Sudden SOC Loss?
Active Enthusiast
Joined: Aug 2006
Posts: 146
From: Dallas
Re: Sudden SOC Loss?
I use my A/C sporadically and I notice sudden SOC drops more often when I've used my A/C some after not using A/C for a while. Usually after the A/C use (usually halfway through the afternoon trip home) I get the SOC drop the next morning.
I really think the meter just measures in/out. It probably has a schedule where this many RPM/Speed means this much charge should be going in(regen) or out(ima assist). It uses the schedules to move your SOC indicator and every so often polls the battery for the real state of SOC and thats when you get the whammy (maybe it does a hard poll 5 minutes after every startup?). I'm sure it re-cals the schedule every so often too (like when you use A/C all the time).
Also does anyone notice this happening a lot in rainy weather? I find myself in low SOC/forced regen after slogging through one inch deep water all the time.
I really think the meter just measures in/out. It probably has a schedule where this many RPM/Speed means this much charge should be going in(regen) or out(ima assist). It uses the schedules to move your SOC indicator and every so often polls the battery for the real state of SOC and thats when you get the whammy (maybe it does a hard poll 5 minutes after every startup?). I'm sure it re-cals the schedule every so often too (like when you use A/C all the time).
Also does anyone notice this happening a lot in rainy weather? I find myself in low SOC/forced regen after slogging through one inch deep water all the time.
Enthusiast
Joined: Dec 2005
Posts: 26
From: Chicago-area
Re: Sudden SOC Loss?
This has happened to me, mainly over the last 6-8 months (06 HCH will be 2 years old in Jan 08). Usually in hot weather, but for the first time, today, high temp of 71 degrees. I was just driving around 35 MPH; dropped from 5 bars to 1 within a block. I'm starting to think there's a problem that causes such a quick discharge.
Active Enthusiast
Joined: Aug 2006
Posts: 109
From: San Jose, CA
Re: Sudden SOC Loss?
I can add that I had this happen to me too yesterday driving home from work. The daytime temp was in the 70's (so I don't think its temp related either). I actually see it happen about once every month, and it never happened until after my last service which included a fix for the recall earlier this year.
The only observation I've made is that the longer you go without a forced regen event, the more likely it is to happen. In the last couple of months I changed my driving tactics from do lots of gliding and assist driving to using moderate regen to avoid falling into forced regen mode. I usually can go several weeks without a forced regen, but I never fill up the battery either.
My theory is that perhaps the battery SOC indicator accumulates error over time and eventually some other low level trigger is hit that causes a battery reset and a subsequent quick drop to one bar. Forced Regen or filling up the battery somehow recalibrate the SOC. But that's all just a theory.
Can any of you that have experienced this comment on whether you went for a long time without a forced regen?
-dan
The only observation I've made is that the longer you go without a forced regen event, the more likely it is to happen. In the last couple of months I changed my driving tactics from do lots of gliding and assist driving to using moderate regen to avoid falling into forced regen mode. I usually can go several weeks without a forced regen, but I never fill up the battery either.
My theory is that perhaps the battery SOC indicator accumulates error over time and eventually some other low level trigger is hit that causes a battery reset and a subsequent quick drop to one bar. Forced Regen or filling up the battery somehow recalibrate the SOC. But that's all just a theory.
Can any of you that have experienced this comment on whether you went for a long time without a forced regen?
-dan
Active Enthusiast
Joined: Aug 2007
Posts: 82
From: Ithaca, NY
Re: Sudden SOC Loss?
I've been following this thread for the 2 weeks it has existed, and I've been assuming nobody's referring to this passage in the manual (my bolding):
I didn't bring it up before because I assume everyone knows about that passage, and thus you're all talking about something else. But if not, there it is!
The battery level gauge does not read the battery level directly. It calculates the level by continuously measuring the current flow, voltage, and temperature.
Since the level is not read directly, small sensing errors can, over time, cause the gauge to read higher than the actual battery level. The system will then perform a correction, and the battery level gauge reading will drop suddenly. When this happens, IMA assist and Auto Idle Stop are disabled until the IMA battery is sufficiently recharged by normal driving. This should take only a few minutes.
