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Discussion Starter #1
Hi!

I wrote this response to the yahoo group and thought it might be interesting in general:

The IMA charge/assist gauge has some life of it's own. It appears to be more of a software-driven indicator to provide feedback to the driver than a direct gauge running off one of the current sensors.

The Insight has several current sensors:
-DC battery current
-DC IMA current
-individual phase currents in the AC cable to the motor

I have a meter rigged to read the output of the battery current sensor. Here is what I know of that relationship with the IMA gauge:

Cruising: If the battery management determines that there is no need for charging the battery, the battery current is exactly zero. So the DC-DC converter appears to be driven off of the IMA motor/generator directly. The generator is controlled such that it delivers the exact amount of power needed for the DC-DC converter. I call it the alternator-emulation mode.

It is this observation that makes me think a dead 12V battery should have little to no effect on the 144V battery, except things like lost computer power (what Geoff mentioned).

Assist: The assist bars will reliably light a few bars every time there is any current drawn from the battery to feed the IMA motor. No bars lit mean there is no assist current flowing. Bars lit mean there is at least some assist current. More bars will light for more current. There is, however, no direct relationship between the number of bars lit and the actual current. (i.e. you couldn't say 10 bars = 20 Amps). For example, flooring the gas in second gear yields 90 Amps initially (full assist shown). After a few seconds, assist drops to 50 Amps, but the gauge still shows full assist! In most gears, full assist is 45 Amps to 50 Amps depending on battery voltage.

Charge: Here, it gets hairy.
When green bars are lit, you know there is some charge current flowing. Again, more bars more current. However, no bars doesn't necessarily mean no current! Many times (especially with the lights or AC an), the car decides to charge during cruising. In this case, the green bars will only light if the SOC gauge is less than about 2/3. E.g. if my car is charging recovering from a recal, there may be 8 Amps charge current and four green bars while I cruise on the highway. Once the SOC hits 2/3, the green bars turn off, but the current stays exactly the same! I call this the hidden-charging mode. So if no bars are lit you cannot tell if the car is charging or not.

There is a strange situation when the car is cruise-charging with a few bars lit: If I step on the gas gently enough, the charge current will gradually reduce (before dropping out of lean burn). If it get's to 1 or 2 Amps, the green bars will start to flicker on and off. I guess, it's not sure if it's charging or not. Great effect to use to maximise lean-burn power!
 
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Charge Lights

I have also noticed this, it manifests itself in the following way.

After my trip to the motorway the battery gauge will generally be between 1/4 & 1/2 full, then whilst cruising at 75-80mph, with no charge lights showing, the battery does recover, so much that when I leave the motorway after about 40 miles the gauge is reading only 1 or 2 bars from full.

The final run down the slip road under light braking pushes the gauge to full, just in time for the country lanes.

It would seam that I have the ideal run for the Insight, the battery gets discharged in town, then gently recharged on the motorway.
 

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I have heard that people with more recent models of the Insight (2001 or maybe 2002?) tend to see green CHRG lights when we 2000 owners do not... like their hidden-charging isn't quite so well hidden? This is just something I vaguely recall from visiting the Yahoo forums a year or more ago.
 

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I have a 2001 5 speed and know that it also does "Hidden-Charging" I have been on the road driving and notices that the battery levels increase even though no green lights were showing on the gauge. I hope that this helps and does not complicate the issue more.
 

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If flooring the gas in 2nd gear yields 90 Amps of assist (for a few seconds), while flooring the gas in 1st gear only yields 50 Amps, is there a way to fool the computer into thinking it's in 2nd gear so I can get 90 Amp assist in 1st gear?

I auto-x race my Insight and 95% of the time I'm driving in 1st gear because it's good until 60+ km/hr.

How many seconds does 2nd gear assist at 90 Amp?
About 4 seconds at a time would be all I need for auto-x racing.

Think about it, 4 seconds at 90 Amp assist in 1st gear might bring down the 0-60 time and 1/4 mile time by 1 or more seconds!

I don't slip my clutch in 1st gear at 4000 RPM just to gain a second like many people do. I've tried it 2 times and it does help a lot, but i'm not willing to wear out my clutch doing that anymore.
 

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Discussion Starter #6
Guillermo said:
If flooring the gas in 2nd gear yields 90 Amps of assist (for a few seconds), while flooring the gas in 1st gear only yields 50 Amps, is there a way to fool the computer into thinking it's in 2nd gear so I can get 90 Amp assist in 1st gear?
Off the top of my head: I believe there is a switch in the gearshift. You may be able to override that by shorting the right set of wires. Do you have an Electrical Service Manual?

How many seconds does 2nd gear assist at 90 Amp?
About 4 seconds at a time would be all I need for auto-x racing.
I have only seen it for a few seconds at a time, accelerating from 1.5k rpm to 3.5k rpm or so. But I don't know if it's time-limited, rpm-limited or limited by some battery metrics. There is not a hill steep enough in my neighborhood to keep it in second at 2500rpm for longer. If it's rpm limiting the current, this won't work for you. In any case, the current will reduce gradually, once the battery voltage drops to 120V. So only with a really full battery could you do this for any extent of time.
 
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