JBD/Overkill vs JK/Heltec BMS

[Sanwizard]

Has anyone done a comparison between the JBD and JK BMS's?
They look very similar to me. The JBD seems to use the Xioxiang app, and the JK uses thr ENJpower app. The apps are also VERY similar. I know Overkill is JBD, ans Heltec is JK based. Is the same manufacturer making both?

I am not as familiar with the JBD/Overkill, but I have 4 of the JK's from Heltec. They are the black case 200amp versions with 2 amp active balance and bluetooth. I would love to see a side by side comparison, but after searching the site, unless i missed it, it seems that has not been done yet.
Andy at off-grid-garage is now testing the JK version, but I have not seen an in depth on the JBD.
I will do a comparison of the Seplos 200amp vs the JK 200amp when mine arrive.

 

[upnorthandpersonal]

I took a spare JK/Heltec apart today and took some pictures. Attached to this post. This is the 100A version (0.6A balancing current).
The MOSFETs are Chinese, a G035N10N from Huayi Microelectronics. Surprisingly, the datasheet is available in plain English:

http://www.szhxmos.com/uploads/soft/2101/HYG035N10NS2P.pdf

Continuous current of 180A at 25C and 127A at 100C. Seems they're not pushing this one.
The micro-controller is an STM, in particular the STM32F103C8T6. I somehow would have expected there to be a Chinese micro-controller on it since the other components are. The Bluetooth module is based on an RTL8762C.

There is one bodge on the board as far as I can see. Not a big deal. This is version 6.0 of the board though. Temperature sensor is well glued in place. Soldering job on the cabling is good.

 

[upnorthandpersonal]

One obvious difference is that the JK/Heltec has active balancing and the JBD/Overkill does not. I found and image of the JBD/Overkill without heatsink:

https://imgur.com/XoDYmZW

(passive balancing bleed resistors circled in red)

 

[Sanwizard]

One obvious difference is that the JK/Heltec has active balancing and the JBD/Overkill does not. I found and image of the JBD/Overkill without heatsink:

https://imgur.com/XoDYmZW

(passive balancing bleed resistors circled in red)

Thank you VERY much for taking the time, effort, and expense of collecting and explaining these data points!

 

[upnorthandpersonal]

No problem - this is fun

 

[Sanwizard]

No problem - this is fun

Looking at the board layout between the JK and the JBD, they look very different, ergo most likely a different engineer and manufacturer? Do you agree?

 

[upnorthandpersonal]

I agree. I would also upon first glance (I need to get a JBD) claim that the design of the JK is better/cleaner.

 

[RCinFLA]

I took a spare JK/Heltec apart today and took some pictures. Attached to this post. This is the 100A version (0.6A balancing current).
The MOSFETs are Chinese, a G035N10N from Huayi Microelectronics. Surprisingly, the datasheet is available in plain English:

http://www.szhxmos.com/uploads/soft/2101/HYG035N10NS2P.pdf

Continuous current of 180A at 25C and 127A at 100C. Seems they're not pushing this one.
The micro-controller is an STM, in particular the STM32F103C8T6. I somehow would have expected there to be a Chinese micro-controller on it since the other components are. The Bluetooth module is based on an RTL8762C.

There is one bodge on the board as far as I can see. Not a big deal. This is version 6.0 of the board though. Temperature sensor is well glued in place. Soldering job on the cabling is good.

Go by Rds_ON.

Five back to back pair on top, five back to back pair on bottom side. 3.2 milliohms x 2 for each back to back = 6.4 milliohms @ 25C.

Ten back to back pairs in parallel = 0.64 milliohm series resistance at 25C.

Heating watts @ 200A = 200^2 x 0.64 milliohms = 25.6 watts. Won't take 200 amps very long before thermal shutdown.

For continuous current rating, no more than 10 watts heating with the limited heat sinking provided, = sqrt (10w / 0.64 millohms) = 125 amps.

Since Rds_ON goes up as MOSFET's get hot, 100 amp max continuous is more realistic. 50% derating, about par for Chinese BMS's.

 

[upnorthandpersonal]

100 amp max continuous is more realistic

Yes, that's what the BMS is specified at. This is the 100A BMS version.

 

[MondeoMan]

What type of Analog Front-End does the JK use?
A dedicated AFE BMS chip?
Analog multiplexers to MCU ADC inputs? But what about Level Translation in this case? Differential amplifiers with high common-mode rejection?

 

[RCinFLA]

In the picture of the Heltec the row of dual inline packages are just HC595 serial to parallel shift registers probably providing enables to the the back to back SOT23 MOSFET's input switches so it has discrete parts for cell voltage sense mux'g.

Discrete input mux goes to sample and hold discrete cap that is mux shifted to ground reference to be read by STM32F103 microcontroller ADC input.

 

[curiouscarbon]

Here are photos of JBD 4S BMS from recent disassembly:

1) front side with heat spreader; 2) front side without heat spreader; 3) back side without heat spreader

front side MOSFET:

back side MOSFET:

Based on the markings I believe it might be rated for 40V and called HYG013N04
Original HYG013N04NA1B6 N channel 40V 354A field effect MOS tube package TO-263-6
Couldn't find datasheet. Only could find datasheet for HY G023N03 Not HY G013N04.

This spammy link seems to describe it: https://www.yoycart.com/Product/626710881473/ (alert, spammy link)

Lastly, left) original thermal pads; right) new thermal pads

(edit: added front side PCB photo)

 

[curiouscarbon]

ehehehe ?
(had to look after reading there was one.. or is it the other spot with the grease blob?)

 

[upnorthandpersonal]

Yep, that's the bodge I found

 

[ShockinglyAverage]

Do the jk bms have low temperature protection?

 

[Sanwizard]

Yup.

 

[MrM1]

What is a good source for either the Heltec or JK (whichever has the better firmware/app etc)? Link?

 

[upnorthandpersonal]

What is a good source for either the Heltec or JK (whichever has the better firmware/app etc)? Link?

I think the latest version of the app can be found on this page - link to the about half way through:

https://www.jkbms.com/support/ (yes, it's a link to an app that's not on the app store even though it uses the app store icon...)

I believe the firmware can be updated, but I honestly never bothered doing that or figuring out the details.

 

[Sanwizard]

I think the latest version of the app can be found on this page - link to the about half way through:

https://www.jkbms.com/support/ (yes, it's a link to an app that's not on the app store even though it uses the app store icon...)

I believe the firmware can be updated, but I honestly never bothered doing that or figuring out the details.

I bought all 4 of my JK's directly from Heltec. I have two unopened 200amp versions I most likely will not use, as I have 2 Seplos BMS's on the way.
I have two 13KW banks running, another being top balanced, and 4 more coming. The Seplos will be for two of the other banks, so I will no longer need the two I bought from Heltec. (The two running will stay in service).
I paid $195 each plus shipping, so $415 for both. They are in NY.
PM me if you need one or both.

 

[Globo]

confuse manufacturers with resellers, the producers in this case are JBD and JK, the others rebrand and sell