Chargery BMS now with Low Temp Cutoff

[DW SD]

I agree with you Captain!
I moved my low disconnect to 3.0V. I don't think much capacity exists between 3 and 2.5V. I didn't like the idea of being so close to a damaging event.
Curious, what was in the 4.1 firmware release? I'm outdated again :-(

When assembling my battery, I did not top balance as I didn't have a voltage adjustable power supply. And noticed that my BMS did some balancing for my initial 13.8V CC / CV charger setting. But when I moved to 14.0, one of the cells jumped way ahead in voltage +150mV compared to the others (hitting my configured cell level limit of 3.6V).
I am confident I'm not leaving much capacity on the table if I maintain 13.8V. But probably will use the recommendation of charging in stages and then allowing the BMS to balance overnight.

Assuming I do that, I'll probably turn off the balancing function after. As if I leave it at >3.35V, it seems that at lower SOC, the balance function would balance my cells "out of top balance" if that makes sense.
Or, I'll set the balance threshold very high just to adjust at the very top SOC.

Given all the parameters, I did expect some "tuning" process. And it affords me some learning.

Doug

 

[Capt Bill]

RE: One of my previous posts with: Heads Up: My Testing for Low Cell Volt Disconnect via using my "Empty Cell Volt" did not do the job for protecting my LiFePO4s from low cell voltage !!! I also do not see any other setting that might be used to protect from low cell voltage (which I believe is the biggest danger to LiFePO4s). ... & IMO: I have a faulty Chargery BMS8T, or a V 4.0 firmware update that needs a further update.

Newer Note from Bill's Learning Curve & Mistake Lesson; from my since then testing the relay triggers. I have since confirmed my BMS triggers a discharge side relay release when one of my LiFePO4 cells hit a low of 2.5v (it's default setting for: "Over Discharge P Voltage"; which you can configure however you want). The "Over Discharge P Voltage" setting works great; ... that was the missing piece of information I needed. (pretty sure P stands for "Protection" / and re "Over Discharge R Voltage" set slightly higher; ... R stand for "Recovery" for when discharge relay is energized again, to close/ & switch its' relay circuit ON again.

 

[Capt Bill]

I agree with you Captain!
I moved my low disconnect to 3.0V. I don't think much capacity exists between 3 and 2.5V. I didn't like the idea of being so close to a damaging event.
Curious, what was in the 4.1 firmware release? I'm outdated again :-(

When assembling my battery, I did not top balance as I didn't have a voltage adjustable power supply. And noticed that my BMS did some balancing for my initial 13.8V CC / CV charger setting. But when I moved to 14.0, one of the cells jumped way ahead in voltage +150mV compared to the others (hitting my configured cell level limit of 3.6V).
I am confident I'm not leaving much capacity on the table if I maintain 13.8V. But probably will use the recommendation of charging in stages and then allowing the BMS to balance overnight.

Assuming I do that, I'll probably turn off the balancing function after. As if I leave it at >3.35V, it seems that at lower SOC, the balance function would balance my cells "out of top balance" if that makes sense.
Or, I'll set the balance threshold very high just to adjust at the very top SOC.

Given all the parameters, I did expect some "tuning" process. And it affords me some learning.

Doug

OPPs on my mention of V 4.1. .. That was a slip in memory. ... I just confirmed I am on V4.0 (just looked in BMS / plus update files on my PC). V4.0 is the latest version I know about. Sorry for that one. I would have edited my original post to be accurate on that, but too late. ... I got that V4.1 number from the new manual. That is where that number came from. So maybe that is on the newest versions of the Chargery BMSs being sold via Jason and Craig. ... and ... Maybe we will be seeing info. about that update option posted in this thread at a later date. I am just seeing my own little glimpse :+)

 

[Craig]

OPPs on my mention of V 4.1. .. That was a slip in memory. ... I just confirmed I am on V4.0 (just looked in BMS / plus update files on my PC). V4.0 is the latest version I know about. Sorry for that one. I would have edited my original post to be accurate on that, but too late. ... I got that V4.1 number from the new manual. That is where that number came from. So maybe that is on the newest versions of the Chargery BMSs being sold via Jason and Craig. ... and ... Maybe we will be seeing info. about that update option posted in this thread at a later date. I am just seeing my own little glimpse :+)

It's model 4.01 with firmware 4.0

 

[Capt Bill]

Re: then allowing the BMS to balance overnight. Assuming I do that, I'll probably turn off the balancing function after.

Just reading what you wrote; I do not see what advantage you would get from turning off the BMS balance functions off afterward. My Take is it would be better leaving all three of balancing setting (Charge/ discharge/ & in storage mode) to ON.

As a newbie on my first BMS set up on my 1st DIY 24v 280Ah LiFePO4 build; from occasionally looking at one of those Chargery BMS pages that shows the graph visual of each cell, ... I see my battery cells can get a bit out of balance (like after after running my batteries through some mid range charge and/or discharge cycles (especially right afterwards, before sitting awhile. I really like seeing that my BMS can set em back to balanced automatically, which is confirmed by my personal look see later. Seeing that balancing cycle happen automatically, give me the confidence to let go of looking. I am learning by my hands on configuration and testing, I can eventually trust my BMS to do its' protection job properly. On Automatic, it is protecting my LiFePO4 investment.

