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Can Hybrid Battery be bypassed and start the ICE?

Discussion in 'Gen 2 Prius Technical Discussion' started by Fro-Dawg, Dec 27, 2016.

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  1. Fro-Dawg

    Fro-Dawg Junior Member

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    Due to a second generation hybrid battery problem, I have not started my 2004 Toyota Prius in over a year. I am afraid that the internal combustion engine (ICE) seals, stale gas for sure, and parts may have a problem now for not starting for so long. I wish to bypass the computer or whatever is needed to at least start the ICE and let it run for a while independent of the hybrid battery. Is there a maintenance switch/bypass/relay of some sort so that I can start the engine? I have searched and searched online with no luck thus far; however today I remembered this site. Anyone please help!
     
  2. jdenenberg

    jdenenberg EE Professor

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    Your Prius uses one of the motor/generators to spin the engine via the transmission using energy from the HV battery so you cannot bypass it. The 12v battery only boots the computer and electronics. There is an HV battery charger for sale here on PC for about $400.

    DoctorD
     
  3. Sam Spade

    Sam Spade Senior Member

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    NO. The engine won't turn over without the HV battery and it won't run without the computers.
     
  4. Fro-Dawg

    Fro-Dawg Junior Member

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    DoctorD you wrote "There is an HV battery charger for sale here on PC for about $400." You did not leave a link so where is here?

    So to be clear the 12 volt DC battery does not start the ICE and there is no way to give the ICE an alternative voltage source and/or single to start if the Hybrid battery is completely dead or in essence disconnected? In fact I just remembered when I last messed with the vehicle the battery was not completely dead it just has some bad cells and this error is being sent to the computer preventing the ready light to come on and thus the ICE can not start. BTW I do have replacement cells I just have never replaced them, charged the rest and balance the battery yet. I just went outside and measured the voltage on the hybrid battery. It currently reads 164 volts DC. I am surprised because I have not measured the voltage on the Hybrid battery for at least 14 months and have not been able to start the vehicle for at least 18 months, I thought the hybrid battery would have trickled down to nothing. This voltage 164 volts DC that is currently on the hybrid batter is not sufficient to at least START the internal combustion engine?
     
  5. bisco

    bisco cookie crumbler

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    prolong battery charger, in the priuschat shoppe. @jeff652 will sort you out. the 12 volt fires the computers and relays.
    the hybrid battery turns the tranny/engine. theres no other way to start the engine that i have seen.
    if your battery cannot be charged, you will have to repair it, or replace with a new or refurbished battery. all the best!(y)
     
  6. Fro-Dawg

    Fro-Dawg Junior Member

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    The 164 volt DC I mentioned earlier was the OCV “open circuit voltage”. There was no load on the battery. I assume that once the load is applied the voltage will drop down more.

    I understand now “There’s no dedicated start motor but instead they have a huge and powerful electric motor driven by the main engine battery, not the accessory battery. And instead of an alternator that same system is used to regenerate power to recharge both the accessory and the main engine battery.” Thus the hybrid battery IS needed to start the ICE.
     
  7. jdenenberg

    jdenenberg EE Professor

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    The HV battery nominal voltage is 201.6 volts. 168 volts is fully discharged (~1 v per cell). 224 volts is fully charged. Note that in actual use the battery is never discharged below 40% and never charged above 80%. Good modules will retain their charge for many months, but yours is very low.

    Bisco gave you the link to the charger, good luck with your project car.

    JeffD
     
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  8. jeff652

    jeff652 Senior Member

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    Give us a call at 800-589-0730. We have people buy our systems all the time to refill self-discharged batteries. You can buy our systems here on the PriusChat shop or our website:
    Online Store - Hybrid Automotive
     
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  9. Fro-Dawg

    Fro-Dawg Junior Member

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  10. ericbecky

    ericbecky Hybrid Battery Hero

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    I would highly suggest buying a full conditioning package and not just a charger.

    Your battery is going to be pretty messed up from sitting that long.
    Doing a series of charge/discharges will be helpful in attempting to recover the pack.

    In addition to a charger/discharger you may want to separately invest in a code reader and some sort of software/app.
    This way you can read any error codes plus look at the voltages of each block of the hybrid battery pack's modules.

    Feel free to call if you need any advice.
    Always happy to help get another hybrid back on the road.
     
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  11. jeff652

    jeff652 Senior Member

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    Yes, that's the one. And Eric is right, a full recon package would be a very good idea. While charging alone is enough to refill the battery and get the car started, you will have much better and longer lasting results from a full reconditioning treatment. :)
     
  12. Tedh1979

    Tedh1979 Member

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    I'm seeing $400-$700 just to charge the hybrid battery pack? I can buy a hybrid battery for that price.
     
  13. Tedh1979

    Tedh1979 Member

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    Sorry to bash, but the Prolong Battey Chargers look to be about $30 worth of material. After shopping online, there is a better charger for 1/3 the price, still too much. I used to be a computer technician. These are computer power supplies that cost about $20 each, with some basic wires. Very sad that ProLong prices are just outrageous! People that buy things like this to "prolong" their battery need to remember this. You bought your Prius to save money on gas. But if you spend $400-$700 on one of these devices, that makes your gasoline twice as expensive, or you could also calculate that your MPG would be majorly cut, which makes the point of owning a Prius a very stupid idea. The idea is to buy a Prius and get good gas mileage. You start adding all this overpriced junk and therefore you need to count that as a gasoline expense! A Prolong system for $400-$700. $400-$700 will buy you a LOT of gas!
     
  14. ChapmanF

    ChapmanF Senior Member

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    Next time I see a pallet of 300 volt computer power supplies, I'm stocking up.
     
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  15. Raytheeagle

    Raytheeagle Senior Member

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    I think you mean it will save you gas if the Prius is running;).

    As someone who owns the setup (as well as shares ownership with 2 other members out here), it is a great tool to have for reconditioning and rebuilding hybrid batteries. Remember, Hybrid Automotive is a business and they had to invest time and effort into the final product I bought and you claim is overpriced :cool:.

    I look forward to seeing how much time and effort you spend in dealing with your failed battery and I’ll compare that to what I have done using the Prolong equipment :).

    Good luck and keep us posted (y).
     
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  16. oldtechaa

    oldtechaa Active Member

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    I think I must disagree with you on that. I have never seen a computer power supply that outputs over 200 volts, nor a computer that runs on over 200 volts DC. I can't imagine what a high-voltage computer would be used for, especially as processors get lower and lower power, such as 0.85V, for the sake of power consumption.
     
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  17. jerrymildred

    jerrymildred Senior Member

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    You can charge a 240+ volt battery with a computer power supply??!! And maintain a constant 1/3 of an amp? That I gotta see.

    The prolong charging and reconditioning system is proven technology with lots of shops using them over the years and lots of other satisfied users including me.
     
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  18. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    You get what you pay for in hybrid batteries.

    As for charging? it's expensive to get a charger that can charge the whole pack with one connection.

    It's very cheap to make or adapt a charger that you could use to charge individual modules, but naturally that means you'd spend a long time getting a whole pack charged up. If you don't mind spending a few days to do the one charge, with 13 reconnections along the way you're set.
     
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  19. Tedh1979

    Tedh1979 Member

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    Less than HALF the price of the Prolong model, and there are even more affordable ones than this.

    2004-2009 Toyota Prius Hybrid EL-1 Traction Battery Grid Charger Balancer USA! | eBay
     
  20. bisco

    bisco cookie crumbler

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    i didn't buy my 3 pri to save money on gas, just to save gas, for a host of other reasons.

    you can't save money buying a prius, you can save gas money... until you can't.
     
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