diy solar

diy solar

Chargery BMS now with Low Temp Cutoff

Why is there Wh and Ah input on the latest firmware update? Cannot one be calculated from the other?

I think the user instructions should spell out clearly each configuration parameters' function.

Am I the only who feels this is missing from the user manual? Or perhaps this is included in the revision, but not yet live?
 
Why is there Wh and Ah input on the latest firmware update? Cannot one be calculated from the other?

I think the user instructions should spell out clearly each configuration parameters' function.

Am I the only who feels this is missing from the user manual? Or perhaps this is included in the revision, but not yet live?
One of the issues was lack of Amp hours it was included with the 4.0 reflash. If you think the Manuel is bad.......You should read the older Manuel's.
 
Why is there Wh and Ah input on the latest firmware update? Cannot one be calculated from the other?

I think the user instructions should spell out clearly each configuration parameters' function.

Am I the only who feels this is missing from the user manual? Or perhaps this is included in the revision, but not yet live?
I sent in the new 4.1 "Owner's Manual" to Jason and he is converting the rest of the manuals to the new format, it is time consuming and likely more difficult for Jason as he is not a Native English speaker. The whole thing has been changed around quite a bit. I did post this last week on Monday the 15th I believe. Patience will reward you in the fullness of time.

I did suggest that it may be more prudent to have One Owner's Manual that covers the BMS8T, BMS16T & BMS24T because the majority of the information is the same, with the exception of specific setting relative to the models and the supplemental battery pack/bank configurations which also remains constant. Jason did say that it seemed like a good idea but I am unsure if he is taking the Master Document and doing that or not.

I do not want to post the Unofficial Version as that may just complicate things more and my time is now limited because it's summer and I am busier than a Long Tailed Cat in a room full of Rocking Chairs. Plus the Heatwave we are having here is slowing everything to a crawl (I do not do heatwaves well).
 
Hi Bill,
Note, I'm not using the latest firmware.

What will happen to your system if your house 24V battery cuts out? Does this just serve the inverter? I think the answer will help with your recommended settings.

I also set SOC @ 0%. But within settings, you also set cell - level LVD. So there is redundancy. So, I disabled SOC cut-off by moving to 0% not wanting to confuse my cutoff point.

In the end, you want your loads (or charging) to stop before the battery BMS has to interrupt. So, your inverter probably has LV cutoff setting. Set this above where your battery BMS cuts out. And if you have non-inverter loads also, you could probably enable the Chargery alarm to sound at some LV threshold before the BMS cuts off.

Think of the BMS as last resort to protect the battery. So ensure your settings protect the battery, but don't think they have to do more or build in a lot of cushion.

I also had initial issues with the voltage differential getting as high as 200mV, before my battery balanced. After one or two charge cycles the balance feature resolved, so I no longer have voltage differential issues. Now, always less than 25mV, usually less than 15mV. I moved my cell-level balance to >3.35V and during storage, charge and discharge. It is now top-balanced, if that term isn't obvious. On an average night, I'm only using 30% of the capacity, so this top balance will suit my application great.

On the charge side setup, I have my Magnum SCC setup to CC/CV and charge @ 13.8V for 6 minutes in the absorb phase. This corresponded to cell voltages around 3.36V. And 95% SOC from one of the detailed voltage / SOC charts posted on the forum. Again, I prefer to have the charging cutoff than BMS "save" the battery. So, my cell-level voltage maximum is higher in the BMS than the charger.

Hope that helps.

Doug
Testing for Low Cell Volt Disconnect via using my "Empty Cell Voltage" setting did not work for me. See my info. below

Hi Doug: Thanks for feedback.

Re Your : What will happen to your system if your house 24V battery cuts out?

I have two MPP LV2424 All In Ones I will eventually wire up for 240vac split phase. I have yet to configure my exact cut outs, but have decided Not to use the Battery Cut Out method. My currently favorite option: I was going to wire the Discharge relay control from my Chargery BMS8T to an SSR to turn off my All In One units if the BMS had a discharge side trigger. That would protect my LiFePO4s from death by low cell voltage which I believe is the biggest LiFePO4 early kill a cell risk. I would be using Will P's SSR Youtube lesson method for that method. I would then likely wire the BMS's Charge side relay control to another SSR that would turn off my All In One's Charger by cutting off my Solar Panel Input (up to 30 amps) if my BMS triggered for a charge related fault.

