Chargery BMS News / UPDATE (Nov.25.2020) Ver 4.02 firmware

[Chargery]

however the BMS shows 192 Ah left = 76.8% SOC based on a 250 Ah battery capacity which is a mismatch.

before discharging, please confirm the SOC reading is 100%, Ah reading is 250AH, and Wh reading is 6500Wh on BMS.
if AH reading is 250AH before discharging, the Ah reading should be 172Ah when SOC is 69%.

 

[Chargery]

Regarding the internal resistance measurements, I would see more value in this data if exported over serial (or in future CAN Bus) so that I can log it and see any trends over time. @Chargery: Perhaps I can request this in a future firmware update? It could be an additional command (e.g. 0x58 or anything else) such that the existing protocol is unchanged. It could also be sent much more infrequently than the other commands.

you mean the resistance value sent over series is too much, and only send whent it changed?

The WH and AH figures are not exported over serial either. @Chargery: Could these be added (again, perhaps as a new message to preserve existing protocol)? When I calculate them myself, if I lose connectivity (e.g. power down raspberry pi), then I cannot rely upon the calculations anymore, and can only make an approximation from the SOC. It would be great to use more data from the BMS if made available.

wh and AH is sent with voltage and resistance, please download the protocol, i added some details explain.

 

[Chargery]

@bdbugbee
please update your BMS8T-300 main unit to V4.04, don't need modify anything. the Ah reading should be correct.
after testing, please post the AH, WH, and SOC reading on BMS and Victron.
@Bob B
thanks.

 

[Doug]

you mean the resistance value sent over series is too much, and only send whent it changed?

wh and AH is sent with voltage and resistance, please download the protocol, i added some details explain.

I didn't spot the updated serial protocol, thanks for sending it. I was still using 1.23. I need to do some updating. That explains why the checksum wasn't matching on the 0x56 message anymore - I need to update the checksum calculation to match 1.25 as this update is not backwards compatible, but that is ok. I need to check my sources before posting - that's twice now!

Thanks @Chargery, you're way ahead of me! I like that you're sending the 0x58 message only on charge/discharge cycle.

The chargery manual (I'm looking at https://chargery.com/doc/Chargery_BMS8T_specification_V4.2.pdf) doesn't mention the protocol change in the change history (for v4.02 Main Unit). Can I recommend this detail is added for future changes as this would save others getting caught out as I just did.

 

[bdbugbee]

@bdbugbee
please update your BMS8T-300 main unit to V4.04, don't need modify anything. the Ah reading should be correct.
after testing, please post the AH, WH, and SOC reading on BMS and Victron.
@Bob B
thanks.

Thank you so much @Chargery. I just installed firmware V4.04 on my main BMS08T and am now charging the battery to 100% to re-synch my SOC settings on the Victron BMV-712. After that I will do a new discharge test and post my results when completed. By the way, I observed that the BMS08T SOC, Ah and Wh readings reset to 100%, 250 A and 6500 Wh respectively when I did the V4.04 firmware update. I also observed that the IR readings are back.

 

[bdbugbee]

You're right, I loaded BMS8T firmware 4.03 and LCD firmware 4.02. I didn't post immediately after doing the update to do some testing and in that time the two versions slipped my mind. To provide further details, I didn't do a factory reset afterwards (after reading @Steve_S's post saying it isn't required), but my AH & SOC figures were already out of whack (due to previous power offs) and I haven't fully charged the battery yet to reset them - so I can't yet comment on accuracy. If I do power down the BMS again, with the new firmware I hope I won't have this problem. I'm using the Chargery 100A shunt without calibration.

I'm using 4 cells for a 12V pack and have the BMS8T powered from external power directly from the same pack. I found this improved accuracy for the first and last cell over using the internal power a while ago. I haven't had any issues with the power being below the 15V minimum for external power, though I'm not powering any large relays. After reading the updated manual and @Steve_S's external power post I added a (non-schotky) diode in the negative supply and have had no troubles. I didn't have a schotky diode on hand and it seems to work fine with the higher voltage drop of a regular diode. I had no issues without this diode before, but I'm happy to follow advice and add it.

