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

Chargery said:
yes, differenct cell manufacture has different storage requirments, because the cell self discharge rate is different. every 3 months, battery pack discharge to 0 and charge to 100% can resume battery original capacity, discharge to 20% and charge to 80% is not the best, but it workable. when charge in 100AH, battery cannot discharge out 100Ah, why? with the cycels increase, when in 100AH, only out 90AH, because the battery meterial microstruture is damaged.
so undertand battery, using battery according to battery datasheet is very important. storage for 3 months, and do a charge-discharge deeply cycel is suggested.
almost good battery or A grade battery manufatured by famous manufactures don't sell in DIY market. the good cell must have almost same volage, same resistance and same capacity before assembel battery bank , fit with good BMS to monitor each cell volage, current, cycles, and other kinds of protecion design, all parameters is preset before delivery, warranty 2000 cycles or 3 years, not only focus on each part performance but also optimize total system performance. these battery banks are used on 5G communication base station at a large volume in China.
Chargey will be ready to provide our customer in DIY market the A grade battery bank in future.
The following picture is the 48V 100AH 16S LiFePO4 battery bank.
Click to expand...
@Chargery
Thanks for that info Jason. You are the first person i have read, saying that you must do a 100% charge or a 0% discharge to maintain capacity. I have EVE 280ah commodity cells, which are not 'matched' from manufacturer, but have been top balanced by myself. If i push the cells into the knees, then i will have divergence problems between cells and potential drift. I'm glad you at suggested that my solution of 20-80% is at least workable.
Do you have any links to charts which show the degradation of capacity, when using less than the 100% ? Everything i had seen up till now, shows that using less capacity enhances the number of cycles....so that is what i was aiming for. I was hoping for approx 5000 cycles at 50% capacity useage?

I just wish to express my thanks, that whilst running your business, you take the time out to respond to enquiries on a forum. Your units might not be perfect for every application, no single item ever is, but your responsiveness is second to none. (y)
 
I should point out that Jason's efforts also include him having to translate everything back & forth and make sense of it in the process. This speaks Volumes with regards to his interest in making Chargery Bigger, Better, and more capable for all of us collectively.

How many Manufacturers or even Vendors have an "Active Presence" on a forum and interact with the members while Listening AND Hearing what is being said to them ? It is RARE ! Even moreso when there is such a Language Barrier.
 
Solarfun4jim said:
I realise there is a big error in my sketch above ....drawn in haste. The diagram below is my corrected one. Unfortunately i couldn't edit the original incorrect diagram.View attachment 30556
Click to expand...
Interesting; ...and to confirm: You get slightly more accurate voltage readings on cell #1, and # 8 in battery bank? by powering the BMS via its' external power plug vs the BMS 8 wire loom? ... And Coud you once again confirm: What is the advantage or purpose of that diode (again)? I think I want to try this out on my next remove and update firmware cycle.
 
Capt Bill said:
Interesting; ...and to confirm: You get slightly more accurate voltage readings on cell #1, and # 8 in battery bank? by powering the BMS via its' external power plug vs the BMS 8 wire loom? ... And Coud you once again confirm: What is the advantage or purpose of that diode (again)? I think I want to try this out on my next remove and update firmware cycle.
Click to expand...
I'm no expert, just learning this as i go along. Jason from Chargery has posted info on this previously, which i need to defer to. My understanding is, there is a potential issue, between the ground of the BMS being different from the ground of the battery pack, so the diode prevents this problem. I might well be wrong in my interpretation.
From my own perspective, i want the sensing loom to only measure the cell voltages the most accurate way they can. Independant power to the DC input, allows me to use greater guage wire(thicker) and also a control element through the disconnect function. Even if this is triggered and it powers down the BMS, i know to look for the problem, but can simply slide the switch to the wiring loom position just to see what the display is telling me, so its not a biggie.

