Overkill bms useless

[bronxfire]

So i have a 48v 280ah thats hooked up to a new 100amp bms. I also have a victron shunt. After a few days i realized my reading for soc was getting out of whack between the ahunt and bms to the tune of about 25 ahrs.so i watched the bms and Seems it wasnt reading any wattage consumed under about 30 watts. Said 0 no discharge. i contacted overkill support and the response was the bms isnt good detecting under amp and a half of discharge . I think its ridiculous that was the answer they gave . i have the email. has anyone else seen this failure of this bms. a cheap amazon shunt is more accurate than that

 

[ChrisG]

I agree with your findings which is why I also use a Victron shunt. AH and SOC are off with the JBD bms. I don’t think they’ve ever been known to be accurate.

 

[bronxfire]

I agree with your findings which is why I also use a Victron shunt. AH and SOC are off with the JBD bms. I don’t think they’ve ever been known to be accurate.

Thank u for reply. I was shocked but i guess as long as the shunt is accurate thats the goto. Would be nice to have the redundancy though

 

[chrisski]

Yes, the Overkill (Rebranded JDB) BMS is innacurate.

Would be nice if the iPhone software had a way to “Reset to 100%.” If you find a way, please say. Perhaps a different BMS software can talk to the BMS. I could not find either a new app nor could I find a way to “calibrate” the SOC.

I use the Victron Shunt to measure the total state of both my batteries. I use the BMS to look at individual cell status.

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I would not call the thread, “Overkill BMS Useless.” Better could be “Overkill BMS SOC reading Useless.” First reading the thread, I thought you got delivered a broken BMS, or perhaps 100 amps on your 48 volt pack did not deliver enough power.

 

[bronxfire]

I agree useless is a bit aggressive it still works and I like the app functionality

 

[time2roll]

The BMS will catch up based on the programmed voltage. If the battery is good for 48+ hours it should be close enough.

 

[Daddy Tanuki]

Don’t fret it, Daly is same i would guess all the Chinese BMS’s use a similar architecture and as such are all about the same

 

[justgary]

I would suspect that it is not the shunt, but the way they digitize the voltage across the shunt. If we assume a 3 volt range to cover from -100 to +100 amps, then we get 0.015 volts per amp. That is only two bits of resolution with a ten bit A/D converter. Add a little noise to the circuit and those two bits become noise.

I would expect a 100 amp shunt to read one amp with that type converter, but a 250 amp shunt would struggle with maybe two or three amps.

For those chasing cost, this may be good enough. A 5 volt A/D would help, as would a 12 or 14 bit converter along with a well-designed circuit. All of those would add cost.

 

[brb58]

I have two batteries in parallel and the JBD BMS shows vastly different SOC for each battery at times. I basically ignore them and use my Victron BMV.

 

[Pierre]

The BMS will catch up based on the programmed voltage. If the battery is good for 48+ hours it should be close enough.

I agree that the JBD BMS‘s do not report well under 1 - 2amps. Overall 2% accuracy , who cares.

 

[Pierre]

So i have a 48v 280ah thats hooked up to a new 100amp bms. I also have a victron shunt. After a few days i realized my reading for soc was getting out of whack between the ahunt and bms to the tune of about 25 ahrs.so i watched the bms and Seems it wasnt reading any wattage consumed under about 30 watts. Said 0 no discharge. i contacted overkill support and the response was the bms isnt good detecting under amp and a half of discharge . I think its ridiculous that was the answer they gave . i have the email. has anyone else seen this failure of this bms. a cheap amazon shunt is more accurate than that

Your statement is very harsh. I have x6 JBD’s in service at home and have sold about x20 of them. I have not been able to kill one of them yet. As to the inaccuracy in ampere readings, have you calibrated both the Victron shunt and confirmed the JBD internal shunt calibration? After that confirm all with an accurate current meter.

 

[wholybee]

IIRC, the JBD BMS does have a procedure to calibrate zero, and also a configurable dead zone where it will read zero. Its there so that noise won't cause a small current reading when there is none. But, the result is that if you do have a small current, it won't read it.

Probably not all software has access to these settings as they are mostly supposed to be done at the factory.