IMO: Leaving the Balance function ON is a good idea that will allow that function to come into play when your cells could use balancing. I think the biggest benefit of a BMS is to cut current draw when just one cell voltage gets too low, cut off charging in freeze temps, plus keep individual cells in balance. I know BMSs also protect form other factors like max limits on current charge or draws, or max differential for cell voltages etc. ... I think leaving all those options on auto pilot is what makes your BMS your backup protection. ... That is My Take :+)

 

[JoeHam]

From the start I have used balance during charging only.

My cells have been kept in balance and power is only wasted in the balance resistor when it is readily available.

Just my choice and my reasoning behind it.

If I ever needed more balancing I could turn more on but that has never been necessary to date.

 

[Tony]

Hello every one, the final manual is released now, thanks to Steven's hard work, we will provide new shunt with base that is small and accurate, and designed a DC contactor specially fit with our BMS. for more details please check the manual. for any mistakes and problems feel free to contact me at jasonwang3a@163.com.

Steve, I noticed in the document that you control the negative side of the battery with the DCCs. That's a change from the original relays where you controlled the positive side. Why the difference?

 

[Tony]

Steve, I noticed in the document that you control the negative side of the battery with the DCCs. That's a change from the original relays where you controlled the positive side. Why the difference?

Sorry, Jason for saying Steve. The question was made to you.

 

[nwillitts]

where do you get the firmware?i looked on chargery site,but only firmware tool is there.

 

[Bob B]

There is a link on the left side of the home page to the updates. It's under latest product list.... Or CLICK ON THIS LINK

 

[nwillitts]

thanks,bob.

 

[DW SD]

Just reading what you wrote; I do not see what advantage you would get from turning off the BMS balance functions off afterward. My Take is it would be better leaving all three of balancing setting (Charge/ discharge/ & in storage mode) to ON.

As a newbie on my first BMS set up on my 1st DIY 24v 280Ah LiFePO4 build; from occasionally looking at one of those Chargery BMS pages that shows the graph visual of each cell, ... I see my battery cells can get a bit out of balance (like after after running my batteries through some mid range charge and/or discharge cycles (especially right afterwards, before sitting awhile. I really like seeing that my BMS can set em back to balanced automatically, which is confirmed by my personal look see later. Seeing that balancing cycle happen automatically, give me the confidence to let go of looking. I am learning by my hands on configuration and testing, I can eventually trust my BMS to do its' protection job properly. On Automatic, it is protecting my LiFePO4 investment.

IMO: Leaving the Balance function ON is a good idea that will allow that function to come into play when your cells could use balancing. I think the biggest benefit of a BMS is to cut current draw when just one cell voltage gets too low, cut off charging in freeze temps, plus keep individual cells in balance. I know BMSs also protect form other factors like max limits on current charge or draws, or max differential for cell voltages etc. ... I think leaving all those options on auto pilot is what makes your BMS your backup protection. ... That is My Take :+)

Captain B,
My rationale is on not balancing...
Apparently, my batteries are well balanced in the 80% to 95% range. But above, they get out of whack. I don't plan to spend much time >95%.
I've also read with low C rates they rarely get out of balance.
So, I if I care to extract a little more performance range. I might top balance and then leave it. Or maybe set balancing to only start > 95%.

I have way more battery than I need. So I might just leave it.

Note when I say SOC 95%... I'm using this chart, found on this website, estimating and maybe even extrapolating between data points:



Doug

 

[Bob B]

Is there a way to tell what version is in the LCD?

The file name I have on my computer has 4.0 in the name, but I don't have the new shunt calibration menu.

 

[Craig]

Go to settings and scroll to bottom.

 

[Bob B]

Go to settings and scroll to bottom.

I thought that was the BMS revision .... it does say 4.0 So ... how do you know the BMS version?

 

[Craig]

When you first turn on it shows BMS version at the bottom of settings shows firmware version

 

[Bob B]

So ... back to the first question. Where is the LCD firmware version shown if the bottom of the paramaters is the BMS firmware version?

I'm just trying to figure out why I don't have the new shunt calibration menu setting. Is it possible that is a feature of BMS 4.01 hardware?

 

[Capt Bill]

Is there a way to tell what version is in the LCD?

The file name I have on my computer has 4.0 in the name, but I don't have the new shunt calibration menu.

I updated both my BMS8T w 300 A shunt / the Main unit /and then the LCD unit ... I used those 2 different files to update around 6/20/2020. I think (w slight ?) the files I used are the same as available at Chargery's website at present (they are exact same size) ... Going into my BMS8T configuration menu named "Program setup"; scrolling to very bottom; my screen shows: V BMS08C3_V4.00 ... The setting for shunt calibration is named "current calibration". (have to set 0 A/ then Charge A / then Discharge A (or vs versa/ follow manual .. if you go there). The manual explains how, plus says you only need to do this if you have a different shunt than you purchased (not sure of time limit parameters on that) /or do this if your BMS shows incorrect result for amp flows.

Web Link to firmware file options can be found in the manual. In the newest improved manual posted above for BMS8T (says V4.1 at top of each page), that web link was on page 60.

Study the manual, then Learn More by doing! It is a bit challenging, but worth it. It would be really easy on a second Chargery BMS. ... Hope that helps :+)

 

[Bob B]

@Capt Bill The new manual shows a new menu for the Shunt calibration .... kind like a menu where you set up balance paramaters.

I see the same revison as you at the bottom of the parameter screen.

 

[Craig]

I will have to look later when I'm home I'm pretty sure I saw 4.01 in settings but could be confused.