New Battery - Better update computer

XC60aches · Post by **XC60aches** » 03 Feb 2020, 15:09

Ok... I learned a lesson today. So 15 months ago, I replaced the battery with a higher AH and CCA rating. I did NOT update values in VIDA, just a manual BMS reset by unplugging the BMS unit. Lately I have been having a low voltage issue. First the start/stop Stopped working for charging, then I would eventually get the low voltage flag.

I was a bit stumped.. battery would check good when tested. Battery at idle was 14.8. Parasitic amp draw tested good. On OBD diagnostics the battery SoC would never ever exceed 81% even when fully charged with external charger and would continually drop.

Come to find out the 14.8 at idle was a little high. When driving the alternator module would request 14.8 to 15v. BMS values matter, It was over charging due to not changing the values within the computer. It was slowly killing my battery.

Today I had the values changed in VIDA and not at idle it is hanging between 13.9 and 14.2. And now my SoC is slowly increasing... currently 86% after 30 miles of driving.

Just wanted to pass this on, because nowadays a battery change isn’t just a simple battery change. Passing on my learned lesson.

Note: 2015.5 XC60, 2.0L

Current battery (15 months old): super start platinum 94R AGM 900 CCA

Post by **RickHaleParker** » 03 Feb 2020, 20:32

The 2015 must be using the a Coulomb Counting Method instead of the voltage/current method to monitor State Of Charge.
I wonder when Volvo converter to Coulomb Counting .... ?

Post by **regent** » 07 Feb 2020, 10:08

RickHaleParker wrote: ↑03 Feb 2020, 20:32 The 2015 must be using the a Coulomb Counting Method instead of the voltage/current method to monitor State Of Charge.
I wonder when Volvo converter to Coulomb Counting .... ?

Ha-ha, the Swedish Elves decided to count the electrons one by one, this method is far more accurate