2010 Prius hybrid battery indicator drops quickly on certain bars

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Luke Boyd, Feb 3, 2020.

  1. Luke Boyd

    Luke Boyd New Member

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    I am new and have had no luck searching for an answer, so I figured I would just post it here. I recently bought a 2010 Prius with 100,000 miles on it from Toyota Fort Worth (I didn't buy the extended warranty) . Within the first week I started to notice when the hybrid battery charge indicator gets around half full it suddenly drops down to two bars within about 20-30 seconds. This happens if I'm driving it using just the battery, or if I'm just sitting at a drive thru. It drops the same no matter what. It causes the ICE to turn on and charge the battery up to about 4 bars (a little under half) and then it's fine for a while. It only seems to drop when I've had it charged fairly high and I drive it using just the battery for a bit.

    I had the 12 volt battery in the back replaced and it didn't seem to help. I'm hoping it's not the hybrid battery, but I don't know. I would really appreciate some help troubleshooting because it's driving me CRAZY not knowing if I'll need to drop $1700 on a refurbished battery or if it's just an easy fix. Any help??
     
  2. Priuslover09

    Priuslover09 Member

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  3. bisco

    bisco cookie crumbler

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    welcome!

    sounds normal. what are you getting for mpg's?
     
  4. Grit

    Grit Senior Member

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    Normal? What about the simultaneous use heater, wipers and colder climate weather while ICE is off most of the time?
     
  5. Luke Boyd

    Luke Boyd New Member

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    I'm averaging around 47 mpg!
     
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  6. Luke Boyd

    Luke Boyd New Member

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    Are you saying the use of the heater and the winter time are the cause of it? Like I said, I drops 50% of the charge in under 20 seconds even if I'm sitting still. Seems like it's more than just using the heater in the winter, but I don't know.
     
  7. bisco

    bisco cookie crumbler

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    i think you're good, but at 10 years old, you have to expect degradation and replacement at some point
     
  8. jerrymildred

    jerrymildred Senior Member

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    That's not bad. Depending on conditions, it might be better. Remember that it's not meant to drive very much in EV. Don't force it into EV because it doesn't have the range and you'll have to burn extra gas to charge it back up. The only thing the EV button is really good for is to move the car out of the garage without needing to start the engine and other stuff like that.

    Not all the bars represent the same percentage of charge range. IIRC, it's the 5th & 6th that are a bigger range. The others move a little more quickly. I'd be concerned, though if those below #5 dropped quickly while accelerating,

    That said, the battery is old enough that it could be getting pretty out of balance. Sounds like a good application for a Prolong grid charger. (Prolong Battery Systems. Extending the life of your hybrid. — Hybrid Automotive) There are lots of threads here about it. It's not a guaranteed cure all, but it's extremely effective in the right situations.

    And please disregard the comment on Greenbean batteries. It's a warranty that you'd probably need to use several times. Lots of threads here about that, too. Better options if you do end up needing a replacement HV battery would be new from dealer or a kit from @2k1Toaster. Some hybrid shops also sell salvage batteries that are lightly used, but have been balanced with something like the Prolong system and still have all the original cells. I got one in 2017 for my wife's '07 that was only two years old. Still runs like new.
     
  9. markjosh51

    markjosh51 Junior Member

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    I have a 2014 and it’s normal. If I use the air, heater, or driving the battery bars do go down. I have noticed that they do go down more when I’m in stop and go traffic. I wouldn’t worry unless it doesn’t charge or it takes a long time to charge.
     
  10. fotomoto

    fotomoto Senior Member

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    I suggest you give Matt a call, discuss, and see if he thinks he should take a look at it. He's in the Weatherford area.

    Texas Prius Battery Replacement
     
  11. Mike72903

    Mike72903 Junior Member

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    My 2010 does the same thing. If It goes to 4 bars a few seconds later it will drop down to 2 bars. I used Dr. Prius and a Carista module to check the batteries condition. It reported the battery was in good condition at 66 percent capacity. That's at the high range of good so I stopped worrying about it.
     
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