Ideally for me, come october, i wish to power down everything bar the BMS. This i want to put to storage mode, but still powered. The disconnect protects me from completely taking my pack to low, but i still get info if/when i decide to check on things. At only 22mA draw, i reckon things should be ok from a 280AH 24V pack, even for six months, but i would check things anyway, say the end of every month.

ps edit... i have not constructed this as yet, still accumulating all parts, so i cant say for sure on the inproved accuracy aspect, however, that is my understanding of it. My charge/discharge relays will output to SSR's of extremely low amp draw, so i wont get so much appreciable difference in accuracy. Think my total will be approx 40mA, but on a 24v system supply, it will be fairly negilable difference on the cell1 & cell 8 readings.
 
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I have to say, i think Will's video on the Chargery unit, done it a bit of a disservice. If you are using the supplied shunt which is already calibrated to the system, then the user functions are a lot easier than Will makes out. I'm a 'not too bright' technophobe user of the system and found it to be fairly straight forward. It is fairly disconcerting when the SOC/kWh readings seem so out of whack, until you complete a capacity test (full charge to full discharge) and input the accurate figures for your own particular pack, then it all comes good and makes sense....in my humble opinion.

If however, you are an advanced user and wish to use a different shunt, then yes, i can get to be a bit of a faff, but how many users will go to the trouble of installing a new shunt?

ps edit...i'd better add, as regards Will's video, it is not a critisism, simply a personal observational opinion
 
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Solarfun4jim said:
At only 22mA draw, i reckon things should be ok from a 280AH 24V pack, even for six months, but i would check things anyway, say the end of every month.
Click to expand...
I would think checking on a LiFePO4 battery bank in storage mode over a six month period, like you say; ... would be a good idea. I would be inclined to check more often at the beginning, to see what is going on. If nothing is connected for IN or Out Amps ??? , ... I wonder what the pros and cons are for the idea of also disconnecting the BMS from a battery bank you intend to leave in storage mode for an extended period of time. :+)
 
Capt Bill said:
I would think checking on a LiFePO4 battery bank in storage mode over a six month period, like you say; ... would be a good idea. I would be inclined to check more often at the beginning, to see what is going on. If nothing is connected for IN or Out Amps ??? , ... I wonder what the pros and cons are for the idea of also disconnecting the BMS from a battery bank you intend to leave in storage mode for an extended period of time. :+)
Click to expand...
I believe that if you have the latest software update, you can power the BMS down, then on resumption of power later, all the settings are retained. I might be inclind to do so myself, except, unfortunately i cannot get the software update and hence i would need to reset all the settings. This leaves a lot of room for error(user input) for something that must work perfectly every time it is called for. I just like the idea of entering the camper, pressing one button and immediately seeing the voltage of every cell. I'd be inclined to do this more often, than if i was having to fiddle with things.
In my circumstances...the pros of disconnecting are, you cant drain your pack. The cons are, i need to reset all settings every time and it becomes a chore.
 
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I have turned off the BMS & DCC on my packs throughout my testing and they've not lost their settings, they're saved into nvram. Some of the stats are reset. Prior to v4.02 flashing resulted in the settings having to be reset and if you used an alternative shunt, it meant recalibrating.
 
Solarfun4jim said:
I have to say, i think Will's video on the Chargery unit, done it a bit of a disservice. If you are using the supplied shunt which is already calibrated to the system, then the user functions are a lot easier than Will makes out. I'm a 'not too bright' technophobe user of the system and found it to be fairly straight forward. It is fairly disconcerting when the SOC/kWh readings seem so out of whack, until you complete a capacity test (full charge to full discharge) and input the accurate figures for your own particular pack, then it all comes good and makes sense....in my humble opinion.

