunately you will have to implement it yourself, I'm overworked :-/

so I would suggest you the first (simpler) approach.

simply add a new "Strategy" to the source code, something like this:

MyStrategy::powerOn() {

  doMyStuff = false;

  TheveninChargeStrategy::powerOn();

}

MyStrategy::powerOff() {

  TheveninChargeStrategy::powerOff();

}

Strategy::statusType  MyStrategy::doStrategy() {

  if(!doMyStuff) {

    if(TheveninChargeStrategy::doStrategy() == Strategy::COMPLETE) {

       SMPS::powerOn();

       doMyStuff = true;

    }

  } else {

    //do my stuff, simplified example

    SMPS::trySetIout(ANALOG_AMP(0.100));

    //or

    if(AnalogInputs::getVbattery() < ANALOG_VOLT(12.000)) {

      SMPS::trySetIout(ANALOG_AMP(0.200));

    } else {

      SMPS::trySetIout(0);

    }

  }

  return Strategy::RUNNING;

}

[Paweł Si]

2015-04-01 23:08 GMT+02:00 Paweł Si <sta...@gmail.com>:

2015-04-01 18:01 GMT+02:00 jarno83 <jarnoo...@gmail.com>:

Like I have understand that then yes, battery is full after "stage 2" and "stage 3" is for battery maintain the battery and keep it 100% full.

I would like to use this on my motorcycle so I can leave the charger connected for long period when I'm not riding and I keeps battery in good shape.

http://all-about-lead-acid-batteries.capnfatz.com

In the bottom of that page there is 2 versions how the "stage 3" can happen, 

What do you think?

both methods are fine

 

I just noticed that the they talk about voltage, not current,

and we are a "current source" so probably: "The second is to actually monitor the state .."

is a better approach

[jarno83]

Thanks. Right now it's over my head, but I'm learning (it's much harder than coding arduino)

I hope I get there one day ;) 

[jarno83]

Hi, Like I see from github, then Djok39 is implementing pulse charging :) is it working, needs testing?

https://github.com/Djok39/cheali-charger

Thanks,

Jarno

[jarno83]

Pb Pulse charging in action on M0517 thanks to Djok39  - https://youtu.be/6ONQ44JCQwM

git - https://github.com/Djok39/cheali-charger/tree/Branch_016cae66394b9023b2407ba38251d10c2590a1a4

Pawel, what do you think about Djok39's code? Safe to use?

Only thing, I added one line to nuvoton-M0517/generic/50W/HardwareConfigGeneric.h

#define ENABLE_PULSE_CHARGE_STRATEGY

Thanks,

Jarno

[jarno83]

Pulse charging in logview.

Tested with my old 6ah bad battery.

[Андрей Куницын]

Hello.

I found this discussion after created the issue https://github.com/stawel/cheali-charger/issues/101 

Is it possible to adopt  Djok39 code to discharge in pauses between impulses and increase the frequency? 

Pulse charging is already well I can connect load (like bulb) to discharge in pauses.

[Андрей Момот]

Hello. Long ago I am interested in the matter. Where it is possible to download a firmware file?

[alex Bor]

Hello. I compiled firmware Djok39 for original charger Imax B6, the size of the firmware has turned 90 kb, while attempting to sewing program for sewing it says that the firmware is too big for Atmega32 processor. Please tell me how to solve this problem.

среда, 8 апреля 2015 г., 7:55:46 UTC+3 пользователь jarno83 написал:

[alex Bor]

That's the problem. The program for the firmware - eXtreme Burner.

[Igon]

.hex file size may vary
.bin must be < 32768

try to change SET(COPT "-Os")
to SET(COPT "-Os -flto")
in avr-compiler.cmake

[alex Bor]

Many thanks. Everything worked, compiled firmware with these options and flash size turned 83 kb.

воскресенье, 6 марта 2016 г., 1:14:00 UTC+3 пользователь Igon написал:

[Михайло Яніцький]

Где можно скачать файл прошивки?

добавить импульсный стратегию заряда

 

В субботу, 5 марта 2016 года в 6:52:38 PM UTC + 2, Алекс Бор писал:

Здравствуйте. Я составил прошивку Djok39 для оригинального зарядного устройства Imax B6, размер прошивки получился 90 кб, при попытке швейной программы для шитья он говорит , что прошивка является слишком большой для процессора ATmega32. Скажите , пожалуйста , как решить эту проблему.

среда, 8 апреля 2015 г., 7:55:46 UTC + 3 пользователь jarno83 написал:

Привет, Как я вижу из GitHub, то Djok39 реализует импульс зарядки :) это работает, нуждается в тестировании?

https://github.com/Djok39/ cheali-зарядное устройство

Благодаря,

Ярно

[Михайло Яніцький]