Beyond P1447 & P1449

[IamIan]

While on a road trip last weekend I got an IMA light and Check Engine light...

~100 miles later I had Auto Zone pull the codes for free...

I got both P1447 & P1449....... .... then seconds latter

Now I have a 120,000 Miles on a 2000 so It should be covered...

But instead I am going to do what most would say is foolish and use the opportunity for testing... Inquiring minds want to know.... I want to know.

I wanted to do some tests... and I figured some here might also be interested in the results...

First off even with both P1447 & P1449 codes the DC-DC has been running with no problem ... I don't even have a DC-DC enable installed.... I had thought it might be a good motivation to finally do so... but instead I wanted to do some other testing....

After a week and over 200 miles of driving... the 12V is being kept up by the DC-DC... Voltage tests confirm the lower voltage when the car is off and the higher Voltage from the DC-DC when the Engine is running....

So the age old question about what to do when you get the code and are past the warranty ... the answer is... you might not have to do anything.... no modifications... or altering or hacking... no big $ expense ... nothing... just drive the car.

Now as soon as I got the IMA codes I lost Regen, Assist , and Auto-Stop.

Lean Burn is still fully functional.

My MIMA is still fully functional... as is FAS.... although with the Auto-Stop disabled... the Car will not auto-restart after FAS... and MIMA still will give me full assist and or full regen... until the BCM starts limiting the current flow at the upper and lower end of the battery SoC as it always did.

The Car still tracks SoC of the 120 cell NiMH battery... and will let me drain it down or charge it up... but only with the use of MIMA.

The Car still starts in the morning with the IMA and not the 12V starter....

In less than 1 second after starting the car the IMA light comes back on and the car will not give assist or regen on its own... but before that IMA light if I am fast enough it will still start to give assist before the IMA light kicks back on.

Letting the Engine run for 15 minutes at idle... after my 200 miles and 1 week of running with the codes and IMA light... the car is also still doing the background charging needed to keep the 120 cell NiMH battery fully charged... no regenerative braking or assist or auto-stop... but it is still keeping the 144V topped up... still useing the DC-DC to keep the 12V toped up... and still running fine other than the loss of the assist , Regen, and auto-stop.

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I just finished pulling my battery from the car... and am going to be doing some tests on it ....

I will post the results as I finish them... I will be taking this opportunity to first balance by battery pack better than I did a year ago... and then I will do a full series of recondition cycles... Then I will put it all back in the car and clear the codes...

Then the next phase of testing will start as I test to see if the codes come back and if so how fast it takes for them to come back.

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Could this bite me on the ass... of course... but that is what I get for being the curious type...

High voltage is dangerous and doing what I am doing like any work with High voltage can kill you and the car.... do not take it lightly.

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Now let the games begin

[retepsnikrep]

Ian

Very Interesting, so for cars with MIma fitted, IMA battery issues are not an immediate kiss of death then! Keeps us updated.

A couple of people in UK are having IMA battery problems at the moment and one has recently been down the re-balancing route and the IMA light has now come on for her after only a couple of weeks.

[Willie Williford]

The "kiss of death" without any MIMA should still NOT be a concern for most people.
I got my first IMA light app. 25,000 miles ago and have had numerous IMA lights since then, Sometimes I get regen and no assist, it depends where the SOC bars are at when the IMA light comes on. Sometimes I can "reboot" (FAS) the system and get regen and assist back. Idle stop does in fact dissappear.
Within the last two weeks of daily driving I have not had an IMA light but the battery has slowely drained like a recal, and stopped at 2 bars showing, but has charged back up to full on the SOC but has taken a "very long time" to reach "full". Probably five times as long as a geniune "recal" action.
After it reached "full" I reboot the system and everything works as normal and no IMA light has been ignited.!
As long as my 12V battery gauge shows 14.2V while running down the road, (I've even seen 14.2V while under a heavy load as I have the small "Hawker" 13A battery installed.........So.........I'm going to just "KEEP ON TRUCKING."

Willie
1447 =Deteriorated Battery Pack
1449 =Battery Pack Overheated

[Insightful Trekker]

Originally Posted by IamIan

But instead I am going to do what most would say is foolish and use the opportunity for testing...

Who me?

A P1449 would concern me somewhat more than the others. _IF_ it is caused by low internal resistance of the IMA pack (one type of age deteoriation) then its current demand is also going up. Thus _increasing_ the duty cycle of all the IMA components involved.

Increase duty cycle = increased heat = increased thermal stress = increased wear.

In a conventional 12v lead acid / alternator car this type of failure ultimately _causes_ premature alternator failure. Seen it many times. Note for the casual reader: It _is_ the least common type of 12v failure and any one individual is unlikely to expereince it in their driving lifetime.

Yes, the IMA components are MUCH different, are designed to carry MUCH higher current loads and the associated heat, but it _is_ another wear / stress factor and these components are much more expensive then the common 12v alternator.

