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Old 09-06-2018, 07:54 AM   #11 (permalink)
Ecky
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Join Date: Dec 2011
Location: New Zealand
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ND Miata - '15 Mazda MX-5 Special Package
90 day: 39.72 mpg (US)

Oxygen Blue - '00 Honda Insight
90 day: 58.53 mpg (US)
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Quote:
Originally Posted by redpoint5 View Post
The alternator energy is only free when you are in DFCO, with the engine being turned by momentum and no fuel being delivered to the engine. The actual brakes have nothing to do with it.

An ideal system would monitor for open loop and then enable the alternator automatically, or any time battery voltage goes too low.

Yet surely there are times when you can't coast to a complete stop, even for someone heavily using DFCO, due to traffic reasons. My car will coast for a very long time before fully stopping (hell even small gusts of wind start it rolling on level ground) but the last minute or two of coasting before a complete stop I'd be going quite slow. That's not realistic unless you're the only person on the road. Plus, I'd have to time my DFCO very well to never use the brakes.

Regen like this makes needing to use the brakes more forgiving.

@Daox, a fun calculation to do might be to convert those amp hours into gallons of gasoline, and compare it a few ways to idle fuel consumption, or how much speed you can get back from your car using that same amount of energy.

Quote:
Originally Posted by oil pan 4 View Post
Saving the battery is more important than saving a little fuel.
Since the cost of a battery is that of at least several fuel fillups.

Unfortunately, that's the conclusion many over on Insight Central came to about hybrid batteries. The battery makes the car a lot more drivable, and leaning on the $2,000 battery with a ~10 year lifespan very heavily to save a bit of gas and prolong the life of a $500 engine which easily lasts 300,000 miles doesn't actually make much economic sense. Better to use it as a driving aid than a fuel economy one, if the latter subtracts from its effective life. $2,000 buys about 50,000 miles worth of gas.

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