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Decrease charging time! 5A High Current Charger Mod


Cranium

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Just wanted to post, that 5A charging should be very fine for ninebot packs, since there was an original ninebot fastcharger available (~250W). I just tried to find a link to it, but failed - either noone wanted to by one extra and the canceled it, i am too dum to search or there were some problems with it ...?

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Just to add another data point... Based on the info here I bought the charger off AliExpress that Cranium mentioned and got it a week ago. They will customize it for you including the EUC connector and  power cord, or adjust the output voltage/current at no additional charge. I have used it a few times and it's awesome to have such a fast charge! This charger is built like a tank and weighs about as much as one! The fan makes a rather loud "whoosh" while it's running. 

I'm in the middle of a 1000km rebuild on my Firewheel and am adding a new battery pack in the process to bring it up to 520Wh, so having this charger will definitely be handy.

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  • 2 months later...

 

I found on https://www.facebook.com/1radwerkstatt/ a comment from 14th of April stating "Zusätzliche Info: Leider fehlt auf dem original Ninebot One Akku der Balancer und das lässt die Lebensdauer erheblich sinken." (rough english translation: Additional info: Unfortionately the original ninbot one accu misses the balancer and this shortens the lifespan significant)

I could not really understand this, since the SH367004 supports balancing - see below the photos/links from @Cranium which lets one suppose that balancing is working fine. So i had a phone call with Chris from 1radwerkstatt who states the following:

There is no external balancing implemented in 9Bot´s BMS (and about all other manufacturers do the same) - they all use the internal balancing function of the IC's. (One can easily identify the empty solder points for 14 Mosfets Q14-Q27 on the BMS - maybe the 15th is hidden under the tape or somewhere else?...)

The resistors Rvcx (between cells and the voltage sense inputs) are according to Chris 1kOhm. So these limit the maximum balancing current to ~4.2V/1kOhm=4.2mA - which has more or less zero balancing effect. The rest of the charging current is still charging the cell!

(From the TI data sheet - different BMS controller chip cranium posted in the beginning of this thread - 40 Ohm is mentioned as minimum value for this kind of resistor, which could balance ~100mA - which still is "nothing" if you have 1 "bad" cell with low voltage leading to a high charge current. And they mention that one has to be careful with cooling/overheat once one uses such "small" resistors...)

So there is the risk that some cells are charged up the the Overcharge protection threshold voltage (can be programmed between 3.3V - 4.5V according to the SH367004 data sheet) - if one cell reaches this value the charge protection Mosfet gets "active and disconnects" the charger...

/Start Edit

So my conclusion to this is: Never leave the charger after the red light (charging active) stopped to start a balancing cycle, because it won't happen.

There could still be some balancing, so maybe it's not the worst idea - imho not enough, but who knows... (see http://forum.electricunicycle.org/topic/5110-e-battery-died-on-me-while-riding/?do=findComment&comment=58493 and the following posts)

/End Edit

There is just the risk that some cells are charged up to supposedly around a bit more than 4.2V! ...And sometimes i'll unwrap the accu pack and control the individual cell voltages, to be on the safe side... ;(

 

 

On 23.1.2016 at 7:51 AM, Cranium said:

I received my heat shrink yesterday and opened up the E+ battery to look at the circuit board.

IMG_20160121_233648.jpg

Typical circuit diagram for a BMS (only showing 1 IC for simplicity whereas the Ninebot's has 3 ICs).  Each IC can be configured for 3, 4 or 5 cell balancing and since the Ninebot has 15, it fully populates 3 ICs.

Typical 5 cell circuit diagram.PNG

 

 

 

On 24.1.2016 at 6:30 AM, Cranium said:

I was asked about low voltage protection so figured I would add the robust feature list of the SH367004 IC that the BMS uses in the Ninebot and other EUs.

SH367004 features:

...

     ·        Precision voltage detection function: (for a single power-saving core)

          o   Overcharge protection threshold voltage: 3.3V - 4.5V (50mV  per  step)

               §  Threshold voltage accuracy: ± 25mV

 ...

     ·        Balancing:

          o   Balanced turn-on threshold voltage: 3.1V - 4.4V (50mV  per  step)

               §  Threshold voltage accuracy: ± 25mV

 

 

On 24.1.2016 at 6:44 AM, Cranium said:

Also, here is the block diagram of the SH367004:

Block diagram of the SH367004.PNG

 

 

Edited by Chriull
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On 22/04/2016 at 11:19 AM, 1RadWerkstatt said:

This is cheap china style...