I had consider other options. I was considering configuring the Chargery's discharge side relay control to turn off the All In One's Inverter (as mine does not have a separate switch for only that function) by using another SSR to disconnect my 120 vac output from my All In One units. The drawback to that method is it would would still leave my inverter and full unit with stand by idle draw on battery. While that configuration has the advantage to recover from a empty cell volt fault trigger without attention by leaving my All In One's MPPT solar charger in tact, ... the Idle consumption of my All In Ones could potentially kill a low battery cell if no one was there to attend the heads up.

********
Re Your : I also set SOC @ 0%. But within settings, you also set cell - level LVD. So there is redundancy. So, I disabled SOC cut-off by moving to 0% not wanting to confuse my cutoff point.

My default for Low SOC cut off was set at 20%. I just tested that Low SOC cut off by configuring that specific setting up high to test BMS relay control with a SSR with led light. Yes, it turns off whatever you might connect to a relay (would turn off my whole All In One). If that is the case, I like idea of keeping that SOC cut off setting. I will likely test my BMS to see just what voltage it cuts off at what % I set it to. I might want shift that setting to 10% after seeing what battery voltage that translates to. Disabling the SOC cut off does not make sense to me.

The only setting I could find in my Chargery BMS8T V 4.0 that resembles a Low Volt Disconnect is labeled "Empty Cell Voltage". I recently upped that setting from 2.5 volt (default for LiFe) to above my current lowest cell voltage (I set it at 3.61v when my lowest cell volt showed as 3.48v), & It Did Not yet trip my connected SSR led light to OFF. !!! 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). I will leave my test in tact for awhile as the battery further drains to see if I can get a low cell volts reading to ever release my connected SRR relay. I wonder if that setting only works at lower voltage than I set if for ??? Currently, I am alarmed by what I just found out via testing what this BMS can do (part of my hands on learning program).

IMO: I have a faulty Chargery BMS8T, or a V 4.0 firmware update that needs a further update. Maybe someone here, or at Chargery has an explanation? I hope this is food for discussion.

IMO: Those with the Chargery BMS8T (especially V 4.0) might want to test to see if you have low cell volt protection.
Doug: Maybe setting your Low SOC cutoff to 0% still allows it to work. I would think setting it at 1% or more would be better. I personally want that redundancy, but it only work related to full battery SOC. ... I wonder if anyone else has the problem of no low cell volt protection I just figured out this morning. ?? Low Cell Voltage Protection is the main reason I purchased this BMS! I do not see any other setting to test for that. I tested the "Cell Empty Voltage" setting on my Chargery , and it did NOT work (in my test). What are you Best Fix It Ideas, or better Test Ideas for that ???

***********
Doug: Re Your: I also had initial issues with the voltage differential getting as high as 200mV, before my battery balanced.... Now, always less than 25mV, usually less than 15mV. I moved my cell-level balance to >3.35V and during storage, charge and discharge.

I just shifted my Balance Start Voltage from default 3.2v to 3.3v ; ... and changed my Stop Diff setting from default of 30 mV to 20 mV. ... Plus favor turning ON Balance for all three: In Charge, Discharge, and in Storage (mode). I kind of liked your ideas on that (while I might go back to default and see if that is less draw down of battery which I noticed before even connecting my battery to my All In One units).

Re Your : ... you want your loads (or charging) to stop before the battery BMS has to interrupt. So, your inverter probably has LV cutoff setting. Set this above where your battery BMS cuts out.

YES, ... I got that idea down early. & Re Your: Think of the BMS as last resort to protect the battery. ... IMO: Absolutely Yes: Use a good BMS as a back up for protecting your kind of big $ LiFePO4 Investment.

