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Hi Guys,
We may be able to use MIMA to erase recals.
A 130K Insight pack that was having regular SOC recals at 6 bars from the bottom , was able to recover full SOC range by using this procedure.
The blog following this procedure,has been started @ http://www.99mpg.com/Projectcars/mimapackwhack/
Early results are very promising.:)
We need any MIMA users that have recal issues to give it a try.

Wow. That is interesting news. When I move to MA, I might have to give you guys my car to experiment on to get me mima in my 03 civic. I'd probably use it mostly to kill assist more than use it for giving me assist.

Veeeeery interesting. I've felt for a while that my pack discharged faster than it used to. I thought it was just due to normal aging of the cells. My pack will recal near the bottom IF the battery temp is fairly high. I've also noticed that I can continue to charge when the SOC reaches the top.

I'll Whack my Pack and let you know! You guys rule!

Hi Chris,
It was great to meet you in person at Hybridfest.
Let us know what your results are.
Mike

Great thread Mike and well said on all the details. No more Recals since Sunday and I am very pleased with my battery packs power output. I can run the power all the way to zero bars and still get assist until the Battery Manager finally shuts me down. I just got my scanner working today and can read battery temp and a host of other sensors. I should be able to report further on battery temp issues if they affect the recals etc. My problems seemed worst when car was hot from being outside on a hot day so I may take it out and run it down on a very hot day.

Trip back from Detroit Airport to Home 135 miles at 55 mph average for the whole trip. Door to door 80.8 mpg. I was very pleased with that.

Hi Ed,
Thats good news. We should be hearing from some other MIMA guys who may have tried the procedure soon .
It will be interesting to see if the recals come back.

Hi Ed!

My recals are definitely heat related as well. So I'll be really interested in any data you collect on that. I gave my pack a bit of a whack the other day. Assist was limited to two LEDs on the MIMA display when I got down to two bars on the SoC meter. It's fun maintaining 40mph with only the joystick. :) Then I began charging it back up, and had it completely charged on my work commute the next morning. I was able to dump probably 2 bars worth of juice in after the SoC reached max. I haven't really had a chance to do any testing to see if battery performance has changed yet. I'll try to give it another whack this weekend and then whomp on it a bit and see if I can trigger a recal. I have an indoor/outdoor thermometer with a probe on the pack right next to the MIMA temp probe, so I'll keep an eye on the temp also. I don't get recals often, but lots of MIMA assist on a hot day will usually do it.

It was a pleasure hanging out with you and Mike at Hybridfest. Glad you decided to join us here at CleanMPG. Now, to lure Jason here also...

While it may not be relevant, there's a patent (http://freepatentsonline.com/6465988.html) on the Prius's
methodology of automatically doing the same game. It's very
infrequent, and sometimes even an aware owner doesn't notice.
.
_H*

Hobbit is correct,
Infrequent should be the guide until we get some more experience with this.

Based on Ed's results, I would say that we probably fixed his recal issue with one whack.
We do not have enough experience with this procedure yet to say for sure We need some MIMA owner that has reliable recals when ever they get to a certain number of bars from the bottom, to try the whack procedure. The way I recommend doing it is to set ABC so that it is charging at 1.5 green MIMA display leds. Move the ABC setpoint to about 50 MPG, and drive normally. I have experienced an interesting behavior when applying regen. I live at the top of a 600 foot hill. I will use full MIMA regen when driving down the hill. If the regen request is maintained, it will stay at full for the duration of the downhill. If I stop the regen half way down, then re apply regen, I will many times only be able to get 2 leds instead of 4.
It seems that the BCM needs a short recovery time before allowing full regen again. By the bottom of the hill, full regen is again available.
The point is that ABC will apply the charge only when above 50 MPG, then turn off completely when the MPG is less. This pulsing relitively gentle charge will allow the BCM to better determine when to cut the MIMA charge. Continue driving this way, and watch the 50% lit green led. when you see it begin to flicker, and get dimmer while your MPG is greater than the 50 setpoint, that is the time to stop.
Then drive normally or with PIMA, and use assist freely while observing the SOC guage.
I am not sure that the second draining and recharging that we did was necessary.
Let us know what your experience was.