Many manufactures say balancing is not required and has no postiv effects and done.

Various EUC manufactures make the same thing....no balance in batterys! I have tell to all my manufactures i need balance in battery´s ever! In my contract with KingSong extra part that battery´s must have a balance function.

This is so important... Can you tell if gotway is affected by this problem ? any other major brand ?

But you get what you pay. Check at Batteryspace.com. You don't have a real BMS below 20s. Instead it is a PCB/PCM which do not always provide balancing (not a security matter anyway). The only 16s balancing PCB/PCM there is 215$...

Maybe you should precise the specs of what you want to balance / how much unbalance you want to be able to correct.

Edited by jbwheel
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On 22/04/2016 at 10:56 AM, Chriull said:

There is no external balancing implemented in 9Bot´s BMS (and about all other manufacturers do the same) - they all use the internal balancing function of the IC's.

The resistors Rvcx (between cells and the voltage sense inputs) are according to Chris 1kOhm. So these limit the maximum balancing current to ~4.2V/1kOhm=4.2mA - which has more or less zero balancing effect. The rest of the charging current is still charging the cell!

which still is "nothing" if you have 1 "bad" cell with low voltage leading to a high charge current.

So there is the risk that some cells are charged up the the Overcharge protection threshold voltage

So my conclusion to this is: Never leave the charger after the red light (charging active) stopped to start a balancing cycle, because it won't happen. There is just the risk that some cells are charged up to supposedly around a bit more than 4.2V!

Can you tell if gotway is affected by this problem ? any other major brand ?

I am not sure about what you mean by balancing current of 4,2mA and the rest charging current still charging the cell. Is it passive (resistive) balancing ? if so it would alternate

About 1 bad cell with low voltage having a high charge current : not sure it is a common situation since a weak cell have smaller capacity so its voltage raises (chargin) or lowers (discharging -> BMS shut off) faster than the rest of the pack. I would also go though more balancing cycles therefore it would also die faster.

Last june I made a small study (here in french) of the specs of 9 "BMS" available on Aliexpress. The cheapest  (20-30$) had no or weak balancing habilities, the most expensive (99$) had a 85mA balancing current. More interesting, the 6 cheapest had a high voltage protection threshold (>4,2V to 4,3V) and even the medium priced at 50$ (4,25-4,275V). So I would conclude that it was a kind of planned obsolescence since a correct setting wouldn't cost more to make (and since there are a lot of li-ion manufacturers located in China if not most of them).

Maybe a better advice would to never let your wheel finish the chargin cycle and interrupt it sooner. On a Msuper 850 with a superior 3,75A charger, it would be more than 2h before the end. See the euc thread

Edited by jbwheel
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1 hour ago, jbwheel said:

Can you tell if gotway is affected by this problem ? any other major brand ?

I was told that almost all (also major) brands have this problem - can be easily seen by a look at the BMS board. If there are also the components "missing" as on thr ninebot BMS board it has no external == effectice balancing. There are enough pictures of the different BMS around this forum - just unfortionately not easy to be found in the threads ;(

Quote

I am not sure about what you mean by balancing current of 4,2mA and the rest charging current still charging the cell. Is it passive (resistive) balancing ? if so it would alternate

The internal balancing circuit of the ic can only let some current run "around" the cell - by the resistances between the cells and the ic this current is very limited. So the cell still get charged.

Quote

About 1 bad cell with low voltage having a high charge current : not sure it is a common situation since a weak cell have smaller capacity so its voltage raises (chargin) or lowers (discharging -> BMS shut off) faster than the rest of the pack. I would also go though more balancing cycles therefore it would also die faster.

Normal cell degradation starts with the cell gettin lower capacity, as you wrote. Imho really bad cells have lower voltage and cannot be charged (much) higher - but could be wrong with that. Is someting i think inread at batteryuniversity - but could be nonsense too.

However by different capacities the cells have naturally and get more and more by different "aging" some cells get overcharged by no sufficient balancing and age faster...

Quote

Last june I made a small study (here in french) of the specs of 9 "BMS" available on Aliexpress. The cheapest  (20-30$) had no or weak balancing habilities, the most expensive (99$) had a 85mA balancing current. More interesting, the 6 cheapest had a high voltage protection threshold (>4,2V to 4,3V) and even the medium priced at 50$ (4,25-4,275V). So I would conclude that it was a kind of planned obsolescence since a correct setting wouldn't cost more to make (and since there are a lot of li-ion manufacturers located in China if not most of them).