Thanks Doug. Any other feedback, info., and/or opinions welcome. :+)
 
Last edited:
Hey Steve,
Thanks for your efforts. It wasn't clear to me which version is which. I had assumed the latest posted manual was the one you had edited. Now I know.
My comments are intended to be constructive.

Doug
 
Bill,
I don't have the latest firmware installed. so i'm extrapolating from what I read here.
Does the 4.0 setup screen not have over discharge protection parameters?
That is cell level LVD.
The screen shots in the latest 4.1 manual suggest it still does:
Screen Shot 2020-06-22 at 9.23.00 AM.png
I believe "empty cell voltage" parameter affects SOC graph and SOC disconnect.

Also, there are comments in the notes sections about those separate parameter settings (over discharge protection) and Empty Cell Voltage.

Doug
 
Unfortunately, the BMS*T-specification_V4.1 is the OLD Format and not my revised edition. :(

HERE is the DRAFT "Master" for the BMS8T. It is unfinished as minor details need to be addressed by Jason because things were changing while I revised it. I AM POSTING IT TO HELP - TEMPORARILY. ALWAYS refer to Official Original Manuals as provided by Chargery, so when the new manuals come out, delete the temp draft.


The Manual is 7,264 kb
 

Attachments

  • Chargery_BMS8T_Owners-Manual_V4.1.pdf
    4.9 MB · Views: 65
I Got my Low Cell Voltage Disconnect to trip SRR Relay to OFF !!! Re my previous: Testing for Low Cell Volt Disconnect via using my "Empty Cell Voltage" setting did not work ... And ) ... The only setting I could find in my Chargery BMS8T V 4.0 that resembles a Low Volt Disconnect is labeled "Empty Cell Voltage". Plus ... IMO: I have a faulty Chargery BMS8T, or a V 4.0 firmware update that needs a further update.

(Quote) ... Getting more into my time suck BMS learning curve lessons; I just found out I am off base. I just read page 10 of 40 Notes of BMS8T V4.0 manual: that say: "Cell Empty Voltage and Cell Full Voltage is to set up cell voltage bar graph, the value should be same as Overcharge Protection (P) Voltage, and Over Discharge Protection (P) Voltage. But that is confusing this way: The default settings I got (in V.4.0 firmware updates) for the "Over Discharge Protection (P) Voltage" is "3.0v" ; while the default setting I got for Cell Empty Voltage was "2.5 V". I am having my questions about this Chargery BMS8T.

Just to Add More Info. while in time window to edit my post: I adjusted Over Discharge P Votalge from 3.00V to 3.49v while my lowest cell was at 3.39v or 3.330v. I had to also adjust Over Dishcarge R Voltage to 3.50v to do that. I then set Empty Cell Voltage to 3.49v. It took about a minute to finally trip my SRR w led to OFF. ... Yeh! ... just confirmed this function works. I will now go back and readjust what I changed. ... I think I might be best off changing the default of the Over Discharge P Voltage from its' default setting of 3.00v to match the default setting 2.5 v for the Empty Cell Voltage setting. Anyone have an opinion about that? I will find a way to get a battery cell that low to see if the BMS is working properly. I just would like to fully confirm that part of the BMS is working properly.

Also: I just read: "Current Calibration is not recommended unless you are using a different shunt than supplied" (also on page 10 of 40 / in BMS8T V4.0 manual). I had previously went by instructions I printed out from page 16 on "Current Calibration", while only able to use 10A of current when more was recommended. I now wish I had left that shunt calibration alone. Learning More All The Time :+)
 
Last edited:
Unfortunately, the BMS*T-specification_V4.1 is the OLD Format and not my revised edition. :(

HERE is the DRAFT "Master" for the BMS8T. It is unfinished as minor details need to be addressed by Jason because things were changing while I revised it. I AM POSTING IT TO HELP - TEMPORARILY. ALWAYS refer to Official Original Manuals as provided by Chargery, so when the new manuals come out, delete the temp draft.


The Manual is 7,264 kb
Thanks Steve S ... I will check it out for any further lessons. Thanks :+)
 
First, thank you Steve for posting the updated manual. Definitely easier to follow and understand.