Anyway, I do see internal resistance values as before, so I don't have the same issue as @bdbugbee :

With previous firmware these internal resistance values were reset on a power down and required a short amount of time both charging and discharging to appear - @bdbugbee: perhaps try charging a bit (even briefly) as I see -9.3A in your photo suggesting you've tried discharging. I haven't used the new firmware long enough with power offs to test this for myself.

Regarding the internal resistance measurements, I would see more value in this data if exported over serial (or in future CAN Bus) so that I can log it and see any trends over time. @Chargery: Perhaps I can request this in a future firmware update? It could be an additional command (e.g. 0x58 or anything else) such that the existing protocol is unchanged. It could also be sent much more infrequently than the other commands.

The WH and AH figures are not exported over serial either. @Chargery: Could these be added (again, perhaps as a new message to preserve existing protocol)? When I calculate them myself, if I lose connectivity (e.g. power down raspberry pi), then I cannot rely upon the calculations anymore, and can only make an approximation from the SOC. It would be great to use more data from the BMS if made available.

Doug, thanks for your suggestion to recharge my battery for a few minutes to see if that fixed the lack of internal resistance data after I updated to V4.03. I had done a recharge after loading the V4.03 firmware but still didn't have any IR readings. @Chargery sent me a link to a V4.04 firmware version to address the Ah concern that I had mentioned (which I plan to test after I recharge my battery), and now while recharging the batteries, the internal resistance values are showing up again. Hopefully the Ah issue is fixed too. I'll post my results when I get them finished.

 

[bdbugbee]

@bdbugbee
please update your BMS8T-300 main unit to V4.04, don't need modify anything. the Ah reading should be correct.
after testing, please post the AH, WH, and SOC reading on BMS and Victron.
@Bob B
thanks.

Test results of the latest Firmware V4.04 for the BMS08T looks good and seems to have solved the Ah issue.

@Chargery, the firmware V4.04 for the BMS08T seems to have solved the Ah error I was getting before. I charged my bank up to 100% SOC this morning to synchronize both the Victron and the BMS08T. I have discharged my bank down to about 78% SOC and the results look very good. The voltages match exactly at 26.51V, the SOCs match at 78%, the Victron says I've used 54.5 Ah and the BMS08T indicates I've used 55 Ah (250Ah -195Ah). The Wh reported by the BMS08T are 5090 Wh out of 6500 Wh to start which equals 78.3% SOC. Very good matches across the board. The Ah issue seems to be fixed.

Thank you @Chargery for your response to my initial inquiry and for the very quick turnaround on the firmware update to V4.04.

 

[Bob B]

@bdbugbee .... Thanks for that update. I probably won't be updating and testing mine til after Christmas.... but sounds like they have resolved this.
@Chargery ....Thanks Jason.

 

[Steve_S]

Ran a partial charge cycle today, shut down for an hour and allowed the bank to settle.
Flashed in 4.04 Base, power cycled the BMS'. to start the 4.04, without a "reboot" the setup still reads as 4.03.
All IR Counters reset to 0.0 as expected.
AH & WH now seem to work as the math supports what they say. SOC ? well... not so much.
No weird AH replacement in upper right either (good, that was quite annoying).

On Reboot of BMS, the "Last Alarm" populates with current cell values and highlight the Highest & Lowest cells in red. So it does not retain the previous alarm info, this is fine.

Restarted charging process with 20A per pack +/- @ 28.0V and observed each pack reach cutoffs and trigger alarms, it took 2X for it to register in the "Last Alarms" screen.

Last Step is I connected the FLA Bank in Tandem while charging to act as a floating buffer, so that as the LFP packs were flipping on / off as they are topping, the FLA can absorb the changes in Amperage without causing the EVO Charger to trip it's charger safeties and subsequently the generator. A reminder, These tests & such are done using a Genset. Besides, we are being drowned for xmas, seriously messed up. So it happened to be convenient after being on battery for 4 days without Sun of any value.

