Author Topic: New lifepo4 battery bank  (Read 1113 times)

ClassicCrazy

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Re: New lifepo4 battery bank
« Reply #15 on: June 07, 2019, 08:15:35 PM »
So I am updating on the performance of my CALB lifepo4  batteries and 123smart BMS.

Batteries seems to be performing well .None or minute differences in voltages at different SOC.Basically like new.

123 Smart BMS however,has been greatly disappointing.
After measuring voltages at different socs and at rest on many occasions I have concluded that this BMS is not accurate in measuring voltages.Readings are all over the place .I even borrowed a fluke just to ensure my radio shack DMM wasn't giving incorrect readings.Turns out my radio shack is as accurate as a fluke and even a klein tool DMM.

This, I have been noticing for nearly a year ,yet I didn't remove it because it was still giving so level of monitoring.
 Finally , for two days one of the the boards kept reading a high voltage shutting down charge to the system.Upon removal and verifying on a different cell it was found that the board was defective .Because of this I have now choose to bottom balance and use the SOC setting on the classic to disconnect the inverter.

Bottom line the 123 smart BMS is not worth the money($500+) US.
I support again when I said I wish there was a wb Sr. that has all the features of the wbjr but with individual cell voltage monitoring and temperature.
Calibration setting would be nice too.

123 smart BMS lack this feature .Board cannot be calibrated.
There are some other less expensive BMS on the market now  - and also a different technology that Ross talked about which balances cells. Sorry to hear your BMS failed.
I tried doing bottom balancing on my Calbs following advice by someone else doing that. I had a few things mess up - might have been my fault but I didn't have any low voltage disconnect. I think the Classic itself took my cells down too low once because it will run to a very low voltage just to be on . So you probably want something that will cut off everything  like maybe contactor in battery line .  Wish I had one then - and also wish I knew what I was doing ! ha ha but they were kind of an experiment .
Check out this store on Aliexpress - this is just one of the many configerations they have listed
I bought a little bms from them and it arrived pretty quickly
https://www.aliexpress.com/item/32888385718.html?storeId=4165007&spm=2114.12010612.8148356.1.388f37feRnpYy4
I have also seen some BMS mentioned in ebike forums that you can connect to via bluetooth via smartphone and the app will show you each individual cell data - not sure if there are those available for bigger size packs like you want but worth checking into .

Larry
« Last Edit: June 07, 2019, 09:22:18 PM by ClassicCrazy »
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

RossW

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Re: New lifepo4 battery bank
« Reply #16 on: June 08, 2019, 02:44:34 AM »
I wish there was a wb Sr. that has all the features of the wbjr but with individual cell voltage monitoring and temperature.
Calibration setting would be nice too.

123 smart BMS lack this feature .Board cannot be calibrated.

http://support.rossw.net/batterymonitor/ are monitoring only of voltage (and optionally temperature) of each cell and cascadable for basically any practical voltage bank or chemistry. Can be (re)calibrated in-situ if its ever required.
3600W on 6 tracking arrays.
7200W on 2 fixed array.
Midnite Classic 150
Outback Flexmax FM80
16 x LiFePO4 600AH cells
16 x LiFePO4 300AH cells
Selectronics SP-PRO 481 5kW inverter
Fronius 6kW AC coupled inverter
Home-brew 4-cyl propane powered 14kVa genset
2kW wind turbine