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Adding battery capacity to the Prime

Discussion in 'Prime Technical Discussion' started by billvon, Dec 24, 2022.

  1. vvillovv

    vvillovv Senior Member

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    fair enough on most of the post above, not that I couldn't give an opposing view to some of it, but this statement quoted below needs some opposing at best.
    I'm pretty sure anyone that adds double traction pack capacity and expects to get double the cars stock range is either grossly misinformed or an electrical genius.
     
  2. Isaac Zachary

    Isaac Zachary Senior Member

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    Grossly? All things considered, why not? Adding more capacity can add more weight, but even 800lbs of weight ain't going to make a huge difference in range. If people would stop driving around wind bricks (aka, SUV's), that would really help range. Sure, more weight and you aren't going to get exactly double the range, but not that far off.

    And if you're thinking cars go by Ah's, they don't. It's too much to keep track of, and too many things that could throw it off. Double the capacity and the battery will supply slightly more than double the Ah (less resistance) by the time it hits the cut-off voltage of the BMS. The BMS isn't gonig to cut off just because you used X amount of Ah. It's waiting for a very specific voltage drop.
     
    #42 Isaac Zachary, Dec 31, 2022
    Last edited: Dec 31, 2022
  3. vvillovv

    vvillovv Senior Member

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    weight - wind - suspension - sure no problem ...
    bms ain't the only box in the car that deals with the electic motor functions. It's one of them, one of how many depends on which model one speaks to.
    Pretty grossly imuo-pinion
     
  4. sam spade 2

    sam spade 2 Senior Member

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    Do you have any direct evidence that it really did work......other than his word ??
    (Edit: I see that "it seemed to work"......except that a few parts went up in smoke. No big deal. :whistle: )

    And the Leaf is an electric only plug in.
    Not nearly as complicated as a hybrid.
     
    #44 sam spade 2, Jan 1, 2023
    Last edited: Jan 1, 2023
  5. billvon

    billvon Junior Member

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    Update - found a great teardown video from John Kelly which suggests that the contactor assemblies inside the battery contain service ports that should allow connection directly to the battery stacks. This is much safer (from a "bricking the car" perspective) than injecting power into the HV bus directly.

    However, the Toyota wiring manual does not show these ports. (See images below.) Next up is disassembling my battery and seeing if they are there, and if they are, start looking for a connector that will fit.
     

    Attached Files:

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  6. billvon

    billvon Junior Member

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    You'll get ABOUT twice the range. The additional battery capacity will give you a little more than twice the energy available (since lower discharge rates allows you to get more energy out of the battery) and the additional 270 lbs will give you slightly more power required for hills. Which one will dominate? Hard to tell - but since they oppose each other, the result will be about twice the range.
     
  7. vvillovv

    vvillovv Senior Member

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    I hope everything works out for you as expected from the research you've already done.

    It shouldn't be to hard, right?
     
  8. Isaac Zachary

    Isaac Zachary Senior Member

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    Do you think adding a bigger lead acid battery to my Prius is going to throw codes too?

    An electric drive train is an electric drive train, be it in an EV, Plug-in hybrid, or hybrid. There is no difference between a hybrid or an EV except maybe the hybrid could have two motors instead of one. (On the other hand there are EV's with 4 motors, one for each wheel). What in the world could possibly make an EV "not nearly as complicated as a hybird" as far as the HV battery and BMS is concerned?

    What are you getting at? Look, the guy did make a stupid mistake. You don't plug two HV batteries into one bus without having a way to make them turn off and on simultaneously. It was a mistake he knew could have happened and he could have prevented if he had done things right. Anyone watching the video now knows what not to do.

    If working on your car is so dangerous and nobody should do it then I must be the worst person in the world for doing my own oil changes. I could seriously ruin something or even kill someone you know.

    EV or Plug-in hybrid batteries aren't voodoo! Just like rebuilding or modding an ICE you need to take precautions and double check your work. If you have no idea what you're doing, then of course "don't do this at home". But believing that the only people that should have the right to touch the internal parts of a car are certified mechanics is ludicrous!

    Can you explain Ohm's law? How do you convert Watts to horsepower? What are watts, volts, ohms, amps, etc? Why does battery voltage sag under load? What's the difference between a series and a parallel circuit? What is a conductor and what is a resistor? And what are the dangers of working around a high voltage lithium ion battery? If you can answer all of those, you're not far off from being competent enough to work on an EV or Plug-in hybrid battery.
     
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  9. vvillovv

    vvillovv Senior Member

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    Just curious which year trim prius you're talking about
     
  10. Isaac Zachary

    Isaac Zachary Senior Member

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    All years. As in filling the trunk with a bunch of extremely large deep cycle 12V LA batteries and hooking them up in parallel and then wiring those in as the 12V battery even if it's a model that has the battery in front (just need to wire from the trunk to the front of car with very thick cables).
     
