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Flat 12V battery on 2007 hatchback: do I have the right plan?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by SarcasticFringehead, Mar 5, 2022.

  1. SarcasticFringehead

    SarcasticFringehead Junior Member

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    Hi everyone,

    Excuse me if this question is redundant, but this is a bit of a « straw that broke the camel’s back » situation, and I have sifted through as many threads as I can. I hope it’s OK to reality check my decision with you.

    My new-to-me 2007 model went un-driven for about a month and this is probably the reason the battery went flat. I found thisbout 10 days ago, when I got a jump start from roadside assistance. I drove it around for a couple of hours, but from what’s been said here I guess I should have driven it for 10 hours. Due to a combination of extreme workload and family emergency, I haven’t had a chance to drive it again since, and you guessed it the battery is flat again.

    In this situation I think (correct me if I’m wrong) I have the following choices:

    Get a jumper pack, start it that way, and drive it for 10 hours.
    - I’m in the UK and am having trouble choosing a jumper pack, as I’m not sure of the minimum amperage and capacity, all I know is it has to be 12V.
    - Part of the extreme workload includes job hunting, so I can’t afford to spend over £100 for the wrong device. If anybody has a suggestion for the best and cheapest jumper pack available on Amazon right now, that would really help me, as my brain broke on the 9th or so YouTube video.

    HOWEVER just jump starting it is not going to be enough, right? I need to drive it for 10 actual hours? Supposing I did that, would it be enough? (It’s on road parking where I live, no garage or driveway.) Isn’t it likely I need a new battery?

    If I need a new battery, I’ll have to get a mobile service to come over and do it as I don’t have the capacity to try to learn and attempt it myself. Halfords don’t have a suitable 12V battery in stock, and I rang them up only to be told I need to take the car to the retail shop and/or ring them up for advice… I can’t deal with going round in circles like that.
    - If I have to source the battery myself, which one should I get?
    - If I can get a mobile company to supply AND fit a battery, can anybody recommend a company?
    - If I can get a mobile company to fit but not supply, does that change the recommendation?

    Finally, do I need to do both these things immediately, or just one?
    - To me, it looks like I need to get the battery replaced as I’ve probably killed my existing one.
    - It also looks like it would be a good idea to get a jumper pack, but as I can’t afford to do even one of these two things, I therefore can’t afford to do both at once. Can I put off getting the jumper pack for now, or should I suck it up and accept having to pay for both a battery replacement and a jumper pack?

    If anyone has answers they’d be willing to write in words of one syllable in crayon, I would be mosf grateful. We look for things that make us go.
     
    #1 SarcasticFringehead, Mar 5, 2022
    Last edited: Mar 5, 2022
  2. sam spade 2

    sam spade 2 Senior Member

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    In the US auto parts stores will test batteries for free or really cheap.
    YOU NEED TO GET THE BATTERY TESTED because it very likely is shot and no amount of driving or charging will fix that.

    A new fully charged battery should keep you going for a year or so......if it is driven a few miles once or twice a week.

    If it still will NOT be driven much, a battery tender is a better solution if you have access to power where it is parked.

    The jump pack is kind of like a spare tire.
     
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  3. SFO

    SFO Senior Member

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    Welcome to PriusChat!!

    How old is the current 12v battery?

    During a normal week, how many hours do you plan on driving?

    This affordable option may not work for you : Fitting mobility 12volt AGM battery. | PriusChat

    FYI : you're moderated until you've posted 5 times.
     
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  4. SarcasticFringehead

    SarcasticFringehead Junior Member

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    thanks for getting back.

    From what you say, sam spade 2, I need to replace the battery, and the jumper pack is not a luxury, but it does sound like it can wait.

    AGE AND CONDITION OF BATTERY: The battery I believe is no more than 3 years old. It was inspected before I bought the car, and also last December by the local Toyota dealership. Both said it was OK.

    HOW MUCH I WILL BE DRIVING IT: When I get a full-time job I'll have a clearer idea of how much I'll be driving it in a context of regular routine. I need to drive it to an interview on Wednesday because if I don't drive, I'll have to spend over £100 on public transport to get there. Because of this constraint, I don't have a lot of time to spend selecting and procuring parts.

    BATTERY TENDER: Not sure what a battery tender is, but no, I don't have access to power where it's parked, so it's moot.

    SFO, thank you for the link. The linked post seems to be recommending the Ritar RA12-55, which I can only find listed at a cost of £10,000 and up. I see there's a long list of other brands in there, some of which turn up some semi-related results, but I am concerned about ordering something with the wrong dimensions or otherwise with the wrong spec. Because I'm under extreme time pressure I just can't handle that level of detail right now, unfortunately.

    CONTEXT AND A BIT OF VENTING: Right now I'm working 20-hour days from home, including job hunting, AND dealing with a family emergency. This is why I haven't driven the car very much over the past couple of months: no time, and also the hazard of driving while sleep-deprived. (Yes I will get the full 8 hours before I drive to the job interview on Wednesday.) Without going into too much detail, I have given this Prius my ALL - time, money, attention - since I got it in November, and today it is demanding MORE money and MORE time and MORE attention from me, or it won't let me go to my interview. If I take public transport, it will cost £100 and take three hours each way, so that is not even going to be a stop-gap answer. The fact for me right now is, I need the car to get a job, I need the car to do a job, and I have to get it running by Wednesday while spending the least possible amount of time and money on an adequately sustainable fix.