Hi Bill,
Glad you could now see how LVD might be redundant with SOC disconnect. Thats why I shut SOC off using 0% setting.

My opinion on moving your LVD lower would be based on what happens when your battery disconnects, how much room for error you have and how much extra capacity. Do you need to eek out every bit of energy from the battery bank? If so, then reduce your room for error.

Also, my first level of disconnect comes from the load: inverter LVCO. If that works for you, then just set the BMS at a low, but safe parameter.
It sounds like you will have the same.

In my case, it will be a VERY rare event when the BMS disconnects. Hopefully, never. :D

Doug
 
Ok, ... I now have my Chargery BMS8T V4.0 configured and balancing individual cells, and finally showing SOC on 1st page gauge properly (after few discharge and charge cycles). I changed a few defaults including diff between cells from 300mv defualt setting to 800mv: as I did not want that trigger to turn off my inverter early like Will had to figure out in one of his Chargery Youtube reviews. I still do not fully understand the SOC setting in this BMS; and I set it at 1% instead of 0 (for now), mentioned in Steve S's draft V4.1 manual (which is also different than the BMS's 20% default setting). I do understand allot more about BMS options, and this specific BMS. I am also happy with my choice. I reset my Current Calibrations (zero, then charge, then discharge) with much higher currents using my All In One and it's 60 Amp charger, and a way to see exact charge and discharge amps; and powered up a coffee pot heater plus a heat gun to get about 90 or 100 Amps on the battery discharge side. That helped my BMS amp measurement to be more accurate than my first Calibration attempt using only a 10 amp (max) voltage controller / charger.
Plus: I might have been better off just not calibration like a closer read of the manual recommends if you are using the stock supplied shunt.

I really do not see how I could replace the value of my hands on lessons. I still have to run the off/on switches of my 2 (soon to be 3) LV2424 All In One units through the SRR controlled by the discharge side of my BMS (to turn all inverters off when the BMS pick up a low cell trigger or other discharge side fault trigger. ... (via hands on testing and lessons; I just figured out that switch on the LV2424 All In Ones turns on or OFF the Inverter draw only, and Solar In and Grid In is left in tack. If I want to control a Charge side fault, I will have to configure my All In On for Solar charge ONLY, and put a SRRs (or relays) on the Solar Input to my All In Ones (if I go beyond just trusting my All In Ones to protect my batteries).

Also: I just configured my two LV2424s in 240vac split phase output 30 minutes ago; and will hook up a third one soon to up my current 2400 watt ability to 4800 watt ability on one of two circuit breaker legs (for 20 amp on one 120vac leg /and 40 amp ability on other more used 120vac leg/ all on 240vac split phase (so my 240vac well pump will work too). :+)

Open to any feedback about setting SOC to1% vs ). ... or anything else. ... One Question I have about the Chargery BMS8T: If I go for another set of 280Ah LiFePO4s to double my battery banks Ah to 560 Ah: and go for a second Chargery BMS8T to manage the second set of batteries: ... Can I use the same 300 amp shunt I have configured now for 2nd BMS, or would I have to put a second shunt on my battery cables for the 2nd BMS? ... Happy Days, Bill
 
Last edited:
Captain!
Good news.

You could wire a second set of cells direct to the first then in pairs. the BMS would then monitor pairs of cells vs. individual. While a compromise, it isn't a great one.
I will do that if I want to double capacity vs. buying another BMS. Were I using more of the batteries' capacity, either charge or discharge rates, I'd feel differently. But small fractional C rates should not be an issue with parallel cells. (.5C or less, usually, .05C or less.)
If paralleling the cells, then you'd not have to buy another shunt, either.

Someone else may have a different opinion.

Doug
 
Captain!
Good news.

You could wire a second set of cells direct to the first then in pairs. the BMS would then monitor pairs of cells vs. individual. While a compromise, it isn't a great one.
I will do that if I want to double capacity vs. buying another BMS. Were I using more of the batteries' capacity, either charge or discharge rates, I'd feel differently. But small fractional C rates should not be an issue with parallel cells. (.5C or less, usually, .05C or less.)
If paralleling the cells, then you'd not have to buy another shunt, either.