 

[Chargery]

Thanks @Chargery, you're way ahead of me! I like that you're sending the 0x58 message only on charge/discharge cycle.

ok, we will cosider it seriously,

The chargery manual (I'm looking at https://chargery.com/doc/Chargery_BMS8T_specification_V4.2.pdf) doesn't mention the protocol change in the change history (for v4.02 Main Unit). Can I recommend this detail is added for future changes as this would save others getting caught out as I just did.

thanks for your suggestions, it will be finished on next manual update.

 

[Capt Bill]

I noticed about V4.03 of the firmware was that there are no Internal Resistance (IR) values being shown anymore. They are all zero.

IR Comment + SOC Question: I recently updated my BMS8T to v 4.03, and LCD unit to v 4.02 ... and my internal resistance shows values. I also see those value changing with charge and discharge current cycles. ... Re: SOC readings: I notice v 4.03 gives me a better fuller SOC reading on LCD dial, but I think my SOC readings are not up to snuff because I have not fully cycled to full minimum soc (to full high soc) cell voltages on my 24v 280 Ah LiFePO4 set. I currently have my BMS8T discharge trigger set up to turn off my inverter (cut battery draw) ... and have had two incidents of my BMS shutting down my inverter early, ...from my SOC getting down to 0% or 1% SOC early, like when my cells were still 3.2 + volts /full volts at 26v +. ... I have searched this forum for "Chargery SOC Calibration", and still wish there was more complete information; ... while wondering: Does setting the "Low SOC cut off" in BMS Setup to 0% turn that setting off? I had it set at at 1% when it turned off my inverter (early). I would like the option to disable the Low SOC cut off setting does' & currently in experimenting mode wo fully understanding that setting/ nor what is needed for the Chargery SOC calibration. ... and while liking the Chargery BMS8T :+)

 

[bdbugbee]

IR Comment + SOC Question: I recently updated my BMS8T to v 4.03, and LCD unit to v 4.02 ... and my internal resistance shows values. I also see those value changing with charge and discharge current cycles. ... Re: SOC readings: I notice v 4.03 gives me a better fuller SOC reading on LCD dial, but I think my SOC readings are not up to snuff because I have not fully cycled to full minimum soc (to full high soc) cell voltages on my 24v 280 Ah LiFePO4 set. I currently have my BMS8T discharge trigger set up to turn off my inverter (cut battery draw) ... and have had two incidents of my BMS shutting down my inverter early, ...from my SOC getting down to 0% or 1% SOC early, like when my cells were still 3.2 + volts /full volts at 26v +. ... I have searched this forum for "Chargery SOC Calibration", and still wish there was more complete information; ... while wondering: Does setting the "Low SOC cut off" in BMS Setup to 0% turn that setting off? I had it set at at 1% when it turned off my inverter (early). I would like the option to disable the Low SOC cut off setting does' & currently in experimenting mode wo fully understanding that setting/ nor what is needed for the Chargery SOC calibration. ... and while liking the Chargery BMS8T :+)

In my setup I have set the Low SOC cut-off to zero, and have not experienced any trips due to low SOC. I have also de-rated my bank by setting the battery capacity to 250 Ah to give me some extra margin once I get to 0% SOC. One time I intentionally discharged the battery until the SOC said zero and it didn't trip, so I'm guessing that setting the Low SOC cut-off to zero did turn it off. For me, I wanted my BMS to cut off based on cell voltage set points rather than SOC.

 

[Steve_S]

I posted this in another thread yet it seems more relevant here.
These are my current settings on a BMS8T-300. Firmware is 4.04 Main 4.02 LCD.
I hope this helps, see notes below table.

