YAPiP - recreating pEEf's approach

Discussion in 'Prius PHEV Plug-In Modifications' started by jdh2550, May 23, 2012.

  1. 2009Prius

    2009Prius A Wimpy DIYer

    Joined:
    Mar 25, 2009
    2,704
    486
    63
    Location:
    USA
    Vehicle:
    2009 Prius
    When you get to it please post some pictures of the location of the plugs and how the wires are attached. I am contemplating tapping into the CAN bus to free up the OBD port. I suppose I need twisted pair and shielded cable? Thanks!
     
  2. jdh2550

    jdh2550 Co-Founder, Current Motor Company

    Joined:
    Nov 16, 2010
    317
    246
    0
    Location:
    Ann Arbor
    Vehicle:
    2005 Prius
    Model:
    N/A
    I just received my ElCon charger. Unfortunately I've been very busy at work and have had weekend family commitments so I've made very little progress...
     
  3. jdh2550

    jdh2550 Co-Founder, Current Motor Company

    Joined:
    Nov 16, 2010
    317
    246
    0
    Location:
    Ann Arbor
    Vehicle:
    2005 Prius
    Model:
    N/A
    Follow on from this thread: YAPiP - recreating pEEf's approach | Page 8 | PriusChat

    I think I'm going to go with Option 3:
    SystemDiagram3.png

    I'm going to use the pre-existing battery ECU. It already has isolation. I'll put pack voltage (via a divider), temperature sensors and BMS control signals in on the 14 existing cell voltage analog input lines. I'll then query the voltage values from this module via the secondary CAN bus - I'll interpret them differently. I'll also read the current from the secondary bus. I'll ignore everything else.

    I think this will work.

    Anyone have any thoughts on this approach?
     
    dave77 likes this.
  4. lopezjm2001

    lopezjm2001 Senior Member

    Joined:
    Apr 14, 2009
    1,146
    403
    5
    Location:
    Sydney Australia
    Vehicle:
    Other Electric Vehicle
    Model:
    N/A
  5. NortTexSalv04Prius

    NortTexSalv04Prius Active Member

    Joined:
    Nov 14, 2009
    915
    111
    0
    Location:
    Texas
    Vehicle:
    2004 Prius
    Model:
    N/A
    jdh/lopez
    Do you know if a 7inch lilliput monitor (USB only) will work with the duniomite mega. I am also thinking there is a usb to vga adapters
     
  6. lopezjm2001

    lopezjm2001 Senior Member

    Joined:
    Apr 14, 2009
    1,146
    403
    5
    Location:
    Sydney Australia
    Vehicle:
    Other Electric Vehicle
    Model:
    N/A
    You can use any 7" monitor. It does not have to be Lilliput. But it needs to be a standard VGA plug. USB plug is normally for a touch screen which will not work with the Duinomite at this time. The Duinomite Mega only has a miniUSB. I very much doubt that the Duinomite Mega can drive a VGA screen through the miniUSB port.
     
    NortTexSalv04Prius likes this.
  7. NortTexSalv04Prius

    NortTexSalv04Prius Active Member

    Joined:
    Nov 14, 2009
    915
    111
    0
    Location:
    Texas
    Vehicle:
    2004 Prius
    Model:
    N/A
  8. jdh2550

    jdh2550 Co-Founder, Current Motor Company

    Joined:
    Nov 16, 2010
    317
    246
    0
    Location:
    Ann Arbor
    Vehicle:
    2005 Prius
    Model:
    N/A
    I've purchased another battery ECU (along with SMR) from ebay - it should be here this weekend. I figured there would be too much risk of leaving my daily commuter stranded if I hacked the one that's currently running the standard NiMH pack!

    I've made up the cables for the battery pack and created a simple pallet to hold everything in place in the trunk while I develop things. In the final version I'll split the cables in the middle and put the fused safety cutout switch in series.

    The only part that I haven't acquired yet is the BMS. I know what I'm going to do - but I don't have the ~$1K to spend on it right now. So, I'll go ahead with the good old organic computer BMS to start with (I'll check the voltages manually and see if any are going out of balance).

    All these words and I haven't yet modified my Prius! Soon now though.

