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I have the bq40z60evm board connected to an EV2300 and a 12V lab power supply for VAC. BqStudio seems to be reading the voltages properly and the battery health correctly, but I can't for the life of me get it to charge or discharge, even if I turn on the CHG/DSG FET's. I also am a bit confused about running the learning cycle calibration since both manual and automated modes specify they need external relays. Any advice in the right direction would be useful!
My bad, I've been confused about where to post the bq40z60 since it is both a charger and a gauge. I'll post questions on there for now on regarding it. I haven't managed to get charging/discharging to work at all, and I haven't tried the learning cycle using bqStudio yet since this first step hadn't been obtained. I will be able to generate a gg.csv file first thing tomorrow, but the battery I'm using is a 3S like the default for this gauge.
Thanks for the reply Tom,
Same as John, I got confused, I considered the bq40z60 as a charger + gas gauge not as a gas gauge + charger.
I still cannot make the discharge path to work. Here's my setup:
Boards: EV2400 + bq40z60EVM-578
VAC to PGND input voltage: Lab power supply, 18.2VDC @3A max.
Batteries used: LiFePO4, 2P2S configuration, type ANR26650M1-B, 2500mAh per cell, selected chemistry ID 0x0440.
The battery pack is connected with the negative at J3.1N.
Although I don't care about the cell balancing feature, I did connect J3.1P between one of the two series cell groups.
The battery pack's positive terminal is connected at J3.2P+3P+4P (shorts between 2P, 3P and 4P).
Jumper J4 is at 2S.
I can get the manual charging to start, but it does not stop at 7.2V, the voltage keeps going up, which makes me think either my configuration profile is wrong or the Chemistry ID is not right, so I had to turn it off when the voltage on the cell pack reached 7.2V.
I have a 68ohms/5W load connected between VSYS and PGND. During manual charging (I mean if I hit the CHARGER_EN button from the COMMANDS panel), I measure 8.52V across the load resistor (VSYS to PGND is 8.52V).
I can never get the discharge fet to turn on. If the battery is not being charge, VSYS stays at 0, I can never get the battery voltage on to VSYS no matter what I do.
My gg.csv file is here: https://www.dropbox.com/s/5yfzqd4grx37jyg/LiFePO4_Config_1.gg.csv?dl=0
Thank you kindly for all the help and support!
Vlad
Hi Tom,
I implemented the changes (DA config to 2S, min volt out to 4124, enable IT) and the charging voltage was correct (7.2V), the discharge started to work great, but it stopped at 5.8V instead of 4.4V (I have a 2S2P LiFePO4 pack) and obviously, I can no longer turn the discharge on.
My CUV Threshold is 2200mV, CUVC Threshold is 2400mV and Recovery for both CUV and CUVC are 3000mV.
How can I get the discharge to go all the way down to 4400mV for the 2S pack?
Vlad
The J3 connector is not strictly used for kelvin connections on the EVM. The cell connections for 1P, 2P, 3P are, but the connections for 1N and 4P will be high current. There are kelvin connections on the PCB to support these terminals. You would not connect the battery to VSYS. The gauge/charger are not designed to power the load without the battery present. I have also had some success when using a resistor divider network on the cell inputs, but I have seen stability issues.
By all means, please see attached. I went through a charging cycle followed by discharge. The discharge stopped at around 5.6V on the cell pack (VSYS was turned off at this point).LiFePO4_Logs_1.zip