  11. vvillovv

    vvillovv Senior Member

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    your statement "my prius" must be another one of you're hypothetical theories,
    Not that I'd care if you wanted to hookup a truck load of anything to your other hybrid.
     
  12. Isaac Zachary

    Isaac Zachary Senior Member

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    My Prius is a 2006. I've replaced a total of 3 HV modules on it. I haven't gotten any codes since except a bad catalytic converter.

    Actually I'd like to add more LA batteries to the Avalon since I have a HAM radio installed in it and would like more talk time without having to start the vehicle.

    And for the record:
    Yes, I know I could start a fire with a bunch of lead acid batteries if I hook them up wrong or short them out.
    Yes, I know they will need to be securely mounted.
    Yes, I know that if they are liquid filled, that liquid could spill out. Better get AGM, Gel or Dry cell or a different chemistry altogether (LiFePO4 for an example).
    Yes, I know that they need to be vented so I reduce the risk of filling up my trunk with hydrogen and oxygen and making a big BOOM!
     
  13. sam spade 2

    sam spade 2 Senior Member

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    Give it a rest please.

    I have been an Electronics Engineering Technician for about 60 years now........and have no desire to play your silly games.

    Good luck with your experiments.
     
  14. Isaac Zachary

    Isaac Zachary Senior Member

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    If you are an electronics engineer then what are you talking about with a hybrid being way more complicated than an EV? Give an example.
     
  15. sam spade 2

    sam spade 2 Senior Member

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    Moronic question.
    And I am a technician, not an engineer.
    Just stop.
     
  16. Isaac Zachary

    Isaac Zachary Senior Member

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    Sorry for keeping this up, but your objection seems to be simply "Too complicated, won't work" without any explanation as to why.
     
  17. sam spade 2

    sam spade 2 Senior Member

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    If you REALLY knew anything about electronics, the answer should be obvious.
    Maybe someone else will be willing to try and explain it to you but I am not wasting my time.
    Because it appears that you only want to argue and not actually learn anything.

    Hint: The drive train basic operation in an electric only car isn't really that much different than
    the drive mechanism in a kids electric toy car.

    I'm done.
     
  18. Isaac Zachary

    Isaac Zachary Senior Member

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    Sorry to waste your time, and I admit I could be totally wrong on this.

    But what I guess I want to argue about is about how I hate counter arguments that are essentially:
    • "Because it's (somehow, but not explained) complicated."
    • "Because it'll (somehow, but not explained) throw codes left and right."
    • "Because it should be obvious (because if it isn't to you, then you must not know anything, so why bother telling you)."
    • "Because you'll probably kill yourself or cause a lot of damage (again, because you don't know anything)."
    Well fine, maybe I know absolutely nothing about electronics and how Hybrids and EVs work, so I'll stop wasting your time becase I wouldn't even understand your expaination anyway.

    All I know is there's a battery, a BMS, a set of contactors, cables, an inverter (or inverters), a motor (or motors), a charging and discharging curve, that the energy is used to combat rolling resistance, which is pretty much the same at any speed, and aerodynamic drag, which the energy required to overcome is the square of the velocity multiplied by the air density, the coefficient of drag and the frontal area.

    But I don't see anywhere where adding more battery capacity and getting those extra Ahs or Whs out of the battery is "complicated", "will throw codes left and right", "obiously won't work", "will likely kill me and cause lots of damage" anymore than changing modules on the 2006 Prius hasn't killed me nor caused a lot of damange.

    Simply that a traditional hybrid is not going to work like a plug-in hybrid or EV without modifying it so it stays in EV mode all the time. But adding more capacity to something that will stay in EV mode by itself, should work as expected without modifying anything to keep it in EV mode longer because it should stay in EV mode until it reaches a certain voltage threshold, which if the battery chemistry is the same should give you the extra Ahs you had added.
     
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  19. bisco

    bisco cookie crumbler

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    imo, the arguments on both sides of this issue are weak, and without backing data.

    i can only go by the fact that no one has ever done it, so there might be a good reason.

    that doesn't mean it can't be done, just that it isn't worth the time, money or effort.

    o/p claims he is going to try, let's follow his progress
     
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  20. sam spade 2

    sam spade 2 Senior Member

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    It appears that is true.
    And yet you keep rambling on and on.

    Let's try this:
    With any hybrid vehicle, plug in or not, the electronics that makes all of the components work together in harmony is designed to work properly with ONLY ONE specific set of hardware, including the battery.
    The odds are HUGE that just throwing in more batteries will upset the system balance and cause things to NOT work properly.

    Do you get that.......on any level ??
    It would appear not.