Chargery voltage incorrect

[myles]

Losing faith in the chargery BMS. Sadly will have to replace them just because i have lost faith and I need the system to operate without issue. Super basic question. I top balanced my lifepo4 battery banks. They are eve lf280K, 16s4p. 4 seperate chargery 16s BMS 100A. I am getting some huge variation between my cells, 60mv or more on three out of 4 bms. At first i thought cells are not great. But upon inspection with a multimeter the cells are within 5mv each.

When i measure voltage across the cell terminals they are all within just a few mv, but the BMS is showing quite a deviation causing me not to charge the pack fully because the BMS will kick out on over voltage protection before they can get there.

Question 1: If i measure across the terminals of the active battery pack is that accurate? Right on the stud of the battery.

I am going to try to power the chargery from external source as I know that can be an issue with these. I am also going to move the chargery main unit around as I have one of the 4 units that appears to be marking the batteries correctly to eliminate any harness error.

 

[OffGridInTheCity]

I've purchased 3 16Ts and 5 8Ts over the last 3 years - and have had mixed results. About 1/2 of them are still working correctly. But it's been a mixed bag - including weird voltage readings - and I say this as someone who loves Chargery design (on/off switch, external display, ...). I agree in the sense I don't think I'd recommend them any more.

I'll be following to see what you replace it with if you decide to go that way.

 

[MisterSandals]

I am going to try to power the chargery from external source as I know that can be an issue with these.

This is a known fix for this issue and it worked for me on both of my 16T's.

I cannot recall exactly now but I think there was a new firmware created that addresses some of this issue.

 

[Steve_S]

I would suggest the following procedure.
FIRST, ensure you are updated to the most current Firmware. http://chargery.com/update.asp
- Ensure the battery pack is NOT being charged/discharged.
- Turn off the Balancing such as it is, so the battery is "static".
- Measure each cell voltage on the Sense Lead (which needs to be on the (+) post) and the (-) contact pad of the cell. Not the busbar or screw. Mark each down individually (better in a spreadsheet) then sum the cells together.
- Measure total pack Voltage at the (+) & (-) take off pads and not on the screws or cable connection.

Compare the sum of the cell voltages to the total pack voltage.
Do use External Power to the BMS, if internally powered through the harness this can & will skew values somewhat.
The external Power Board: https://www.chargerystore.com/index.php?route=product/product&product_id=94

NOTE, when I used Chargery BMS8T-300s with 300A DCC's I powered them externally (from Batt Terminals) and added QNBBM-8 Active Balancers which resolved most issues including "lazy passive balancing" which really is not suitable for large capacity cells. FYI: I have since switched my entire fleet of Battery Packs to JK-BMS with Active Balancing so I have a "Box Full" of DCC's, BMS8T's and accessories to go with that.

Also NOTE that the T-Series is one generation back now, the newer P Series has many improvements.

 

[myles]

Good to know! I just switched the main BMS unit from one pack to another and the whacko cell voltages followed the unit. So it's NOT the cabling or anything like that. It's definitely in the unit the issue.

 

[myles]

I would suggest the following procedure.
FIRST, ensure you are updated to the most current Firmware. http://chargery.com/update.asp
- Ensure the battery pack is NOT being charged/discharged.
- Turn off the Balancing such as it is, so the battery is "static".
- Measure each cell voltage on the Sense Lead (which needs to be on the (+) post) and the (-) contact pad of the cell. Not the busbar or screw. Mark each down individually (better in a spreadsheet) then sum the cells together.
- Measure total pack Voltage at the (+) & (-) take off pads and not on the screws or cable connection.

Compare the sum of the cell voltages to the total pack voltage.
Do use External Power to the BMS, if internally powered through the harness this can & will skew values somewhat.
The external Power Board: https://www.chargerystore.com/index.php?route=product/product&product_id=94

NOTE, when I used Chargery BMS8T-300s with 300A DCC's I powered them externally (from Batt Terminals) and added QNBBM-8 Active Balancers which resolved most issues including "lazy passive balancing" which really is not suitable for large capacity cells. FYI: I have since switched my entire fleet of Battery Packs to JK-BMS with Active Balancing so I have a "Box Full" of DCC's, BMS8T's and accessories to go with that.

