YAPiP - recreating pEEf's approach

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

  1. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    YAPiP = Yet Another Plug-in-Prius.

    Introduction & Background:

    (This is somewhat wordy - but I want to be upfront and (a) provide acknowledgements & (b) describe my "for fun not profit" approach).

    I'm about to start on a project to try and recreate pEEf's approach. More accurately, I'd say that I've always wanted to do the complete pack replacement and had planned to use a software based approach. pEEf has already done that - so I'm standing on his shoulders. He's very generously shared some key information and I'm feeling optimistic.

    Probably overly optimistic! (But, hey, isn't that how all DIY projects start???).

    Go on over and read that thread (and hey I'd recommending just buying his car if you just want the end-result): http://priuschat.com/forums/gen-ii-...-plug-in-hybrid-electric-vehicle-project.html

    I plan on documenting my progress here depending on how well the forum approach works for me. If not, I'll move to a blog format. I hope to follow an open-source philosophy - I'm doing this for fun - not profit. If I get this working and you "copy" me - then more power to you! If I get this working and you want my help or my software then chances are if you ask nicely you can just have it - but with no warranty expressed or implied. If you get your own PiP working and you feel that I was helpful then I'll always gladly take a PayPal donation so that I can fund my next "for-fun-not-profit" project. But I won't even entertain taking money for a specific product - with that comes the responsibility for support. Support is fun when it's not required. It can become tiresome otherwise ;-)

    If this goes really, really well then I'm toying with the idea of a self-published book. But that's just idle chatter at the moment.

    BTW - my day job is Current Motor - Home - so I have access to everything I need (and if you want to go for a 2-wheel EV instead then check us out - OK, I promise that's the only advert I'll post!)

    Next post will detail my proposed BOM (bill of materials - no explosives required)
     
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  2. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    OK, as promised here's my proposed high-level BOM:

    • Car: Gen 2 Prius - I don't actually have one yet. Anyone have an '04 or '05 for < $10K? Anyone want to take an '03 Ford Focus SVT as trade? Yeah, I didn't think so... I actually have quite a few possibilities from the internet - so I just have to pull the trigger on one. But if anyone knows of a bargain please let me know!
    • Pack: 72 x 40Ah GBS cells. That should give me more than enough EV only range for my needs (my guesstimate, based on 250 wh/mile, gives me about 29 miles range using an 80% DoD).
    • Charger & BMS
      • option 1: Elkon 2.5kW plus miniBMS
      • option 2: three charger/BMS from our 24 cell bike
    • Controller: Atmel AT32UC3C-EK
    • Springs: Where can I source stiffer springs? I've got a request in to PIS for just the springs but I can understand if he doesn't want to supply just those. Anyone out there know of a good source?

    This pack will give me about the same voltage that pEEf used - his A123 cells have a nominal of 3.3V whereas the GBS's list a nominal of 3.2V (however I'll have far fewer interconnects than pEEf's pack because of a simpler pack topology).

    Also, 72 happens to be 3 x 24 and I have access to a reliable supply of excellent 24 cell BMSs. I might go up to as high as 78 cells - depending on packaging and depending on if the higher voltage causes any issue.

    If you're going to "play along" with me then you should be able to use pretty much any pack that outputs a nominal voltage around 230V and can supply at least 100A of output current. Also, you'll need to go with your own charger and BMS combo (perhaps the option 1 of an Elcon charger and miniBMS if you're going LiFePO4) - because ours aren't for general sale. If any of you have that Mr. Fusion project or over-unity hydrolysis working just configure it for 230V - 250V of nominal output and you're golden.

    The Atmel eval kit is the real find (thanks to my brother! thanks Dave!). It appears to be the ideal development platform for this - even has an on board touch screen. All for only $299. Such a bargain! To program this you'll need a couple of tools. I recommend the AVR Dragon as the hardware programmer (as it also supports JTAG debugging - whereas a simple programmer such as the AVR ISP doesn't do debugging) and using AVR Studio 5 as the IDE (free download). For any coders out there the IDE is built on top of Visual Studio.

    Atmel Eval Kit: Atmel Store / Atmel AT32UC3C-EK
    Atmel Dragon: Atmel Store / Atmel AVR Dragon

    If anyone has any comments, suggestions or questions please let me know.

    Step zero: get a darn Prius!
    Step one: when the Eval Kit arrives (on Friday) write a CAN packet sniffer application that outputs info to the LCD.

    I wouldn't rush out and buy anything yet if I were you - but if all goes well then this should be about the easiest of all the PiP conversions to perform. All of them need a battery pack - so that's a wash between all of them. pEEf's approach involves removing the factory pack, putting in our own pack (it was so nice of Toyota to give us that plastic tray area to use!) and replacing one of the control boxes with one of our own.

    Game on!
     
