Battery is being charged on the way: normal or trouble?

Discussion in 'Prius c Technical Discussion' started by DKTVAV, Jun 30, 2013.

  1. DKTVAV

    DKTVAV Active Member

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    I asked the dealer twice at 5,000 and 10,000 miles service they all said no problem. But before it hit 5,000 miles I didn't have the battery meter all the way up before. If I remember correctly it was from a trip downhill from Big Bear at winter camp, my battery meter was full until I hit traffic at 10 & 15 freeways. Since everytime I'm in a hurry and don't care about hypermiling, floor it at any traffic lights, my battery meter is full. So is there a problem with charging or just normal?
     
  2. BJ_EVfan

    BJ_EVfan Member

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    I'm not sure I follow, are you saying the battery consistently appears fully charged? I'm unsure if much can be taken from describing the issue, would have to drive the vehicle to really understand what is going on. The first question I'd ask is if you are getting good fuel economy. If so, its probably just your driving habits that keep it fully charged. Driving harder tends to rely on engine power more, so the harder you drive, the more it'll probably stay full or near full.
     
  3. DKTVAV

    DKTVAV Active Member

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    As I posted everytime I floor the pedal in a hurry I got full bars in just about eight miles trip in city driving. After that I get back to hypermiling so I still have a good fuel economy. I also said it started about time after Big Bear winter camp, it used to be 80% charge at about 6 bars I think.
     
  4. ztanos

    ztanos All-around Geek!

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    So my guess is that you aren't getting great economy. Probably high 40s low 50s? If so, then you are fine. The BCM designed by Toyota won't let the battery get overcharged or undercharged.
     
  5. DKTVAV

    DKTVAV Active Member

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    For life, about 10,500 miles, it's at just a hair above 60. If I didn't have fully charged battery, meaning using more of its power, it would be better MPG. Freeway driving is still OK at about 80% charge around here in LA/OC Southern California.
     
  6. ztanos

    ztanos All-around Geek!

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    The fully charged battery may be helping you out as well. It helps on acceleration even when above the 45mph range.
     
  7. Ashley7

    Ashley7 Active Member

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    From my experience, the battery doesn't really get low at all unless you drive any distance in EV. If you're typically flooring it and the ICE is on most of the time, the your battery isn't going to drain much. (My very, very basic understanding makes me think that, although battery power is being used, it's also being charged while the ICE is running, which would lead it to never appearing very low. Someone else might want to correct/clarify that statement though.) Like ztanos said, though, it's still working for you. If it wasn't, you wouldn't be getting 60 mpg.
     
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  8. DKTVAV

    DKTVAV Active Member

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    I use EV as much as possible but never lower than two bars because the ICE will come on. It used to be from two bars low up to six bars high, but now it's all the way up to eight bars high. I believe I read somewhere here it's not supposed to charge all the way. No one has the same problem?
     
  9. ztanos

    ztanos All-around Geek!

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    You must have a long steep descent at some point on your trip. That "should" be the only way to fill it up.
     
  10. DKTVAV

    DKTVAV Active Member

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    But those trips are in the city here in Orange County CA which I can say no long steep hills surrounded by 405, 605, 22, 5, 55 freeways.
     
  11. RocMills

    RocMills Active Member

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    I had my battery top off to all bars ONCE only, on a level street, coincidentally just seconds after I told my passenger (who was thinking of buying a C) that the battery would "never" be full. DOH
     
  12. Rob.au

    Rob.au Active Member

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    When people talk percentages here, it's typically a reference to State of Charge (SoC) as read on a ScanGauge. The relationship between the dash meter and the ScanGauge is probably not what you'd expect.

    6/8 on the dash battery display equates to about 60% SoC, which appears to me to be the C's natural habitat, the SoC level its computers tend to always work towards.

    8/8 on the dash battery display equates to about 73-74% SoC. This is not that hard to achieve on long descents and if you do get to these levels, you should find the car to be a bit perkier than usual, but most things still remain pretty much normal at these levels.

    The car doesn't want the SoC above 80%. As you'll have long since hit 8/8 on the dash, you won't have any dash indication of hitting 80%, but don't worry, you'll know about it. It's reasonably hard to get to 80% because by this stage the car will be using the electric motor to help the ICE a lot more than it normally would, but if you do get there, the car will take action. What will happen is that the car will start using the electric motor to spin the ICE around unnecessarily, which at the end of the day basically converts the additional energy into heat. You will know this is happening becuase it's just about the noisiest this car ever gets and given it's not associated with power going to the road wheels (not to mention occuring at an arbitary point), it can freak you out the first time. Basically you need a fairly long and significant descent to end up in this situation, but you don't really need to think about it because the car will deal with it.

    I'm very surprised you're managing to keep it above 6/8 on flat road driving, but I'm fairly confident you're not actually hitting 80%. If you had the ability to take it out on a flat freeway and stick the cruise control on, it should get itself back to spot on 60%.
     
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  13. DKTVAV

    DKTVAV Active Member

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    Thanks for your details post!

    I got full 8/8 only when I need to floor the gas pedal all the time: I need to be in a hurry once a day at about 8 miles round trip. It's charging fine at 6/8 when driving on freeway around here at about 16 miles one way.

    As I posted it just happened from after the way home from Big Bear winter camp at a very long steep 7,000" mountain.

    I might need to get a scangauge.
     
  14. Rob.au

    Rob.au Active Member

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    If it's trending back towards 6/8 bars when you drive normally then I wouldn't be concerned.
     
  15. DKTVAV

    DKTVAV Active Member

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    Yes, it does. But I just wonder why it used to not doing that.

    Will it explode when overcharged? It's already so dangerous with just a little li-ion batteries, 18650 to be exact (about the size of a pinky), will explode when overcharged.
     
  16. minkus

    minkus Active Member

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    I've gotten to 7/8 when doing a bunch of short trips (including one this afternoon, when it was about 80 degrees out), because the car insists it isn't warm enough so it runs the ICE every time, and since much of the stops are driving through parking lots, the ICE's warm-up fills the battery faster than I can drain it.

    The only time I've gotten to 8 bars is on a long downhill when I started out with 5-6/8.
     
  17. Rob.au

    Rob.au Active Member

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    The car won't let it go above 80%, so this won't happen. Also I believe it's a NiMH battery in the c.
     
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  18. jonb505

    jonb505 Member

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    Impossible to overcharge the battery, the computer won't let you, not to worry.
    The prius is fairly idiot proof, the worst you could really do to the battery is to run out of gas and keep driving in ev mode until the car won't go anymore. afaik this would require a special boost/recharge from toyota and possibly shorten the long term life of the battery, but there are plenty of warning lights, noises to encourage you not to run out of gas.
    I live in a hilly area and see full bars on my prius v all the time, as others said it just makes the car a little peppier for a few miles until the computer gets the battery down to its happy 60% soc level.
    As for flooring it and seeing not much battery drain i notice too if i push hard going up a hill or drive more aggressively the gas engine will just work harder and actually charge the battery more often than the battery providing assist.
     
  19. Rob.au

    Rob.au Active Member

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    Even in non-agressive driving, my c is often charging the battery when going up hills, particularly if you've settled onto a constant speed. If you're anywhere below 60.0% SoC, it happily takes any opportunity when the ICE is running to put something back into the HV battery.
     
  20. ztanos

    ztanos All-around Geek!

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    Correct. The battery is not LiOn. It's Nihm.
     
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