    I don't think I have the time to select, source, and order the right kind of mobility battery AND get it fitted before Wednesday.

    I have a quote from clickmechanic to supply and fit for just under £140. Is there any reason why I shouldn't just go with that? Some hidden gotcha?
     
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    Try charging it? Not by driving around; with an external charger. Owner’s Manual specs max amps, think it’s around 3 for 2nd gen. Smart chargers are best. CTEK is Rolls Royce but very dependable.

    that said, your current battery may be too depleted, but worth a try.
     
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  6. edthefox5

    edthefox5 Senior Member

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    Your 12 volt battery is done. It was discharged perfectly by the minor keep alive load in the car then held low at zero volt for a long time. Its the perfect way to destroy a 12 volt battery. That just cooks the electrolyte. It will never hold a good charge again.

    The Prius G2 needs to be driven at least 10 miles a day to keep the 12 volt battery alive and more importantly the hybrid battery. Your killing the hybrid battery too letting it sit. 12 volt battery replacement is nothing couple hundred bucks. The hybrid battery is a whole 'nother thing: $$$$.

    If you cant drive the car everyday do yourself a favor and sell it. Or join the thousand's of other folks who killed there battery during Covid.

    You do know the car wont even start without a good hybrid battery right?
     
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  7. SarcasticFringehead

    SarcasticFringehead Junior Member

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    I'm aware that both batteries need to start, but I have no reason at this point to think the hybrid battery is dead yet.
     
  8. edthefox5

    edthefox5 Senior Member

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    I’m saying that letting it sit is very bad for the hybrid battery too. It’s a 15 year old battery. It excites corrosion at the very least. And if it falls below the 210 volt threshold the car won’t start then your screwed and will need a Prolong type high voltage dc charger and cable. Good luck with that.

    2 ways to lose with this car. Covid killed hundreds of G2 battery’s just browse all the threads.
     
  9. edthefox5

    edthefox5 Senior Member

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    If your concerned about mileage do a test bed run.

    Find a nice flat road turn off all accessory’s like lights radio ac get Up to 60 miles an hour and turn on cruise control. Reset consumption meter on the mfd.

    Go a few miles.

    My car before it’s new battery and after being Prolonged charge/discharged for 3 years pulled a 38 mpgs.

    After new NPB install it pulled 60 mpgs.
     
  10. sam spade 2

    sam spade 2 Senior Member

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    Yet another piece of incredibly BAD advice.

    It does NOT have to be driven "every day", just regularly.
    30 miles or more a couple of times a week should be plenty.......IF the 12 V battery is otherwise healthy.
     
  11. sam spade 2

    sam spade 2 Senior Member

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    Given your current situation, I think that is your best first move.
    Just make sure that it is fully charged before they install it.
     
  12. Another

    Another Senior Member

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    Solar maintainers work
    This is a good one
     
  13. SarcasticFringehead

    SarcasticFringehead Junior Member

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    Hello Another, the idea of a solar maintainer sounds interesting - did you mean to link to a specific one?
     
  14. sam spade 2

    sam spade 2 Senior Member

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    Some users here can not see Amazon links that are posted the way that you did it, including me.
    An actual full URL link would be better.
     
  15. Another

    Another Senior Member

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    Search Amazon for
    Battery Tender 5 Watt Solar Battery Charger 12V and Maintainer - Weatherproof Mountable Solar Battery Charger 12V with Windshield and Handlebar Mounts, Ring Terminal Cable, OBD II Connector - 021-1172
     
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  16. Another

    Another Senior Member

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    PC automatically converts URL which I posted to image.
     
  17. sam spade 2

    sam spade 2 Senior Member

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    SIGH.
    This is a real link:

    Edit:
    Son of a bitch.
    This fricking site won't let you post a real link to Amazon.
    Adding a few extra spaces should fix that. They need to be removed for actual use:
    Second edit:
    Screw it. This site and it's worthless owner SUCKS.

    Note: Any 5 watt charger is barely enough to keep up with the "self discharge" current inside a wet cell battery.
    The PEAK output is a bit less than half an amp.

    In some vehicles, it might NOT keep up with any actual parasitic drain that is present.
    On cloudy days, it's output probably will be close to zero.
    Overnight the output will be zero.

    It might fit your needs......but it might not too.
    A periodic check of the battery voltage would still be a good idea.
     
    #17 sam spade 2, Mar 7, 2022
    Last edited: Mar 7, 2022
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  18. Another

    Another Senior Member

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    Solar charger works with mine.
    Not sure what your experience with it is.
     
  19. sam spade 2

    sam spade 2 Senior Member

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    IF you are not checking the battery occasionally you don't really KNOW if it is doing anything useful or not.
    All you know for sure is that you aren't having any battery related problems.
    It might be being "maintained" at a voltage WAY below what it should be.
     
  20. Another

    Another Senior Member

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    All I know is that I don’t have ‘battery related problems’ when using it.
    Works well for me to maintain starting performance when not plugged into the grid.