It has been really hot this week. On my way home from work Monday, I decided to be a little more free with the MIMA assist and see if I got a recal. When I got down to around 5 bars or so, she started force charging and auto-stop was inhibited. I didn't check normal IMA mode to see if it would give me assist. I still had MIMA assist.

So I guess after 1 pack whack, I still have heat related recals when the SoC gets low. But as you said, there are different kinds of recals. I've never had guaranteed recals at an exact SoC like Randall did with his old pack.

I am thinking that the Recals at a specific SOC are "memory effect" related, with an additional recal point push from high temps.
Thats how Ed's pack was behaving.

Then there is the type where it does a positive recal right before it does a negative one. I believe that several of the MIMA guys have that type.

How would you describe your recals?
Did you whack the pack with forced regen at about 20A until it began to be limited. That way we know that it was brought to the MIMA self limit point which I believe we will find is at about 180V.
A voltmeter on the pack while forced charging would be informative.

It was that type of charging that we did to whack Ed's pack.

By the way, Ed informed me that his pack has started to act weird again, and will likely be reporting about it soon, so the whack does not appear to be a permanent:( fix.

After discharging the battery with lots of assist, I began charging back with the regen I normally do in city driving plus some extra with MIMA. When it reached full, I used MIMA to put more in at the rate of about two LEDs until that was limited. So the recharge was intermittent, with assist interspersed.

I've seen positive recals before, but they are rare and only occur when recovering from a negative recal. They typically happen like this: SoC is low, battery is warm. When SoC gets down to about 4 or 5 bars, SoC drops to zero, begins forced charging and assist and auto stop disabled.

Now that I think about it, what happened the other day I don't think included the SoC dropping to zero, but I still got the forced charging and no auto stop. I think assist was limited, but not completely inhibited. So maybe it wasn't a true recal. I guess I wasn't paying enough attention. ;)

I can usually go below 4 bars without a recal, even down to 2 bars (I try not to let it go beyond that), and I don't always get forced charging or assist/auto stop inhibit. In that case it is almost like the BCM wants to let the SoC go to zero, and presumably force charge it back up. I spend so much time in Mode 1 that it isn't always clear what the BCM is up to.

I wonder if the BCM changes its behavior over time, or "learns". I used to get 4 bars of regen while cruising anytime the SoC was about 3/4 or less. Now, sometimes I do, sometimes I don't. Curious.

You might want to try it again and keep pushing the battery to the bottom even when it starts its forced charging. I think somehow one of the modules gets messed up as to where the batteries bottom is. MIMA gives you the option of ignoring this module until the battery module comes through with the final word.

Mike and I ran the A/C the whole time and forced juice out of the battery until the battery controller took over and allowed no more assist even with MIMA.

I am now able to view all data from the IMA system with my scanner but need an experienced fellow driver to help me log data and watch the system while I drive.

I definitely had a recal this morning. I was down to 6, maybe 7 bars on the SoC. It dropped down to 2 bars, 1 bar at a time. Assist limited in standard IMA mode, no auto stop, forced charging. According to the thermometer I have stuck to the pack, battery temp was only 97.5. Warm, but not that warm. I still managed to land with 81.3mpg. :)

I installed MIMA last week and have been trying to figure out the limits of my battery. When I first installed MIMA I took the car for a drive just leaving IMA on, and just experimenting with the joystick to see what it could do for charge and recharge. Within about 10 miles I ended up draining the battery to about 5 / 20 bars, then got a recal. So I force charged it back to full. Btw, my pack would recal at 5 / 20 bars before MIMA

The next day everything seemed fine, but I still got a recal at 5 / 20 bars again. So I decided to do a pack whack and used assist even after the soc gauge zeroed out, a minute or so later and no more assist. So I force charged it to full, then past until it wouldn't take anymore charge. I estimate I was assisting for 3 bars under SOC, and charging 3 bars over.

Next day I do my normal stop and go drive through out the day, total distance about 10 miles, just using regen and assist at stoplights and stop signs. Battery life looks good, SOC comes down to 15 / 20 bars or so and wham ..... recal to 2 / 20 bars. I get an estimated additional 3 bars assist below empty soc, then nothing. I get home and force charge back to full+ like the day before.