If however, you are an advanced user and wish to use a different shunt, then yes, i can get to be a bit of a faff, but how many users will go to the trouble of installing a new shunt?

ps edit...i'd better add, as regards Will's video, it is not a critisism, simply a personal observational opinion
Click to expand...
I think that video clip of Will P's might be worthy of an update; plus think it, along with dialog in this forum, and Steve S's collaborative input to Jason helped Chargery improve their product. I am saying that while remembering how that heated up energy sucking orange colored relay got retired (I think those used to be supplied by Chargery?), and replaced with a new line of DDC Contactors; plus we have seen a few ongoing firmware updates making for improvements over past firmware versions. IMO; That Will Prowse review of the Chargery BMS8T IS outdated by Chargery's ongoing improvements since then. ... & It IS Good to compare notes and opinions here ... :+)
 
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Solarfun4jim said:
Do you have any links to charts which show the degradation of capacity, when using less than the 100% ? Everything i had seen up till now, shows that using less capacity enhances the number of cycles....so that is what i was aiming for. I was hoping for approx 5000 cycles at 50% capacity useage?
Click to expand...
please read this article on https://batteryuniversity.com/index.php/learn/article/how_to_prolong_lithium_based_batteries
the smaller DoD, the longer battery life.
 
Capt Bill said:
I think that video clip of Will P's might be worthy of an update; plus think it, along with dialog in this forum, and Steve S's collaborative input to Jason helped Chargery improve their product. I am saying that while remembering how that heated up energy sucking orange colored relay got retired (I think those used to be supplied by Chargery?), and replaced with a new line of DDC Contactors; plus we have seen a few ongoing firmware updates making for improvements over past firmware versions. IMO; That Will Prowse review of the Chargery BMS8T IS outdated by Chargery's ongoing improvements since then. ... & It IS Good to compare notes and opinions here ... :+)
Click to expand...
I agree. It seems that Will's major criticism was more directed at those old Chargery relays instead of the Chargery BMS itself. I had already quit using the old version of the Chargery relays because of the heat that they generated just to keep their coil energized. Instead, for battery disconnect I use the Chargery BMS output leads to drive two small SSRs whose output is connected in series with the coil of a 500A TE Connectivity EV200AAANA Normally Open mechanical relay across my 24V bus. With this change, the Chargery BMS has performed very well for my application. I do not plan to use the new Chargery Contactors because the EV200 mechanical relay performs great and doesn't use a lot of power.
 
I have loaded the new 4.02 firmware on my Chargery BMS and I am very happy with the update. I really like the return of the precision of the amps in/out as well as lowering the threshold for storage mode, since I have some low current loads that can add up over time and were previously ignored. The firmware update went without a hitch. I welcome the future offerings including CAN Bus as I've been experimenting with this for other devices and can see some advantages over serial. Thank you to Jason and the Chargery team for these continued improvements.
 
doug said:
I have loaded the new 4.02 firmware on my Chargery BMS and I am very happy with the update. I really like the return of the precision of the amps in/out as well as lowering the threshold for storage mode, since I have some low current loads that can add up over time and were previously ignored. The firmware update went without a hitch. I welcome the future offerings including CAN Bus as I've been experimenting with this for other devices and can see some advantages over serial. Thank you to Jason and the Chargery team for these continued improvements.
Click to expand...
Go ahead and do the 4.03 while your at it .... it will keep from loosing SOC and settings in case of a power down.
 
doug said:
I have loaded the new 4.02 firmware on my Chargery BMS and I am very happy with the update. I really like the return of the precision of the amps in/out as well as lowering the threshold for storage mode, since I have some low current loads that can add up over time and were previously ignored. The firmware update went without a hitch. I welcome the future offerings including CAN Bus as I've been experimenting with this for other devices and can see some advantages over serial. Thank you to Jason and the Chargery team for these continued improvements.
Click to expand...
 
I just got done loading V4.03 of the main unit and V4.02 of the LCD firmware from V4.00 and recalibrating the BMS08T to use 500A Victron Smart Shunt. This version is vastly better and the BMS Current and SOC readings are now very close to my Victron BMV-712. The Wh reading is what I expected at 80% SOC. However, Ah are still off a bit - Victron says I've used 50 Ah, the BMS says I've used 38 Ah when both report 80% SOC (I have setup my bank capacity as 250 Ah) but it is much improved over the V4.00 version. Not sure why there is so much discrepancy in the Ahs used. Any thoughts or ideas?
 
bdbugbee said:
I just got done loading V4.03 of the main unit and V4.02 of the LCD firmware from V4.00 and recalibrating the BMS08T to use 500A Victron Smart Shunt. This version is vastly better and the BMS Current and SOC readings are now very close to my Victron BMV-712. The Wh reading is what I expected at 80% SOC. However, Ah are still off a bit - Victron says I've used 50 Ah, the BMS says I've used 38 Ah when both report 80% SOC (I have setup my bank capacity as 250 Ah) but it is much improved over the V4.00 version. Not sure why there is so much discrepancy in the Ahs used. Any thoughts or ideas?
Click to expand...

