[mpg_numbers_guy]

Originally Posted by Ecky

This reflects my experience. 55mph is without a doubt worse than 50. I've found that I can get 100+ while cruising at lower speeds, but it seems like head-winds, hills, and things which interrupt steady-speed cruising affect the car more at lower speeds.

Those shifting points do not reflect my experience. I find shifting below 2250 delivers the best numbers, but our driving conditions may be different and you almost certainly have newer computers than are in my car. However I do find it easier to maintain throttle at 50 than at lower speeds

I can easily maintain at least 75 MPG cruising speed with lean burn in any conditions once the car is warmed up, with or without the battery, on both highway and non-highway driving. That's with the missing engine bay belly pan and still a little bit of drag on the wheels from the brakes (it's better but not gone yet).

Originally Posted by Ecky

Sounds like you had a catastrophic cell failure - one of them died in a way that could short out the pack, so it disconnected it entirely. Many packs die very gradually instead. Sorry to hear it happened.

Good fuel economy though, considering the conditions!

...

I doubt a grid charger would bring it back based on how it went. You could probably pull it apart and try to find the cell that died, but this isn't a long term solution - any replacement cell would likely get out of balance more easily and would need to be balanced regularly.

Even though the gauges weren't showing any assist or regen, I didn't notice any difference in acceleration, and the engine still started off the hybrid battery. It also didn't stall, indicating that the hybrid battery was still working somewhat. The only thing that didn't function was Autostop (guessing because of the CEL and IMA lights?). If all the signs are that the hybrid battery seems to be working at least somewhat, why isn't it showing assist and regen?

Do you still think that's what happened (the cell failure)? It didn't seem to noticeably affect the car's performance except for Autostop, yet none of the assist or regen gauges were ever lighting up. The battery went to one bar away from full and has stayed there ever since.

Originally Posted by Ecky

I think the car handles better without it personally, and you may not need Scott's rear springs since simply removing all that weight from the back will stiffen the rear up somewhat. You'll need to cut the rear springs a little if you want to keep the same ride height in the back. If you ever decide to go with a new pack or make the car a plug-in hybrid with a small lithium pack (150+++ mpg) I still have my uncut original springs which you're welcome to, and they're quite easy to put in.

How much would I need to cut them by? How much higher does the rear rise up with the battery removed?

Definitely would be interested in a relatively cheap lithium replacement whenever it becomes available. NiMH is a nighmare lol.

Originally Posted by Ecky

And yes, the car will still accurately track economy with a kill switch, it's only if you key-off to turn the engine off that you'll get inaccurate numbers.

Can it be wired up just like a kill switch on a "normal" car, or is there an Insight-specific method I need to follow?

Originally Posted by Ecky

Unplugging the BCM works great. 12v will stay charged, though without the battery buffering it, charging will shut off for a few seconds if you rev over 4,000. I never found this to be an issue.

Haven't revved it past 2600 yet. Is there a minimum RPM threshold limit too for charging the 12V? Or did unplugging the BCM remove that issue?

After bypassing the battery I drove into town to have my 12V tested. Bad battery as expected. Will consider a lithium replacement if I end up keeping the IMA bypassed. 6 miles into town and 6 miles back, with 4 stops, stalling it once, and taking almost a minute to exit the driveway (still learning how to drive a manual at slow speeds), and got 55.2 MPG on the cold engine. I did notice that the acceleration was slightly worse with the bypass compared to yesterday with the IMA light on...once again making me thing that the IMA isn't completely dead??

Originally Posted by Ecky

When you pull the battery out entirely you need to connect the high voltage leads that went to the battery directly to the pigtail coming from the DC-DC, so it can get voltage from the MDM to step down to 12v. Hit me up when you decide to do this, it's a pretty simple operation.

You'll have a CEL but no IMA light unless you add an Arduino to fool the ECU. Total cost can be less than $10 to make this, but you need to cut up the wire harness that went to the IMA system which makes it irreversible unless you have a spare. I might have a spare. Most cars won't lose lean burn, mine seems to be one of the rare cases. There are workarounds, but it ends up being a slightly more complicated procedure.

Hope this helps!

Will do. Thinking I might hook the IMA back up again and see how it does. If the battery is still assisting somehow without displaying it on the dash, does that mean it is regenning too without displaying it on the dash? What's the worst that can happen if the IMA just completely dies? Assuming I could just do the quick bypass and start it off the 12V then.

EDIT: Oh, another thing, I finally figured out how the grid charger works that came with the car. Plugged it in for a couple seconds and the voltage read 163V. Not sure if that indicates anything.