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Manually charging the hybrid battery?

Discussion in 'Gen 2 Prius Main Forum' started by SteveO, Jan 2, 2006.

  1. SteveO

    SteveO New Member

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    Sorry if this has been asked before, but I couldn't find much when I searched for it.
    I know about the complete hack to install more batteries to make the Prius a full plug-in electric, but has anyone tried anything to just charge the stock hybrid battery to max capacity (full bars) while the car is parked? The reason I ask is that I'd like to start my morning commute with a fully recharged battery - and drive in EV mode as far as possible. If a plug-in adaptor is not feasible, would a battery charger (like the kind you connect to your regular 12v battery when you go on vacation) or something similar work?

    Thanks,
    Steve.
     
    #1 SteveO, Jan 2, 2006
  2. galaxee

    galaxee mostly benevolent

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    well... there is a hybrid battery charger... but it's worth thousands (if not tens of thousands) and only regional toyota reps get them.

    you're best off just letting the car charge up the battery on its own.
     
    #2 galaxee, Jan 2, 2006
  3. Bill Merchant

    Bill Merchant absit invidia

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    Remember, Steve, that your Prius is a close-to-zero emissions car. The coal-fired electric power plant which would supply the juice to fully charge your HV battery is decidedly NOT zero emissions. Even if you could charge the HV battery, it wouldn't be good for the planet.
     
    #3 Bill Merchant, Jan 3, 2006
  4. efusco

    efusco Moderator Emeritus
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    There are several issues involved here.
    The Toyota charger connects simultaneously to the HVbattery ECU and the battery and slowly charges to a nominal level (I'm not sure if it will/is capable of "topping off") for starting/running. Also, 'topping off' is not as easy/safe as it sounds.
    Do you charge to the 100% SOC level? If so you will shorten the battery life.

    Do you charge to the 80% level (all green bars on the MFD SOC graph)? Probably won't shorten battery life, but the problem there is finding the proper shut off point so that you don't over charge (thus the complex Toyota charger).

    Finally, even if you could cheaply, cleanly, efficiently and conveniently charge up to that 80% SOC level you've only gained yourself maybe 1/2 mile (probably less) of 'stealth' over the 5-6 bar level that the Prius typicaly maintains anyway.

    Those who've added additional battery power have been able to charge the auxillary batteries on the grid while the OEM battery is off-line. Thus, upon start up, the auxillary passively charge the OEM HV battery and 'fool' the HVbattery ECU once the car is in Ready mode.

    I will add here (and please don't ask for details--I'm not currently at liberty to share more) that I know of at least one individual who did add additional battery packs and charged his aux batteries from the grid who required replacement of his OEM HV battery when it failed. It is not at all clear why this occured, but certainly speculation is that the combination of grid charging and additional batteries without the Toyota safeguards led to the premature demise. The SOC is held within a very tight range of SOC in normal operation to ensure prolonged battery life.
     
    #4 efusco, Jan 3, 2006
  5. Ovi

    Ovi Junior Member

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    there is a way to fully charge the battery. Put the car in D, then fully depress the brake, keeping it firmly. Then, just floor the accelerator. The drivetrain will cut power to the wheels and will send it to the battery instead. You should be using a ScanGauge or some other gadget to monitor the battery/HV inverter's temperature. My battery overheated while I was doing this and cut off the current and turned on the cooler until it reached normal temps. Don't do this with a cold battery! Turn the car on, leave it for a couple of minutes or just don't fully depress the accelerator so you don't force the system too much. At full throttle it will push some 50 amps into the battery - that's a lot of power at 200+ volts - about 10 kilowatts. It will charge your battery in 2-3 minutes, but don't expect miracles - the charge will only last for a few miles and the fuel efficiency will suffer, as the engine won't move the car while it charges the battery, which translates to zero mpg. Also, I'm not sure this kind of forced charging won't actually harm the battery if abused.

    Conclusion: the Prius, with its small battery, has not been designed for prolonged use of electric-only mode. The best way to achieve good MPGs is still the old one: drive conservatively with the use of pulse and glide. Or go to specialized folks who can install a bigger battery. Or buy a Tesla. :)
     
    #5 Ovi, Mar 1, 2014
  6. bisco

    bisco cookie crumbler

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    i do this several times a day, really bumps up the mpg's!(y) i hope steveO is still around to take advantage of this new tech.:p
     
    #6 bisco, Mar 1, 2014
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