Custom Enginer PHEV (8kWh)

Discussion in 'Prius PHEV Plug-In Modifications' started by krousdb, Aug 29, 2009.

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  1. Flying White Dutchman

    Flying White Dutchman Senior Member

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    do you manually shutoff the dc -dc converters when you get the low voltage alarm or is the dc-dc converter shutdown when then voltage is to low?
     
    #101 Flying White Dutchman, Sep 14, 2009
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  2. krousdb

    krousdb NX-74205

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    In a perfect world, the converter would shut down automatically before you get a low cell voltage alarm. But that hasn't been the case for me. I have two cells that have lower resistance than the rest, and they will always alarm before the converters shut down.

    Likewise, I have two different cells that alarm (high) before the charger shuts off automatically. I am hoping the four cells in question will eventually start behaving after a few more cycles.

    The charger is programmed to shut down when the pack voltage reaches 56V. The converters are programmed to shut down automatically at a pack voltage of 48V.

    When using two converters, and I hear the alarm, I just shut down one of them. The reduced load lets the pack voltage bounce back and I get another 5-10 minutes with one converter before I hear the alarm again. Then I shut down the second converter.
     
    #102 krousdb, Sep 14, 2009
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  3. krousdb

    krousdb NX-74205

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    #103 krousdb, Sep 16, 2009
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  4. kiettyyyy

    kiettyyyy Plug-In Supply Engineer

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    #104 kiettyyyy, Sep 16, 2009
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  5. krousdb

    krousdb NX-74205

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    Installed the third converter today. Since I didn't get a cable and switch assembly, I decided to use a 2 to 1 phone adaptor and daisy chain the signal power between converter #2 and #3. That way they will both turn on with the second switch. So for one converter, switch #1, for two converters, switch #2 and for all three converters, switch #1 and #2. But for some reason, daisy chaning doesn't work. Both converter have a green LED, but only the first converter provides power. I reversed the connections and again, the first converter in the daisy chain worked, the second had a green LED, but no power. Need to talk to Jack about what he suggests.

    Anyway, I went out for some EVing today, two converters only. I used EV mode and began climbing a pretty steep hill. The converters were putting out 20A combined and there was another 30A coming from the OEM pack, then I got a code, P0A90. I cleared the code, rebooted and got another code, P0000. Cleared, rebooted again and all was good. I finished climbing the hill but used only 20A from the OEM pack and had no more codes.

    Next I engaged the 52 MPH hack for the first time. I was limited to where I could go with ony two converters but did manage to go 21 miles total before I arrived back at home. Judging from the LiFePO pack voltage, I would guess that I was at 3/8 remaining capacity. So I would guess the total EV range is 32 to 35 miles.
     
    #105 krousdb, Sep 19, 2009
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  6. Flying White Dutchman

    Flying White Dutchman Senior Member

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    P0a90/604 drive motor ”a” performance. Dtc
     
    #106 Flying White Dutchman, Sep 20, 2009
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  7. krousdb

    krousdb NX-74205

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    Just to summarize my results so far, on my normal commute I can make the 135 mile round trip running one converter without completely draining the pack. My guess is an 80%DoD. In dry, warm and not too windy conditions, I normally see about 80 MPG on the way to work and 88MPG on the way home. The difference is due to warmer temps in the afternoon and a different (less highway) return route. The average is about 84MPG. On the weekends, I run errands and go to chrch, movie etc. I have been able to average 100 - 150 MPG over 100-120 miles. The average this tank so far is 89.x, about the same as the last tank. Total highway miles is about 60%, 40% city. Waiting on some parts before I can try three converters at once.

    I just had a converter fail yesterday. But since I have two installed, I just switched over the the other one. One benefit of multiple converters is the redundancy. Jack informs me that my converters are of the old design, new and improved ones will ship this week.
     
    #107 krousdb, Sep 22, 2009
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  8. cabledave

    cabledave Member

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    Do you know the spec difference between the old and new style converters?
     
    #108 cabledave, Sep 23, 2009
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  9. krousdb

    krousdb NX-74205

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    I do not. I will let you know when I find out.
     