    Real soon...
     
    dave77 likes this.
  9. Flying White Dutchman

    Flying White Dutchman Senior Member

    Joined:
    Dec 29, 2007
    4,374
    305
    0
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    Cellogs?

    -Htc Tapatalk ( sorry for auto spell correct )
     
  10. jdh2550

    jdh2550 Co-Founder, Current Motor Company

    Joined:
    Nov 16, 2010
    317
    246
    0
    Location:
    Ann Arbor
    Vehicle:
    2005 Prius
    Model:
    N/A
    No, three of our 24 cell BMS's from our bikes.
     
    dave77 likes this.
  11. Flying White Dutchman

    Flying White Dutchman Senior Member

    Joined:
    Dec 29, 2007
    4,374
    305
    0
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    ok so you already have a bms? because you said "the only part that I haven't acquired yet is the BMS"
    i geuss you wnt that one but do not have it yet ( funds to? )
    i was thinking you need something temporarily and cheaper so thats wy the cellogs.
     
  12. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

    Joined:
    Feb 14, 2010
    5,982
    3,781
    0
    Location:
    Rocky Mountains
    Vehicle:
    2006 Prius
    Model:
    Three
    Well I've read through the thread and it seems like many people are experimenting with their Prii nowadays :)

    I have a question for you that you may be able to answer. (Individual thread here: Solicited CAN Messages, Anything special required? | PriusChat )

    Basically I can receive all passive messages on the bus, the ones that are just being broadcast normally, but I cannot get any "solicited" messages. Have you had any luck with that? Anything special you have had to do, like a CRC, or anything like that?
     
  13. jdh2550

    jdh2550 Co-Founder, Current Motor Company

    Joined:
    Nov 16, 2010
    317
    246
    0
    Location:
    Ann Arbor
    Vehicle:
    2005 Prius
    Model:
    N/A
    See this thread:My Duinomite Mega Canview V4 equivalent Project | PriusChat lopez has successfully retrieved solicited messages.
     
  14. planetaire

    planetaire Plug in 20 kWh 85 km/h or > 208km range

    Joined:
    Aug 11, 2009
    190
    138
    15
    Location:
    France
    Vehicle:
    2007 Prius
    Model:
    II
    Which dongle or device connected on the canbus do you use ?
     
  15. jdh2550

    jdh2550 Co-Founder, Current Motor Company

    Joined:
    Nov 16, 2010
    317
    246
    0
    Location:
    Ann Arbor
    Vehicle:
    2005 Prius
    Model:
    N/A
    It arrived today (haven't opened the box yet) - so I can start on making it into my new whole pack monitor (pack voltage, pack current, pack temperature(s)).

    Watch this space.
     
    NortTexSalv04Prius likes this.
  16. miscrms

    miscrms Plug Envious Member

    Joined:
    Aug 21, 2007
    2,076
    520
    5
    Location:
    Phoenix, AZ
    Vehicle:
    2005 Prius
    Awesome project, and great that you are doing this all out in the open! Keep up the great work!
    Rob
     
    jdh2550 likes this.
  17. roflwaffle

    roflwaffle Member

    Joined:
    Feb 23, 2012
    381
    74
    0
    Location:
    Orange County
    Vehicle:
    2005 Prius
    Model:
    Five
    Like miscrms said, awesome thread! I also have a question... Are you going to design the system such that both packs will be used equally when recharging, and if so, are you concerned about wear on the Li pack? I ask because it looks like a unit of energy stored in the NiMH pack will be roughly half the cost of a unit of energy stored in the Li pack (~5c/kWh stored versus ~10c/kWh). The energy stored in the Li pack is still probably cheaper than gas, but at the same time I think the system could be more cost effective if there was some way to dump energy from regen into the NiMH pack first and then utilize the Li pack. That said, have you thought about this, and is it even feasible?
     
    dave77 and jdh2550 like this.
  18. jdh2550

    jdh2550 Co-Founder, Current Motor Company

    Joined:
    Nov 16, 2010
    317
    246
    0
    Location:
    Ann Arbor
    Vehicle:
    2005 Prius
    Model:
    N/A


    To answer your question: I'm ripping out the NiMH pack entirely. It's heavy and only has a small capacity.