  3. lopezjm2001

    lopezjm2001 Senior Member

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    Great. At the moment I am using a ICE kill switch. Although I am happy using an ICE kill switch It would be nice to have a board that would make the Prius use more battery than ICE when I do long trips that would require me to use blended mode instead of pure EV. The BMSplus does this to a extent to draw out 40 Amps on average by SoC spoofing but I believe this JDH2550 board would have more ability to make the Prius draw a lot more than 40 amps on average and less ICE.

    Incidentally you may also be recreating the ECM controller that was programmed by Kiettyyyy for the PIS kit. For this reason I will not call it an ECM controller but I will refer to it as the JDH2550 board.

    I have volunteered to be a test pilot. (You can call me test guinea pig #9).
     
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  4. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    As far as I understand things the PIS "ECM Controller" by Kiettyyyy is doing something similar but not the same. I think it's a read-only device (reading the CAN messages - or possibly using remote frames to request specific PIDs?) that sends signals to the PIS "front board" which allows the "front board" to control the "back board". The "back board" then controls various hardware aspects of the vehicle (by wiring into various I/O lines? - I'm getting very fuzzy at this point).

    A better description from Kiettyyyy would be most welcome!

    The pEEf approach monitors the CAN bus and also writes it's own messages to the CAN bus. It also separates the engine ECU onto it's own CAN bus. So it acts as a gatekeeper between the main controller (The Hybrid Vehicle Controller or hvController) and the engine controller (or iceController). The controller we're replacing is the battery controller (or bmsController). I'm inventing some terms here as I go (consider it a hybrid of pEEf's terminology (also the official Toyota nomenclature?) and my own abstract model).

    So, if I'm understanding it correctly, the PIS control flow looks like this:

    1) A combination of hardware inputs and digital input from Kiettyyyy's ECM controller is processed on the front board
    2) the front board sends control signals to the back board
    3) the back board twiddles some hardware to affect changes in Prius operation
    4) Kiettyyyy's controller sees the affects of those changes on the CAN bus.

    Whereas the pEEf approach looks like this:

    1) Read the CAN bus
    2) Replace old messages with new messages

    The *BIG* difference (IMO) is that pEEf's is a much higher-level "software only" approach to fooling the Prius into doing what we want. Whereas PIS (and other similar solutions) fool the Prius by overriding some of it's input signals. pEEf's requires no hardware hacking - PIS requires some hardware hacking.

    Does that make any sense? At some point I'm going to draw up a diagram to help keep it straight in my head (at which point I will ask pEEf to critique said diagram).

    I've been reading up on CAN this evening - getting ready to tackle the job of beginning to passively monitor the CAN frames. Oh what fun! :)
     
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  5. DaveAK

    DaveAK New Member

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    This is a project that I've been toying with for a while. I would have loved to play along with you, but now my money is tied up in another project that probably shouldn't be mentioned in these parts. :D

    First thing I'd say is are you sure 40Ah batteries are up to the task? I know we're comparing apples to oranges but my bike runs 60Ah Sky Energy cells and I run at around 1.5C on them cruising. When I open it up I can get over 3C from them. I'd be much happier running under 1C. Until my money was tied up I was considering going to A123 pouch cells which you can now get for less than my original SE pack cost me. I'd be happy cruising at 2-3C on these.

    I'm sending a response to your email now.
     
  6. lopezjm2001

    lopezjm2001 Senior Member

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    I would have expected that the PIS ECM controller would be fooling the hardwire electrical Inputs on the ECM. Hence ECM controller. The front controller only reads the Canbus through the OBDII plug? The ECM controller does not intercept can frames on the Canbus? Still a bit fuzzy myself.

    The pEEF approach requires replacing the OEM HV battery and Battery ECU? Yes/no
     
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  7. cproaudio

    cproaudio Speedlock Overrider

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    I want to know if this can be done to Gen III Prius.
     
  8. lopezjm2001

    lopezjm2001 Senior Member

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  9. Flaninacupboard

    Flaninacupboard Senior Member

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    Not really. From what I understand the sensors from the nimh pack now feed directly to the HV controller, as do the sensors from the engine. That makes spoofing battery information impossible, and divorcing the engine from CAN impossible. Not sure how PIS are doing it (I suspect they are doing something to encourage the ICE not to run, setting some condition or error, maybe saying the ICE is over temperature or something like that)
     
  10. Flaninacupboard

    Flaninacupboard Senior Member

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    I'd be very interested to see some more data on seperating the ICE from the CAN. I have had a project in mind for a while of removing the ICE from a gen2, replacing it with a ~50kw DC motor powered by a ~20kwh pack. Intercepting the CAN messages requesting ICE RPM controls the motor speed, and stops any "oh my god the engine is missing!" messages getting back to the HV ECU. Leave everything else as is, so total power output is the same, regen just goes to the stock nimh pack, and you have a ~85 mile range nice EV.
     
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  11. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    Hi bro! Your secret is safe with me (hint all the gas I save my brother burns...) Oops. Never trust me with a secret.

