rare charging moments

[Chris G]

I have had similar charging experiences. I have even seen charging occur during uphill drives with a light foot on the pedal. These experiences have seemed to become more frequent as the wear and tear on my car and battery have increased (I have about 115K on it now). As far as maximum regen braking, I have come to realize, albeit to late, that since brake jobs are far cheaper than battery pack replacements, perhaps I should have paid less attention to regeneration than to battery conservation.

Chris

[GICU812]

I too have whitnessed the "phantom charge"

I cant quite figure out why it will charge in neutral, but only if rolling at a high speed. Theres no mechanical explanation for it, when in neutral there is no signifigant link between the tires and the engine, there might be a little bit of force, like if you've ever had the engine on with the wheels in the air they will spin, but you can stop and hold them easily.

So the engine is just idling on its own, but supporting charge. I would assume this indicates that the engine will support charge at stopped idle as well if you could force it. I wouldnt mind being able to tell the engine to charge when idling, so like when I start the car to defrost and warm, its doing something useful with the gas. It might use more gas, but it would also speed warming, so it wouldnt take as long.

[Mike Dabrowski 2000]

If any charging is taking place while idling in neutral, it would have to be quite low level. Even 7-10A of charge could stall the idling engine.(experience speaking).
If regen is requested when in neutral, the 4 regen green leds light, but the MIMA amp display will only show ~ 3-5 A (One dim regen led)
Bottom line as Nemystic indicates, the charge assist leds are not indicating the true charge assist current.

[Tonpilot1]

Originally Posted by nemystic

It seems like most observant 5 speed Insight owners have noticed this rare phenomenon.
Since installing additional instrumentation, I've learned that the stock "CHRG" display (which indicates the variable component of the battery pack regeneration current) has a significant fictional component. In other words, you shouldn't believe what you are seeing on that display in all cases, because sometimes it's just bogus.
I'll forego offering specific examples to preclude any discussion of MIMA
It's possible that this "coasting in neutral" regen display phenomenon isn't really happening as the display would indicate.

That is good info. Base on the information you have from your additional instrumentation, the charging episode is probably just a false indication. I like to say there is a "gremlin" in the system! Easy way to explain the unexplainable!

BTW, what instrumentation did you add to the Insight?

[nemystic]

Tonpilot1 wrote:

"BTW, what instrumentation did you add to the Insight?"

With the home built MIMA_L modification I installed in 2005, I used a small DVM to display a voltage that's directly proportional to the IMA current.
That was later replaced with the MIMA_C modification (links to a website with detailed information are on a sticky thread in the technical branch of this forum), which in my configuration, includes an 8 LED display, 4 amber for assist, and 4 green for regen. The most significant LED illumination intensity is variable. That display doesn't offer as much resolution as the DVM, but it's about as good as the stock bar graph display, and more importantly, it provides an accurate representation of the actual IMA current in either direction.

It's not necessary to have the MIMA modification to monitor the IMA current accurately. I had connected the original small DVM to the IMA hall effect current sensor output and the MCM logic ground. It was set to the mV scale.
A "cleaner" way to implement that would be to build a relatively simple analog circuit (as Armin has done) to create a virtual ground from the +12V and -12V connections at the hall effect sensor, and to scale the output voltage by about 0.5x to provide a display in actual amps (1mV per amp).

[Dougie]

Not that it has anything to do with charging, but I added a connector to the speedometer sensor wire so I can connect a TimeWise rally computer to the car. My idea was to do some coast-down testing to get some real-world data on the "A/C versus open windows" discussion. A rally computer can take many very exact readings of time and distance, which is what you need for this sort of experiment. Also what you need, though, is a very long, flat road. So far I have found that the Insight coasts so well that it is hard to get decent data--you need miles of road to coast down from 60 mph to 10 mph.

What I need is a road about three or four miles long that is perfectly level, has no traffic, and located where the wind doesn't blow. There ain't any such place in Colorado...as far as I know.

[nemystic]

'Continuing the off-topic discussion, which should probably be in the "coasting" category; I'd considered running some experiments with my Insight to quantify the effect of open windows on aerodynamic drag.
There's a hill in the town where I'd previously lived that is relatively short, but very steep and straight. On that hill, I can get to 40mph on some bicycles without pedaling while going downhill.
The plan was to coast downhill from a very precise starting point, with the windows closed; then in subsequent runs, opened in several increments to 100%, all on the same day, to ensure consistent environmental conditions.
The metric was to have been the coasting speed at a marked location around the bottom of that hill. (Even though it is a rural road, coasting to a stop may have irritated other motorists.)

Since my Insight doesn't have air conditioning, I couldn't do a quantitative, comparative study.

Since the original plan was never carried out, this may all be irrelevant, but considering that the Insight open-window-aerodynamic-drag discussion has never been resolved to my satisfaction, I'd re-consider the experiment (described above) if enough fellow Insighters would be sufficiently interested in the result.