YAPiP - recreating pEEf's approach

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

  1. DaveAK

    DaveAK New Member

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    Check out Grid Connect. They've got similar products, (although not sure about dual channel), and they're US based. I have one of their devices I could send you if you'd like.
     
  2. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    It looks like they're a distributor for Peak - so they do have all the dual channel stuff: PCAN Adapters | Grid Connect

    If you're not using your CAN device now then yes, it would be a great addition to the arsenal. I'm kind of guessing your latest project vehicle doesn't have CAN .... ;) (at least not yet)

    This looks like the most cost effective option: CAN PC104 - PCAN-PC104 Adapter with 1 or 2 Channels | Grid Connect

    Combined with something like this: Welcome To NEUTRONEXPRESS.COM

    But then I'd spend a bunch of time getting all that to work together. I'll stick with the Atmel for now...
     
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  3. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    Yay! I have the SD Card working (just a simple test routine at the moment). I'll start writing some logging code next. Then some analysis code for the files produced.

    I'll be hosting this on GitHub - so you'll be able to see the code then...
     
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  4. ericbecky

    ericbecky Hybrid Battery Hero

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  5. mrbigh

    mrbigh Prius Absolutum Dominium

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  6. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    Thanks for the springs info. Most of the time I'll be solo-driving (now don't hate me - I also ride an electric super scooter for most of the summer and fall) or with my wife and kid (neither are big). I'll start off with no extra springs but probably end up adding them.
     
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  7. ericbecky

    ericbecky Hybrid Battery Hero

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    For the most part, you may not need different springs. Just was sharing the info since I hadn't seen anyone else reply to your question about them yet.
     
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  8. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    Yup & I appreciate it. I'll see how things go.
     
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  9. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    Status Update:
    1) I've officially named her Pippy.
    2) Battery pack is repaired and back on the road.

    Details:
    OK, I have Pippy back on the road. Changing the battery module wasn't too bad - and I doubt I did it in the most efficient manner (I took apart more than I needed to - but it was all a good learning experience). The biggest jigsaw puzzle was figuring out the ducting seeing as I hadn't labeled anything when I tore into her (typical me!).

    However, once all back together she just sat there and said "Problem" on the MFD but didn't produce any fault codes...

    Hmm. I tracked it down pretty quickly to the SMR not engaging (i.e. 220V on the battery side, 0V on the car side). Well this first one had me checking the service disconnect and trying to probe the connector to see if the "reed switch"(*) was closing. Futzed around with this for a while. Eventually I took it off the service disconnect assembly so that I could take a better look on the bench (it's awkward to get to on the car). Turns out what I thought was a switch within the socket is actually a set of extra contacts that are only engaged when the safety connect switch handle is slid down. Duh! I'd been closing the handle but forgetting that it then also slides down. That problem was solved.

    * BTW, I'm sure I've seen that extra interconnect called a "reed switch". That's not what I think of as a reed switch (nor does google: reed switch - Google Search). That's what slowed me down because I thought the little white box at the end of the wire was the switch. It's not, it's an interconnect. Oh well.

    Next I got two fault codes and no READY indicator (and hey, that felt like progress!). One which I forget the number of indicated a bad current sensor - but that cleared up itself and was probably due to the second one: AA4. I got to dig into the Prius service manual at this point. AA4 says SMR3 is stuck open or closed (depending on the sub info on that DTC - but my reader wasn't showing me sub-info). Wiggled the wires (always a good first test!) - still no go. Took out the relay hooked it up to a 12V battery on the bench - clunked close, clunked open. All looking good. Re-install SMR3.

    Ta da! READY and no more MIL. I've been on a couple of drives yet and Pippy is now acting more like what I expect she's supposed to (remember that before she had a bad battery module and the SOC would yo-yo - well that meant pretty much zero battery only operation).

    Having a normal baseline will make ongoing experiments much easier to interpret. I still plan on taking a friend's Prius for a drive and collecting data so that I can compare the operation of his car with mine.

    Next up - time to log some CAN data and create some tools to analyze the log files.
     
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  10. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    OK - I've successfully started gathering timestamped data. At the moment it just logs the first 10,000 records (microsecond resolution timestamp + message id + message data).

    10,000 records takes just over 13 seconds and results in 52 unique IDs. Ultimately I'll log all the data from each run of the car - if I have my math right I can store around 24 hours of data on a 1GB SD card.

    Also, with the same math caveat, I think the bus is only being utilized at about 16% capacity (the bus baud rate is 500kbps and we're seeing around 81kbps of data).

    That all seems plausible. So, now it's on with analyzing / understanding the data. And for that I'll create a couple of things:

    1) A database of known IDs (from kinetic's excellent document: Decoding CAN messages 0x348 & 0x3C8 as described by pEEF | PriusChat). The database will map the ID to a description and to the necessary routines to decode the data payload.

    2) Some visualization tools. Three views spring to mind: (a) a timeline to look at interactions between messages & (b) graphing appropriate time varying signals (RPM, volts, amps etc. etc.) & (c) something to help visualize shifting bit patterns in "flag fields".

    That should keep me busy for a while...

    Progress is progressing.
     
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  11. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    BIG DATA...

    Well, not really, but that's a cool buzzword in the tech industry these days.

    I have my logger working so that it captures every CAN message during a drive. Which means big files. So, now I'm working out how to make my analysis ideas work.

    I'm getting there...
     
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  12. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    OK, as I dig into analysis of the data I think there are 7 PIDs of interest for this project.

