2nd gen Honda Insight parallel portable plugin hybrid battery pack build thread

[S Keith]

I didn't see it discussed, but I might have missed it. The Honda IMA system counts current when discharging, and there is an upper limit where the car will stop using assist, so it doesn't matter how much extra capacity you might have, the car will not use it. How does this affect your project?

[RedDevil]

Originally Posted by S Keith

I didn't see it discussed, but I might have missed it. The Honda IMA system counts current when discharging, and there is an upper limit where the car will stop using assist, so it doesn't matter how much extra capacity you might have, the car will not use it. How does this affect your project?

Got a source of that info for me to follow?

Cobb had an Enginer kit in his 2nd gen Insight, which worked fine except for the DC booster quitting at a hump. Based on that I can't see why my plan would not work.

[S Keith]

Originally Posted by RedDevil

Got a source of that info for me to follow?

Cobb had an Enginer kit in his 2nd gen Insight, which worked fine except for the DC booster quitting at a hump. Based on that I can't see why my plan would not work.

Lots of discussion over on IC about that. For G1 it can be partially overridden with MIMA and maybe OBDIIC&C. Multiple accounts of how Honda IMA will not use more capacity than the design capacity. Higher capacity packs will provide more margin for squeezing out the max allowable.

[Daox]

Can't you just introduce the extra pack power before the ammeter on the car so it registers the parallel pack as charging the OEM pack?

[S Keith]

The car is still counting mAh "consumed" regardless of where the boost pack is installed.

[Daox]

That doesn't make sense. How does it keep track of regen?

[S Keith]

Originally Posted by Daox

That doesn't make sense. How does it keep track of regen?

It counts current in and current out while monitoring pack and subpack voltages.

[Daox]

That makes sense. So you add the parallel pack in so it detects it as regen, aka before the current sensor / ammeter. This should allow the car to detect the additonal capacity.

[RedDevil]

Yes I know InsightCentral, I got most of what I know about the IMA system from there.
By my knowledge the first gen is different in this than the second gen.
AFAIK Cobb's Enginer kit just connected to the terminals without any meddling with the electronics up front.
It allowed him to do 100+ mpg while hypermiling and 49 mpg maintaining 80 mph.
Cobb did document his experiences well at the time. (sadly he removed some of it later... but I know what I bookmarked and why).

I have not seen any proof that the Gen 2 does total current used and block further use at any point. Rather the IMA system seems to measure pack voltage, and that is very much under my control in this setup.
That also might explain why Gen 2 pack problems are rare or nonexistent, as weak cells would make the voltage drop or rise more than usual and have the IMA system compensate for it, while a current totaling system would drain or overcharge the ailing cell without mercy.

So with all due respect I will follow up on my plan.
If I missed the crucial part where it shows that the second gen Insight IMA system cannot handle a constant feed of power please point me to it now.
Monday morning will be too late!

[S Keith]

Service manual manual page 12-35:

"Motor Control Module (MCM)
The MCM calculates the battery module SoC and controls the IPU module fan. The SoC is calculated using voltage, temperature, input current, and output current readings of the battery module."

Page 12-39 identifies a "battery current sensor" on the pack junction board. What it doesn't say is that it counts current.

"The current detected by the sensor is used to compute the battery SoC"

If it tracks a relationship between voltage at various current levels, and it doesn't actually count current, then you should be good to go.

Sorry to throw the last minute wrench in there.

Good luck!

Steve