Road Trip for battery?

Discussion in 'Honda Hybrids' started by Mendel Leisk, Jan 28, 2013.

  1. Harold

    Harold Well-Known Member

    How often is the charger to be used? Probably when the car starts recal again. Mind you it would be nice to start the day on a full pack. H
  2. herm

    herm Well-Known Member

    My WAG, from experience in RC planes and medical equipment you should slow charge (overnight, the so called C/10 rate) old nimh cells about every 10 cycles, or lets say once a week.. no need to discharge them since you do that driving. Dont let old nimh cells sit around unused for a long time.

    A slow charge equalizes all the cells and prevents trouble when you fast charge/discharge as you drive. This is a basic engineering practice with nimh and nicads, I am very surprised Honda did not implement it.
  3. Jess

    Jess Well-Known Member


    So far, from my experience, even though the battery is topped off in the morning, the car still doesn't recognize it as full. It only seems to recall what it was before it was shut down. In my case, I'm usually at 5 bars when I shut her down for the day. The next morning, even though the GC charged it full, the car still thinks it's at 5 bars. Each morning, I've been getting a recharge early on in the commute, but nothing like the recals I was getting before.

  4. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member


    When you say recharge vs recal, what do you mean? My take is any time autostop is locked out (with warmed up engine), and the car shows charging bars at idle, it's recalibrating. Maybe some are milder?

    Have you tried a 12 volt disconnect, to maybe reset the car's memories? Be sure to have your radio code on hand.

    I've got to say I'm a little unsure as to how much the GC can do. Likely it varies depending on how far depleted and/or out-of-balance the pack is. Say for example there's corrosion in the connectors of the cells. There's likely some physical or chemical states that can't be reversed, just held in check.

    Still, even if your pack "dies on the operating table", and you elect to go with a new pack, you have the tool for keeping that new pack in the pink.
    Last edited: Mar 9, 2013
  5. Jess

    Jess Well-Known Member

    Mendel, I say recharge vs recal because the hybrid system is still functional with autostop and assist. Yet while moving it has 2 or 3 bars of regen. The engine isn't working very hard either like it does when there's a recal.

    I haven't disconnected the 12V yet.

    You have a point about not knowing the condition of the pack, but already mine is operating like new again and it only took a week's worth of discharge cycles. If the pack does die, I'll get it replaced and use the GC to keep it conditioned.

    I have to say I feel really good knowing that I can live with having this car for years to come again. For a while there I was in a state of " OMG how much longer am I going to have to drive it like this?" and having Prius envy.

  6. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    To have a Prius, and still have Prius envy, LOL.

    Do you have the latest software? That might be part of the reason for the softer recalibrations. That was my impression, post-update.

    Just for kicks I'm going to register Arrows Automotive as a favourite on our Garmin. ;)

    And then get back to wearing down my (sensible) son, who wants to wait until the warranty expires.
  7. Jess

    Jess Well-Known Member

    LOL yes I do have a Prius but its my wife's daily driver, not mine.

    I do have the latest software update, but knows if that's the reason.

    The pack just had 3 cycles of discharge. It took about 22hrs. I think now I'm going to layoff the daily discharge and see what happens.

  8. Jess

    Jess Well-Known Member

    Friday night I set the GC up with a 3 cycle discharge. It finished around 4 or 5pm on Sat. afternoon. I then let the car sit for the remainder of the day and all Sunday. Monday the SoC read 5 bars. I'm able to drive out of my neighborhood, but within a mile or two I get the dreaded recal. No problems the rest of the commute though. The afternoon commute was much the same way. So, the car is able to be driven further now before a recal occurs. Before, I would no more than turn it on and put it in gear and it would be recallibrating. To me, the GC is working but it's going to take more time. So tonight it's going through a 1 cycle discharge.

    The GC does have a 'soak' feature on it which is supposed to put the pack through multiple deep discharge cycles, but Mike says that it could take a few days. It's supposed to really help rejuvenate the pack though , but I don't have the time yet to commit to it.

  9. flyer351

    flyer351 Member

    I recommend disconnecting the 12V battery after each set of cycling or topping to reset the SOC. Yes, it's a pain in the rear to reset the radio code every time but it's much safer.

    Here was my first experience with the charger.... I ran the battery down to 4 bars SOC on the way home and plugged in with the pack showing ~165 volts. Did a full topping charge and left the next morning with the pack over 179 volts. The next morning on my commute the BCM still expected the SOC to be around 4 bars so the IMA continued charging the full pack. This caused the cells to throw off a ton of heat because they were fully topped off and within about 20 minutes the car set off CEL and IMA lights with a code for IMA overheat.

