- Joined
- Jun 25, 2025
- Messages
- 259
- Reaction score
- 387
- Location
- Torrance, Ca
- Cars
- Spark EV, Dec2025 GGT
FOB battery life issue seems to be resolved!!
According to my latest micro-current measurements battery life has gone from 7 days worst case to greater than 1 year!
How can this be? software
1. Keeping fob stationary for >70 seconds, even within auto-open range now drops current to ~5uA. Previously you had to stay away ~50ft or equivalent or you got ~5mA (1000 times more). Didn't capture all the exact details of the previous version because I updated the fob before I had worked it out so maybe it wasn't this bad.
2. Inside the car as soon as you switch to drive the current drops to ~10uA, no matter if you move the fob or not. Previously any fob movement would turn on power to ~5mA level. That explains why they had fob battery problems on EV race.
So the bottom line is:
Throw away your faraday bag!
Store the fob anywhere outside the car where it won't be physically disturbed.
If your going to sit in a parked car put the car in drive and then back in park to sleep the fob.
One last important point. Replace the fob battery now. The fob-battery system may still try to communicate when the battery is to low to due so correctly. This may cause some of the weird startup behavior.(my guess) But now that the battery consumption is resolved there is no reason to try to extend a dead batteries life. Put in a fresh one and be good for a year.
Hope I don't have to eat my words !
According to my latest micro-current measurements battery life has gone from 7 days worst case to greater than 1 year!
How can this be? software
1. Keeping fob stationary for >70 seconds, even within auto-open range now drops current to ~5uA. Previously you had to stay away ~50ft or equivalent or you got ~5mA (1000 times more). Didn't capture all the exact details of the previous version because I updated the fob before I had worked it out so maybe it wasn't this bad.
2. Inside the car as soon as you switch to drive the current drops to ~10uA, no matter if you move the fob or not. Previously any fob movement would turn on power to ~5mA level. That explains why they had fob battery problems on EV race.
So the bottom line is:
Throw away your faraday bag!
Store the fob anywhere outside the car where it won't be physically disturbed.
If your going to sit in a parked car put the car in drive and then back in park to sleep the fob.
One last important point. Replace the fob battery now. The fob-battery system may still try to communicate when the battery is to low to due so correctly. This may cause some of the weird startup behavior.(my guess) But now that the battery consumption is resolved there is no reason to try to extend a dead batteries life. Put in a fresh one and be good for a year.
Hope I don't have to eat my words !