Just a different factor to consider...

HTH !

[billysan]

Very interesting results, and quite comforting in a way. I think Im on the verge of getting a dead battery and its nice to know that I wont be completely left in the lurch if it does go. I'd love to take the car off the road for a while now but unfortunately job hunting is sort of getting in the way!!

Slightly worried about what you said above Peter, regarding the person who recently rebalanced their pack getting codes already!! I priced up a new pack in Honda yesterday actually and it is just about "gulp" swallowable price wise. A '03-'05 civic IMA pack is £750 cheaper though out of interest!!

[IamIan]

Originally Posted by billysan

Slightly worried about what you said above Peter, regarding the person who recently rebalanced their pack getting codes already!!

There are several unknowns...

We do not yet know 100% of all the reasons why the car gives a IMA code... that is the biggest one.

While it is known that the 120 cells get out of balance... and while fixing the balance issue is not overly complicated... it does only address one issue... no way to know for sure if that was the issue that caused the IMA code... also even if it was the cause... the conditions that lead to the out of balance state are still there so it will happen again.

Also reconditioning is a separate procedure to balancing... and also only addresses one more possible issue...

Also if the balancing and or reconditioning are not done properly you can actually do more harm than good....

Also even with balancing and conditioning... the cells do not experience equal stresses... some are stressed much harder than others... so while balancing and conditioning can help prolong total pack usable life ... they are not 100% fixes... as such... I would not expect to get the same distance again before another IMA code... in my case that is 120,000 miles... It would be nice... but I expect to go less than that before the balance and conditioning issue comes up again....

The best solution is if the car did an active balancing and regular conditioning cycles.... ideally at least as often as you get an oil change... but the hardware and software to do that were not put in the car... and Honda Technicians are not trained or equipped to do it... so it is left to the few people like me... hobbyist types ... at least until more HEVs and PHEVs and EVs are on the road and then there will be more demand for it... but by then I expect them to just build it into the cars electronics to happen in the back ground.

I hope to have finished the first initial discharge cycle numbers tomorrow ... I have 13 of the 20 done now... this will show the current SoC balance issues in the pack... already see some... will report when cycle is finished.

Then after the following Charge then Discharge cycles I will know more about the capacity balance issues that are creeping into the pack.... that will take longer... could be a bit over 60 hours just for the charging cycle of all 20 sub-packs... then another 20 hours at least for the discharge cycle.... and I only get to work on it after I get home from work starting Monday... so it will easily take the rest of the week to finish the first round of cycle tests... although it depends on how things go... I am hoping for at least 3 complete cycles before putting it all back into the car.... but only time will tell if I will be able to get that far before needing it back in the car.

My wife will be driving me to work in the morning and picking me up at the end of the day while I run these tests ... so I don't want to run them too long before getting my car back on the road.

[retepsnikrep]

Originally Posted by billysan

I priced up a new pack in Honda yesterday actually and it is just about "gulp" swallowable price wise. A '03-'05 civic IMA pack is £750 cheaper though out of interest!!

How much are they then?

[IamIan]

on :

http://car-part.com/

they have Insight and Civic battery packs from $300 to $500.

or wait for a deal... or go local...

I got my 2 Civic packs locally for $250 each.

[IamIan]

Here is some of the data from the initial state tests and initial discharge.

A significant SoC balance issue is apparent. The highest initial SoC was 3.04 Ah. The lowest initial SoC was 1.05 Ah. The maximum difference in initial voltages was 0.07 V from the highest to the lowest initial voltages.

Before the pack was pulled from the car the dash SoC display read full.

It is clear to me at least one reason why the Insight did a IMA code was with the balance issue.

There also seemed to be a differences from sub-pack to sub-pack in the dV from initial rest condition to discharge condition even with the same discharge current.... although it is known that the internal resistance of a NiMH battery changes over the SoC state... so I want to confirm those initial dV variations after all sub-packs have been charged up and can be discharged from a full SoC condition for the first full capacity Ah test.... if it turns out that a variation has happened in the internal resistance of the cells or sub-packs , that would mean that the out of balance state will be expected to return after not too long back in the car.... on each regen or assist without balancing in the car a difference in internal resistance will lead quickly to SoC balance issues.

Further testing continues.

http://www.geocities.com/ian_p_george/IanInsightAhi.jpg

http://www.geocities.com/ian_p_george/IanInsightVi.jpg

http://www.geocities.com/ian_p_georg...kpositions.jpg

[retepsnikrep]

Interesting that the lowest capacity and voltage subpacks are in the middle of the entire string just about.

How much current do you think is reqd for active low level balancing, can we push enough down the bcm sensor wires and through the 150R resistors to do the job as that would make a nice plug in balancer much easier. 10-20ma perhaps?