CarlPace
Posts: 16
Joined: Tue Mar 15, 2022 6:03 am

Jump in max range, Regen Pause

Tue Jul 12, 2022 3:54 pm

Hello all,

Our family FFE tends to "budget" a different number of miles each time we turn it on fully charged. I perceived this to be totally normal, and assumed it was calculated based on current temperature, and the driving habits from the previous ride. It's usually around 65 miles, with a once-in-a-while 70.

The other morning, it jumped to 81, which was a first. Considering the normal fluctuations, I wouldn't have thought it was a huge deal if not for the second oddity: The regenerative braking didn't kick-in until I had driven about 6 miles (street, not highway.) Is it possible the computer was interpreting the battery to be overcharged or something? Can anyone educate me on what might have caused this?

For the sake of mentioning all variables: I had washed the car the night before. Is there perhaps a world where water might have gotten somewhere and messed with a sensor? Or is the timing of the wash just a coincidence?

Thanks.
2014 White FFE Lemon
65-mile range at full charge
Battery replaced under warranty in 2020

Heima
Posts: 245
Joined: Thu Feb 21, 2019 11:46 pm

Re: Jump in max range, Regen Pause

Tue Jul 12, 2022 8:20 pm

I do not know the exact percentage, but until the battery SOC gets below 95-90%, regenerative braking is turned off. This is to prevent overcharging the battery. I believe most electric cars have it. When I owned a Fiat 500e, I lived up in the San Jose hills. If the SOC was about 50% at the top of the hill, getting down the hill would increase it to 54%. But if the battery was at 95%, at the bottom of the hill, it was still 95%. I felt robbed.

In warm weather, when everything else is the same, the guessometer will show greater range. That same Fiat 500e when normally would show 88 miles range would often peak over 100miles on hot days. My FFE has shown 135 miles at times. But in reality, that kind of range wasn't actually attained. Maybe 5% less, so 95 miles on the 500e and 128 on the FFE.

I don't think that water in a sensor is going to give you extra range. The range is computed from the State Of Charge (SOC) and past power consumption rates. SOC is determined from the battery pack resting voltage. The sensors for measuring power consumption and voltage are inside of the battery, so I don't think hosing the car down will affect that.

Anti_Climax
Posts: 338
Joined: Fri May 20, 2016 12:22 pm
Location: The Valley of the Sun

Re: Jump in max range, Regen Pause

Tue Jul 12, 2022 10:18 pm

Not only is regen disabled, but if you take a short drive after a full charge, it won't top back to 100% if it didn't go below that threshold.

My "raw" SoC shows full charge at 95% and it seems like it won't top off the charge unless it goes below something like 93%.

As for the change in range noticed, if you do some atypical drive, it can drastically change the number on your next trip. My normal range on a full charge is something like 100 miles even with my AC running during the summer.

If I do a few lead foot trips that drops to high 70s low 80s. If I drive around on slow residential streets for a lot of miles, my range estimate will show 10-20% higher than normal (100-teens). It strongly tracks with the last trip.

One of these days I really hope to capture enough data to confirm exactly how they are modeling the estimate.
Last edited by Anti_Climax on Thu Jul 14, 2022 7:26 pm, edited 1 time in total.
2012 Candy Blue FFE
33.5kWh battery pack
CHAdeMO DC Fast Charging

CarlPace
Posts: 16
Joined: Tue Mar 15, 2022 6:03 am

Re: Jump in max range, Regen Pause

Wed Jul 13, 2022 8:45 am

Fascinating, and just the education I was hoping for. Sounds like a case of all-is-well. Thanks!
2014 White FFE Lemon
65-mile range at full charge
Battery replaced under warranty in 2020

Return to “Technical Discussions”