    Now a question for you - I'm not sure I understand your numbers?

    If we look at price per kWh
    - Let's say a used Prius pack is $1895 for ~6Ah * ~230V = 1.4 kWh. That's about $1350 per kWh
    - My lithium pack is $4000 for ~40Ah * ~230V = 9.2kWh. That's about $435 per kWh.

    Or are you talking about expected life? In which case I think it would be more about price per mile, not price per kWh. Furthermore, it's not really valid to compare the NiMH battery used mainly for engine assist vs. a Li pack used for main traction. So, I'm not even sure how to do that comparison.

    Or are you talking about charging efficiency? I've no idea on those stats at all!

    So, I'd love to understand your figures (I'm not doubting them - I'm just not understanding them).

    Thanks to both of you - I'm having a blast. I just need more time in the day - won't be able to do much on this in the next couple of weeks - too much other stuff going on... :(
     
    dave77 likes this.
  19. roflwaffle

    roflwaffle Member

    Joined:
    Feb 23, 2012
    381
    74
    0
    Location:
    Orange County
    Vehicle:
    2005 Prius
    Model:
    Five
    I'm looking at the cost per kWh stored. A 1kWh NiMH pack, when cycled at ~20% should last ~100,000K cycles according to ECD, and should store ~20,000kWh. At ~10% dod that could approach ~50,000kWh.

    http://www.energyconversiondevices.com/pdf/NiOH2_cycle_life.pdf

    LFP batteries otoh will store more energy at a higher depth of discharge, but less overall when compared to NiMH at a lower level of discharge. For instance Winston batteries appear capable of storing roughly 5000 kWh of electricity for every kWh of battery capacity.

    http://download.solarshop.net/english/uploads/WB-LYP100AHA.pdf

    So, a kWh of LFP cells at $500 storing 5000kWh would run about $.10/kWh stored. A NiMH pack used at 10%-20% dod would likely store at least 20,000kWh and run about $1000 used, at least IME, and would run about $.05c/kWh stored. Not a huge difference, but still substantial, maybe moreso if the pack is being cycled in a very shallow fashion. I'm pretty sure this is why Toyota doesn't recharge the Li packs on their PHEVs. It's more cost effective to continue to use the NiMH pack for shallow cycling than the Li pack. The big, ok well, technically small, takeaway from this is that if you can charge the NiMH pack first using regen, then charge the Li-pack, that's preferable in terms of cost compared to predominantly charging the Li pack. Of course as NiMH pack costs rise that would change.
     
    jdh2550 likes this.
  20. miscrms

    miscrms Plug Envious Member

    Joined:
    Aug 21, 2007
    2,076
    520
    5
    Location:
    Phoenix, AZ
    Vehicle:
    2005 Prius
    Not sure I understand where you are going rofl. Sounds like you're comparing apples and oranges as it were. I don't think the lifetime advantage of the stock NimH pack is necessarily inherent to the battery technology, but is a function of the shallow discharge/charge range allowed. That seems backed up by the chart you linked. A typical regen event is going to be a very small fraction of the Li pack's capacity, and should not count as a recharge event from a life-cycle perspective. From what I understand, pretty much all the damage that happens which degrade the lifespan of the pack happen at the very low and very high end of the capacity range. If the Li pack is sitting at 50%, and then you go down a big mountain and generate 60A @ 240V for 5 minutes straight, that's still only 1.2kWh of power. That would be enough to run the stock pack over its whole range, but in a 10kWh Li pack its only ~12%. Going from 50% up to 62% seems unlikely to do anything to the pack at all. If the Li pack is already near full (or is smaller and gets full), the controller will need to be smart enough to make sure the traditional protections are in place, and CCL goes to zero to protect the Li pack just as it would have protected the NimH pack. It seems like there is no particular advantage to charging into the NimH pack, the advantage is in having the controller smart enough not to overcharge the pack (NimH or Li) during regen.

    I'm also not sure you're correct that the PiP doesn't store regen energy into the Li pack. That seems contrary to what I've read, although I'm pretty behind on my understanding of the final PiP implementation.

    Rob
     
    jdh2550 likes this.