Heltec (JK) 200A Smart BMS with 2A Active Balance

[Nami]

Hello NAMI.... Question.. How to update the BMS itself ? ( Not the App ) And once it is updated, will settings remain or be deleted ?

In fact, we have been updating our products according to the needs of our customers. However, with the update, there will be some problems. The original customers will feel bad, but it is these needs that drive us to pursue perfection and provide customers with a better experience. We are customizing the BMS communicating with victron, GPS functions that can support other countries, and jk-b2a4s20p. These are all things that need to be completed in 2022

 

[upnorthandpersonal]

Any word on releasing the firmware source code?

 

[Nami]

The firmware needs tools to be updated. This process is being followed up

Any word on releasing the firmware source code?

 

[Dacflyer]

Wow,, what was this light used on? Or purpose?

 

[Ai4px]

Does anyone have any ideas for a precharge enabling pin on the JK BMS? Right now mine is a "arm strong" switch and a 100ohm resistor.

 

[maxx-v0]

Does anybody connect JK BMS to can BUS and get data? I have JK-B2A24S15P
On image https://ae01.alicdn.com/kf/Sb1c91bebcb474493bf5d9459cf2a7089c.jpg?width=1000&height=1470&hash=2470 we have GND (why? CAN don't need GND), CAN_H, CAN_L. I don't have any adapter, i just connect H and L to my test bus, set speed to 250k and run candump - no data. Osciloscope don't show any signal on CAN_H/CAN_L.
@Nami how i can connect my JK BMS to my CAN bus? I want to get data from CAN, convert to pylontech US2000 format and send to invertor.

 

[Messier11]

Is this a workable way to instal the JK BMS?


I was also thinking about adding a 9v battery with a push button to the BMS so that it can be started by just pushing the button. Do you guys think that would work?

 

[Choco]

Is this a workable way to instal the JK BMS?
View attachment 84040

I was also thinking about adding a 9v battery with a push button to the BMS so that it can be started by just pushing the button. Do you guys think that would work?

Near identical to mine.

 

[Ai4px]

Near identical to mine.

I made some brackets. They are on thingiverse.

 

[Cool kid]

I made some brackets. They are on thingiverse.

I made some brackets. They are on thingiverse.

Which inverter do you use for this setup? and also how many batteries are those ? Cable management is very good, the setup is also very organized .

 

[Ai4px]

Which inverter do you use for this setup? and also how many batteries are those ? Cable management is very good, the setup is also very organized .

I have two sunny islands. 16 cells.

 

[GXMnow]

That's looking good. Very clean.

I don't know why JK does not put mounting tabs on the BMS housing. I ended up getting longer screws to replace the ones holding the case together. And then bolted 4 of them through a rack panel that is bolted into my battery cabinet. IT was a major pain to get the holes to line up, and then I also realized how NOT flat the back of the BMS housing is. So I used a few varying layers of thermal transfer tape. The stuff that is used to attach small heat sinks onto IC chips. Just one layer on the highest part, and then stacked up more layers to fill the gap as the case curved away from the plate. I was worried about heat build up, so I wanted the large aluminum plate to act as more heat sink, but it turns out it never gets more than just warm at the 80 amps my system maxes out at.

The cheap basic dumb Daly BMS units I used on my second battery bank are nearly flat, and have cast in metal mounting ears for screws. It made it so much easier to hold it where I wanted it, and just mark through the holes and drill them. Maybe JK could learn something there.

 

[Messier11]

I made some brackets. They are on thingiverse.

OMG, that looks amazing!!

Can I ask three questions?

1. Did you have any concern about all the BMS cables not being the same length (if they aren’t) or did you mitigate any effects it may have in any way?

2. How did you crimp the two blue cables from the BMS into one lug?

3. How are the cables from the BMS mounted to the busbars? Since the busbar is going from the positive to the negative, it doesn’t really matter that isn’t directly on the pole right?

 

[Messier11]

Near identical to mine.

Thanks!

 

[Ai4px]

OMG, that looks amazing!!

Can I ask three questions?

1. Did you have any concern about all the BMS cables not being the same length (if they aren’t) or did you mitigate any effects it may have in any way?

2. How did you crimp the two blue cables from the BMS into one lug?

3. How are the cables from the BMS mounted to the busbars? Since the busbar is going from the positive to the negative, it doesn’t really matter that isn’t directly on the pole right?

Both awg 7 cables twisted together are same size as awg 4. So I used a Hydraulic press to crimp and then also soldered the lug.

Bms cell sense cable length is (edit…. Pretty much )… irrelevant

I used flexible buss bars and cut a notch out of the heat shrink in the middle of each bus bar and soldered the sensing wire to it.

Not shown in these photos is the last sense wire soldered to the positive lug.

 

[GXMnow]

I don't know if I would say the balance lead wire length is irrelevant, but it is certainly not critical. If the wires were only used for voltage sensing, it would not matter at all, but since the BMS can pull AMPS of balance current, there will be drop in the lead wires. But then the JK BMS actually measures the resistance of the balance wires. So when it pulls or pushes balance current, it calculates the wire voltage drop to still have an accurate cell voltage reading. Actually a very clever system.

 

[Ai4px]

I don't know if I would say the balance lead wire length is irrelevant, but it is certainly not critical. If the wires were only used for voltage sensing, it would not matter at all, but since the BMS can pull AMPS of balance current, there will be drop in the lead wires. But then the JK BMS actually measures the resistance of the balance wires. So when it pulls or pushes balance current, it calculates the wire voltage drop to still have an accurate cell voltage reading. Actually a very clever system.

I have watched the JKBMS as it is balancing. It draws current off of one Cell and Samples all the others. When It finds one that is higher voltage than the one it’s pulling from it will switch. Finally when the charge current for the capacitors gets below 2 A it will begin to discharge those capacitors into the lowest cell. It is my belief, without seeing the code, that the BMS measures cell voltage from the cell that it is not balancing at that moment. So the length of the balance cables is probably very low importance. If it was Reading cell voltages on cell it’s balancing, then the resistance of the volt sensing wire would be important. I think the programming is smarter than this.

 

[sato]

Ambos cables AWG 7 trenzados entre sí son del mismo tamaño que AWG 4. Así que usé una prensa hidráulica para engarzar y luego también soldé la lengüeta.

La longitud del cable de detección de la celda Bms es (editar... Más o menos)... irrelevante

Utilicé barras colectoras flexibles y corté una muesca en el termorretráctil en el medio de cada barra colectora y le soldé el cable sensor.

En estas fotos no se muestra el último cable de sentido soldado a la lengüeta positiva.

I thought that in this position it was not advisable to put the batteries?

 

[Ai4px]

I thought that in this position it was not advisable to put the batteries?View attachment 84511

I don’t know. Hmmm. Anyone!?

 

[upnorthandpersonal]

I don’t know. Hmmm. Anyone!?

I wouldn't put them stacked flat. The aluminium cases are rather thin, and it's a big mass pressing down on those lower cells.