Just had my imiev in the dealers' shop to have my sup. restraint fixed, and my traction battery analyzed. They did something that drastically improved my range. Before I took it in, my range remaining guess-meter showed 50 miles, with 16 bars. When I got car back I noticed the drive home seemed to take less "bars". I drove my typical routes for the next few days and my range remaining shows 65 to 75 miles after full charge and it definitely takes less bars to do the same routes! My car has about 42,000 miles and I drive mountains and city usually less than 60 mph.
dealer improves battery!
- Thread starter boscoe
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PV1
Well-known member
They may have done a full calibration. How long did they have the car?
Through EVBatMon, I've watched the capacity of Bear's pack drop at a rate of .1 Ah per 1-2 weeks. Then I charged from 2 bars to full and I suddenly gained 2 Ah of capacity. Have you completed a charge from 2 bars or less to full without interruption lately?
Through EVBatMon, I've watched the capacity of Bear's pack drop at a rate of .1 Ah per 1-2 weeks. Then I charged from 2 bars to full and I suddenly gained 2 Ah of capacity. Have you completed a charge from 2 bars or less to full without interruption lately?
phb10186
Well-known member
Just wondering if disconnecting the 12V battery helps at all by clearing out driving data, and could be a factor? It does this in the Insight, and often re-baselines the predictive MPG and range.
So my stoke on a vastly improved battery is diminished. While driving yesterday, I depleted my battery down to 2 bars with about 10 miles range remaining and the car went into turtle mode. Luckily I was just cresting a mountain and I could get some energy back coming down hill, enough so I could make it home. Apparently the battery/ computer/car has been reprogramed/ updated to go to turtle about 10 miles earlier. Before I wouldn't get to turtle till 1 mile remaining and zero bars. So my thoughts of my range improving 20 miles is actually more like only 10 miles.
mdbuilder
Well-known member
The earlier turtle may have more to do with climbing the mountain than anything else. Climbing takes more power and you were near the end of charge so the higher current drops the voltage more.
PV1
Well-known member
I've noticed the charge and RR being a little off after the dealer worked on the car where they had to reboot the car. It seems like rebooting wipes out charge history. Three times I've had the same RR value after picking the car up.
To really know what's going on with your battery, you need the CANION app and the recommended OBDII port connector. Then you can see the charge/discharge levels of each cell in the battery along with battery temps. A proper balancing of the pack is critical. If the CANION shows levels out of balance after a full charge, then you need to do full charges until they do. It is also advisable to monitor cell voltages at a complete discharge (down to turtle) and look for weak cells. The amount of usable energy in the pack to drive the car is determined by the weakest cell--the first to reach cutoff voltage. The battery management system (BMS) hides the degradation of the pack from the user. With CANION you can see (as the pack ages) the BMS allows the pack to use more and more of the pack capacity by allowing the weaker cells to discharge further. Although there is not much capacity in the lower voltage regions of the cell, it is enough to allow the stronger cells to keep the I-MiEV traveling nearly as far as it did when new. If the battery is disconnected, controllers reset etc., there is still embedded things in the BMS that cannot be changed. Figured into the algorithms that run the BMS are things like the date the pack was assembled. Also, there is a complete history of charge and discharge cycles. This algorithm is part of a pre-determined curve for the battery life of the pack and is one of the things that allows for a change over time of the lower limit the cell voltages can reach before shutdown. Owners of older I-MiEV's should see a fairly rapid loss of range after the first cell in the pack reaches the absolute lower limit of cell voltage allowed by the BMS.
