Forum Discussion

PaulJ2's avatar
PaulJ2
Explorer
Jan 14, 2019

Battery chargers.

Maybe a question for Mex.
Stone dead 12 volt battery on my Prius. Gone for a week and door ajar causing dome light to drain battery.
Brought out 2 different battery chargers,neither one would put out any voltage. One an automatic 10 amp unit and the other 1.5 amp battery charger/maintainer unit.
Measured voltage at the dead battery was .3 volts.
I then drug out my 30+ year old 1 amp motorcycle manual charger. Worked fine! Is this some safety thing so you can't spark the two clamps together?
I guess they have to see a couple volts before they will operate.
Geeeez!
  • PaulJ2's avatar
    PaulJ2
    Explorer
    Jan 15, 2019
    time2roll wrote:
    camperdave wrote:
    It's good to keep the old dumb stuff around sometimes, for things like this. That's what I tell my wife about me anyway...

    My wife's Ford Fusion hybrid wouldn't start a while back because of a dead starter battery. It amused me that there's 300v of lithium sitting in the truck, but the car wouldn't start because the lead acid battery under the hood was dead. She didn't find it amusing.
    Getting to be a bigger issue with all the telemetrics that never shut down on these new cars.

    Especially frustrating with the EVs that really need a deep cycle battery since zero need for the start surge.

    I think the OP has the answer. Although I am surprised a dome light did it. Even my old 2001 F150 will cut all power at about 30 minutes if this is detected.

    Yes, my 2004 Chev truck shuts it's dome lights off after 10 minutes, however this was a 2001 Prius and i guess they had not thought of that back then.
    Interesting is that the instant i connected the good charger i jumped into the car, turned the key and it started right up.
    The now 12 volts activated some relays connecting up the 276 volt battery and the engine started immediately. Just needed 12 volts to operate some relays i guess.
  • beemerphile1's avatar
    beemerphile1
    Explorer
    Jan 15, 2019
    LittleBill wrote:
    smart chargers need to see a minimum amount of voltage to turn on. usually because its a bit dangerous to charge a 100% dead battery


    ^This

    Parallel a good battery with the dead one. After the charger starts disconnect the good battery.
  • pianotuna's avatar
    pianotuna
    Nomad III
    Jan 15, 2019
    Speaking of Mex has anyone heard a peep from him? I tried to email-but received no response.
  • Sam_Spade's avatar
    Sam_Spade
    Explorer
    Jan 14, 2019
    PaulJ2 wrote:

    I guess they have to see a couple volts before they will operate.
    Geeeez!


    You answered your own question.
    What do you intend to do NEXT ?
    Shopping for a new battery would be good.

    Exact fit batteries for Prii are hard to find sometimes.
  • camperdave's avatar
    camperdave
    Explorer
    Jan 14, 2019
    MrWizard wrote:
    'truck' ?

    do you mean 'trunk' ?

    auto correct spell check strikes again


    yes, trunk. No autocorrect on my computer, and of course spell check is no use when you type the wrong word. Life goes on...

    time2roll, agreed. Like on her car, it can go 15 or so miles in EV mode. The starter battery literally does nothing other than tell the computer it's ok to drive now. There should be a way to manually turn on the DCDC, in a similar way that we can combine the house and chassis batteries in a motorhome when it won't start.
  • MrWizard's avatar
    MrWizard
    Moderator
    Jan 14, 2019
    'truck' ?

    do you mean 'trunk' ?

    auto correct spell check strikes again
  • time2roll's avatar
    time2roll
    Nomad
    Jan 14, 2019
    camperdave wrote:
    It's good to keep the old dumb stuff around sometimes, for things like this. That's what I tell my wife about me anyway...

    My wife's Ford Fusion hybrid wouldn't start a while back because of a dead starter battery. It amused me that there's 300v of lithium sitting in the truck, but the car wouldn't start because the lead acid battery under the hood was dead. She didn't find it amusing.
    Getting to be a bigger issue with all the telemetrics that never shut down on these new cars.

    Especially frustrating with the EVs that really need a deep cycle battery since zero need for the start surge.

    I think the OP has the answer. Although I am surprised a dome light did it. Even my old 2001 F150 will cut all power at about 30 minutes if this is detected.
  • camperdave's avatar
    camperdave
    Explorer
    Jan 14, 2019
    It's good to keep the old dumb stuff around sometimes, for things like this. That's what I tell my wife about me anyway...

    My wife's Ford Fusion hybrid wouldn't start a while back because of a dead starter battery. It amused me that there's 300v of lithium sitting in the truck, but the car wouldn't start because the lead acid battery under the hood was dead. She didn't find it amusing.
  • LittleBill's avatar
    LittleBill
    Explorer
    Jan 14, 2019
    smart chargers need to see a minimum amount of voltage to turn on. usually because its a bit dangerous to charge a 100% dead battery
  • 2oldman's avatar
    2oldman
    Explorer II
    Jan 14, 2019
    I'd jump a known good battery to it, and try charging again.

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