News for hackers. Stuff that matters.
Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by cmrdporcupine on Saturday April 29, 2017 @08:18AM (#14226226)
GM seems to have the best battery health system. Doesn't let you charge past 85%, 90%, always keeps 10% or 15% in reserve. Only reports the chunk between. Dedicated robust temperature control system.

Volt has been out since 2011 with as-far-as-I-know no battery degradation issues. Some people have driven well over 300,000 miles with no problems.

Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by jessriedel on Saturday April 29, 2017 @09:42AM (#14226548)
Why do we even call "90%" if the battery is disallowed to charge higher for (presumably) longevity reasons? Why not call that "100%"? Assuming I disabled the automatic cutoff at the filling station, I could squeeze a bit more gasoline in my tank by filling the pipe up to the gas cap, but I wouldn't say I'm at 95% for not doing this.

(In contrast, it makes sense to say that the car reports "empty" even when it's at 10%, because you can keep driving it .)

Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by dsfyu404ed on Saturday April 29, 2017 @11:39AM (#14227035)
For discussions of longevity actual capacity is relevant because where the full/empty lines are drawn has a big effect on how much wear and tear gets put on the pack in a cycle. A literal 100% charge is very different than a nominal 100% charge.
Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by jessriedel on Saturday April 29, 2017 @11:59AM (#14227135)
The degree to which each percentage point effects longevity surely varies depending on battery design. It would be a lot more useful it describe it in terms of recharge-discharge cycles than to say "it is limited to charge only up to 90%" and let the listener try to infer what that means about lifetime.
Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by patrickpkt on Saturday April 29, 2017 @08:59AM (#14226371)
That's how the i3 works as well. There are 22kwh of batteries in board, but it only uses about 18kwh for the sake of efficiency and longer life.
Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by Shivetya on Saturday April 29, 2017 @09:51AM (#14226585)
The issue I have with the i3 is that it was hinted they could upgrade the batteries but they won't do so, at least in the US.

I am very happy with my second generation Volt, averaging 66 miles per charge since I got it in March (Georgia weather) and it should squeak out a few more as summer progresses. I am really curious what my range will be in Winter seeing as a friend with an i3 loses twenty miles per charge in our coldest and the Tesla 80 at work goes under 200 range max by a good number.

still not sold all battery is the way to go, range is always there, but recharge times and sheer weight of so much battery is contrary to where manufacturers want to take cars (lighter weight is better regardless of propulsion method)

Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by greeneggs on Saturday April 29, 2017 @01:50PM (#14227740)
> (lighter weight is better regardless of propulsion method)

This is true for efficiency reasons, but lighter cars also save lives. Here's a recent discussion:

The Effect of Fuel Economy Standards on Vehicle Weight Dispersion and Accident Fatalities

Antonio Bento, Kenneth Gillingham, Kevin Roth

http://papers.nber.org/tmp/22190-w23340.pdf http://www.nber.org/papers/w23340

> we find that CAFE has been providing safety cobenefits because it encourages down-weighting. Using the Department of Transportation’s value of a statistical life, at $9.4 million, the welfare benefits of reduced fatalities, found in our simulations to range between 393 and 439 lives nationally, are more than $3.5 billion annually. ... our findings suggest that CAFE would pass a cost-benefit test based on benefits from reduced fatalities alone. This is particularly notable because the current EPA analysis does not include benefits or costs from fatalities, but relies heavily on myopic consumers realizing large future fuel savings to pass a cost-benefit test, which recent economic evidence brings into question (Busse, Knittel, and Zettelmeyer, 2013; Allcott and Wozny, 2014; Sallee, West, and Fan, 2016). Our results suggest CAFE standards may have positive net benefits even without any undervaluation of fuel economy.

Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by makomk on Saturday April 29, 2017 @11:17AM (#14226913)
GM have apparently been putting a serious amount of work into their battery engineering: https://www.wired.com/2016/01/gm-electric-car-chevy-bolt-mar... It's just that no-one seemed to notice until recently.
Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by aphextron on Saturday April 29, 2017 @12:10PM (#14227202)
>Volt has been out since 2011 with as-far-as-I-know no battery degradation issues. Some people have driven well over 300,000 miles with no problems

This is nice but anectdotal evidence is useless when looking at failure rates. Does GM put out any actual data on the Volt/Bolt? Im really curious how they stack up against Toyota for reliability.

Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by cowmix on Saturday April 29, 2017 @12:31PM (#14227304)
http://insideevs.com/zero-first-generation-chevrolet-volt-ba...

I have a 2013 Volt with 67K (50K ev) miles and there is, so far, no change in ev range.

Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by secabeen on Saturday April 29, 2017 @08:08PM (#14229498)
Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by zwily on Saturday April 29, 2017 @08:42AM (#14226305)
Best out of who? Tesla's seems very robust as well.
Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by sremani on Saturday April 29, 2017 @09:28AM (#14226480)
Best of affordable cars. I get your point, but none of the Tesla's available on the market are really outside high end luxury segment.
Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by mtgx on Saturday April 29, 2017 @09:00AM (#14226379)
> Some people have driven well over 300,000 miles with no problems.

I assume at least 2/3 of those miles were on gas?

Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by sremani on Saturday April 29, 2017 @09:22AM (#14226445)
The Volt with most miles (in real life) is 379201.03 and its has 132643.18 ev miles, so you are about right for that one.

edit: https://www.voltstats.net/Stats/Details/1579

There may be longevity tale unfolding with PHEVs, but we can only guess.

Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by swozey on Saturday April 29, 2017 @10:18AM (#14226678)
I've heard complaints about how during the winter months the Volt will keep the gas engine on to keep things heated up and it will cut the range almost in half (60ish to mid 30s) during the winter. I'm not sure if that's the overall range or the electric range.

That's probably enough for a lot of us commuters, especially if you've got charging options at work but that'd make it a non viable winter getaway car (which you'd probably already know if you're researching hybrids).

Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by labcomputer on Saturday April 29, 2017 @11:01AM (#14226846)
The range drop applies only to electric mode, and it doesn't drop by half unless you're driving very slowly (in other words, you spend a lot of time with the heater on and don't go very far). Pre-conditioning the cabin while the car is plugged in helps tremendously in moderately-low temperatures.

There's a setting on the center console screen to adjust how aggressively the Volt uses the engine for heating.

Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by swozey on Saturday April 29, 2017 @12:55PM (#14227453)
Yeah that makes sense. The pre-conditioning is a really cool thing.
Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by mikeash on Saturday April 29, 2017 @12:49PM (#14227411)
How would that make it nonviable? The whole point of the gas motor in a Volt is to let you drive beyond battery range. Once you deplete the traction battery, you're essentially driving a standard hybrid that still gets excellent gas mileage and has similar range to standard gasoline cars. It's not like the i3 range extender where you lose substantial power once it kicks in, it has a microscopic fuel tank, and it's really just a last resort if the batteries can't get you where you're going.
Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by swozey on Saturday April 29, 2017 @12:53PM (#14227443)
I said that I wasn't sure if that was the TOTAL or the electric range. My point was that if that's the total range it's a problem.

I know nothing about these cars beyond the Winter complaint I heard.

Re:BMW i3 Long Term Battery Capacity Report: Better Than Exp... by mikeash on Saturday April 29, 2017 @01:03PM (#14227509)
OK, I was unprepared for that level of cluelessness. Maybe take a few seconds to look it up before spreading misinformation? I mean, not to be harsh, but I don't see how it's in any way believable that the total electric plus gas range of a Volt could be as low as 30 miles.

For the record, total range for the Volt is officially 420 miles. Chop the electric range in half and it would be about 400 miles. Chop both in half (range on gas won't be nearly as badly affected in the cold) and it's still 210 miles.