New 2A Active Balancer with BMS Function won`t run

Tigil

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Oct 17, 2020
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I
Hi there
I bought this ( https://de.aliexpress.com/item/4000529723243.html?spm=a2g0s.9042311.0.0.493e4c4d6I7yk6 ) Active Balance with BMS function. My existing Active Balancer works as it should. But the new one doesn't want to go on. The cables are the same for both.Both devices have the same connection diagram. Do I have to activate it somehow? With my old one I just have to plug in the cable and then it works and I can access it via Blueooth. Not so with the new one; nothing works there.
Has anyone got this balancer / BMS working?
For a better understanding, here is a video
 
Last edited:

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
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Vendor = ICCogogo
Let us know how that goes. That is one company we are VERY AWARE OF and not for any good reason either...
 

dRdoS7

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Hi,

Have you given the BMS a "kick-start"?

You need to apply a voltage a few volts higher than the pack voltage to the "P-" cable.

I use a 12V battery. Connect one terminal to cell #3, then the other I have a wire which I touch to the "P-". The BMS will beep, and LED will come on. Don't get the polarity wrong! I used a DMM to double check voltage BEFORE touching the BMS.

Probably could do the same with a 12V battery charger.

It is described in some manuals, a few post here also.

After confirming that the above operations are correct, you can power on the protection
board. The protection board does not have a power-on control switch, and is designed to be in a
charging activation mode. That is, after the battery is assembled, a charger needs to be connected
to start the protection board.

dRdoS7
 
Last edited:

Tigil

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Oct 17, 2020
Messages
15
Hi,

Have you given the BMS a "kick-start"?

You need to apply a voltage a few volts higher than the pack voltage to the "P-" cable.

I use a 12V battery. Connect one terminal to cell #3, then the other I have a wire which I touch to the "P-". The BMS will beep, and LED will come on. Don't get the polarity wrong! I used a DMM to double check voltage BEFORE touching the BMS.

Probably could do the same with a 12V battery charger.

It is described in some manuals, a few post here also.



dRdoS7
Do you mean the same device as me?
I have a 48V 16S battery.
 

Tigil

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Oct 17, 2020
Messages
15
Found the thread and read it through.
I actually had to connect an additional 5V. Now it works.
thanks
 

Tigil

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Everything connected, worked for about 1 hour and then that was it. BMS simply went off while 40A were discharged. Cannot be revived.

Refund has already started.


IMG_20201227_113145.jpg
 

dRdoS7

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Messages
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Hi,

Do you mean the same device as me?
I have a 48V 16S battery.

Yes, same BMS device. My bank is 18S, 48V nominal.

Found the thread and read it through.
I actually had to connect an additional 5V. Now it works.
thanks

I didn't have anything other than 12V, that's why I connected @ #3, gave me about 3V over bank voltage. IIRC.

Everything connected, worked for about 1 hour and then that was it. BMS simply went off while 40A were discharged. Cannot be revived.

Refund has already started.

That's a pain.

dRdoS7
 

Mark81

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Jan 19, 2021
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Hello!
Any updates?
Did they refund you or maybe BMS got back to life?
 

Tigil

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After a long back and forth I finally got a 50% refund.
The return simply failed because I couldn't get the Chinese address into a standard shipping form. I complained about it and then got the repayment after the negotiation. At least a little.
 

GXMnow

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Do you still have the BMS?
Looking at the screen shot, I bet I know the problem. This happened to mine. Mine lost cells 3 and 4, your looks like it lost cells 13 and 14. When you see two next to each other go dead like that, it is a balance lead issue. I had the exact same error message show up. "Cell count does not match settings". You will also notice the total battery voltage is just the good cells added up, and 2 cell voltages lower than what the pack actually measures if you use a separate meter. This was the dead give away that it was a measuring problem and not an actual cell failure. Measuring the voltages at the balance leads, I was still worried it was a BMS failure, because the voltage was close, but measuring cell 3 and 4 even at the very light load of a Fluke voltmeter, it was down about 50 millivolts from measuring it right at the cells. When I did that with all of the other cells, the voltage was identical to the reading at the cell, so I knew something was up. Evidently, the BMS pulls a bit of current when it goes to measure each cell. And that current is enough to make the voltage drop below 1 volt so it goes blank. The final cause turned out to be the balance wire between the 2 cells that are not showing any voltage had failed. In my case it was a poor crimp connection in the JST connector. A few other pins didn't look great either. Mine worked for about 6 months, but then I guess a little corrosion killed it. After repairing the connections in the JST connector at the BMS it is all working perfectly again. It appears that some of the crimps are on the wire insulation and didn't fully punch through to the conductor inside, so the contact was barely connecting when it was new.

