Looking for reliable battery monitor suggestions

[teckersley]

I have a 16s 48V pack made with EVE 105ah cells and I am having a hard time finding a monitor that is fairly accurate. I have tried a few but not making much progress.

In the latest example, the pack is fully charged and at rest. The voltage reading is fairly good given that it’s only I decimal. Meter says 54.7V, BMS says 54.78V. Arguably ok.

What is annoying me the most, is the % and battery level. 84% is not even close to accurate by measure and I assume that is what the gauge level keys on too.

I have gone through every word of the manuals and there is no way to calibrate. I suspect the ones I have tried have a fixed Ah profile so thats throwing off the % and level display. I am guess in need something that has an adjustable Ah profile setup.

Have you guys found something that doesn’t cost an arm and a leg that is either more accurate and/or has the ability to calibrate?

Need a small display. Square or round doesn’t matter.

Any suggestions are appreciated.

 

[Rocketman]

Victron:
Smartshunt if you are ok with only getting data on your phone (Bluetooth), and lower bluetooth range. 10’ or less.

BMV712 has a round display (costs a little more), and because the Bluetooth antenna is in the display- good bluetooth range.

You get access to the resetting logic, so the battery monitor can get reset when the batteries are full. (Voltage, tail current, and time delay).

If you want to see the phone screens -
download the VictronConnect app
Go to Demo Library
Select the device you are think of getting
Play with those screens.

Voltages 2-digit (mine is 13.49v right now). Lots of historical data.

Good Luck on your decision.

 

[Hank Waconda]

I use the AiLi battery monitor with shunt. Has worked well for a few years and shows discharge also.

 

[ShaneC]

Can you connect to your BMS via uart? I use an esp8266 and ESPHome to send the data to my home assistant server but you can do something similar to log it elsewhere if you aren't running home assistant.

GitHub - syssi/esphome-jbd-bms: ESPHome component to monitor and control a Xiaoxiang Battery Management System (JBD-BMS) via UART-TTL or BLE

ESPHome component to monitor and control a Xiaoxiang Battery Management System (JBD-BMS) via UART-TTL or BLE - syssi/esphome-jbd-bms

github.com

 

[42OhmsPA]

I've been running the juntek / wonvon for a few months, I use a cheap tablet to connect to it via Bluetooth.
It's darn close to the BMS(Shunt capacity is intentionally lower than BMS).

WonVon 600A Smart Battery Monitor - RV Battery Monitor with Shunt Support High/Low Voltage Programmable Alarm for Battery 0V-120V Support Bluetooth https://a.co/d/9dF0GRs

 

[Hank Waconda]

Can you connect to your BMS via uart? I use an esp8266 and ESPHome to send the data to my home assistant server but you can do something similar to log it elsewhere if you aren't running home assistant.

GitHub - syssi/esphome-jbd-bms: ESPHome component to monitor and control a Xiaoxiang Battery Management System (JBD-BMS) via UART-TTL or BLE

ESPHome component to monitor and control a Xiaoxiang Battery Management System (JBD-BMS) via UART-TTL or BLE - syssi/esphome-jbd-bms

github.com

No I don't think so it's just a stand alone and connection from neg terminal with a small hot power wire....No very expensive is all.

 

[ShaneC]

No I don't think so it's just a stand alone and connection from neg terminal with a small hot power wire....No very expensive is all.

Do you have a model number for the BMS?

 

[Quattrohead]

Yeah I was going to ask about the BMS used. Most if not all of them have some kind of uart output.