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Discussion Starter #1
I've had this car for 4 years now, and over the course of 2016, the following has happened at least 3 times, most recently this morning during my 18 km commute.

1.) Got in car, didn't have time for a full charge as I charge on level 1 I had 9/10 bars and 43 km of estimated range (the other times this has happened I had a full charge. Normal estimated charge in current weather conditions is 50-51 based on 10 full bars
2.) Shortly into commute, estimated range shoots up to 80 km (max of what my display can show) 10th battery bar is now full.
3.) Regen braking is disabled, I drive in L, but for half of my commute, car operates as if it is in D
4.) Estimated range varies wildly as I drive. Goes down to 60-65 km over short distance, but when the regen is working recoups back up aggressively (despite level terrain)
5.) I don't lose my first bar of capacity until quite far into my commute, heat is on, highway speeds, usually first bar goes fairly quickly.
6.) By the time I arrive at work, I've lost close to the normal amount of bars of capacity (not today though, had 7 bars left, should have had 5-6, considering I didn't start with 10 bars
7.) Usually corrects itself after next charge (I will have a full charge when I leave work, so I'll monitor this)

I'm not crazy about bringing it to the dealer because, no check engine light, or codes are thrown that I know of, it's extremely intermittent, and I'm not convinced they can replicate the issue. I'm assuming any diagnostics will be covered if it's under the voltec warranty component, but if they don't find an issue, I have to pay for diagnostic.
 

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Just for the sake of asking, but how old is your 12V battery?
 

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Sounds like the car is having trouble determining the state of charge accurately. Sometimes that is helped by fully discharging and then fully charging the battery. That does not explain why it works well most of the time, but it is worth a try since it is easy.

Do you have a scan tool to check for codes that might be stored without a CEL?
 

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Discussion Starter #4
Sounds like the car is having trouble determining the state of charge accurately. Sometimes that is helped by fully discharging and then fully charging the battery. That does not explain why it works well most of the time, but it is worth a try since it is easy.

Do you have a scan tool to check for codes that might be stored without a CEL?
12V is original, I will have to test it again.

No scan tool, I can discharge it fully, but I'm confident that it will perform normally on my commute home without a full discharge, and it has discharged in between previous instances of this happening.
 

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If you are worried about diagnostic charges, get an OBD2 reader. They do not have to be expensive. It could give you helpful information.
 

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I believe the procedure is to disconnect then reconnect the 12v battery to reboot. (assuming the battery is OK) Check thread.
 

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Best to test it under load. A local auto parts/service shop should be willing to do that for you.

KNS
How much of a load would you put on it? this battery only powers 500 watts or so, and only for 10 seconds or so. the standard auto parts store test is based on a starter motor, which might draw 4-5 times that much power.
 

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I am guessing with a base elevation of 37 m there were not big hills on you drive :)
 

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Sounds like the car is having trouble determining the state of charge accurately. Sometimes that is helped by fully discharging and then fully charging the battery. That does not explain why it works well most of the time, but it is worth a try since it is easy.
This. The computer is having trouble knowing what the battery SOC is.

I'm fairly certain charging is a separate process entirely from the vehicle computers (i.e. the charger always charges per its own parameters of voltage/whatever cutoff point per its own circuitry standalone). So you probably did have a full charge. But the computer was reading it as 9/10.
Then as you drove it attempted to recalculate SOC and thought you were above 10/10 so disabled regen to prevent overcharging
Then later it on it finally got a decent estimate and operated normally.

Try fully depleting the battery (switch to gas pump, but the engine doesn't need to run if you don't have to), let it sit for two hours before plugging in. Fully charge the battery, unplug the car and let it sit for two (or more) hours.
Repeat this every time at least 6 times to give the car a bit of time to relearn the battery charge states.

If it's still acting weird, then there's probably a failing component in the battery computers that hasn't quite failed enough to trigger MIL.

You said you get to work typically about half or more?
Try doing a full work and home commute for the next few days, sucking out every last electron (do a few laps around the block if you need to, to get it right empty) before charging.
 

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Discussion Starter #12
Sounds like the car is having trouble determining the state of charge accurately. Sometimes that is helped by fully discharging and then fully charging the battery. That does not explain why it works well most of the time, but it is worth a try since it is easy.
This. The computer is having trouble knowing what the battery SOC is.

I'm fairly certain charging is a separate process entirely from the vehicle computers (i.e. the charger always charges per its own parameters of voltage/whatever cutoff point per its own circuitry standalone). So you probably did have a full charge. But the computer was reading it as 9/10.
Then as you drove it attempted to recalculate SOC and thought you were above 10/10 so disabled regen to prevent overcharging
Then later it on it finally got a decent estimate and operated normally.

Try fully depleting the battery (switch to gas pump, but the engine doesn't need to run if you don't have to), let it sit for two hours before plugging in. Fully charge the battery, unplug the car and let it sit for two (or more) hours.
Repeat this every time at least 6 times to give the car a bit of time to relearn the battery charge states.

If it's still acting weird, then there's probably a failing component in the battery computers that hasn't quite failed enough to trigger MIL.

You said you get to work typically about half or more?
Try doing a full work and home commute for the next few days, sucking out every last electron (do a few laps around the block if you need to, to get it right empty) before charging.
I fully depleted the battery last night, car was only on a level 1 charger for 8 hours so I wasn't expecting a full charge this morning, if I did have a full charge I suspect I'd have a different problem.

As I suspected since charging my car is now back to normal, but it will happen again, just a matter of when. I have tried the full battery depletion for an entire week a while back. FMM ran on Sunday I'm going to make note of whether this happens next time FMM runs. I'm leaning towards the 12v battery being an issue, and I'll probably grab a scanner as someone mentioned above. Surprising that I've never heard of this issue from anyone else. I've been a long time lurker here and on Facebook. :)
 

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Pick yourself up a aux plug voltmeter and plug it into the outlet on top of the dash. When you turn your car off, leave the radio on and turn on the headlights. Retained accessory power will run for 10 minutes. Monitor the voltage and see how fast it drops. It should not go below 11.8 volts during the 10 minutes if the battery still has decent capacity.
 
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