The next two day's it does the exact same thing ..... so on the last day I only recharged to 50% SOC. Now, the weird thing is I seem to have more of a capacity range, and can run it down to 2 bars (haven't ran it empty), and all the way back to 15/20 or so, and haven't recaled once. Today I have actually been more aggressive with assist and regen, so I doubt the recals were heat related, and I seem to have more juice available than when I had the recals at 15/20 bars.

Any ideas on what might be going on? If this behavior stays I'm tempted to not even bother charging to full to avoid the recals I experienced last week. It also seems to debunk the idea of pack whacking, at least with my battery as recals actually got worse.

More interesting feedback.
When we whacked Ed's pack, we still got the recal on the next cycle, but assist was available after the SOC guage dropped to minimum SOC.
It was only the next day that we saw the recals disappear.
The discharge part of the whack in my opinion is not as important as the charge part of the whack, and has the most potential for pack damage, as we do not know if any of the cells are being reversed during the last part of the discharge. The cells can take a slight overcharge, but not a reversal.
Ian has "reconditioned" the silver Insight's pack, and he put ~800 miles on it with only one unusual event. He had a dip in SOC then a positive recal.
We reinstalled his original pack yesterday, which he did the same reconditioning process on, and over the next two weeks with his normal commute, we will see if that helped or changed his battery behavior.
He is now going to recondition the pack from the blue Insight (on the stand), to see how that pack stacks up with the others. His reconditioning involves initial voltage recording, several full discharge and charge cycles for each subpack while measuring and recording capacity, and a final full charge before reassembly.
This should rebalance the pack, and record any initial imbalance so we can get a basic understanding of how the packs age, and if a simple cycle or two can rebalance.
Stay tuned.;)

Today I plan on going out and timing some charges and discharges from full, and from 50%. Essentially I want to quantify what happened yesterday compared to the 15 / 20 recals I had last week.

If you are going to play with the SOC like that, I suggest that you put a battery pack thermometer. Walmart has a nice indoor outdoor for $9 that works fine.
If the pack gets hot fast, while you are Whacking it, stop.
Assist and regen will begin to limit at ~120F. 100-110 is not unusual in summer.


The other useful information would be battery voltage. I have been watching mine for the last two years, and have never seen over 180VDC. I believe Armin's experience is nearly the same. It would be very useful to see where the car stops regen, and where MIMA allows you to go.
My pack does not recal so I can't do the test. You have the full pack potential across your test leads when measuring voltage, so be careful if you try it.;)

Ok, here are my results, and I did see some limits on regen and assist after Attempt #3, and after attempt #4. So I took a break between #3 and #4.

Test conditions:

Each test start from a set point on a country road.
The car was accelerated to 35 mph via ICE, and the mileage was reset.
MIMA was then used to maintain 35 - 40 mph, with my foot off the gas, in 3rd gear

Run #1
11 / 20 Bars of SOC (I started with 11 bars only because that is what is was at from yesterday

Distance traveled before assist was cutoff - 1.4 miles, approx 1 - 2 bars SOC below empty
Time - approx 1.86 minutes of assist average 3 LEDs, max 5 LEDs (spike)

No Recals

Run #2
11 / 20 Bars of SOC

Distance traveled before assist was cutoff - 1.7 miles, approx 1 - 2 bars SOC below empty
Time - approx 2.3 minutes of assist average 3 LEDs, max 5 LEDs (spike)

No recals

Run #3 (same as run #2)
11 / 20 Bars of SOC

Distance traveled before assist was cutoff - 1.7 miles, approx 1 - 2 bars SOC below empty
Time - approx 2.3 minutes of assist average 3 LEDs, max 5 LEDs (spike)

No Recals

Run #4
20 / 20 Bars of SOC (estimated 1 - 2 bars over 20/20) Took over two to three times as long to charge this as 11 bars ( 25 minutes vs 10 minutes at 1 - 2 LEDs).

Distance traveled before assist was cutoff - 1.8 miles, approx 1 - 2 bars SOC below empty
Time - approx 2.4 minutes of assist average 3 LEDs, max 5 LEDs (spike)

Recal at 15 / 20 bars, down to 2 / 20 bars within about a 5 second period.


