1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Jump Start Prius w/ cheap batteries?

Discussion in 'Knowledge Base Articles Discussion' started by CCC712, Aug 8, 2008.

  1. CCC712

    CCC712 New Member

    Joined:
    Jul 31, 2008
    22
    0
    0
    Location:
    Nashville, TN
    Vehicle:
    2008 Prius
    I read somewhere that because the Prius uses far less energy to start than a traditional gas car you could actually use two 6V camping lantern type batteries to jump start a prius. I was thinking of keeping some handy in the car with jumper cables as a cheap emergency kit. Has anyone jump started their Prius like this before? If so, instructions would be greatly appreciated!!
     
  2. taggart

    taggart Member

    Joined:
    Apr 4, 2008
    249
    14
    0
    Location:
    Texas
    Vehicle:
    2008 Prius
    I don't know about that, but if the "Amp" commercial is true, you can jump start any car using a fat guy's nipples.
     
  3. tochatihu

    tochatihu Senior Member

    Joined:
    Apr 10, 2004
    9,156
    3,562
    0
    Location:
    Kunming Yunnan China
    Vehicle:
    2001 Prius
    In my experience (2001 Prius) 2 of those lantern batteries would not do the jump start. A 7 amp hour gel cell (the typical brick size) was adequate though, and smaller ones might be as well.

    As always, exercise extreme caution to connect the polarity correctly with any external 12 volt battery. Expensive repairs await those who get it backwards.
     
  4. kohnen

    kohnen Grumpy, Cranky Senior Member

    Joined:
    Jun 13, 2007
    317
    58
    0
    Location:
    Fullerton CA
    Vehicle:
    2007 Prius
    So, just throw a set of jumper cables along with a fat guy into the trunk. :rolleyes:
     
  5. rigormortis

    rigormortis Active Member

    Joined:
    Feb 14, 2007
    1,340
    26
    0
    Location:
    san jose, ca
    Vehicle:
    2007 Prius
    ive also heard about the 6v latern batteries being able to jump start a prius and i also heard about using 10 aa batteries.

    please run your battery low so we can finally put this to the test. we need more researchers on priuschat.

    it all supposevely involves putting the batteries in series...

    run ground to negative post, postivive on battery one to negative post on battery two and then positive post on battery 2 to the jump start terminal, then start.
    well run for your life, then start !

    negative post -------(-) (+)---(-) (+)----------prius jump

    as a safety precaution do not actually touch the positive to the jump point, until someone is ready to push start.

    another thing you can try that is probably safer is to keep your two 6v latern batteries connected to the jump points for a time to let it charge the main 12 v battery, and then disconnect them when you start

    if the latern batteries start to even feel the slightest bit warm disconnect immediately
     
  6. miscrms

    miscrms Plug Envious Member

    Joined:
    Aug 21, 2007
    2,076
    523
    5
    Location:
    Phoenix, AZ
    Vehicle:
    2005 Prius
    I think the consensus last time was maybe. It takes very little power to boot up the computers and connect the HV sytem, at which point you are ready to go. The problem occurs if one of any number of 12V pumps or do-hickies decides to activate during this process. They can draw a number of Amps, and will kill and or crash the voltage of a little battery preventing a proper startup. This occurance is made more likely by the fact that you have to press the brake pedal before starting.

    Rob
     
  7. eddie27970

    eddie27970 Junior Member

    Joined:
    Mar 20, 2005
    56
    6
    0
    Location:
    Eastern North Carolina
    Vehicle:
    2005 Prius
    Model:
    Four
    Hold up guys! First off, "if" the battery in the trunk hole is "dead," then what ever you hook up, supposedly using the terminals under the hood, in the black box, where it says to hook jumper cables, will not work because you have a dead battery in the system that will pull all the power out of what you hook up. You would need to disconnect the wires going to the "dead" battery. Then, I suppose, form what I have read, you are simply energizing a few relays with the 12-volts, and yes, it is like turning on few 12-light bulbs, not much current at all.

    My wife's 04 prius hatchback does not like to fully close. I've dealt with jump starting many, many times. First time, I was not at home. Wife called road side service. They sent deputy sheriff to house, and then they crawled into back hatch area (hatch will not open on dead battery) and opened hole to put jumpers on battery in back. When I got home, thought there had to be a better way!

    Looked under hood and opened black box. Instructions right there. Took paint stick and wrote on black box. Open here for jump starting. ha ha

    I'd say, yes, only turning on a few relays to start a Prius with 12-volts. But if dead battery in back draining your input, it will not work. Disconnect dead battery.
     
  8. rigormortis

    rigormortis Active Member

    Joined:
    Feb 14, 2007
    1,340
    26
    0
    Location:
    san jose, ca
    Vehicle:
    2007 Prius
    we need someone to do the experiment !!!

    well do not try this at home????

    i think the chances are that the 12v is going to try and charge those small batteries
    instead of the other way around, and it is probably going to cause them to overheat and explode, but we need to see if this works or put a nail in it

    time for the mythbusters
     
  9. eddie27970

    eddie27970 Junior Member

    Joined:
    Mar 20, 2005
    56
    6
    0
    Location:
    Eastern North Carolina
    Vehicle:
    2005 Prius
    Model:
    Four
    Already had to install new gell-cell battery in 04 prius (wife's), and have same CD Toyota mechanics use when working on these things.