    After you disconnect the 12V battery, the IMA will initiate a calibration by slowly charging the pack until it no longer accepts a charge. If the pack is mostly full this will happen within 1-3 minutes and the IMA will gracefully acknowledge the new SOC. However, if you don't disconnect the 12V after each charge the IMA will just keep jamming charge into the pack and cause a possible overheat condition.

    The grid charging community is still trying to determine the optimal period between cycling. For my battery, I let it go until the first forced recalibration or every couple months (whichever comes first). I also do a topping charge if the charge sits unused over a week or so.
    Glad to hear your experience has been generally positive so far.
  10. Jess

    Jess Well-Known Member


    Thank you for the feedback! Mendel has been suggesting the power reset, but I had no idea it would help alleviate a more serious situation. I will try it this morning.

    Also thanks for sharing a little of your experience with GC. This is helpful as I feel like I'm playing it by ear.

  11. Harold

    Harold Well-Known Member

    Good feedback flyer351, thanks, H
  12. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    Yeah, I think with you interceding with GC, the car's computer is clueless about what's happened. It's sort of analogous to navigation purely by GPS, and the GC has intervened, shifted you over, but the car's not aware of this.

    Just pulling off the 12 volt negative cable (leave it off for say 30 min's?) is pretty easy.
  13. Jess

    Jess Well-Known Member

    Mendel, I took both cables off for a few seconds and that worked. I guess I could have just taken the negative off?

    It worked very well though. I had the recal for not even half a mile and it went right to 8 bars.

    I was in some really bad stop and crawl traffic in the morning commute for several minutes and the SoC never went past 6 bars.

    The afternoon commute went well too. It started with 6 bars, down to 5 and then down to 4, but it did get back up to 6 again before the end of my commute.

    Ok, so I need to add "disconnecting the 12v" to the morning routine. Now I just need to find my radio code :D

  14. flyer351

    flyer351 Member

    I pull the negative cable for about 30 seconds. Works like a champ.
  15. Jess

    Jess Well-Known Member

    Today is the first day that we have had temps in the 70s and boy did the mileage jump. It's especially sweet because I drove all over Charlotte today with no recals. Almost 50 miles total and at 68mpg. The SoC pretty much sat at 5 bars for most of the day. At times it dropped to 4 and other times went up to 6. I've been giving the pack 1 discharge cycle each night and a power reset in the morning. I'm very happy that I took the leap and bought a GC.

    Harold did you order yours yet?

  16. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    Thanks for the update Jess. I look forward to your updates. ;)
  17. Jess

    Jess Well-Known Member

    Hi, just a little update. This week, I've been using the Run Mode 3 which is delaying when the GC charges the pack. Plugging it in at 10pm, it will not charge for another 4hrs. This way it completes the charging just before I have to leave in the morning. I heard Jason Holder mention this on the What Drives Us Podcast. Pairing this with disconnecting the 12V, has definitely improved the performance of the pack. As a result my mileage efficiency is steadily increasing back to what it used to be.

    Yesterday I had to wait in the dreaded car line to pick up my son from school. I only had 5 bars of charge to begin with. It eventually went into that recharge mode where it will charge the battery, but still allow Autostop to engage and does not have the aggressive idling that comes with a recal. It seems to do this until it gets to 5 bars and then stops.

    Again, I'm very pleased with how the GC has brought my pack back to life. I'm so happy with my car again. For a while there, I was really disappointed with it and was ready to count down the years to getting a replacement. Now I don't care if I never replace it.

  18. ericbecky

    ericbecky Member

    While not all batteries will respond to charging, it is a good place to start since a replacement pack is ~$2,500 installed.

    Some people's packs have just been too far gone by the time they brought it by my shop for rescuing.

    But a regular preventive routine based around how your pack responds to this kind of cycling is a good thing.

    Keep us update with your progress. Some good info to share is how often you are charging and how often recals return.
  19. Jess

    Jess Well-Known Member

    Eric, that's the million dollar question: How often do I need to be using the GC? Honestly though, I live in a bowl within a bowl, within a bowl, starting with my driveway. Meaning, it's one incline after another to deal with before I can really get moving on my commute. Since I typically end the day's commute with 5 bars, I prefer to charge it each night to have a full SoC to work with in the morning. There's nothing flat about Charlotte, unfortunately.

  20. ericbecky

    ericbecky Member

    I guess if you are cycling every day, it is kind of a moot point.

    You will be putting extra cycles on the battery, so that will have some effect. But then again, I do a similar thing with my PHEV Insight I built. You are running the fan for cooling while charging right?

    I would at least get a baseline for the pack as it is right now and put that information in a file somewhere. At the very least, how long it takes to discharge from a set voltage after being charged. That way you can do the same test in the future and compare them.

    I do that when working on other people's old packs so that I have some comparative data. I also use it to check new packs I build for people.

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