    Yeah, it's a bit too much of a difference to compare. I'm going to be operating at ~240V so @ 100 Amps that's 24kW. You have an 84V system I believe so your Amps will be higher.

    In fact the system limit for the Prius is approx 20kW - limited by the DC-DC boost converter (info courtesy of pEEf).

    My cells are a touch on the "skinny" side for sustained freeway speed (pEEf reports an approx 100A load at sustained freeway speed).

    I may look at those A123 pouch cells - I keep hearing about them. Can you give me a link to a supplier?
     
  12. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    Yes.

    The new "Battery ECU" sits between the main HV ECU and the ICE ECU. Another way of saying that is that we put the ICE ECU on it's own CAN bus and the new ECU creates a bridge between the original bus and this new bus (and that's how it changes the messages).
     
  13. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    Agreed - this is a Gen 2 only mod - sorry.

    However, at the end of pEEf's original post he responds to a similar question by saying:
    On the 3rd gen: It's very hackable, maybe even more so. I have looked at it a few times and it should be possible to do many interesting things. Since I don't currently own one, I haven't investigated further.
    So, don't give up hope. However, I don't have the budget to buy a Gen 3 - so it's strictly Gen 2 for my project for now...
     
  14. mrbigh

    mrbigh Prius Absolutum Dominium

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    Here you have the best deal of today days, EBAY.
     
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  15. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    That sounds very doable by taking the same approach as I'm contemplating. Basically the control messages from the HV ECU boil down to "give me this much additional power" or "spin at this RPM" and responding to requests from the ICE to "warmup". So, you'll have no need for the latter messaging and on the former messaging (RPM and Power) it doesn't matter to the HV ECU what's providing the power or doing the spinning (anyone with enough hamsters could also play along).

    But my question is "why?" (and if it's just because you want to climb Everest then that's a fine reason).

    I used to be a "purist" - I wanted a BEV not a PHEV. After all a PHEV has twice the complexity of a BEV, right? And one of the things I like about BEV's is their relative simplicity - no "warmup", no "NOx" issue, no etc. etc. etc.

    However, with current tech, a PHEV suits my needs exactly - most of the time I'll be doing < 40 miles and be on EV only. When I want to do a longer trip then I have "unlimited range". And, here's the kicker, converting a Prius from HEV to PHEV is, IMO, much easier than doing a BEV conversion. It's certainly far less expensive (I can get a PHEV on the road for $15K including the car!)

    Put it another way with a 40 mile range PHEV I can cover 100% of my needs and about 90% of those will be covered by EV only. Whereas with a 100 mile range BEV I can cover maybe 95% of my needs - the other 5% I'd have to rent a car. That 5% is no big deal if everything else were equal - but it's not. Also, there is the "range anxiety" issue - or, in my case not so much about anxiety as about a complete lack of planning...

    If you want to do a HEV to BEV conversion - go for it! I'm not trying to dissuade you - just describing how I "evolved" on this subject.
     
  16. Flaninacupboard

    Flaninacupboard Senior Member

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    Well I want a BEV, and a it to be a good car. The Leaf is great, but costs $40k here, even a second hand one is $29k. Two year old second hand iMievs are $21k. If I could make a 85mile range BEV Prius for $20k I'd be quite happy, particularly as all the HV components would remain standard/known/reliable/replaceable, and the BEV components could be upgraded/enhanced as desired. i.e. If I build a 192V pack with 10 paralleled Headway cells, I could at some point add 2 cells to the paralleled ones for a 20% range jump. To do that to a Leaf or iMiev is still a big unknown at the moment, so would be gutting if I got one and found I need just a -little- more range.
     
  17. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    Sounds good to me. You're right that the Prius makes a great starting point for a BEV conversion.

    BTW, I missed the fact that you're in the UK. I'm an ex-pat - I believe it was Oscar Wilde who said "The UK and the US two countries separated by a common language"... I can certainly agree with that sentiment! :) My folks live in Shrewsbury and I'll be there at the end of June.
     
  18. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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  19. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    Here's a possible vehicle for you. I know this is far away but, I'd be remiss if I didn't mention him to you. Steve @ Autobeyours is a longtime member here with an excellent reputation. He may be able to work something out with you but, I'll let him speak about that. He has been very active in the Prius/PHEV community.

    DISCOUNTED INSURANCE SALVAGE
     
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  20. DaveAK

    DaveAK New Member

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    I just worked on the principle of 100A = 2.5C from 40Ah, regardless of volts, vehicle, etc. Not sure what GBS rate their cells at, but that would be a little more than I'm comfortable with. If it's a peak that you don't expect to see much then not so bad, but my bike cruises at 1.5C which is too high for my liking on these prismatics. Still going strong though.

    Don't have a URL, but here's a quote from elMoto.net:

    There's still the argument over authenticity and quality, but the price is hard to argue with. I think they're testing out to be around 18Ah's or so. I also think that for the quantity you'll need you may be able to do even better on price.