    #109 krousdb, Sep 23, 2009
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  10. kiettyyyy

    kiettyyyy Plug-In Supply Engineer

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    It just protects the DC/DC converter from bus voltages that constantly fluxuate.. In the long run, DC/DC converters won't fail as often..
     
    #110 kiettyyyy, Sep 24, 2009
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  11. hill

    hill High Fiber Member

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    Haven't yet seen a post yet ... but have you tried to go on a long (600+ mile) trip with no recharge? It'd be interesting to see what the 300lbs does.

    .
     
    #111 hill, Oct 2, 2009
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  12. mrbigh

    mrbigh Prius Absolutum Dominium

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    I will be like having a really obese passenger seating in the trunk munching a lot of goodies but with out the farts.........:eek:
     
    #112 mrbigh, Oct 2, 2009
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  13. Flying White Dutchman

    Flying White Dutchman Senior Member

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    well without the farts then there are no setbacks ;-)
     
    #113 Flying White Dutchman, Oct 3, 2009
  14. sub3marathonman

    sub3marathonman Active Member

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    Back to the 8kWh kit, I had another question.

    Is it possible to have both voltage converters draw from the same battery pack? (Yes, I know about the repercussions to the 40ah batteries, I was just wondering if it was theoretically possible.)
     
    #114 sub3marathonman, Oct 9, 2009
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  15. mrbigh

    mrbigh Prius Absolutum Dominium

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    theoretically YES, it will work. Now, how long the full charge of the battery pack will last? I'm guessing 1/3 less than rated for one converter on line. Is it worth it, NAH.........
     
    #115 mrbigh, Oct 9, 2009
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  16. coulomb

    coulomb Junior Member

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    Sure, quite possible. At peak output, the converters are rated at 3000 W each. Assuming the cells sag to 2.8 V each, and 85% converter efficiency, that's 3000/(16*2.8)/0.85 = 84 A, or 2.1C for a 40 Ah pack. The cells are rated at 3C continuous, 10C for short spikes, and I'd guess 5C for intermittent loads as the converter might demand.

    So two converters takes the pack from a solid but well-within-ratings 2.1C peak demand to 4.2C, more than the continuous rating of the battery, but arguably within the capability of the pack.

    At the higher discharge currents, the cells will sag more and get hotter. The extra sag will cause the converters to demand more current (to satisfy their power needs, voltage times current), which will lead to a little more sag and a little more heat. But nothing outrageous.

    So suppose one 40 Ah pack was out of commission for a week; it would be reasonable to put both converters on the one pack as long as you babied the pack a little. Long term, I wouldn't leave two converters on one pack; it's asking for trouble one hot, high demand day, and the extra heavy cycling of the cells will shorten their life.
     
    #116 coulomb, Oct 9, 2009
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  17. mrbigh

    mrbigh Prius Absolutum Dominium

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    Well, at least our Aussie, freshly sign up friend, came up to provide the well needed technical support in this dedicated Enginer's threads.
    Do I remember right?........... is the USA Enginer Co. a branch of a Chinese corp owned by an Australian entity? What a coincidence and the great convenience of "Screen" names.
     
    #117 mrbigh, Oct 9, 2009
  18. coulomb

    coulomb Junior Member

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    I have nothing to do with Enginer; I merely quoted numbers from memory that came from elsewhere on PriusChat.

    Of course, if there really was a conspiracy here, I'd be expected to say that. :eek:
     
    #118 coulomb, Oct 10, 2009
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  19. mrbigh

    mrbigh Prius Absolutum Dominium

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    Welcome aboard of PriusChat, "Coulomb".
    At least you seem to be honest in your answer but some times to many coincidences of new people jumping in, in a very specialized thread and with the proper information make me suspicious.
     
    #119 mrbigh, Oct 10, 2009
  20. cabledave

    cabledave Member

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    :rolleyes: Was that really necessary? I don't recall the post where everyone selected you to be the forum police. Lighten up Nancy Drew . . .

    Coulomb, :welcome: to the discussion, most of us have picked up some manners during our life so far.
     
    #120 cabledave, Oct 10, 2009
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