All but the one pin measured fine. With just a little cleaning, I did see a decent drop in the contact resistance to the BMS. I am going to put a little dielectric grease on the pins to keep any moisture from getting in the pin sockets.

I used a small resistor lead to insert into each pin of the BMS connector and measure the resistance back to the wire at the battery connection. And then I went a step further and lit a car tail light bulb with a battery to pull a bit of current through each lead. I pulled out the pins from cells 23+ and 24+ that I will never use and used them for the Cell 3+ and 4+ positions which showed the worst resistance. They are not the easiest to remove from the hood, and you have to be careful not to mess up the retaining clip on the metal pin. I am going to order all new pins and hoods and make a new harness soon. But since my repair, it has been back running fine for over a month now.
 

GXMnow

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Can you show me the thread or confirm how you wired it to get it started?
It is actually simple to do, once you understand what it needs, but it drove me crazy for a solid hour without instructions. The board just seem dead.

The initial start up requires a voltage that is 5 volts greater than the battery bank on the BMS. But I found an easy cheat around that. Even after I found out about needing the extra 5 volts, I was kind of stuck for a bit. My battery bank was charged to about 90% so it was at about 4.08 volts per cell. With 14 cells, that is 57.12 volts, and my charger tops out at 58.8 volts (4.20 volts per cell), for 100% charge on these Li NMC cells. So what do I do now? If your battery is at a lower state of chare, it is easy, connect the charger, and it turns on.

So here is the easy trick I have used a few times now when I have shut my system down and need to restart it. It also worked from a full factory reset, so I don't think it will give you any problem.

You do not need much current at all, and I found an 11.1 volt RC car battery pack works great. A normal 9 volt battery might even work. To be safe, I put a 10 ohm resistor in series to limit the current, but it does not seem to pull any. Connect the positive side of the kick start battery to the negative end of the battery bank, at the cell terminal, before it goes to the BMS. Then just touch the negative side of the kick start battery, through a resistor to the negative output lead from the BMS. In my case, this adds the 11.1 to my battery bank 57.12 so it is quite a bit more than the 5 volts more required, and it powers up. It does a series of beeps, and you can take off the kick start battery after the first beep. This has worked for me every time. Next time I shut it down, I will just try a 9 volt battery with no resistor. Even dead shorted, they can't put out enough current to hurt a 200 amp BMS. Maybe, I can put a light bulb in series and see if it will even make it flicker. Basically, the BMS just needs more than 5 volts across the blue and black high current battery leads. The blacks needs to go more negative.
 

UV-PWRD

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Messages
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It is actually simple to do, once you understand what it needs, but it drove me crazy for a solid hour without instructions. The board just seem dead.

The initial start up requires a voltage that is 5 volts greater than the battery bank on the BMS. But I found an easy cheat around that. Even after I found out about needing the extra 5 volts, I was kind of stuck for a bit. My battery bank was charged to about 90% so it was at about 4.08 volts per cell. With 14 cells, that is 57.12 volts, and my charger tops out at 58.8 volts (4.20 volts per cell), for 100% charge on these Li NMC cells. So what do I do now? If your battery is at a lower state of chare, it is easy, connect the charger, and it turns on.

So here is the easy trick I have used a few times now when I have shut my system down and need to restart it. It also worked from a full factory reset, so I don't think it will give you any problem.

