TheSpaniard47
New Member
So, recently I had an issue involving the 4-8S 200A JK BMS (B1A8S-20P - not the new "inverter" type model). It is protecting eight EVE LF280K cells in 8S configuration and had been running perfectly for almost a year. At some point, the BMS shut off charging and discharging, and displayed the error "cell count is not equal to settings". In the app, cells 3 and 4 show no voltage readout. Everything else is as normal, but emergency mode must be toggled in order to enable charge/discharge.
I have checked all the basics (battery posts, balance cables, JST-XH connector), and can verify there is continuity all the way into the BMS. Thanks to some relevant posts on here, I have also checked the 0.01Ω resistors leading into the JST terminal. I am far from an expert, but I have not detected any obvious faults. There are pictures attached for those more knowledgeable than myself.
Here's where it gets really confusing. I reached out to the vendor who sold me the BMS, Hankzor (on Aliexpress). Once I explained the problem, sent them photos, etc, their first question was: "do you have an inverter connected?" When I told them yes, they responded:
"Connecting the inverter is easy to burn out and will not alarm, friend. bms cannot be connected to the inverter."
I went back through their listing, and the only section that mentions inverters is simply explaining how inverters can have an inconsistent current draw which can trigger false alarms and measurement irregularities. It does not warn against using inverters, in fact, it specifically states: "this does not affect the normal use of BMS."
I sent them a screenshot from their own description and asked for elaboration. They said:
"Power BMS does not have a built-in communication protocol and cannot communicate with the inverter. Even if it is connected and can be used normally, app will give an alarm and BMS will be damaged if it is used for a long time."
The BMS doesn't have the necessary communication protocol, true. But this is exactly why I purchased it - neither does the inverter! And for those wondering, it is a Xijia 24V 3000W pure sine inverter which rarely sees over 1000W of continuous load. The BMS is intentionally very oversized for this application, and over-current protection is set to 125A. I watched Andy's video (off-grid garage) on this exact BMS where he pulled well over 200A for 5 min and, understandably, popped a mosfet. He used an inverter very similar to mine in this testing. Ironically enough, Hankzor was the vendor who sent him the BMS, and they did not say a thing about the inverter, even when he blew the fet....
So, what the heck do you all make of this? Hankzor's stance seems to be that the standard JK BMS is not to be connected into a system with an inverter under any circumstances. Have I gravely misunderstood the nature of this BMS? Or are they spewing nonsense? I had understood Hankzor to be a somewhat reputable supplier (as far as AliExpress vendors go), but my experience with them has been remarkably slow and tedious.
Thanks in advance for all responses, this is a lot to read!
I have checked all the basics (battery posts, balance cables, JST-XH connector), and can verify there is continuity all the way into the BMS. Thanks to some relevant posts on here, I have also checked the 0.01Ω resistors leading into the JST terminal. I am far from an expert, but I have not detected any obvious faults. There are pictures attached for those more knowledgeable than myself.
Here's where it gets really confusing. I reached out to the vendor who sold me the BMS, Hankzor (on Aliexpress). Once I explained the problem, sent them photos, etc, their first question was: "do you have an inverter connected?" When I told them yes, they responded:
"Connecting the inverter is easy to burn out and will not alarm, friend. bms cannot be connected to the inverter."
I went back through their listing, and the only section that mentions inverters is simply explaining how inverters can have an inconsistent current draw which can trigger false alarms and measurement irregularities. It does not warn against using inverters, in fact, it specifically states: "this does not affect the normal use of BMS."
I sent them a screenshot from their own description and asked for elaboration. They said:
"Power BMS does not have a built-in communication protocol and cannot communicate with the inverter. Even if it is connected and can be used normally, app will give an alarm and BMS will be damaged if it is used for a long time."
The BMS doesn't have the necessary communication protocol, true. But this is exactly why I purchased it - neither does the inverter! And for those wondering, it is a Xijia 24V 3000W pure sine inverter which rarely sees over 1000W of continuous load. The BMS is intentionally very oversized for this application, and over-current protection is set to 125A. I watched Andy's video (off-grid garage) on this exact BMS where he pulled well over 200A for 5 min and, understandably, popped a mosfet. He used an inverter very similar to mine in this testing. Ironically enough, Hankzor was the vendor who sent him the BMS, and they did not say a thing about the inverter, even when he blew the fet....
So, what the heck do you all make of this? Hankzor's stance seems to be that the standard JK BMS is not to be connected into a system with an inverter under any circumstances. Have I gravely misunderstood the nature of this BMS? Or are they spewing nonsense? I had understood Hankzor to be a somewhat reputable supplier (as far as AliExpress vendors go), but my experience with them has been remarkably slow and tedious.
Thanks in advance for all responses, this is a lot to read!
Attachments
-
Screenshot_2024-07-12-16-26-20-53_bd59be8c3f820c1e3d6fc2892aab342d.jpg -
Screenshot_2024-07-13-18-09-20-73_bd59be8c3f820c1e3d6fc2892aab342d.jpg -
IMG_20240713_173058.jpg -
IMG_20240713_173159.jpg -
Screenshot_2024-07-19-17-21-19-21_57e717c094f371a1dada6567a1123b99.jpg -
IMG_20240715_151408.jpg -
Screenshot_2024-07-19-17-22-04-85_57e717c094f371a1dada6567a1123b99.jpg
