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Extra miles from battery

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by John in LB, Apr 3, 2017.

  1. John in LB

    John in LB Life is good

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    The other day, I had driven our 2012 plugin to a mall that is 20 miles away. I had depleted the battery pack and was just in Hybrid mode. At the mall, my wife went shopping while I stayed in the car for about an hour. During this time I had the car in accessory mode, listening to radio, fan blowing... anyway, I ended up depleting my 12V battery and the car shutdown (right before shutdown, display said low voltage, shutting down).

    I realized what happened and tried to immediately start the car.... but to no avail !... I could tell the ECU had reset. Before calling AAA to get a jump, I tried waiting a few minutes, turning off all accessories. ... and gave it a last shot... sure enough, it started!

    The ECU, radio presets and other stuff had reset.... However, to my shock, the car had 6 miles on battery power available. ... I couldn't believe it... so I carefully drove the car on battery power and sure enough it lasted the entire 6 miles before the engine started.

    Prior to this event my full estimated range was 9.5 miles... and I was fully aware of all the discussions that these are just estimates and not actual battery performance.... however, there has not been any discussion about rebooting the system when the battery pack is depleted... does this mean that there is a benefit to a periodic reboot? And if so, can we just disconnect the power to a single circuit to achieve this (rather than disconnecting the entire 12V battery)? Has anyone studied this aspect?
     
  2. bisco

    bisco cookie crumbler

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    i hate to say it, but it sounds like something is wrong with your car.
    are you only getting around 10 miles in slow back road ev? if so, maybe something is preventing full use of the battery.
     
  3. jerrymildred

    jerrymildred Senior Member

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    It looks like your car was smart enough to shut itself off before the 12V got too low. And batteries will bounce back up a little bit after the load is removed. Yours apparently had enough juice left to fire up the computer and close the hybrid battery power relay.

    Had you just left it in READY mode, you could have sat there for days with a full tank of gas. The traction battery would have supplied the 12V battery and the engine would have charged the traction battery as needed.

    I would keep an eye on that 12V battery to make sure it wasn't damaged by being run down so far.

    As for the EV range anomaly, I have no idea! (n)
     
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  4. fuzzy1

    fuzzy1 Senior Member

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    Consider also another possibility, that this may be a curse, not a benefit.

    For battery life expectancy reasons, the car normally does not allow you to use the entire battery capacity, but restricts the normal cycling to the center portion of its range. If the reboot erased some information or confused the car about its charge level, the reboot might have allowed it to dip into the bottom levels that are normally set off limits. Good in the short term if you need that portion in an emergency, but bad in the long term for battery life.

    If this is what happened,hopefully it won't take long for the car to get back on track and again cordon off that portion of the battery.
     
    #4 fuzzy1, Apr 3, 2017
    Last edited: Apr 3, 2017
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  5. John in LB

    John in LB Life is good

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    I agree with both of you.

    Regarding the bottom levels of the main battery pack, I think Toyota's algorithm may be too conservative. Besides, if battery is to die, I want that to happen under warranty... at 90K miles now.

    I am going to replicate the experiment at home by first depleting main battery, then disconnecting 12V battery.

    Has anyone figured out which specific fuse will do the trick?
     
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  6. Pluggo

    Pluggo Senior Member

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    While you are looking for that fuse, bear in mind that the Plug-in tries to maintain its state-of-charge between 20% and 80%. So, a "full" charge always stops at 80% and the engine starts at 20%. (Verified with a ScanGuage II in the OBD port).
     
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  7. John in LB

    John in LB Life is good

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    Yes... but 20% and 80% of what? I think the algorithm keeps upping the 0 % value.... resetting ECU resets the 0% value to a default low value.

    As you charge / discharge battery that low value is adjusted in an effort to extend battery life.
     
  8. bisco

    bisco cookie crumbler

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    how does this explain your phenomenon?
     
  9. John in LB

    John in LB Life is good

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    You are accessing a larger portion of the battery capacity and correspondingly stressing the weaker cells during the few days it takes the system to reset the 20% and 80% back to their learned values.
     
  10. bisco

    bisco cookie crumbler

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    well, with all the 12v disconnects and new batteries and such, no one has ever reported this happening before. can you try to replicate it?
     
  11. ppimd

    ppimd Member

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    My 2012 PIP sat for more than 2 weeks and the 12 volt battery was dead after jumping and recharging the EV battery fully next day it read 14 miles, the longest it's read since purchase.
     
  12. bisco

    bisco cookie crumbler

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    when 12v is disconnected, ev estimate goes back to factory default. the real issue here is, are you getting any more actual miles?
     
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  13. ppimd

    ppimd Member

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    Why did the battery die after sitting 2 weeks? Rarely using ICE is my explanation, yours? Also it seems 12 volt battery replacement is $400-600 as Toyota decided to use a battery in the PIP that no one carries and is unusual?
     
  14. bisco

    bisco cookie crumbler

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    no, it was probably drained at some point previously. after that, they lose all their gusto. the inverter charges the battery when you drive ev, otherwise, there would be a lot of pip 12v problems. i have 32,000 ev miles and 18,000 hv miles. i drive only ev for weeks at a time, except for the mandatory 124 mile engine exercise.

    i leave my pip for 5 weeks every winter, still measure 12 .6 volts.

    you can pick up an aftermarket battery for around $150. or a toyota for $200. there are 4 or 5 aftermarket batteries now. installation is easy, if you don't want to, a local mech shouldn't charge more than $75.
     
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  15. ppimd

    ppimd Member

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    Could you provide a link to the online source for a battery, and is the battery the same for all 2012 PIP 's,? Thank you for your help
     
  16. bisco

    bisco cookie crumbler

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    yes, the same battery for all gen 3 including pip. optima is available on line. you can get a duracell at batteries plus bulbs stores, and there are a couple others available at auto parts stores.
     
  17. fuzzy1

    fuzzy1 Senior Member

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    ICE time doesn't matter to the 12V. It is charging all the time that the car is Ready, which includes all EV time.

    My Liftback is the same age as your PiP (I bought it three days before you joined here), and its 12V is showing signs that it is nearing the end of its life. Knowing that, I shut SKS off for a 6 week trip last summer, the 90F temperatures on return probably helped it start. Right now, snowing on dad's farm, it hasn't been moved in ten days and the voltage is low. It will get a lot of on-road charging time tomorrow.
     
  18. ppimd

    ppimd Member

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    I have 27000 miles you?
     
  19. fuzzy1

    fuzzy1 Senior Member

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    Mine has 64k miles, so it has spent vastly more time in 'Ready' mode charging than has yours. Waking it up in non-Ready mode a moment ago to check, my ScanGauge is showing 11.3V. Good thing I brought along a portable jump pack, in case it doesn't want to start tomorrow.
     
  20. priuscatprimeguy

    priuscatprimeguy Senior Member

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    Depends on how fast you're going. The slower you go, the more EV actual miles you get:D
     
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