Failed JK BMS

[upnorthandpersonal]

I still have to get back to it. It's been a bit hectic...

Can you recommended recommend a 48V bms?

At this time, not really. I'm going to try some others, but my hope is that the JK issues are fixed.

How fiddly is the repair of the B2a8s20p? I don't have a heat gun just soldering iron. Not a newbie to smd but my hands are not as steady and my eyes are fixed focus to the applied lenses.

With just an iron, it's not the easiest thing in the world. You would need hot air, or a steady hand and very thin tip, ample flux, and some desolder wick.

I wish sending stuff from the UK to mainland Europe wasn't such a pain right now. I'd fix it for you...

 

[Horsefly]

I'm going to try some others, but my hope is that the JK issues are fixed.

I may have missed it (I don't spend as much time here as I used to), but.... Has anyone opened up one of the newer JK BMSs and checked to see if the suspect components have been replaced?

 

[upnorthandpersonal]

I may have missed it (I don't spend as much time here as I used to), but.... Has anyone opened up one of the newer JK BMSs and checked to see if the suspect components have been replaced?

That's what's on my todo list still - I have it sitting on my desk (sadly with another pile of work to go through first).

 

[-g-g-g-]

I wish sending stuff from the UK to mainland Europe wasn't such a pain right now. I'd fix it for you...

That's very decent of you to offer. Sounds like you have enough to do at the moment though.

I can't believe there's no one else with your skills a bit nearer to me. I'm surprised that you're the only person on the forum who seems to be interested in investigating products let alone repair them.

Looks like a new inverter and bms and I will have to add the failed ones to the increasing pile of equipment. And not just cheap brands, I've quality equipment that has failed as often as the cheaper brands. More often than not two bargain products are more economical than one leading brand. It's just such a waste of resources. I've a whole box of dead phones, most just need a battery but replacements are useless and manufacturers refuse to supply parts. It's a sick world we've created.

I own the flux, solder, braid, solder sucker etc. and I can make a tip any size or shape I need, but my creaky hands might be a limiting factor if it's a small smd in a tight position. I manage some repairs if I stack several pairs of glasses over each other so I can see.
Maybe a hot air station will be a viable addition to the workshop once I have an AC supply again. I do repairs to the limit of my skills and I'm learning all the time, but my brain is slowing down these days whilst my body is creaking along behind. The joy of getting old lol.

 

[upnorthandpersonal]

PM me your address, I can send you the chips - you can then give it a try. If it fails, so be it, but you if you can get ti fixed - less waste.

 

[Horsefly]

Well, my Overkill / JBD 8S from 2016 seems to be having some issues, which may have been caused by my bad JK BMS running on a parallel pack (I am the OP of this thread, so the failure is in the first post). The Overkill BMS seems to mostly be doing what a BMS absolutely needs to do, but any attempt to access it via app while charging causes things to go a bit crazy.

So, I'm taking a chance and ordering a new JK b2a8s20p, hoping that since last November they have fixed the issues I was having. I'm also hoping that I can search back in this thread and find what @upnorthandpersonal found to be the bad part numbers, so I can open it up and make sure there are none in this new one.

Wish me luck, and stay tuned!

 

[upnorthandpersonal]

I'm also hoping that I can search back in this thread and find what @upnorthandpersonal found to be the bad part numbers, so I can open it up and make sure there are none in this new one.

As far as I can tell from the newer ones I bought, the issue is not present. The difficulty is finding out what part exactly is used. Most of the part numbers are not really pointing to anything, so I have to remove the chips and measure their characteristics. This is a bit time consuming...

 

[Frank in Thailand]

Is there anyway to tell when the error started and stopped?

Hardware version?
Manufacturing date?



Mine are "old" , no problem.

A friend likes to buy also and obviously better a version without known trouble.

Outside I see only a sticker



With no "batch" information or anything.

Is there a way to know before you start the BMS and look inside the app?,

 

[upnorthandpersonal]

I've had confirmation from the manufacturer that this problem is solved now. I also tested a new one to check, and it looks like the fault has indeed been fixed. I'm still trying to find what the replacement chip now actually is, but have not had time yet.

 

[Frank in Thailand]

I've had confirmation from the manufacturer that this problem is solved now. I also tested a new one to check, and it looks like the fault has indeed been fixed. I'm still trying to find what the replacement chip now actually is, but have not had time yet.

Thank you for informing!!

Obviously there is a danger of getting older stock with the error.

Can you tell us the HW version that is good again?

And what seller you obtained it from?
I'm not sure if it's still allowed on Diysolarforum to post direct links to sellers.

