openinverter forum

I am about to wire up my ISA shunt, but I'm a little unclear about its power supply requirements. I had thought I'd power it permanently, but the datasheet says it draws 30mA. The alternative will be to power it only during driving and charging. What are other people doing with this?

I was originally only powering when in use, but it doesn't store the data so I was losing the consumed counters, I tried contacting them to see if there was a command to have it store the counters to EEPROM before powering down, but they never got back to me. I decided to go with KISS and leave it on.

Bigpie wrote: ↑Sun Apr 24, 2022 7:00 pm I was originally only powering when in use, but it doesn't store the data so I was losing the consumed counters.

Thanks, this is exactly my concern. The datasheet says it stores the counters every 15 minutes, which seems completely useless, and I couldn't see a way to save them manually. After spending considerable effort to get my BMS power consumption down to 0.5mA, I'm not thrilled at the idea of adding 30mA by powering it permanently.

The option I'm currently considering is having the BMS power up the IVT when the charger or ignition are on, and persist the coulomb count in the BMS instead, polling the IVT for its "since reset" cont and updating the counter in the BMS accordingly.

I hoped I was missing something simpler!

A solution is to have a curcuit for the BMS, ivts plus anything else powered by an IC with a low power sleep mode that detects if the ignition hasn't been on for 24 hours shutdown the curcuit and have wake triggered by the door light.

rstevens81 wrote: ↑Sun Apr 24, 2022 7:24 pm A solution is to have a curcuit for the BMS, ivts plus anything else powered by an IC with a low power sleep mode that detects if the ignition hasn't been on for 24 hours shutdown the curcuit and have wake triggered by the door light.

You could use a DUE circuit to store can value to its eeprom and reset values when 100% max voltage set is reached.
I keep some things connected allways because i charge and drive every day...
I think it is more important to have a low aux voltage control loop. That way your 12v aux battery cant be drained even if your car would be left in parking for a week.

rstevens81 wrote: ↑Sun Apr 24, 2022 7:24 pm A solution is to have a curcuit for the BMS, ivts plus anything else powered by an IC with a low power sleep mode that detects if the ignition hasn't been on for 24 hours shutdown the curcuit and have wake triggered by the door light.

This is a fantastic idea idea! I already have a board with a low power sleep mode that wakes up when the ignition or charger are active. I could have this board power itself and the IVT off 60 minutes after the car is powered down. That would guarantee that the data is saved.

I'm not so sure. The 15 min saving didnt seem to work for me. Maybe I was doing something wrong though. I'd test it before putting too much time into design.

Thanks! I'll test it and see

catphish wrote: ↑Sun Apr 24, 2022 9:48 pm

rstevens81 wrote: ↑Sun Apr 24, 2022 7:24 pm A solution is to have a curcuit for the BMS, ivts plus anything else powered by an IC with a low power sleep mode that detects if the ignition hasn't been on for 24 hours shutdown the curcuit and have wake triggered by the door light.

This is a fantastic idea idea! I already have a board with a low power sleep mode that wakes up when the ignition or charger are active. I could have this board power itself and the IVT off 60 minutes after the car is powered down. That would guarantee that the data is saved.

May i suggest you save data selectively.
1. if Enable or PP pins are active (car is running/charging) save each minute
2. If Enable / PP pins are not active then save in hourly intervals

Problem is i couldnt get data back when new cycle beginns. We would have to feed the old data to IVS to start from there...

On page 25 of the datasheet there is info on putting it in run mode it also indicates that it saves every 15 minutes in run mode.

Most likely the sensor is not in run mode by default.

I did also try putting it in run mode, but it didn't seem to reload the values, but I didn't spend too long messing around with it.