Summary: It looks like it isn't worth charging my pack to the top or over. It should be noted this pack would recal at about 10 / 20 before, and as low as 8 / 20 on the rare occasion I drive in the mountains. In the next few weeks I will try to determine how high I can charge the pack without getting recals, and also determine if there will be more available charge. I doubt the recals are heat related as the recal at 15 / 20 happed the exact same way as last week, and under that situation it was multiple mini commutes throughout the day adding up to 10 miles.

If you are going to play with the SOC like that, I suggest that you put a battery pack thermometer. Walmart has a nice indoor outdoor for $9 that works fine.
If the pack gets hot fast, while you are Whacking it, stop.
Assist and regen will begin to limit at ~120F. 100-110 is not unusual in summer.


The other useful information would be battery voltage. I have been watching mine for the last two years, and have never seen over 180VDC. I believe Armin's experience is nearly the same. It would be very useful to see where the car stops regen, and where MIMA allows you to go.
My pack does not recal so I can't do the test. You have the full pack potential across your test leads when measuring voltage, so be careful if you try it.;)

To late :) But I will take your advice and get a thermometer in the next few days. However (as far as measuring high voltage) I don't want to run a high voltage connection out or leave the back open, as I don't want my 5 year old son to get fried. If it was just me I would have already done it.

Today I did some normal driving starting at 11 bars like yesterday (not sure why I keep ending up at that magic number. Driving about 10 miles in town the level fluctuated from a low of 5 bars to a high of 11. It seems like if it is below 10 bars I get an automatic light charge of 1 LED (10 amps?), which I don't mind atm. I had to drive via the interstate about 25 miles, and during that time while using some occasional manual assist at 75 mph the battery level crept up to about 15 bars.

However, when I exited the interstate I did some heavy charging and had a 'slow' positive recal from 15 bars to 20 bars over a 15 - 20 sec period exiting the off ramp. However on the way back I took the old highway for 25 miles, keeping speed between 55 - 60, and using occasional assist, and the first 3-4 bars dropped rather fast. After getting back in town I continued using assist / recharge. After about 5 miles in town of doing this lightly I approached 15 / 20 bars and got a negative recal down to 2 bars.

So far it seems that as long as I keep the battery in the lower 15 bars everything works fine. But if I push it any higher the recals start happening. And in the case of force charging above full is a waste of time as it takes 2 - 3 times longer to charge, just to get a guaranteed recal at 15 / 20 bars.

It sounds like your pack is behaving nearly opposite Ed's in MI.
We will be watching for more feedback as you continue to test your system.

If you are going to play with the SOC like that, I suggest that you put a battery pack thermometer. Walmart has a nice indoor outdoor for $9 that works fine.
If the pack gets hot fast, while you are Whacking it, stop.
Assist and regen will begin to limit at ~120F. 100-110 is not unusual in summer.

It's very likely I bought that therometer.

The sticky has insulation so I have to mentally add about 5F to it's reading for the real battery pack temperature - i.e. when it reads 115F - the battery is probably 120F.

After a few days of short distance stop and go driving:

2 mile drive to work .. park .... drive my son to daycare at noon ... 2 miles each way .... back to work, pick up my son after work, 2 miles each way. Stop lights and stop signs the whole way, 10 miles total.

I can safely say I can use manual assist and regen longer starting in the 5 / 20 bar range, going as low as 3 bars and as high as 11ish, than if I fully charge to 20 / 20 or higher due to the guaranteed recal at 15 / 20. And that is using heavy assist (3 - 5 LEDs) at every stoplight and stop sign in 1st gear (most the time), 2nd & 3rd (all the time), and occasional assist in 4th to maintain or gain a few mph. I have even started avoiding down shifting on turns and using electric to maintain. Sometimes I will even start off in 2nd as with assist the engine won't lug.

I do have a background charge going most of the time via IMA, but am still getting 60 - 65mpg, vs the 50 - 55 mpg I used to get on the same route. Sure I could get better if I toned down my aggressiveness, but I only have 30 minutes to get him to daycare and get back to the school.

Prior to MIMA I did get recals, but never above 12 / 20 bars, and usually closer to 8 / 20, so I'm not sure exactly what is going on. The pack seems in it's prime between 3 - 11 bars (maybe even a little higher).

No positive or negative recals since my last post, but the system also hasn't been above 16 / 20 bars on the SOC gauge. Also starting to get the hang of PIMA.