    These first two will be used when implementing a bECU that handles the larger pack
    • 3CB - reports CCL, CCD, Delta SOC, SOC, Min & Max battery temps
    • 3CD - reports battery DTCs & voltage
    These next three will be used when implementing "ICE control" to allow high speed EV operation and to provide control over warmup operation. These are the 3 PIDs ** that pEEf refers to:
    • 38 - originates from the hECU & contains control flags and torque and power info
    • 348 - originates from the hECU & contains control flags and an engine speed request
    • 3C8 - originates from the eECU & contains control flags indicating warmup request
    These last two PIDs report information of interest to use in the algorithms above:
    • 39 - engine temp
    • 3B - current & voltage
    Sorry if this post doesn't wow you with my amazing progress. I'm using these posts to record what I consider important pieces of information and also to document clarifications as I go. Of course, if someone sees something that is wrong or wrongheaded then please let me know!

    It's progress. Of a sort.

    ** Note: I'll continue to research these 3 PIDs- but I'm not going to implement anything until I have the large pack handling completed. That means not only the software for the bECU but also the purchase and installation of a large pack. And that might take a while... (what with me being just a tad over-committed...)
     
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  13. Flaninacupboard

    Flaninacupboard Senior Member

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    You can test with a much smaller pack. Say you go with ~72cells series, 4 cells parallel (i.e. Headway) and approx 40AH. Well, you could make a 72 cell 1 parallel pack, to test your charger, BMS and overall operation, just make sure you are controlling CCL and CDL to VERY low values (or be happy to lose those 72 cells pretty quickly!). 72 Headway cells from
    Electric Bike Batteries | Headway Headquarters | LiFePO4 Battery
    would be $1,300, and you could set CCL to 20A and CDL at 30 amps, which hopefully wouldn't make the car too dog awful to drive for testing.

    Just a thought that may help you get through the "proof of concept" stage, and done with all the software and integration, before you make the large outlay for the pack. If you don't toast the cells you've got a quarter of your pack already!
     
  14. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    That's not a bad idea. In fact it's a very good idea. And I never follow good advice... ;)

    Actually, I have a fair amount of experience with batteries, BMS's and chargers. I'm going to go with GBS 40Ah cells. I'm not too worried about smoking the batteries. I'm more worried about the control algorithms hurting the ICE, MGs or inverter...

    Plus I should be able to get the GBS's at the wholesale price :cool:

    Attached is my first attempt at a proposed layout. yapid-layout1.PNG

    The cells are 208mm tall. The connections are recessed and covered by a plastic cover so I don't have to add any height for cables. My rough and ready measurements of the Prius trunk space shows that I have about 150mm to 180mm of depth. So, I'll end up raising the floor of the trunk by about 3 cm. I can live with that.

    The charger has a CAN interface which I'll use in conjunction with the BMS outputs to control the charging profile.

    I imagine two battery boxes - one of which will be on gas-struts so it can hinge upwards to allow access to the spare tire. Or, I might recess some cells in the tire well and put the spare tire on top of them. We'll see...

    But I will have to save up my pennies for a while for that pack.
     
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  15. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    WAIT UP!

    If I have my math right the pouch cells result in a pack with about half the volume of the GBS cells. Yes, I did take into account that they're 20Ah pouches. 44 liters for the raw pouches vs. 84 liters for the "fully packaged" GBS cells. Even if I add 10% volume with packaging then it's still about a 40% space saving. I'd no idea the pouch cells were quite so compact. However, higher density also probably means they run hotter.

    Dang, now I'll have to think about pouches again...:confused:
     
  16. Flying White Dutchman

    Flying White Dutchman Senior Member

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    Do NOT run hot
    Not sure how those gbs di but rheden a123 bags stay pretty cool

    -Htc Tapatalk ( sorry for auto spell correct )
     
  17. lopezjm2001

    lopezjm2001 Senior Member

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    I am using 70 of those A123 pouch cells in series. They do not run hot at all. They have a small internal resistance. They were originally meant for supply to automakers only but A123 lost control. See specs here A123-Systems-AMP20-Spec-Sheet.pdf - Google Docs
    they are the best cells you can get in my opinion as long as you get them with full tabs.
     
  18. ericbecky

    ericbecky Hybrid Battery Hero

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    Thanks for linking to the document I put up. It give some high level info about the A123 cells. (Although I wish I could get even more.)
    I also have other info about the cells at the bottom of the second post on this thread:
    Is there interest in a group buy of A123 20ah prismatic pouch cells? | PriusChat
    Some videos of people testing them, etc.

    Since these cells can take a whole lot of power in/out of them, the amount from the Prius is not really much of a problem. There is a gentleman by the name of Peter Perkins who has been running with 50 of these cells in series in his Insight with no external heating/cooling in England for over two years with no ill effects.
     
  19. lopezjm2001

    lopezjm2001 Senior Member

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    I keep my cells sealed inside tupperware containers with 14 cells and a centralised miniBMS board. Heat is not an issue. They need all the heat they can get in winter. 25degC is ideal temperature.
     
  20. lopezjm2001

    lopezjm2001 Senior Member

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    I keep my cells sealed inside tupperware containers with 14 cells and a centralised miniBMS board. Heat is not an issue. They need all the heat they can get in winter. 25degC is ideal temperature. This shortcut on ebay has more specs
    72P A123 20ah Batteries | eBay
    Each cell has 0.6mohm internal resistance so power loss = 3.84 watts each cell at 80amps flow. How much of it is heat losses I do not know.