23rd to 27th September - Range drops sharply when low

Monday 23rd

On Sunday the Volt said I had used 7.8kWh. The meter says it took 10.4kWh to recharge. So Saturday nights recharge of 10.3kWh had a 1.7kWh overhead but Sunday's 7.8kWh recharge had a 2.6kWh overhead.

For Monday there;s not a lot to report. Estimated range in the morning was 43 miles. I drove 32 miles (morning and evening) and had 12 miles range remaining. That seems about par for the course, nothing odd happens until the battery is getting low and I didn't take it low enough today.

 

However, I see my 7.2kWh used on Monday took 10kWh to recharge. That's a 2.6kWh overhead. For some reason the less energy the car records using the more overhead there seems to be recharging. (Absolute overhead that is, percentage overhead I would expect to get higher.)

Tuesday

Morning range estimate was 44 miles. The trip into work lost slightly against this, the trip after work gained a bit.

Interestingly, here I drove 5 miles and the estimated range remained the same. My guess would be that the day warming up (11C first thing but now 18C) had an effect on the battery consumption.

The last 4 miles today dropped 8 miles off the range. Unfortunately I didn't have time to go any further, but I think it was beginning to drop quite rapidly at the end.

8.9kWh used, overhead on recharging 2.0kWh.

Wednesday

Morning range estimate 44 miles, after 13 miles I have 29 miles range remaining (42 total), after 28 miles for the day I have 21 miles remaining (49 total!), after 37.7 miles I have 10 miles range left (47 total). Then it starts to get interesting...

 The last two pictures were taken when I stopped for some shopping at 6:17. I got back to the car about half an hour later, and although the odometer has ticked over to the next mile this next picture was taken at the traffic lights just a couple of hundred metres down the road. When I set off again the range began counting down rapidly.

 Two miles further on and the range has dropped to 2 miles.

And a total of 3.2 miles after the range estimate said 10 miles, we're running on petrol. Also that appears to be 2.0kWh used for 3.2 miles which I think would be pretty well impossible even if Oxfordshire was moved to the Alps.

It seems to me that the software update has changed the behaviour here. Where previously a stop of maybe 10 minutes with 12 or fewer miles remaining resulted in a large range drop when I came back to the car, now the range drop is being smoothed out. It still happens, but only after I restart the car at which point the range drops every few seconds and the kWh meter ticks up alarmingly quickly.

However, on Sunday it seemed that leaving the car for hours rather than minutes still results in a sharp drop and reduced total (apparent) consumption.

Thursday

Morning range estimate still 44 miles:

 Dropped one mile off the range during the day:

After 32 miles, 16 remaining which would give a total 48 miles if it stayed that way:

... but a mile later it's down to 13 miles range which gives 45 miles total, pretty much in line with the morning 44 mile estimate.

... and after 35.8 miles total I have 8 miles range left, right in line with the morning 44 mile estimate.

I stopped for about 10 minutes, then drove the remaining 0.7 miles home. Over that last 0.7 miles the estimated range dropped by 3 miles.

When I got home, I decided to see if I could replicate the sort of drop I saw on Sunday, so instead of putting the Volt on to charge I left it for 2 1/2 hours and sure enough another 3 miles disappeared from the range.

Friday

On Friday I gave the Volt (and my phone's camera) a rest. Overhead for the recharge seems to have been 1.9kWh.

Summary

The behaviour does seem to have changed a bit with the software upgrade. I'm pretty certain there's a repeatable sharp drop to the range any time I stop with 10 miles or less remaining. It no longer seems to drop significantly while the car is off unless I leave it for several hours.