Also NOTE that the T-Series is one generation back now, the newer P Series has many improvements.
View attachment 120638

Steve does JK BMS have the ability to be use common port with a contactor? I'd like to keep my setup other than the chargers. JK is my next up pick. These things are hindering my ability to charge fully and be protected

 

[Steve_S]

JK's do not use Relays/Contactors.
See my "About my System" page to get a better idea of how it all evolved.
In case you cannot see Signatures link below.

My DIY off-grid Cabin setup in Ontario Canada (24vdc-120vac)

NOTICE: UPDATING November 2022 WIP Good Day everyone, Overview: There is no grid here, no phone lines, cell is so-so (to be polite) so satellite internet is here (not bad actually). I do not have 240VAC, this is a 120V system only. My Solar Panels are mounted separately from my Powerhouse...

diysolarforum.com

 

[myles]

Also when using external power for the chargery. I bought a 12v DC adapter from amazon. I assume it's as simple as plugging that into the house power and powering it like a conventional piece of electronic hardware? Or do you have to still use battery power for this and some kind of voltage converter?

 

[MisterSandals]

Or do you have to still use battery power for this and some kind of voltage converter?

I've been pulling it off the strongest 4 consecutive cells in my 16S pack, with alligator clips no less (ya, but it started as a test and works).
I was expecting it to show signs of imbalance but i have not noticed anything yet. If/when i do, i'll get a 48V to 12V converter and power it from there.

 

[OffGridInTheCity]

I've been pulling it off the strongest 4 consecutive cells in my 16S pack, with alligator clips no less (ya, but it started as a test and works).
I was expecting it to show signs of imbalance but i have not noticed anything yet. If/when i do, i'll get a 48V to 12V converter and power it from there.

Interesting All of my chargerys are powered by the battery - e.g. 24v or 48v as the case my be - rather than external power.

 

[myles]

i'll give it one more chance before I ditch them and purchase 4 JK's.

peace of mind and sleep at night is worth a lot to me!

Again though can I power the chargery with this:

https://www.amazon.ca/gp/product/B07H2T31JJ/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

what is strange is that it followed the BMS unit to the new bank, so this tells me there is maybe an internal issue with the unit itself, but i'll give it one last kick at the cat :D

 

[Steve_S]

Also when using external power for the chargery. I bought a 12v DC adapter from amazon. I assume it's as simple as plugging that into the house power and powering it like a conventional piece of electronic hardware? Or do you have to still use battery power for this and some kind of voltage converter?

It's lower energy to use a 60V->12V buck converter from your common DC Bus.

 

[Larsea-DK]

Losing faith in the chargery BMS. Sadly will have to replace them just because i have lost faith and I need the system to operate without issue. Super basic question. I top balanced my lifepo4 battery banks. They are eve lf280K, 16s4p. 4 seperate chargery 16s BMS 100A. I am getting some huge variation between my cells, 60mv or more on three out of 4 bms. At first i thought cells are not great. But upon inspection with a multimeter the cells are within 5mv each.

When i measure voltage across the cell terminals they are all within just a few mv, but the BMS is showing quite a deviation causing me not to charge the pack fully because the BMS will kick out on over voltage protection before they can get there.

Question 1: If i measure across the terminals of the active battery pack is that accurate? Right on the stud of the battery.

I am going to try to power the chargery from external source as I know that can be an issue with these. I am also going to move the chargery main unit around as I have one of the 4 units that appears to be marking the batteries correctly to eliminate any harness error.

I have totally same issue with my chargery. It has been very nice to use and I line the screen. If just cells showed correctly voltage I am happy.
I have already shipped on back to Jason to get it calibrated… quite costly but actually worked. But is did only last for 3-4months. I had to demount my battery and after reinstall, it showed wrong voltage again. My cells are actually well balanced, but with incorrect voltage readings, no settings make sense and I always have to calculate adding or subtracting the deviation!
Now Jason do not answer mails anymore. I asked if it was possible for enduser to adjust readings manually as if I has long sensing wires, just like some other bms’s can.
I just expected more of Chargery and Jason, so its sad that the Chargery support is none existing!