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Frequent jump starts?

Discussion in 'Prime Main Forum (2017-2022)' started by Kedavis, Mar 30, 2021.

  1. Kedavis

    Kedavis Member

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    Does anyone else have to jump-start their Prius Prime almost every day? I’ve posted about this previously & the answer is always “trickle charger.” That is too impractical for me & would be subject to vandalism or theft, as I park in an alley.
    I usually charge my EV battery at a public charging station. The rare times I charge it at home I run an extension cord through my open front door, letting in hot & cold air, insects, lizards, & other pests including thieves. If I installed an outlet, it would cost too much & I’d need permission from my neighbor to run a wire through or past his condo, & he’s reluctant. Plus vandals would tamper with it, steal any equipment, & plug in their own devices (it’s already happened). A solar charger would be stolen. If it was inside my car, they’d smash the window.
    Till now I’ve never had this problem in the 40 years I’ve owned cars For the last 18 years they’ve all been hybrids (1 Civic & 4 Priuses). For the 1st 8 months with my Prime, I drove mainly in EV mode, switching to flex more on the highway. Since the pandemic started, I only use gas mode, & drive on the highway 20 minutes every other day just to keep the 12V starter battery charged. I still have to jump it.
    I’ve had the battery tested twice at the Toyota dealer. He says it’s fine & to drive more. Yesterday I told him to replace the 12V battery & he refused. If this keeps up, I’ll buy one somewhere else.
    I plan to write Toyota about this once I can find an address. My next car will be an EV without a starter battery. If Toyota doesn’t have one when I need it, I’ll look elsewhere, even though I love Pruises.
     
  2. john1701a

    john1701a Prius Guru

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    The 12-volt battery is just like you have been familiar with in the past. If it is deeply
    discharged (drain entirely), it will never be the same. The plates inside build up corrosion, which reduces available contact for the chemicals within. Doing that repeatedly (many jumps), the battery must be replaced. You'll find the new replacement far more reliable.
     
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  3. rdgrimes

    rdgrimes Senior Member

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    Pretty obvious you have a bad battery. Not surprising the dealer can't figure that out.
     
  4. Salamander_King

    Salamander_King Senior Member

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    Yap, assuming you do not have a faulty wire or something draining the battery if you have not replaced the 12v battery yet, then that would be the first thing I would suggest trying. Unless you can convince the dealer to replace it free under warranty, it will be cheaper DIY with a third-party battery. The replacement 12v battery is now readily available in many local auto shops.
     
    #4 Salamander_King, Mar 30, 2021
    Last edited: Mar 30, 2021
  5. EdPalmer42

    EdPalmer42 Member

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    Even if you buy a new battery, it will quickly fail if you don't keep it charged. 20 minutes every other day doesn't appear to be enough time to keep it charged. So you're still back to the trickle charger. You should consider buying a battery monitor that installs in the car and continuously monitors the battery voltage. There are various ones around. I have a BM2 monitor that records the battery voltage and then transfers the data to your phone.

    I'm not sure if you're thinking that using gas mode helps keep the battery charged - it doesn't. The 12V battery is charged from the traction battery through the inverter/converter assembly so as long as the car is in Ready mode, the battery is being charged.

    Something else you should do is check the water level in the battery. I use a large coin to unscrew the caps. They're quite tight so go slowly and only use distilled water.

    AFAIK, many (most?, all?) hybrids and pure electric cars still have a 12V battery because most of the subsystems are still 12V i.e. lights, motors, electronics, etc. It could be quite difficult to avoid them. Add in the generally higher parasitic load that all modern cars have and life is tough for 12V car batteries. The pandemic just makes things worse by reducing the amount of driving done today.

    The only other suggestion I can make is to move to a better neighbourhood so that you can safely plug in a trickle charger. ;) Yeah, I know, but I couldn't resist!
     
  6. john1701a

    john1701a Prius Guru

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    Huh? My wife doesn't drive her Prime that often and usually goes several weeks between the engine running. It's been fine that way. No big deal. How could it not be a bad 12-volt?
     
    #6 john1701a, Mar 30, 2021
    Last edited: Mar 30, 2021
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  7. Trollbait

    Trollbait It's a D&D thing

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    I wouldn't have thought a solar charger worth the bother of smashing a window for, but then most used inside car use the 12v outlet, which will be turned off on a parked Prime.

    The standby loads on cars' batteries have been steadily increasing over the years. The cut back in many people's driving has made that a bigger strain on the battery. You might able to turn some of these off, or put into an energy saver mode. Older Prii had a off switch for the SKS, which was a big drain at the time while the car was parked for extended periods.

    If the fluid level of the battery has dropped, topping it off with pure water will extend its life; I've done so in the past. It does mean working around exposed strong acid, so take precautions. But your battery has already needed multiple jump starts, and deep discharging is what shortens lead-acid battery life.

    The 20 minutes driving rule of thumb for recharging a starter battery of the energy it had used to start the car. If the charge was low to begin with, it will remain low. A longer time on is needed for low batteries. Hybrids don't drain as much for start up, but they might have a smaller battery. As noted, the engine doesn't need to be running on a PHEV. Just be in Ready mode for driving.

    With a full traction battery, you could top off the 12v without using gas. Just put the car in Ready mode once a day to once week for a half hour to a couple of hours. A basic multimeter will make determining the specifics possible, if you don't want to overdo having the car on for driving. Charging up a dead battery should possible this way.

    Another option, and one good for non-plug ins, is to get a battery charger; an automatic one can be found for under $50. Just hook up it up once in awhile; once a week should be enough. It means running extension cords, but not 24/7 like with a battery maintainer.

