VH battery amperage rate while acceleration (phev safe and easy. Mayby)

Discussion in 'Gen 2 Prius Accessories & Modifications' started by Staska, Dec 3, 2011.

  1. Staska

    Staska New Member

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    Hello. This is my first post. No, I don't own a prius. Because ready available models are not plug-in. I was figuring different approaches of phev'ing prius - from Engineer kit, to PriusPlius DIY. But they all have disadvantages. I had found some mentions of using additional prius HV battery in parallel. But they used complicated electronic and have a risk of overcharging, if charging in parallel.

    So, I come to this simple solution, according to my knowledge of electronic:

    Resistors to separate batteries then charging on line, and diodes to connect them then discharging. Also one diode, to regenerative charging. Such solution should maintain original bms on regeneration, and solve problem with charging from grid. That is more - if oem charging controllers could be used as bms for charging - it should have safety of original equipment.

    Value of SOC should be fooled too, as in every phev conversion too.

    So question is simple - does original battery give off 250 amps ? Ar more at full ev assist? (50kw/200 ~250 amps)
     

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  2. seilerts

    seilerts Battery Curmudgeon

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    Max current is 100 amps. There is a 125 amp fuse in the service plug.

    I encourage you to ignore everything about Enginer, PriusPlus, etc., and focus on learning everything you can about NiMH chemistry. It is this step where people fail to focus enough attention and blow up their pack due to thermal runaway during charging. You circuit will not protect against that. Develop a fool-proof method for charging three parallel packs of 28 battery modules in series on the bench in your workshop. The most reliable way that I know of to shut off charging is dT/dt -- change in temperature.
     
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  3. Staska

    Staska New Member

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    Thank you for an answer.

    How then toyota claims of 50kw e-assist power using 125 amps fuse ?

    I understood you arguing of parallel charging. and irony to not read of working designs. Now i try to find all info of stock battery ecu. Till now, i had found that it does need any info from other ecu to begin charging. Just present can connection.

    So then - three oem battery with three battery ecu charged at home with three separate chargers could work ? And device to emulate can interface.
     
  4. seilerts

    seilerts Battery Curmudgeon

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    Traction battery is rated at 21 kW in Gen II and 27 kW Gen III.

    I think Lithium (LiFePO4) is a better approach, with custom battery ECU. But it is more expensive.

    Three separate chargers would be very helpful, and as well, have multiple failsafes: timer, thermistors, -dV/dt, etc. Since the battery ECU does support an external charger, if you can figure that out, it might save you some hassle.
     
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  5. ken1784

    ken1784 SuperMID designer

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    25kW from battery + 25kW from MG1 = 50kW
    Another bottle neck is "BOOST IPM", 201V to 500V DC-DC converter.
    So, three BOOST IPM's are also required.

    I think your project is not practical.
    An affordable solution is to order new Prius Plugin.

    [email protected]

    [​IMG]
     
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  6. seilerts

    seilerts Battery Curmudgeon

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    Ken! Nice to see you.
     
  7. Staska

    Staska New Member

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    Now, i could not afford a new prius.

    According to You - BOOST IPM is needed for charging ? But in my case, they will work only as charging current controller. BMS will be done by battery ecu. If I am right.

    As far as I understood, CAN commands from battery ECU are decoded, and we need charging controller for each battery with can interface reading SOC and CCL at least.
     
  8. jdcollins5

    jdcollins5 Senior Member

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    Boost IPM is used to boost the 201 VDC battery voltage to 500 and 650 VDC and then inverted to AC for MG1 and MG2.
     
  9. ken1784

    ken1784 SuperMID designer

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    Prius plugin is starting $32000.
    I believe your project will cost more than $32000.
    I believe your goal is to get the full EV assist from the three battery packs.
    If you would like to get an advantage of three parallel battery packs on acceleration and regenerative charging, three BOOST IPM's are needed.
    If you don't need an advantage of three parallel battery packs on acceleration and regeneration, only one standard BOOST IPM is required.

    [email protected]
     
  10. jdenenberg

    jdenenberg EE Professor

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    The difference is that Toyota now rates the Gen3 modules at 130 amp peak current vs. the 100 amp peak current in the Gen2 modules. Has Panasonic actually improved the modules, or is this specsmanship plus a firmware change to drive the batteries harder in the Gen3 Prii?

    JeffD
     
  11. seilerts

    seilerts Battery Curmudgeon

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    Plastic Case Prismatic Module | Primearth EV Energy Co., Ltd.

    Based on the technology we accumulated during the development of HEV batteries, we started mass production of plastic case prismatic Ni-MH battery with new structure. Specific power of this new battery module is 1300W/kg (1.3 times higher than our conventional prismatic battery), and energy density is 46Wh/kg.

    Staska, please review the following thread, for an example of a well-done PHEV project.

    http://priuschat.com/forums/gen-ii-...-plug-in-hybrid-electric-vehicle-project.html
     
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  12. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Toyota said better cooling enabled more power from the GenIII battery.

    As seilerts pointed out, cells are rated even higher than GenIII pack.
     
  13. ken1784

    ken1784 SuperMID designer

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  14. V8Cobrakid

    V8Cobrakid Green Handyman

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    completely off topic... but... it's good to see a prius battery can fail (or.. added pack in this case) and the car doesn't burn to the ground... one more point towards the prius and away from the volt... (ok.. i'm done ranting)
     
  15. Staska

    Staska New Member

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    I had read it before creating a new thread. And tried to contact with pEEf. Without success. Project from bristol show me an idea of using power from few parallel original prius packs. And how not to charge packs too.

    pEEf way is superb. It could be affordable. But - i had build tens of different inventors. Some was my design. Some was copy-paste. They are easy in 100 watts range. But on 500 watts or more you need a lot of know-how to make it work, and even more know-how to make it bullet proof and suitable to work in a car environment. I always prefer KISS idea in any of my project. Not because I don't know how, but because I know - more complex system is always less reliable. Same is with BMS for lifepo4 cells.

    I would try to explain ideas of project.

    1. Use additional battery pack to store plug-in energy only. Not to recharge it. with existing bms to charge them propertly. (second batteries)
    2. Use existing hv battery as is. And maybe charge it from mains too. (primary battery)
    3. Use can device to spoof SOP ratio of primary battery.

    1 - in theory is doable. I had graduated CS, i know how to work with CAN-bus, can bus commands for bms are known. To store more energy from braking, we will need bigger generators.
    2 - solution is same as for first.
    3 - it has been done before.

    Adding second or third inventor would require also second/third mg2 with suitable controller.

    That is all. It won't be full EV. And it would not be as power full as new prius.
    It should be easy, safe by using existing bms, it should give adequate boost of energy.

    Also - i had seen, report of ev regenerative braking. It increased range in ~10%. So if we have plug-in hybrid, we will not use capacity of bigger battery at regeneration at all. In my ~25 km work trip i have 10-20 stops in general. If i could gain 10% energy from braking, it means that i main pack would be charged for on 30%.
     
  16. R-P

    R-P Active Member

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    Some parts of the discussion are out of my league, but I hope this is due to too little knowledge of existing plug-in conversions and the inner Prius workings...

    But as an EE, I should be able to keep up, and since I have over 5kWp of solarpanels, I NEED this conversion to get rid of surplus electricity... So lead the way...:cheer2:
     
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