Chargery BMS false specification

[yabert]

Hi
I had some trouble with my Chargery BMS16 and after lot of emails exchanged with Jason (Chargery support) the conclusion is Chargery give false specification of the product. So be warned!
In fact, they indicate on their web page and on the manual this: BMS16 will alarm and cutoff charge or discharge according to users’ setup.
But it's completely false. The discharge will stop based on Under SOC protection. Despite if you set the low discharge protection to 2.8V, by example, the BMS will stop discharge based on SOC. This stop can be set from 5% to 90%.
At first, it don't seem a big problem, right? Up to the moment I realize that the SOC isn't adjustable and that 7% SOC is 3.65V.
So, 3.65V is the nominal voltage of many NCA or NMC cell chemistry (so around 50% SOC), but for Chargery 3.65V is near dead cell
Consequence of all that, you would not be able to use 20-40% of your battery capacity simply because the BMS SOC is dump.
The lost in capacity will depend of the discharge rate and the cells temperature, but you will lost battery capacity for sure.

I like the Chargery design (on/off switch, external display, ...), but it's unacceptable to sell a product with false spec.
Don't lose money and time like me and be warned.

If you have suggestion for a relay BMS with adjustable settings, it will be welcome.

 

[RCinFLA]

Most BMS's also have a 'minimum time below' requirement. This is to prevent a momentary heavy load from tripping low cell cutout.

 

[yabert]

Most BMS's also have a 'minimum time below' requirement. This is to prevent a momentary heavy load from tripping low cell cutout.

Yes. On the BMS16 the Cut-Off Delay Time is adjustable from 0s to 60s.
Still, stop the relay after 1s or 60s, the main problem is the low cell cutout happen when there is important % of the capacity still in the battery.

 

[grizzzman]

I had a bad experience with the Chargery system. I had just figured out that cell 1 had a 30 mv error and cell 4 had a 10 mv error causing balancing issues. ( Think ping pong) The reason I bring this up is I had "turned" off the unit. Later I walked by the office and noticed that the display was on. The display showed the background colors but no data and would not respond to the buttons. The Arm possessor had turned into a heater. As such I would not trust the off to save your cells. I was lucky in that it was caught before failure of the cells.

 

[Bob B]

Hi
I had some trouble with my Chargery BMS16 and after lot of emails exchanged with Jason (Chargery support) the conclusion is Chargery give false specification of the product. So be warned!
In fact, they indicate on their web page and on the manual this: BMS16 will alarm and cutoff charge or discharge according to users’ setup.
But it's completely false. The discharge will stop based on Under SOC protection. Despite if you set the low discharge protection to 2.8V, by example, the BMS will stop discharge based on SOC. This stop can be set from 5% to 90%.
At first, it don't seem a big problem, right? Up to the moment I realize that the SOC isn't adjustable and that 7% SOC is 3.65V.
So, 3.65V is the nominal voltage of many NCA or NMC cell chemistry (so around 50% SOC), but for Chargery 3.65V is near dead cell
Consequence of all that, you would not be able to use 20-40% of your battery capacity simply because the BMS SOC is dump.
The lost in capacity will depend of the discharge rate and the cells temperature, but you will lost battery capacity for sure.

I like the Chargery design (on/off switch, external display, ...), but it's unacceptable to sell a product with false spec.
Don't lose money and time like me and be warned.

If you have suggestion for a relay BMS with adjustable settings, it will be welcome.
View attachment 122949

I thought the SOC cutoff could be set to zero ... which disables that function.

I will look at mine, but I'm pretty sure it is set to zero.

 

[Bob B]

I thought the SOC cutoff could be set to zero ... which disables that function.

I will look at mine, but I'm pretty sure it is set to zero.

Yes .... I have the SOC cutoff set to 0%. I'm running version 4.04 software.

I resolved inaccurate cell voltage indications by upgrading the software and by supplying external power. There are threads outlining how to do this .... I think the 16 may be more susceptible to inaccurate cell readings than the BMS8T that I'm running.

 

[yabert]

Yes .... I have the SOC cutoff set to 0%. I'm running version 4.04 software.

Wooh! Really? Worth a try for sure.
But are you sure you have BMS16 or not the BMS16P or BMS16T?

 

[Bob B]

Wooh! Really? Worth a try for sure.
But are you sure you have BMS16 or not the BMS16P or BMS16T?

I have a BMS8T ..... not sure if the software in other models works the same, but setting the SOC cutoff to 0% works with my model.

 

[MurphyGuy]

A Chinese product with misleading specifications?

 

[yabert]

I have a BMS8T ..... not sure if the software in other models works the same, but setting the SOC cutoff to 0% works with my model.

The BMS8T and 16T seem to have an adjustable SOC by setting empty cell voltage.
For the BMS16 the SOC isn't adjustable and empty cell voltage is near nominal voltage of NMC chemistry.

 

[yabert]

I complain about Chargery BMS16 who don't stop discharge based on user setting, but like Jason of Chargery wrote to me:
''You bought the cheapest BMS16, but ask the highest performance, if it is BMS16P, all is not problem.''
Well, I didn't know that stop the discharge at the voltage setting I enter in the BMS was high performance

 

[Bob B]

It seems they are naming the settings differently than in mine ..... Under discharge protection parameters, there is SOC battery gauge .... Have you tried to set that to zero? The documentation seems to indicate 5 is the lowest it can be set, but that may only be the lowest valid setting .... it is possible that setting it to zero will disable that function just as it does with mine.

With that disabled, the "Over Discharge Protection Voltage" should determine when the discharge protection is triggered.
I think the cell empty voltage is used for the SOC calculations ... not the voltage cutoff.

 

[yabert]

View attachment 123237

Have you tried to set that to zero? The documentation seems to indicate 5 is the lowest it can be set, but that may only be the lowest valid setting .... it is possible that setting it to zero will disable that function just as it does with mine.

I hope the same (set at 0 = disable), but it cannot be set lower than 5%.
It's just so stupid than Chargery programming allow low discharge voltage setting from 2.75V, but stop the discharge at around 3.55V based on SOC ?

 

[tim0shel]

I'll be soon be moving away from my Chargery as it has been in use for few years and have set it foget it. Have had connection issues as mobile installation but was able to overcome that issue. Seems most all BMS's are from China and they all have issues so it makes it risky for all.