Someone else may have a different opinion.

Doug
I know about that option. Thanks for reminding me. I think I would spend the money to monitor each cell, vs two cells at a time (thinking: that me protecting my bigger battery investment). I wonder if I would need to put in the second shunt if I used a second Chargery BMS8T ???, or if I could use one shunt for two Chargery BMS8T. ... I original thought the Chargery BMS16T could be used for the second set of 24v LiFePO4s in parallel to monitor twice the Ahs, but since learned the 16S means up to 16 cells in series only, so that is for one line of cells for up to a 48 v configuration. ... Learning More All The Time :+)
 
For those of you who think the Chargery won't top balance .... This is my 2p4s using BYD 190 AH cells for a total size of 380 AH.

I have had them for quite a while and finally am getting around to putting things together .... this is the first charge on the cells since I received them. I did not put them in parallel and charge them first.

The AH reflects the amount of charge I put in the batteries. I only had a stand alone 10 A charger so it took a while. I charged them to 3.4 V and let them sit overnight .... then to 3.5 and let them sit overnight .... then the rest of the way to 3.65.
I had the Chargery set to balance while charging with a 15mv difference setting.

I think I am going to have to fully discharge the battery and then charge it again to get the SOC and AH fully in sync ... that's the one thing I am not sure about. I was kinda hoping that once the battery got to full charge the SOC would go to 100% and reflect the full AH rating.

TopBalancedRotated.jpg
 
Testing for Low Cell Volt Disconnect via using my "Empty Cell Voltage" setting did not work for me.
Just in case this correction helps someone: I now know my Chargery BMS will trigger a discharge side relay to off/ when one single battery cell gets below the voltage set @ the: Over Discharge P Voltage (BMS setting), ... which works for that. I found value in testing this out; to know my BMS will protect me from early LiFePO4 cell death; which can happen when one cell drops below it bottom voltage. I set this for 2.5 volts, but think a cell could drop a little lower (maybe as low as 2.0 volts???, but not sure/& would not risk going that low) ... before suffering early cell death (the biggest danger to LiFePO4 according to Will P Lessons). I went with battery specs that said 2.5 was cut off voltage for my 3.2v 280Ah cells from Xuba.

I figured out the slightly higher Over Discharge R Voltage setting reflects "Recovery" Voltage (for when cell voltages go back upward after some kind of charging). At that slightly higher than the Over Discharge P Voltage setting; the R setting = The Discharge side Relay circuit gets (12v/ up to 2.5 amps of) current again, to switch ON however you set up your relay switch(s).

With three LV2424 All In Ones, Instead of putting a high amp rated relay on one main battery cable, I instead configured one 5 amp dc-dc SSR relay that needs to be energized by my BMS8T's discharge side out /via 2 wires ... to close a circuit connecting all 3 of my All In One's Inverter OFF/On switches. I have it set up in way: All 3 of those switches still work individually for turning on/off ... off = putting one or all 3 of my LV2424s' inverters in standby mode (found out solar IN, and AC in operate independantly of those 3 switches). I wired my Chargery BMS8T, and 24v LiFePO4s, and my one SRR to turn off all my inverters at that low "P" 2.5 volt cell setting. The All In Ones' "cut off voltage" setting also protects my battery bank, but it is set higher than BMS cut off, plus only measures full voltage of total battery bank (not individual cells). Confirming this part of my BMS works properly was a very good lesson for me. :+)
 
Last edited:
Just in case this correction helps someone: I now know my Chargery BMS will trigger a discharge side relay to off/ when one single battery cell gets below the voltage set @ : Over Discharge P Voltage, ... which works for that. I found value in testing this out; to know my BMS will protect me from early LiFePO4 cell death by getting such a cell dropping below it bottom voltage. I set this for 2.5 volts, but think a cell could drop a little lower (maybe a low as 2.0 volts???, but not sure/& would not risk going that low) ... before suffering early cell death (the biggest danger to LiFePO4 according to Will P Lessons). I figured out the slightly higher Over Discharge R Voltage setting reflects "Recovery" Voltage (for when cell voltages go back upward after some kind of charging). At that a higher than the Over Discharge P Voltage setting; the R setting = The Discharge side Relay circuit gets (12v/ up to 2.5 amps of) current again, to switch ON however you set up your relay switch(s).