 

[Daddy Tanuki]

Your statement is very harsh. I have x6 JBD’s in service at home and have sold about x20 of them. I have not been able to kill one of them yet. As to the inaccuracy in ampere readings, have you calibrated both the Victron shunt and confirmed the JBD internal shunt calibration? After that confirm all with an accurate current meter.

so you sell them and do not want anybody to speak badly about them..... too bad.

 

[Pierre]

so you sell them and do not want anybody to speak badly about them..... too bad.

Not the case. I sell 3 other brands as well. Just stating facts. Use them for a couple of months first and then post constructive criticism.

 

[Daddy Tanuki]

Not the case. I sell 3 other brands as well. Just stating facts. Use them for a couple of months first and then post constructive criticism.

stop attempting to prevent others from telling their problems on a public forum when you have a vested interest to hide data.

 

[Pierre]

stop attempting to prevent others from telling their problems on a public forum when you have a vested interest to hide data.

Happy New Year to you as well !

 

[chrisski]

For those who say it will reset itself and have actually done the procedure, wht is it? I use the XiaoxXiangBMS APP as I’m sure the OP does, and it has not worked for us.

If there is a simple fix, what is it? I’m on two years and one BMS with everything I’ve tried has not reset it.

It’s something I and many others live with, but if there is another app, a procedure, or anything to calibrate it, would be nice to know.

IIRC, the JBD BMS does have a procedure to calibrate zero, and also a configurable dead zone where it will read zero. Its there so that noise won't cause a small current reading when there is none.

What is this procedure or how do you access it with what software or app?

As to the inaccuracy in ampere readings, have you calibrated both the Victron shunt and confirmed the JBD internal shunt calibration?

How do you confirm the JBD internal calibration.

I agree that the JBD BMS‘s do not report well under 1 - 2amps. Overall 2% accuracy , who cares.

Mine is off by 30%, and I am interested in fixing that. I haven’t found a thread, setting, or instructions to do that everywhere I’ve looked.

The BMS will catch up based on the programmed voltage. If the battery is good for 48+ hours it should be close enough.

This is my second year with the battery and it has not caught up.. Still 30% off.

 

[42OhmsPA]

For those who say it will reset itself and have actually done the procedure, wht is it? I use the XiaoxXiangBMS APP as I’m sure the OP does, and it has not worked for us.

If there is a simple fix, what is it? I’m on two years and one BMS with everything I’ve tried has not reset it.

It’s something I and many others live with, but if there is another app, a procedure, or anything to calibrate it, would be nice to know.

What is this procedure or how do you access it with what software or app?


How do you confirm the JBD internal calibration.

Mine is off by 30%, and I am interested in fixing that. I haven’t found a thread, setting, or instructions to do that everywhere I’ve looked.

This is my second year with the battery and it has not caught up.. Still 30% off.

There is PC software you can use to change settings. I've also noticed when you change the settings in the app it will reset the SOC.

I see the same issues with my 3 JBDs when I I go days without a full charge... Look how even my packs are ?
I trust the wonvon shunt and JBD voltages reported to SA...

 

[chrisski]

There is PC software you can use to change settings. I've also noticed when you change the settings in the app it will reset the SOC.

What is this software? Is it Blue tooth or direct connect? I could not find the PC software or missed it in the overkill manual.

I trust the Vivtron Shunt to give SOC of batteries and trust the BMS to keep track of pack voltage and cell voltage And over currents.
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EDIT: I now see the part in the Overkill manual about the software for the PC. Apparently it can do this, but the software is in Chinese, and the how to change the capacity is not pictured. I'm unwilling to drop money on the PC connector or download the software until I have better instructions.

I also see that the app is downloadable from this site:\

Product Files Support

Product Specifications AP Series Specification Sheet JBD-AP21S001-6-21S of 60-200A Smart bms JBD-AP20S006-7-20S of 200A Smart bms JBD-AP21S002-7-21S of 200A Smart bms DP Series Specification Sheet JBD-DP24D002-L24S-200A-200A-B-U-R-K_V1.2 JBD-DP04S007_V1.5-LiFePO4-Specification_Sheet...

jiabaidabms.com

 

[Quattrohead]

JBD tools can be set to English or American too.
You can use any RS485 to USB adapter. I like this one because it has visible tx/rx leds.
Stop making excuses, get er done !!!