You do not need much current at all, and I found an 11.1 volt RC car battery pack works great. A normal 9 volt battery might even work. To be safe, I put a 10 ohm resistor in series to limit the current, but it does not seem to pull any. Connect the positive side of the kick start battery to the negative end of the battery bank, at the cell terminal, before it goes to the BMS. Then just touch the negative side of the kick start battery, through a resistor to the negative output lead from the BMS. In my case, this adds the 11.1 to my battery bank 57.12 so it is quite a bit more than the 5 volts more required, and it powers up. It does a series of beeps, and you can take off the kick start battery after the first beep. This has worked for me every time. Next time I shut it down, I will just try a 9 volt battery with no resistor. Even dead shorted, they can't put out enough current to hurt a 200 amp BMS. Maybe, I can put a light bulb in series and see if it will even make it flicker. Basically, the BMS just needs more than 5 volts across the blue and black high current battery leads. The blacks needs to go more negative.
Many thanks, have since learned all this in my own thread but cheers.

I have a 60v charger to pickup for a quick loan today then I will get myself a boost converter to add to my 30v power supply for next time.
 

dRdoS7

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Hi,

I've often wonder why we need to do this. Why didn't they just have it turn on when connected? Or even put in a On switch?

dRdoS7
 

GXMnow

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Jul 17, 2020
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Hi,

I've often wonder why we need to do this. Why didn't they just have it turn on when connected? Or even put in a On switch?

dRdoS7
Passive balancing is wasteful.
All it can do is take power from fully charged cells and burn it off as heat as the rest of the cells are still being charged. If they let it run, it would keep pulling power out of the highest cell all the time. Any time they drifted off balance, it would just waste more power. Keeping it low at just 30 ma, it will take a real long time to pull down large cells, but some people use them on a small E-bike pack at less than 10 amp hours. Some of the smarter BMS units will let you set a threshold voltage, and that helps a lot. If any cell is above this setting, it can start pulling balance current. It should be smart enough to only pull current when the cells are out of balance by a delta value. So it could balance when cells are above 3.0 volts, but if all the cells are within 0.01 volts, it will still stop balancing. Then only pull the balance current when a cell is more than 0.01 above the lowest cell. But then still others will only activate the balance current if the battery is being charged. The problem here is that virtually any charger will push more than 0.03 amps into the battery and still push more into the cell that is going over volt. If the cells are very closely matched, then when the pack voltage reaches full, the charger should go into the constant voltage mode. If we are talking just a 4S 12 volt LFP system, this should work just fine. Most of the cheap LFP BMS boards I see, will not trip over voltage until 3.7 volts. The charger should go into CV mode at 3.65 per cell. Let's say you have one runner going up to 3.7 while the rest are only up to 3.63 volts. Ideally, the charger current should fall all the way down to just 30 ma and the one cell sitting at 3.7 volts is now getting no charge current while the other 3 are still seeing 30 ma. The full cell will start to settle back and hopefully drop under 3.65 as the other 3 catch up to it. But for this to work, the cells need to start pretty closely matched. As long as they are "Top Balanced" it is still fine if the cells are not capacity matched. On discharge, a weaker cell may drop faster, but all of the cells will still give out the same amp hours since they are all in series. The weaker cells will drop voltage quicker and you will see the balance drift. But when it charges back up, the weak cells will also climb voltage faster. And they should all hit full charge together. If on is a little ahead, that 30 ma balance draw should be enough to keep it in line.

The main function of the BMS is to protect the cells. Balancing is a nice feature and can help keep your maximum capacity available, but it is more important to have the shut down to protect the cells from one getting pulled too low or too high when something goes wrong. With my large 360 amp hour bank and higher charge and discharge currents, I did get an active balancer that can pull or push 2 amps from a cell to pull them into balance. I really like how it works and the fact it is not just wasting the power into heat. It pushes the power from a high cell to a low cell. But once I got my battery into a good top balance, the balancer is not doing anything. My cells are all staying within 5 mv now.
 

UV-PWRD

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Screenshot_20210301-175213.jpg

Ok how do I get around this, as soon as I switch the breaker to the inverter it says this.

I assume it's trying to fill the caps in the inverter?

Error goes away of If I switch off breaker.
 

UV-PWRD

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Nm, used the power supply to precharge the caps in the inverter :)

Working now.
 
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