Setting​	Default​	My settings​	NOTES​
Over charge P Voltage​	3.65​	3.65​	​
Over charge R Voltage​	3.55​	3.55​	​
Over charge Current​	50​	86A/150A​	0.5C rate for 174AH/280AH​
Over Discharge P Voltage​	3.00​	2.65​	CUTOFF Trigger​
Over Discharge R Voltage​	2.00​	2.75​	Release @ this V.​
Over Discharge Current​	300​	175A/250A​	1.0C Rate (174/280)​
Low SOC cutoff​	20%​	0%​	forces cutoff @ X% (faulty)​
High Temp cutoff​	50C​	70C​	Refer to Manufacturer specs.​
Diff of Batt Temp​	10​	15C​	​
Diff of cell Voltage​	30mv​	200mv​	Unmatched cells drift,​
Temp Unit​	C​	C​	Celsius​
Key Beeper​	ON​	ON​	​
LCD Backlight​	10​	10min​	​
Cut off Delay Time​	10​	10S​	​
Current Calibration​	​	-SET-​	​
Temp Alarm​	ON​	ON​	​
Cell Empty Voltage​	2.50​	2.50​	​
Cell Full Voltage​	4.20?​	3.65​	​
Default Setting​	​	Enable​	​
Balance Parameter​	​	-SET- (OFF)*​	Passive is ON charge only, start at 3.40V, 30mv diff.​
Battery Capacity AH​	1​	174 | 280​	Label Value of cells​
Battery Power WH​	1000​	4554 | 7168​	see FORMULA​
Low Temp cut off in Charge​	2C​	2C​	​
Low Temp cut off in Discharge​	-10​	-10C​	​

"Over charge Current" should be 0.5C Charge Rate which is the max recommended. 50A for 100AH battery, 140A for 280AH battery.
"Over Discharge Current" should be 1C Discharge Rate which is the Max recommended Discharge. for 100AH=100A, 280AH=280A
"Diff of cell Voltage" Commodity cells will deviate / drift at the High & Low ends. Any cells that goes beyond this limit will trigger cutoff.
"Low SOC cutoff" This depends on Chargery's SOC % reading which is not reliable. It will override other cutoffs if this % is reached and cutoff the Battery Pack.,
WH Formula: 3.2V X #ofCells X AH rating. 3.2 x 8 x 280 =7168
AH Calculation: remember to correct IF not using the cells from 2.50-3.65V.
Main Voltage Curve for LFP: 3.000-3.450 Below 3V = about 7%, above 3.50 = about 5% usable. LFP will always settle post charge to 3.400-3.500 depending on grade.
Passive Balancing: * TEMPORARILY, I am trying to use the passive balancer to further try & keep the "Runners", even with using the Active Balancers. I'm not sure if it will help... TESTING ONLY.

 

[Bob B]

@Capt Bill I'm pretty sure @bdbugbee is correct. If you set the SOC cutoff to zero it disables that function. I have mine set to zero now, but may actually start using it with the SOC calculations getting more accurate.

 

[Capt Bill]

Balance Parameter
-SET- (OFF)*
Passive is ON charge only, start at 3.40V,​

I appreciate your educational info. Steve; and think this reference would be especially valuable to any BMS newbie setting up a Chargery BMS. One of my remaining Question areas is: Re: Setting Balance Parameter to start at 3.40V: Using this setting means balancing will happen at 3.40v and above voltages (I think that is what I read recently/ thought I made copy, but can not find it/ my way of retaining lessons). ... I had previously thought this meant started at 3.4v and then worked for all voltages < 3.4v ... but lately think I was educated that means balance start & then works @ > 3.4v / and none happens below 3.4v. .... Is that correct?? ... and if it is; Why not set balance to start at a lower to 3.25v, or 3.20V ?

 

[Steve_S]

With some tweaking and adjustment I think I finally found a tweak to optimize as much as possible.
NOTE... I have a QNBBM-8S Active Balancer on each battery pack, this makes Passive Balancing a seriously odd dance.

I'm now doing another heavy charge run.
Chargery BMS Passive Balancing is set as follows:
- Balance start at 3.35V
- Diff between cells = 10mv YES 10mv
- Balance during CHARGE ON, other modes off.

Balance to start at 3.350 is below where any runners start running. It helps knock the edge of it down, allowing the lazier cells to keep up a bit.
DIFF is set to 10mv, to try and keep cells closer together, the Active Balancer is not doing enough, fast enough, so a little extra help there... I had it set to 30mv diff but that allowed for too much extra deviation, the 10mv forced more to be burned off the cells, letting the Active Balancer do a bit more on the shifting side in combination... well so it appears at this time. I'm now at 15 minute checks on packs because they are getting up there in cell voltage.
Also Passive is on ON only during Charge as that is when the runners are the problem.

