12-volt battery update

Discussion in 'Hyundai Ioniq 5' started by CharlesBranch, Jan 16, 2023.

To remove this ad click here.

  1. I have posted my experience using a BM2 monitor to examine the defective Ioniq 5 12-volt battery management system. https://tinyurl.com/ycx7m997. Several times my car has had a dead 12-volt battery because of the failure of the traction battery to charge the 12-volt battery. Two dealers have failed to solve the problem and even refused to contact Hyundai for help. And when I contacted Hyundai directly, they simply referred me to the dealer. I think that qualifies as a Catch22. :)

    Recently I returned from a trip with about 15% left on the traction battery and noticed a change in the behavior of the charging system. I decided not to charge it immediately after the trip to see if the total failure occurred again. This time the system again refused to recharge the 12-volt battery, but this time the 12-volt battery did not go into the "death spirals" I reported previously. The system appeared to periodically check the voltage for a day or two without activating charging. I let it continue, and then it looks like the system then quit even checking the voltage. But unlike before, the battery did not go into the spiral. I finally took it to a charger when my BM2 sent me a warning that the 12-volt battery was down to 68%.

    For comparison, this is an image of the last time the car had a couple of near misses in which the spiral began, but I charged the traction battery before the 12-volt battery completely failed. Note the small negative spikes 2 or 3 times per day, which I assume must be the system checking the voltage to see if it needs to charge from the traction battery. On the two near misses, the small negative spikes continued even more frequently, but the charging system never came on. In the first near miss, I just happened to take the car to a charger before total failure. In the second near miss, I got a warning from the BM2 monitor and took it to a charging station.

    And this is the BM2 monitor of the more recent experience. The recording begins just after I charged to 100% in preparation for trips of 94 and 77 miles the next day (a total of 171 miles). The traction battery was at about 15% after the second trip. This time the small negative spikes continued for about 2 days, but the charging did not begin. Then the negative spikes quit altogether. I let it continue for about 4 more days as the 12-volt battery voltage gradually fell. At 68% I got a warning from the BM2 and took it to a charging station.

    I'm wondering what has changed since the previous incidents. Has Hyundai possibly installed an update that partially fixed the problem? The only notice I received of an update was to the entertainment system. There is still a problem with the traction battery not charging the 12-volt battery, but this time the death spirals did not occur--at least not for 6 days. One never knows if it would have happened eventually if I had not charged the traction battery when I got the warning.

    I worry that between problems with the car plus problems with the Electrify America chargers, the nay-sayers might convince people that EVs are just not ready for prime time, and that would be a real shame.
  2. To remove this ad click here.

Share This Page