    What happened was, when leaving door open 30-minutes or so, battery so dead it would not start. Looked on CD for "alternator" HA, Tain't one. That's where I found out about the many "relays" the 12-volts turn on. After wards, there is a charging inverter, just for the 12-volt system, coming off the High Voltage batteries, making exactly 13.8vdc, no matter if gas motor running or not. This, in affect, is just like traditional alternator, running headlights, radio, ac fan, radiator fan, and all the other 12-volt goodies.

    To initiate this inverter, to get the 12-volts coming from the High Voltage batteries, is just a matter of energizing those relays. So, I am thinking, so long as a "dead" 12-volt battery not killing the alternative 12-volts hooked up to the terminals under the hood, then car will start up. Don't know if dry cell type batteries will explode, or not, when hit with large amounts of 13.8vdc after starting? Those batteries are not meant to accept a charge

    By the way, my 05 prius has a bigger gell-cell in the hole in the back. The 04 battery is smaller, but the hole iw beg enough for the bigger battery. It looked like between 04 and 05 Toyota decided to go with a bigger battery. And I bought mine from Advance Auto. Had to rearrange the positive realy and leave off original starp, use alternative bunjee cord, and it fit right in. Saving couple hundred over Toyota's battery and installation.

    Oh yea, "gell-cell" versus traditional lead acid, because battery actually located "inside" car, and acid fumes from lead acid battery would be inside the breathing area of car. No exhaust system like High voltage batteries.
     
  10. avocadoman1

    avocadoman1 Member

    Joined:
    Jun 23, 2008
    217
    36
    0
    Location:
    Fallbrook-CA
    Vehicle:
    2022 Prius
    Model:
    Limited
    now i'm confused...
    - yesterday i left the ACC (fan & radio) on while away from vehicle for an hour (in a parking lot).
    - when i returned, the battery was low enough that the vehicle refused to go to the READY position.
    - i crawled thru the back to manually open the rear hatch (can be done as seen in owners manual).
    - then attached jumper cables from another vehicle's 12v battery (while his car ran).
    - we then waited (and waited) almost 45min while the battery was being trickle charged.
    - finally, there was enough to fire up the vehicle.

    is this the only way to get the car up and running when you have a dead battery???
     
  11. miscrms

    miscrms Plug Envious Member

    Joined:
    Aug 21, 2007
    2,076
    523
    5
    Location:
    Phoenix, AZ
    Vehicle:
    2005 Prius
    There's a 12V jump port under the hood :D

    Your cables or connection may have been poor? Any vehicle running or not should provide more than enough current to boot the computers, get to ready and connect the HV to start charging the 12V battery. I would think only a damaged aux battery with a shorted cell or something could drag the other cars voltage down enough to still not be able to get the Prius to Ready mode. After 45 minutes in that condition, a battery with a shorted cell probably would have just exploded, not got better.

    Rob
     
  12. avocadoman1

    avocadoman1 Member

    Joined:
    Jun 23, 2008
    217
    36
    0
    Location:
    Fallbrook-CA
    Vehicle:
    2022 Prius
    Model:
    Limited
    that's what i thought.
    the battery is fine, prob the cables or connection.
    well, now i know to go directly to the jump ports inside the fuse box.
    thanks for the help.
     
  13. Stomper88

    Stomper88 Member

    Joined:
    Dec 3, 2011
    33
    52
    0
    Location:
    Las Vegas, NV
    Vehicle:
    2005 Prius
    Model:
    II
    I think it depends on how dead your battery is. My door didnt shut all the way and my battery was already on its last legs (7 years old), so I wasnt surprised when it wouldnt start the next day. I took the opportunity to test several ideas. My battery was at 1.5 volts, which is very low, so this might be why so many ideas didnt work for me but might work for someone else.

    AA batteries - FAIL
    I used 9 brand new alkaline batteries. When I hooked them up, the lights came on and the dash key light started blinking. When I pushed the start button, everything turned off for a few seconds then back on. The batteries started getting warm after a few minutes, probably trying to charge the dead 12v aux battery. When I pulled them out, the AA voltage dropped from ~13v to ~10v.

    Old 12v PC back up battery - FAIL
    The ups battery registered 8 volts so I didnt have much hope. It had the same result as the AA, except leaving it hooked up to the aux battery for a while raised the aux battery from 1.5v to 5v. Eventually the UPS dropped too low to keep charging.

    Roomba battery 14.4v - FAIL
    I tried this battery two ways because I was sure it would work. The first way, I just hooked it straight up the the aux battery and tried starting. Same result (lights turned off then back on). Then I recharged the roomba battery, disconnected the aux battery, and hooked the roomba battery up to the jumper cable spots under the hood. There were sparks as I hooked it up and I had a good feeling. This time when I hit the start button, lots of whirring noises and sounds for about 5 seconds, then warning lights popped up on the dash and eventually the lights turned off. Roomba battery dropped to 12v (from 14.4v).

    I finally surrendered and jumped it from a plug in jump starter. A new Optima battery should be in there soon. :)
     
  14. kenmce

    kenmce High Voltage Member

    Joined:
    May 4, 2004
    1,539
    513
    0
    Location:
    NY
    Vehicle:
    Other Hybrid
    Model:
    Limited
    Correct. The 12 volt just powers up a relay and some circuit boards. It doesn't try to spin the ICE.

    I've done it.

    If you're using a little hand held battery then you don't need auto jumper cables. They are made for much more power than that little unit can put out. Little patch cords will do.

    Yes. It worked.

    Under *NO* circumstances allow it to be jumped backwards.
     
    102mm likes this.