    BEVs have starter batteries for the same reason as hybrids do; boot up the computer, and reconnect the traction pack. Most of what is currently available would be in the same boat as your Prime. Some, like Teslas, will automatically reconnect the traction pack to charger up the starter when it needs it. Tesla is also moving to Li-ion starter batteries. The Ioniq and Niro already have one in the hybrids. If it gets too low to start the car, push a button, and the traction pack charges it back up. I would guess it is the same for the PHEVs, but the BEVs still use a lead-acid battery.
     
  8. Salamander_King

    Salamander_King Senior Member

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    Sorry, this is off-topic... Our daughter living in a city and parking her car on street had her car broken in last year. The only thing stolen was sanitizing wipes. You would be surprised what thieves are after in your car.;)
     
    #8 Salamander_King, Mar 30, 2021
    Last edited: Mar 30, 2021
  9. Trollbait

    Trollbait It's a D&D thing

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    Shouldn't the bigger concern be the cat here.
     
  10. Salamander_King

    Salamander_King Senior Member

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    Yeah, her car is Gen2 Prius. So it is always a concern. But, the CAT thieves are pros, whereas sanitizing napkin snatcher probably was an amateur. lol
     
  11. EdPalmer42

    EdPalmer42 Member

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    It certainly could be a bad battery, but the dealer has tested the battery twice and said it's good but needs charging. Granted that some dealers are idiots, but how stupid do you have to be to screw up a battery test? Ooooh, famous last words! If you want to schedule a battery replacement every couple of years, that's not an unreasonable thing to do and then you just don't have to worry about it.

    Regarding your wife's(?) car, you said she goes weeks between running the engine. Remember that, as described above, running the engine has nothing to do with charging the 12V battery. As long as the car is being driven, the 12V battery is being charged.
     
  12. Mendel Leisk

    Mendel Leisk Senior Member

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    With your situation, no easily accessible 120 volt source, and risk of vandalism/theft, maybe a battery kill-switch?

    This goes in series between battery neg terminal and ground, isolates the battery, eliminates the background draw on the battery which runs it down fast. It’s inconvenient, probably wipes some memory, but effective.
     
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  13. Trollbait

    Trollbait It's a D&D thing

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    Wouldn't that be like putting a new battery everytime, and requiring those procedures followed? Losing radio presets may not be a big deal, but installing a new battery calls for resetting the TPMS. Phone settings might also be lost.

    It's a good solution if it didn't introduce too much hassle.
     
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  14. dbstoo

    dbstoo Senior Member

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    If the battery tests good, I.E. proper voltage levels under charge and after resting as well as under load....

    Then the most likely problem is a load that you are not aware of. This can be many things, including a defective light switch in the glove box or a dongle plugged into the ODB2 connector. As I mentally walk though the car, I remember that the visors have a light switch in them for the visor mirrors. There is a light in the luggage area that may be "on" even if the light is obscured from view. It's sort of like having the light in the refrigerator staying on when the door is closed. I once had a car with a light under the hood. When the switch came loose the light stayed on 24/7. It drained the battery in just a couple days.

    The dealer should be able to look for such things. an amateur with a volt meter can also find those little drains on the battery. There are youtube videos on how to look for it.
     
  15. Mendel Leisk

    Mendel Leisk Senior Member

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    I’m not sure about the loss of TPMS. That’d be the set pressure right? I’ve had ours disconnected infrequently, for brake work, never reset TPMS. But could be fool’s paradise, not sure.

    for sure radio presets and trip meters ARE lost. And the engine does an odd rev up during the next few start ups.
     
  16. rjparker

    rjparker Tu Humilde Sirviente

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    A free meter from Harbor Freight and a couple of lightweight jumpers can measure the parasitic draw which should be 30 ma or less.

    Prius v series ammeter setup.jpeg
     
  17. FuelMiser

    FuelMiser Senior Member

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    I'm afraid you'll be sadly disappointed finding a BEV without a 12V "starter" battery. Just like Prius Prime, BEVs use a 12V battery for accessories and booting up the traction battery. As for your "jump starting" issue, why not get a portable jump starting battery pack you can carry out to your car to get it going? You seem to have exhausted all other means of keeping the installed 12V topped up, so I'd say this is your best bet.
     
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  18. BiomedO1

    BiomedO1 Senior Member

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    This sounds like a bad battery to me; but you should do a parasitic draw test - as RJ stated. The dealer may be telling you the battery is good; based on those crappy hand-held digital battery tester. Get it load tested with one of those large load resistors; I'll bet you it'll fail.
    If it doesn't pass the parasitic load test; I'd go after the alarm system. You mentioned a bad neighborhood; aftermarket alarms tend to draw a lot of current; especially when they are not installed properly or going off all the time. Most alarms tells you when it got triggered, but they usually don't tell you how many times it's been triggered - that alarm horn draws a lot of current and drains a battery quickly.

    I'm assuming the car hasn't been in any accidents and no major repairs has been done to it.
     
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  19. sam spade 2

    sam spade 2 Senior Member

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    No, no, NO.....NOT a "trickle charger".
    A smart, automatic tender type charger......maybe. There is a difference.

    If you get a battery tender with a capacity of 4 amps or so, it likely would keep the battery topped up with only a few hours a week of use.
    Unless there is something else going on here.

    You should contact Toyota NOW.
    You likely are out of warranty and should expect to pay for a new battery but the dealership refusing to sell you one is ridiculous.
    Find another dealer ??

    And finally another option that is often overlooked:
    Get a "jumper pack". Fully charge it and then connect it to your battery for a few hours.
    That should bring your battery up if it is down a bit.
     
  20. dbstoo

    dbstoo Senior Member

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    I read somewhere (don't remember where) that the 12 volt battery is also required in order to power the emergency flashers, headlights and and brake lights in the event that the "engine dies". Of course in the case of the hybrid it would be when the HV battery system breaks.