That's the issue I have as well .... While the % and WH seem to track closely, the AH reading is not working right. I have brought it to the attention of @Chargery in previous posts, but he seemed to think it was something I was doing wrong ... it isn't. Several other people are reporting this issue now.
 
bdbugbee said:
I just got done loading V4.03 of the main unit and V4.02 of the LCD firmware from V4.00 and recalibrating the BMS08T to use 500A Victron Smart Shunt. This version is vastly better and the BMS Current and SOC readings are now very close to my Victron BMV-712. The Wh reading is what I expected at 80% SOC. However, Ah are still off a bit - Victron says I've used 50 Ah, the BMS says I've used 38 Ah when both report 80% SOC (I have setup my bank capacity as 250 Ah) but it is much improved over the V4.00 version. Not sure why there is so much discrepancy in the Ahs used. Any thoughts or ideas?
Click to expand...
could you please take a short video? i want to see the difference of SOC, wh and AH reading on BMS and Victron .
thanks and Merry Chrismas.
 
Chargery said:
could you please take a short video? i want to see the difference of SOC, wh and AH reading on BMS and Victron .
thanks and Merry Chrismas.
Click to expand...
@Chargery, thanks for your interest on this. Here is a photo that I took just a few minutes ago showing the status of my Victron BMV-712 alongside the LCD screen of my BMS08T. I have set my usable battery capacity at 250 Ah on both units and 6500 Wh on the BMS. Notice the pack voltage is very close (Victron 26.45V, BMS 26.47V), the SOC is very close (70% on Victron, 69% on BMS), the instantaneous current is very close (-9.26A on Victron, -9.3A on BMS) but the consumed Ahs are different (Victron Ah = -77.0 Ah, BMS is at 192 Ah or -58 Ah from the 250 Ah starting point). Let me know if you have any suggestions as to what may be causing that. The BMS shows 4520 Wh left = 69.5% SOC based on 6500 Wh battery capacity, which matches the SOC shown on both units, however the BMS shows 192 Ah left = 76.8% SOC based on a 250 Ah battery capacity which is a mismatch.

NOTE: The battery configuration is 8S 24 V 280 Ah LiFePo4. Is it possible that the BMS is calculating Ah by multiplying the SOC percentage by 280 Ah? If so I'm not sure where the BMS is getting the 280 Ah battery capacity from, because I set the battery capacity to 250 Ah. See the Ah capacity settings on both the BMS08T and the BMV-712. I've included a screenshot of my other BMS settings for your reference.

IMG_0007.JPG IMG_3843a.jpg IMG_3845.PNG IMG_3844a.jpg
 
@Chargery, one other thing I noticed about V4.03 of the firmware was that there are no Internal Resistance (IR) values being shown anymore. They are all zero. See attached photo.

IMG_3846a.jpg
 
doug said:
I have loaded the new 4.02 firmware on my Chargery BMS and I am very happy with the update. I really like the return of the precision of the amps in/out as well as lowering the threshold for storage mode, since I have some low current loads that can add up over time and were previously ignored. The firmware update went without a hitch. I welcome the future offerings including CAN Bus as I've been experimenting with this for other devices and can see some advantages over serial. Thank you to Jason and the Chargery team for these continued improvements.
Click to expand...
Bob B said:
Go ahead and do the 4.03 while your at it .... it will keep from loosing SOC and settings in case of a power down.
Click to expand...
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 :
bdbugbee said:
@Chargery, one other thing I noticed about V4.03 of the firmware was that there are no Internal Resistance (IR) values being shown anymore. They are all zero. See attached photo.

View attachment 31118
Click to expand...
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.
 
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