I was VERY HESITANT with the Balancing as this can be conflicting (see what happens if all is on, with an Active Balancer. But yesterday I had one runner take off and hit 4.05V even though the BMS tripped and dropped the line... BTW: This is one of the used 174AH cells from that Shunbin mess, NOT one of the EVE 280's.

OBSERVATIONS:
Well as hesitant as I was with this, it seems a good thing now... that itty bitty bit (1.2A is itty bitty) being pulled off the high cells is certainly helping the others keep up, I am seeing a more consistent rise above 3.400 with all the cells. I still expect the runners will take off but if I can keep that from happening for a longer period of time, that will allow the remaining cells to absorb more juice.
- The one QNBBM which has a defective B7 (which Deligreen got stupid over and won't replace) has absolutely had a deleterious effect, it is THAT ONE which allowed the one cell to run over 4.0V, it will not transfer the juice off that cell.

One Problem, when the BMS cuts off due to too much DIFF between cells or the runner triggers HVD the Passive Balancing seems to go stop which is unfortunate as that does not help knock the runner back down. That should not be the case IMO.

RE QNBBM, They work and do quite well. DeliGreen is FULL OF S*** for support. Sadly, they bought the QNBBM company & product family. As a result I can NO LONGER RECOMMEND QNBBM / DeliGreen.

NEW CHARGERY BMS:
I have my fingers crossed that Jason comes out with the new BMS' that have Active Balancing and fewer "quirks" than the BMS*T models. It's an upgrade I would consider once they hit the market space and people report back. I do NOT know the details and what is going on with the new series of BMS other than what Jason has shared on here, which is minimal. Hopefully, he'll have reasonable docs come out too (I will not be editing those).

I'll have to seriously think on the BMS, as I have spent far more on the BMS Adventures than I had ever planned or had budget for. Had I known that this adventure would have been so costly, I likely would have made another decision & choice. HINDSIGHT = 20/20 !

 

[Bob B]

I finally got around to installing the 4.04 update. Haven't done a lot of testing yet but .... the incorrect reporting of AH does indeed appear to be fixed.

After the update, all SOC indications reset to 100%, so I fully charged the pack and then put a load on it. The AH tracking seems to be good now.

The only thing now preventing accurate AH readings is the requirement for .5 A to drop out of storage mode. While this is better than before, small loads could still cause inaccuracies over time. I personally don't think that storage mode is needed. While it's true that as it is now, the only way to put the BMS in stop mode is to press stop while in storage mode. Seems like this could be changed and storage mode eliminated.
Charging the pack to 100% occasionally should prevent this from being a significant issue in most cases.

 

[Capt Bill]

I finally got around to installing the 4.04 update. Haven't done a lot of testing yet but .... the incorrect reporting of AH does indeed appear to be fixed.

After the update, all SOC indications reset to 100%, so I fully charged the pack and then put a load on it. The AH tracking seems to be good now.

The only thing now preventing accurate AH readings is the requirement for .5 A to drop out of storage mode. While this is better than before, small loads could still cause inaccuracies over time. I personally don't think that storage mode is needed. While it's true that as it is now, the only way to put the BMS in stop mode is to press stop while in storage mode. Seems like this could be changed and storage mode eliminated.
Charging the pack to 100% occasionally should prevent this from being a significant issue in most cases.

Bob, ... is that a typo? ... or how do you get the newest update before posted at the web link I just copied from beginning of this thread ??? https://chargery.com/update.asp ??? :+) :+) :+)

 

[Bob B]

Bob, ... is that a typo? ... or how do you get the newest update before posted at the web link I just copied from beginning of this thread ??? https://chargery.com/update.asp ??? :+) :+) :+)

Jason posted the 4.04 update in post #143

 

[Solarfun4jim]

Jason posted the 4.04 update in post #143

yeah....but nothing for a 600 shunt. :-(