Low battery warning - an investigation
Your intrepid investigator has been examining the low battery range ...
So I had an extra errand today using up most of the battery, and so ended up just a couple of streets away from home when the final 3 miles showing disappeared into dashes, --, with the SOC needle around 1/3rd of an octal above the lowest point of the bottom octal.
There is a village and a gentle road that I know to be a 3 mile round trip, so I thought I'd just drive up there and see what happens. I reset the gauge and carried on.
At 0.6 miles past the loss of the range indicator, the regular low battery warning came on, the one that runs every 15 seconds or so. (You can turn the longer interval alarm off in the menus, which I have done, but you can't turn this very low indicator off.)
At 2.7 miles a 'performance limited' sign came up. By then I was already virtually back home, into the back streets near the house. I couldn't tell if the performance was limited, seemed OK for a while and could give 30kW (didn't try harder).
I was back home by 3.2 ish miles and everything still seemed normal so I drove around the block a few times. Just a little later the power seemed to limit to around 17kW. I suspect it'll give you that power but will limit speed, which I couldn't tell as I was doing less than 30 by then.
The needle was properly at the bottom of the lower bar by 3.5 miles or so. I pottered around a couple more times and reached 4.9 miles. Discretion being the better part, I parked up.
I kept an eye on the mi/kWh gauge throughout and it was fairly consistently, as makes any odds, around the 4.2mi/kWh range. Roughly, then, I had at least 1.2 kWh when the range disappears and the repetitive alarm goes off. Clearly, I had not stopped or even ended up crawling along, so there may still be a little margin beyond that even.
My further study I brought out the brick-lead to see how long it said it would take to charge up. Indeed, the first thing it said was 8:30hr (per a recent thread) but the time estimate was creeping upwards. 90 seconds later it said 9hr, and 5 minutes later it peaked at 10:10hr before falling back. (I'm sure I have seen 10:30 up on it before when I first got the car, hmm, wonder if that reflects a little battery loss?)
I shall be monitoring input energy tonight with an overnight charge, and we'll see how much energy the battery takes, back to full.
I was running the AC and ran it throughout. It did not turn the AC off at any time. I would've though that would be one thing the car would shut down automatically if it is already limiting the power output, but it didn't.