I bought my Insight a few weeks ago. Just before I bought it the seller did a rebalance with the kit bought in the UK. He said the recals were fairly frequent.
When I picked it up I didn't notice a recal for about 6 days, which the previous owner said was far better.
After about 3 weeks I noticed that the battery was in a charge state alot more than previously. I left it car unused for about a week and then did a rebalance with the kit, and took out the fuse etc etc and all seemed to go OK.
The car seemed alot more peppy with far less charging going on.
However it has just done a negative recal after 2 days!
Is this normal or does this indicate my battery is dying?
Or is it because I had the car left unusued for a week previous?
I supply the kit in the UK. But you need to persevere with it and the car. As long as no codes are being set then just carry on. Use it upto once a week and see how it goes. Also try not pulling the fuse afterwards and see what happens. The charger can't cure all ills but it can help. Your battery is obviously weak and may fail later in which case you will need a recon one or a new one from Honda.
Positive and negative recals are the cars own onboard systems managing the battery. They happen on most insights from time to time. The less frequent they are generally means the better the battery is.
Try to drive the car every day, if one of your cells has bad self discharge even a week left standing will throw it out.
Please add some details to your profile about you and your car. Where did you get it? Where are you in UK etc
I have to grid-charge my battery everytime before I use it. The battery works fine then but it hasn't cured the permanent illness as I only have about 20% of the capacity. If I don't charge it I have no IMA and more problems.
IMO the charger is good to prevent early detoriation if you don't drive it daily. But if some imbalance is there and people continue neglecting it the battery gets worse and so bad that it can't be cured.
Another thing to remember is that there are more than one failure modes to the cells, the grid rebalancer only helps with the balance issues, and only if the pack is discharged fully after the charge.
The topping gets them all charged (assuming you wait a sufficient time for all the cells to get there), but without a discharge, you are not cycling the pack to restore capacity.
From the battery manual:
"The voltage drop occurs because only a portion of the active materials is discharged and
recharged during shallow or partial discharging. The active materials that have not been
cycled change in physical characteristics and increase in resistance. The active materials are
restored to their original state by the subsequent full discharge-charge cycling."
Dried out cells with high internal resistance do not respond to grid charging at all.
A shorted cell or one with high leakage may not even charge during the low current grid charging.
Pulling the fuse causes the car to relearn the SOC of the pack with some unknown internal procedure, but the car will relearn as you drive given your 50 mile commute, and if the IMA reacts differently, it may provide more information about the pack issues?
Good luck
When you pull the fuse for a relearn, the car will charge until it detects that it is full, but there is nothing in that process that will help it learn the point to where it should be empty. I'm not an expert on how Honda set things up but I'd speculate that until it gets a negative recal or a few, the car isn't going to know the capacity range to work in until it bounces off the bottom and the top a few times. ...it could be possible that negative recalibrations might be something to live with, or the IMA system might learn the points and adjust the battery gauge to the capacity your pack provides. If it seems like it's something that you might need to live with, but it seems like it recalibrates negatively at roughly the same point, you might need to consider this and adjust your driving to avoid the recals. Possibly installing the clutch switch mod to prevent the pack from providing assist to the point to where it would recal.
I suppose if this was happening, I would probably give it a good charge with the grid charger(overnight or possibly a little longer) once after that cars gauge showed it was full already to ensure the cells are as full and balanced as possible, and leave the fuse alone and not charge it, let it recal negatively about a dozen times and see if the car is learning its capacity or if it shows it recalibrating at the same point every time. If it doesn't get better than charging it from time to time will likely help it a bit but it sounds like your pack is compromised a bit and it will either be something to live with or something to fix.
When you pull the fuse for a relearn, the car will charge until it detects that it is full, but there is nothing in that process that will help it learn the point to where it should be empty. I'm not an expert on how Honda set things up but I'd speculate that until it gets a negative recal or a few, the car isn't going to know the capacity range to work in until it bounces off the bottom and the top a few times. ...it could be possible that negative recalibrations might be something to live with, or the IMA system might learn the points and adjust the battery gauge to the capacity your pack provides. If it seems like it's something that you might need to live with, but it seems like it recalibrates negatively at roughly the same point, you might need to consider this and adjust your driving to avoid the recals. Possibly installing the clutch switch mod to prevent the pack from providing assist to the point to where it would recal.
I suppose if this was happening, I would probably give it a good charge with the grid charger(overnight or possibly a little longer) once after that cars gauge showed it was full already to ensure the cells are as full and balanced as possible, and leave the fuse alone and not charge it, let it recal negatively about a dozen times and see if the car is learning its capacity or if it shows it recalibrating at the same point every time. If it doesn't get better than charging it from time to time will likely help it a bit but it sounds like your pack is compromised a bit and it will either be something to live with or something to fix.
From what I have seen I would tend to agree. The bms seems to be designed for a specific capacity, but can reset (recal) based on voltage hi / lo. It can also hang at three bars if capacity remains within a limit before throwing a code, as Pete in the UK discovered.
I used to see my pack hang at 3 bars, but since I installed the replacement, that does not seem to happen? It is possibily an indication of a pack with high internal resistance in some subpacks, which was the main issue with my pack?
Remember the first MIMA pack whack, after topping off the pack with regen well beyond the top of the guage, we immediately did a discharge, when we got to the recal point, the guage still did a recal but we had assist available for several minutes after that.
The next day the guage worked normally from top to bottom and the recalibration was gone.
That final discharge is the part of the full cycle that the stock Insights have trouble reaching, especially if they have recalibrations that disable assist.
I suspect that the car uses it's running SOC calculations to determine the guage position, but has a max V and cell drop off detect as a backup?
Still a lot of speculation.
I wonder if letting the car sit with the lights on so the HV battery via the DC/DC is supplying the current would discharge the HV pack a lower point than while driving, but still stop when a cell drops out?
Leaving the lights on is something that Honda must have considered in the design, and would hopefully have put in some safety mechanism to stop the HV pack from reversing a bunch of cells? The BCM is always powered, even when the ignition is off.
Who will be the first to try it.
OK so I filled up this morning and my average MPG was 71.3.
On my trip into work after filling up I got 82MPG. I also had rebalanced the battery last night without pulling the fuse.
This replicates pretty much exactly what happened when I bought the car. It was rebalanced.. I got 80MPG on the first trip.... as the 2-3 weeks went by and it degreaded I got an average of 72MPG.
So there seems to be approx 10MPG hit over the 2-3 weeks from the battery degrading.
I will try to rebalance every Sunday night and see how the next tank goes.
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neg recal after rebalance