This correction of the battery level gauge is normal and does not indicate a problem. If the IMA battery develops a problem or becomes deteriorated, the IMA system indicator will come on. If this happens, have the vehicle checked by your dealer as soon as possible.
Since the level is not read directly, small sensing errors can, over time, cause the gauge to read higher than the actual battery level. The system will then perform a correction, and the battery level gauge reading will drop suddenly. When this happens, IMA assist and Auto Idle Stop are disabled until the IMA battery is sufficiently recharged by normal driving. This should take only a few minutes.
This correction of the battery level gauge is normal and does not indicate a problem. If the IMA battery develops a problem or becomes deteriorated, the IMA system indicator will come on. If this happens, have the vehicle checked by your dealer as soon as possible.
Active Enthusiast
Joined: Apr 2007
Posts: 151
From: Palm Bay, FL
Re: Sudden SOC Loss?
I think Soybean is trying to say RTFM! Oh wait... I'm included in that statement as well 
Honestly I wouldn't have thought they would have documented something like that. BTW, is there anything in there about the 'iFE Samba'?
I'm still too lazy to read the manual!
Honestly I wouldn't have thought they would have documented something like that. BTW, is there anything in there about the 'iFE Samba'?
I'm still too lazy to read the manual!
Enthusiast
Joined: Aug 2006
Posts: 48
Re: Sudden SOC Loss?
And then the bottom line is the the 'gauge' on the battery level is no more than a rule of thumb.
The lesson for the driver is to minimize the assist , and watch the heavy A/C use or during traffic. The only time I hit one bar was a hot summer day with road flooding so bad that I crawled for an hour to move 2 miles. Wouldn't have had the A/C on except for that I had a passenger.
The lesson for the driver is to minimize the assist , and watch the heavy A/C use or during traffic. The only time I hit one bar was a hot summer day with road flooding so bad that I crawled for an hour to move 2 miles. Wouldn't have had the A/C on except for that I had a passenger.
Thread Starter
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Ridiculously Active Enthusiast
Joined: Mar 2006
Posts: 655
From: Anaheim Hills, CA
Re: Sudden SOC Loss?
Hmmmm. I missed that, too! Thanks, Soybean, for pointing this out.
Wonder why this seems to only happen in very high temps. Incidentally, it's turned much cooler here in the past week, and my car is performing beautifully again! What started out as one of my lowest tanks ever, ended as a "so-so" 51.4 mpg. Less than my 52 average, but better than I thought it was going to be!
Wonder why this seems to only happen in very high temps. Incidentally, it's turned much cooler here in the past week, and my car is performing beautifully again! What started out as one of my lowest tanks ever, ended as a "so-so" 51.4 mpg. Less than my 52 average, but better than I thought it was going to be!
Enthusiast
Joined: May 2007
Posts: 11
Re: Sudden SOC Loss?
I am beginning to think the computer program outsmarts itself in my 07 Civic. Last week while stopped at a light the battery gauge dropped instantly from 5 to 1 bars and I had no battery assist for the next few minutes. It took maybe five miles before the charge came back to 5 and normal operation. Today I drove about 4 miles and parked for an hour. When I parked, there were 4 bars on the gauge. When I started the car the gauge went up to 6 for only the third time since I bought the car. Halfway home it suddenly dropped to 2, no assist, and it did not want to charge. Drove another mile and the gauge was up to 4 with everything normal.
I went to the dealer on the first occasion since I was headed that way. The service writer of course had never heard of the problem. Told me to drive it until there was something wrong they could identify. The first problem sounds similar to those reporting possibly due to high temperature. The second has me baffled but I intend to drive it until it stops.
I went to the dealer on the first occasion since I was headed that way. The service writer of course had never heard of the problem. Told me to drive it until there was something wrong they could identify. The first problem sounds similar to those reporting possibly due to high temperature. The second has me baffled but I intend to drive it until it stops.