I would really appreciate it.
My friend really doesn't have the Budget (or time) to buy 2 or 3 and swap swap swap before finally getting a good one.

He is now struggling with the 40A Jikong who are clearly from a whole different quality level then the 200A big brother...
To anyone thinking about them..
Don't..
just don't.

He only had 2..
The list of lockups, not responding to settings (like no charge / discharge)
Voltage levels for production ignored..

Not always..
Some are set.
They are all shown in the app.
(He tried 3 different version, and uses 2 year old galaxy tab) it's Russian roulette if it will work or not.
His MOS temperature is 8-10 degrees higher then the battery temps.

By me classified as the familiar "China crap"...
Using their good name to sell some inferior products.

He also could just have had 2 lemons.
As stated....
Not the time nor the budget to do QA for jikong...

Anyone with good working Jikong for sale... Please PM

(I personally have 4 x 200A 2A balancer, and a happy puppy with them, in use, so not for sale)

 

[upnorthandpersonal]

I only get them from Hankzor directly - they are also the manufacturer and sw developer (or at least, the way it's done in China). No idea of the exact HW versions, but you can always contact them and make sure you get the latest version, mentioning you know about the issues with the converters...

 

[Frank in Thailand]

I only get them from Hankzor directly - they are also the manufacturer and sw developer (or at least, the way it's done in China). No idea of the exact HW versions, but you can always contact them and make sure you get the latest version, mentioning you know about the issues with the converters...

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Correct shop?

 

[upnorthandpersonal]

Correct shop?

Yep.

 

[Frank in Thailand]

I've had confirmation from the manufacturer that this problem is solved now. I also tested a new one to check, and it looks like the fault has indeed been fixed. I'm still trying to find what the replacement chip now actually is, but have not had time yet.

Did you already have time to power it up and look at the hardware version??

Thanks!

 

[upnorthandpersonal]

No, sorry - too busy with other things...

 

[Horsefly]

Well, my Overkill / JBD 8S from 2016 seems to be having some issues, which may have been caused by my bad JK BMS running on a parallel pack (I am the OP of this thread, so the failure is in the first post). The Overkill BMS seems to mostly be doing what a BMS absolutely needs to do, but any attempt to access it via app while charging causes things to go a bit crazy.

So, I'm taking a chance and ordering a new JK b2a8s20p, hoping that since last November they have fixed the issues I was having. I'm also hoping that I can search back in this thread and find what @upnorthandpersonal found to be the bad part numbers, so I can open it up and make sure there are none in this new one.

Wish me luck, and stay tuned!

I thought I should post back here. I did get the new B2A8S20P (the version without the heat port) and replaced the old JBD at our cabin. I was out hiking when the majority of the bulk charging happened today, but it seems to work fine. So I'm thinking that JK did fix what ever the problem was.

 

[Skypower]

I thought I should post back here. I did get the new B2A8S20P (the version without the heat port) and replaced the old JBD at our cabin. I was out hiking when the majority of the bulk charging happened today, but it seems to work fine. So I'm thinking that JK did fix what ever the problem was.

Great to hear ?

 

[Horsefly]

I thought I should post back here. I did get the new B2A8S20P (the version without the heat port) and replaced the old JBD at our cabin. I was out hiking when the majority of the bulk charging happened today, but it seems to work fine. So I'm thinking that JK did fix what ever the problem was.

After observing the new JK BMS side-by-side with the one I got in early 2022 (which still works great) I noticed that the new one seems to display a moving average for the current, which results in a pretty stable number. The old one would jump around at least every second, and by quite a bit. It made it hard to even guess what the current was, if you cared. The new one is much better.

 

[upnorthandpersonal]

After observing the new JK BMS side-by-side with the one I got in early 2022 (which still works great) I noticed that the new one seems to display a moving average for the current, which results in a pretty stable number. The old one would jump around at least every second, and by quite a bit. It made it hard to even guess what the current was, if you cared. The new one is much better.

I remember that this was discussed with them, so they must have now implemented it. I did not notice that while testing, so good to know!
I so wish they would have a better versioning/changelog process...

 

[MrM1]

After observing the new JK BMS side-by-side with the one I got in early 2022 (which still works great) I noticed that the new one seems to display a moving average for the current, which results in a pretty stable number. The old one would jump around at least every second, and by quite a bit. It made it hard to even guess what the current was, if you cared. The new one is much better.

Moving average of the current displayed in the app? Yeah the older ones I got (like maybe 2021) Do this but seem to work fine.

But I need two more. Glad to hear it's fixed.

@Horsefly , where did you get your new ones? Did you request no heat port?

Can you post the model again?