The voltage thresholds in ic's like the one above can be programmed - wrong/bad choices can be just missing knowledge or some manufacturers just don't program them and leave them with factory defaults. Planned obsoloscence is however also quite possible - but needs planning;)

Quote

Maybe a better advice would to never let your wheel finish the chargin cycle and interrupt it sooner. On a Msuper 850 with a superior 3,75A charger, it would be more than 2h before the end. See the euc thread

Yes. Best solution is a serious BMS...

edit: ps: here is a nice description of how internal balancing works: http://forum.electricunicycle.org/topic/3700-why-fast-charging-rocks/?do=findComment&comment=38206

 

Edited by Chriull
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On Saturday, April 23, 2016 at 9:32 PM, Chriull said:

I was celat almost all (also major) brands have this problem - Ninecan be easily seen by a look at the BMS board. If there are also the components "missing" as on thr ninebot BMS board it has no external == effectice balancing. There are enough pictures of the different BMS around this forum - just unfortionately not easy to be found in the threads ;(

edit: ps: here is a nice description of how internal balancing works

BNMS working : still not sure if a cell can be charging and bleeding in the same time

here some picture of GW and KS BMS. look quite different from Ninebot

KS

 

20160110_182711s.jpg.94999afeca375335f1b2356036ef71b3.jpgGW

 

13803322-1.jpg57152f410cf5c_20160418_204924(Copier).thumb.jpg.8c08245933b03177d1dcf258111ae923.jpg

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  • 4 years later...
On 4/29/2016 at 1:07 AM, jbwheel said:

57152f410cf5c_20160418_204924(Copier).thumb.jpg.8c08245933b03177d1dcf258111ae923.jpg

this is strange, like on the kingsong, when i rip off the battery i saw that :
on the
two battery, only one have the protected BMS connected to stop the charge, because the other battery is supling the currnet to the other battery pack by skipping the safety mosfet like on this picture, and the charge continu even if the cell reach 4.3v

Edited by Cody
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11 hours ago, Cody said:

this is strange, like on the kingsong, when i rip off the battery i saw that :
on the
two battery, only one have the protected BMS connected to stop the charge, because the other battery is supling the currnet to the other battery pack by skipping the safety mosfet like on this picture, and the charge continu even if the cell reach 4.3v

No it isn't. Obe xan count 16 "strands" of conparators/logic - one "strand" for each cell. If one carefully analysis this double (more?) layer PCB one will find the connections from each cell to one of this "strands".

Each "strand" performs the logic for bleeding resistors and single cell overvoltage cut off.

Edit: or did i understand you wrongly - do you mean with second battery the independend second battery pack or some of the cells in this one pack?

Edited by Chriull
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  • 1 year later...

I have opened my Monster v3 100v charger to try increasing charging speed.

IMG-20220514-131349.jpg

The screw in front of the fan is the voltage controller. The other one i dont know what it does (tried to tune it up and down but nothing seem to happen).

So to increse speed (or amperage) is it fine to tune the voltage up? Or there should be the current controller one?

Edited by meepmeepmayer
link fixed :-)
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you need to put something like a watt meter inline between the battery and charger to adjust the amps,

when adjusting that screw when nothing was happening, something was happening

you just couldnt see the amps going up and down

but to try and increase the amps will probably fry your charger.

it can only put out so many watts

100 volts at 5 amps is 500 watts

100 volts at 3 amps is 300 watts

increasing voltage wont speed up anything, it will overcharge the battery

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i have a watt meter plugged into the wall before the charger and the watt reading doesnt change. 

doesnt the battery has some sort of circuit that will protect it from overcharging? 

i can still manually unplug it when the battery reaches 100v.

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the bms might protect it or it might just catch fire and  blow up :shock2:

dont over volt, its a really bad idea, it will just turn the bms into an electric heater

you need to have the watt meter inline in between the charger and battery to measure the amps going from the charger to the battery

then adjust the potentiometer in the charger

try 5 amps if you want, maybe your charger was over engineered and wont overheat and die

you can try modding it with a bigger fan or bigger heatsink

i would buy higher voltage chargers than my battery packs then turn voltage down and amps up but still remain at the wattage rating of the charger with no issues

 

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