With three LV2424 All In Ones, Instead of putting a high amp rated relay on one main battery cable, I instead configured one 5 amp dc-dc SSR relay that needs to be energized by my BMS8T's discharge side out /via 2 wires ... to close a circuit connecting all 3 of my All In One's Inverter OFF/On switches. I have it set up in way: All 3 of those switches still work for turning on/off ... off = putting my inverters in standby mode. I wired my Chargery BMS8t and SRR, and 24v LiFePO4s,to turn off all my inverters at that low "P" 2.5 volt cell setting. Confirming this part of my BMS works properly was a very good lesson for me. :+)
Why so low I thought cutoff was 2.5 for lifepo4
 
Why so low I thought cutoff was 2.5 for lifepo4
That is what I set in BMS8T for the one cell voltage cut off; I set 2.5v BMS as cut off for one cell. I put my LV2424 cut off voltage at 22.5v for full 8 cells (which is much higher per cell/ could be lower / but one time at maybe 21.5 cut off, the LV2424 cut off, & would not reboot until I use a different battery charger to up my battery voltage a little.

I think I once got a cell reading slightly below 2.5v; ... like 2.47 or similar. I would not want to go much lower than that. I do not know what the limits is before a 3.2 v LiFePO4 cell take a dump . & do not want to go there by accident.
 
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.
 

Attachments

  • Chargery_BMS16T_specification_V4.1.pdf
    5.3 MB · Views: 51
  • Chargery_BMS8T_specification_V4.1.pdf
    5.3 MB · Views: 71
  • Chargery_BMS24T_specification_V4.1.pdf
    5.1 MB · Views: 12
I now have a Chargery BMS8T set up on my first DIY 24v 280Ah LiFePO4 build. I have also studied 2 previous manuals. This new manual is definitely an improved manual. On first glance: I notice the improved info. on relay configuration options, new lesson material on internal Cell resistance (Impedance), and pictures of the newer shunt version (and know there is more)! Thank You Jason and Steve S.

Note to folks considering the Chargery BMS: If you took in Will Prowse's 2 valuable YouTube reviews of this BMS, and might be discouraged by Will's frustration in his shunt calibration learning curve; Register this newer info: In the last two manual I have studied; ... in the Current Calibration(Shunt) section; it says: "calibration is only required if you change the Shunt from the one supplied by Chargery which are calibrated at the factory." Likely Will's review helped make that happen, or make it clearer (Thanks Will). I ended up I calibrating my shunt after my firmware update to V4.0, before I took in that Information. I likely could have left my Shunt Calibration as is, and wish I had (but not absolutely sure; as I have a previous version shunt as compared to the picture of a newer shunt version shown in this newest manual).

I had to study the Chargery manual details for my first ever set up of a BMS. I considered the easier Daly BMS for its' also good reputation, combined with its' simpler plug and play type install. I decided to go with a BMS that shows monitoring details, plus configuration options. I liked Chargery' higher 300 amps charge or discharge specification (an option available by choosing the BMS kit with 300 amp shunt). The Daly BMSs I was looking at all had their internal adjustments set up at the factory for your battery type, with no visual look see, or user adjustment options, and came with lesser amp ratings. I do notice some newer Daly options with blue tooth look see & adjustment options lately.

I am happy I choose the Chargery BMS8T. I learned from having to read the manual, and then from my hands on experience. I learned from testing the relay triggers. I made sure my BMS would trigger 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). I learned from looking at all the information available on the Chargery's LCD interface by scrolling through it page options, and especially by going into and studying the configuration options.

I think "hands on" experiences anchor the lessons we can get by reading type study. ... If you are considering what BMS to buy, I'd say the Chargery line is a great option. I am glad I choose the Chargery BMS8T. ... Learning More All the Time :+)
 
Last edited by a moderator:
Back
Top