So whats the difference in old BCM and new BCM

[JimIsbell]

I have a set of old MCM and BCM and I am wondering what the difference is between them and the replacement units that Honda placed in the re called cars.

In my car I have the newer units and on a spare battery pack I have the old units. Will I see any difference if I swap out the entire unit? If so, what difference will I see?

The reason I ask these questions is that I am an engineer, and sometimes the "new" engineer doesnt know what the "old" engineer had in mind. Sometimes the old guy knew what he was doing and the new guy just didnt understand it so he redesigned the thing. Maybe thats what happened here, or maybe they really did fix something. I dont know, but I would like to know and understand.

[bryankwalton]

What is public record from Honda:

In 2001, there was an update to the BCM that helped prevent power demands on the IMA battery during very cold weather from damaging the battery. At this time, they only provide a P/N for a kit that includes both the BCM and MCM. That kit's P/N is 0060-PHM-305.

In 2004, Honda says to replace the BCM if car suffers from P1447 or P1449 (battery module deterioration). All they say is that if the BCM P/N is not 1K100-PHM-A01, then the BCM needs to be replaced.

In May and August of 2006, Honda states that the "BCM allows the battery to overcharge". Fix is to replace the BCM. At this time, the BCM P/N is still the same as that listed in the 2004 notice. At this time, the BCM P/N is still listed as 1K100-PHM-A01.

Cheers,
Bryan

[Insightful Trekker]

As Bryan outlined above its IMA battery management programming.

With only the highlights described for us.

The information is in the _stickied_ warranty extension thread here:

US IMA warranty 10 year extension UPDATED to all 50 states!
viewtopic.php?f=1&t=4796

and in older threads as Bryan described

HTH!

[Hybrid-Battery-Repair]

Originally Posted by JimIsbell

I have a set of old MCM and BCM and I am wondering what the difference is between them and the replacement units that Honda placed in the re called cars.

In my car I have the newer units and on a spare battery pack I have the old units. Will I see any difference if I swap out the entire unit? If so, what difference will I see?

The reason I ask these questions is that I am an engineer, and sometimes the "new" engineer doesnt know what the "old" engineer had in mind. Sometimes the old guy knew what he was doing and the new guy just didnt understand it so he redesigned the thing. Maybe thats what happened here, or maybe they really did fix something. I dont know, but I would like to know and understand.

Jimm

Give me the part numbers and I'll look them up in Alldata. Note that the modules are different for CVT and MT. The later modules appear to restrict the usable band of charge (x% - y%) which will reduce the tress on the batteries (extending their life), but reduce the available power (less available Ah). Since you can rebuild the batteries, you may not want the newest modules.

[Mike Dabrowski 2000]

Jim,
From the performance side, I had the cold weather BCM swap done,back in 2002 and noticed after the change that the battery fan would come on when the car was first started if the pack temperature was below 35 f. The other thing I noticed was that the SOC would get stuck at 3 bars from the bottom, sometimes for several days. I also noticed that the initial (cold battery) regen was a sawtooth rather than a steady DC charge .

After MIMA, which lets me somewhat override the battery management software, I have had no problems with my pack even after 140K on the pack. No recalibrations or other issues even though I am pretty aggressive using assist and regen, and tend to cycle the pack top to bottom on nearly a daily basis.

I have helped install the system on 10 or more Insights of different years, and during my initial test drive after the install, I mostly found that the newer BCM/MCM firmware seems to use assist less aggressively than my car and it tries to keep the SOC in the middle or in the top 1/3.
Of course this is a very limited test, and I expect that people that had the upgrades done on their car will have a better feel for what effect the various upgrades have had.
I see the upgrades as hondas way of stretching out the pack life, hoping to not have to do a pack replacement before the car reaches the end of it's life.
A lot of evidence is pointing to the pack becoming unbalanced due to not being cycled, so in my opinion the honda fixes are not fixing anything, but instead they are trying to mask a problem with their battery management firmware rather than fix it.
Of course this is only my opinion, and is based on a small sampling of different cars.

[Insightful Trekker]

Originally Posted by Mike Dabrowski 2000

After MIMA,... <snip>

I see the upgrades as hondas way of stretching out the pack life, hoping to not have to do a pack replacement before the car reaches the end of it's life.

As a reminder to ALL members MIMA discussion is RESTRICTED to its stickied thread at the top of this forum.

Honda's battery management system is limited. The trick in programming is just how to "tweak" its usage in order to maximize service life. More significant improvements would require an extensive redesign of the IMA system. i.e. active battery balancing at the individual cell level.

[JimIsbell]

Excellent information!!
I may try the old modules since I dont live in cold country. I have installed a 20 position barrier strip on the top, aft side of that battery pack that will allow me direct access to each sub pack. This will allow for dynamic balancing so I think using the larger range of the battery should be a good thing. As you say, Mike, with proper management the larger range can be used without danger to the life of the battery. My current battery has 183,000 miles on it and still, knock on wood, has not thrown an error. Only RECALs and by battery management I have cut them down from once every two days to once every two weeks. I just drove 400 miles yesterday in rolling hills and was able to keep the SOC between 16 and 20 bars with no RECALs the whole trip. After I remove and recondition the thing I am hoping for no RECALs at all.
BTW, Mike, that comment you made about the voltage peak during charging indicating the point of full charge, you were spot on. That is a perfect indicator of the full charge point of the pack. I am using the CBA-II and I can monitor and record the charge curve and at each charging the voltage (which has been moving slowly up during the charge) moves up a little faster just before full charge about 1 volt and then declines about 2 volts. This "spike" is the full charge point. At least that is what happens on my two spare packs, an Insight pack and a Civic pack.

[freezin4]

Originally Posted by Mike Dabrowski 2000

...I am pretty aggressive using assist and regen, and tend to cycle the pack top to bottom on nearly a daily basis.

Mike,

Just curious, do you mean it is good for the health of the battery to run it down to a minimum using assist and then charge it back up throughout each day?

thanks,
-pete

[Hybrid-Battery-Repair]

Originally Posted by freezin4

Mike,

Just curious, do you mean it is good for the health of the battery to run it down to a minimum using assist and then charge it back up throughout each day?

thanks,
-pete

Yes it is good, but it isn't a complete solution. Minimum on the gauge isn't really minimum, it's more like 20%. Maximum on the gauge is about 80%. So you aren't ever getting to the extremes. Mike has recently started overriding the minimum and maximum (he built the equipment to allow it), but you won't be able to get out of that 60% band.

That being said, exercising the battery within the allowable range won't hurt and very likely will help longetivity.

[JimIsbell]

Just using the car will make a big difference. My car had been lightly used in the recent years and the battery was not in great shape but in the 6 months I have owned/used it as a daily driver the battery has steadily improved...also I did a few "SuperCharge"s...charged for 36 hours at 100 to 200 ma.