That being said, to keep the pack healthy and delay the onset of real range anxiety, there are a few things you can do--all of which have been discussed on this forum before. First, drive and enjoy the car but be aware of the limitations of the battery. Hot cell temperatures and a high charge level are about the worst thing you can do to a Li-Ion battery. Next, is having a pack out of balance. If you don't need all of the range of the vehicle, don't charge it fully. If you need full range, try to finish the charge just before you need to drive. This will limit the time the pack "soaks" at a high charge level. Try to recharge at night when it is cooler and after the cells have had a chance to cool off on their own. This will minimize the heat buildup in the pack. If it is very hot out, a little box fan placed in front of the car will help cool the charging system and to a limited extent, the pack itself. There is a radiator under the hood that cools the invertor, motor and charger by liquid cooling. For some reason (unless very hot) the radiator fan doesn't operate during charging. The components of the charging system run much cooler with airflow through the radiator and the pack enclosure gets some external airflow which in a small way will help. To keep the pack in balance, it is very important to let the balancer system work from time to time. Again, let it complete the charging and balancing just before you need to drive, and with a CANION as a guide, you can determine when the pack needs balancing. Going to partial charges, or shutting off the charge cycle before the vehicle does it on its own (even if all bars are showing) does not let the balancer do it's job. This is most likely the next most important thing beyond temperature and charge level control to keep a battery healthy. If you have a Chademo or cold weather package equipped car, do the A/C into the pack mod by removing the servo motor connector and the motor itself from the floor vent and place the damper into the position that directs air into the pack. This works in summer to cool the pack and in the winter provides heat to the pack. Heat kills these batteries. They are happiest being stored at 77 degrees. The calendar life degradation of the battery cell really picks up above that temperature. In summer, try to park if possible in the shade. Not so much for the interior temps of the car but so the area on which you park the car (like asphalt parking lots) isn't a hot as a frying pan and radiating heat into the pack located inches above it while you park. If you are not going to drive the I-MiEV for several weeks, try to park where the temps will be 77 or lower if possible, have the car at 50% or less state of charge and put a battery tender on the 12v battery to allow it to power the various "always on" systems in the car without killing the battery. If you have no way of powering the battery tender, you could use a small solar panel to do the job or just disconnect the 12 volt battery.
It's a lot of stuff, but a few small things will make the time the range starts to fall off (and it will) happens months or years later then if you didn't take these few steps. There are other issues with the I-MiEV that need to be watched if you want to drive it until the end of time but the battery health should be the number one priority. So, as to the "dealer improves battery!" topic, there is nothing that the dealer can do that you cannot do by just following some simple things. Beyond bringing a pack into balance, you cannot reverse any other things that may have shortened the life of a cell. However, you can limit further damage. Happy motoring!
That being said, to keep the pack healthy and delay the onset of real range anxiety, there are a few things you can do--all of which have been discussed on this forum before. First, drive and enjoy the car but be aware of the limitations of the battery. Hot cell temperatures and a high charge level are about the worst thing you can do to a Li-Ion battery. Next, is having a pack out of balance. If you don't need all of the range of the vehicle, don't charge it fully. If you need full range, try to finish the charge just before you need to drive. This will limit the time the pack "soaks" at a high charge level. Try to recharge at night when it is cooler and after the cells have had a chance to cool off on their own. This will minimize the heat buildup in the pack. If it is very hot out, a little box fan placed in front of the car will help cool the charging system and to a limited extent, the pack itself. There is a radiator under the hood that cools the invertor, motor and charger by liquid cooling. For some reason (unless very hot) the radiator fan doesn't operate during charging. The components of the charging system run much cooler with airflow through the radiator and the pack enclosure gets some external airflow which in a small way will help. To keep the pack in balance, it is very important to let the balancer system work from time to time. Again, let it complete the charging and balancing just before you need to drive, and with a CANION as a guide, you can determine when the pack needs balancing. Going to partial charges, or shutting off the charge cycle before the vehicle does it on its own (even if all bars are showing) does not let the balancer do it's job. This is most likely the next most important thing beyond temperature and charge level control to keep a battery healthy. If you have a Chademo or cold weather package equipped car, do the A/C into the pack mod by removing the servo motor connector and the motor itself from the floor vent and place the damper into the position that directs air into the pack. This works in summer to cool the pack and in the winter provides heat to the pack. Heat kills these batteries. They are happiest being stored at 77 degrees. The calendar life degradation of the battery cell really picks up above that temperature. In summer, try to park if possible in the shade. Not so much for the interior temps of the car but so the area on which you park the car (like asphalt parking lots) isn't a hot as a frying pan and radiating heat into the pack located inches above it while you park. If you are not going to drive the I-MiEV for several weeks, try to park where the temps will be 77 or lower if possible, have the car at 50% or less state of charge and put a battery tender on the 12v battery to allow it to power the various "always on" systems in the car without killing the battery. If you have no way of powering the battery tender, you could use a small solar panel to do the job or just disconnect the 12 volt battery.
It's a lot of stuff, but a few small things will make the time the range starts to fall off (and it will) happens months or years later then if you didn't take these few steps. There are other issues with the I-MiEV that need to be watched if you want to drive it until the end of time but the battery health should be the number one priority. So, as to the "dealer improves battery!" topic, there is nothing that the dealer can do that you cannot do by just following some simple things. Beyond bringing a pack into balance, you cannot reverse any other things that may have shortened the life of a cell. However, you can limit further damage. Happy motoring!
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