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Enginer PHEV automatic over/under voltage protection

Discussion in 'Prius PHEV Plug-In Modifications' started by Daox, Jan 6, 2010.

  1. Daox

    Daox Member

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    The arduino will definitely be on while charging. In the original setup (with no dc to dc converter disconnect), I had planned on powering the arduino with a wall wart type power supply. When you plug in your extension cord to the car it will power up the wall wart which will power the arduino. Once the arduino boots, it will close the relay and allow 110V power to the charger. However, when the car is on, the arduino will be powered off the car's 12V.



    The thought had occurred to me. Also, Eric posted the same concern. The VOX circuit does have an adjustment potentiometer on it to adjust sensitivity. This will need to be adjusted for it to work properly and should filter out any quieter noise the VOX may pickup. However, I have also programmed logic into the arduino to identify beeps versus normal noise. A few clunks here or there will just be ignored by the arduino. I'm confident that (perhaps with a little tweaking) it will work not disconnect the pack unless an actual alarm is going off.

    You could crack open the balancers and tap directly into the alarm signal that goes to the speakers, but I'm trying to design this so you don't have to cut any wires or take anything apart. It'll just be a few connectors that go between other things in the kit.



    Haha, not at all. Questions just make me mull things over and rethink things to verify them. Nothing wrong with that at all. It eventually leads to a better design. Case in point, what happens if you have the car on and its charging? The arduino will have 12V from two sources. I'll have to see if this will be a problem.
     
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  2. dan2l

    dan2l 2014 Prius v wagon

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    Hi Doax,
    You may need the relay closed before the charger is "Plugged-in". If both are on the same primary power the charger may see the relay open and shut itself down while the arduino is booting.

    Thanks,
    Dan
     
  3. Daox

    Daox Member

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    I don't quite understand what you are talking about.

    As it is now, the 110V relay is normally open. The arduino must power up first in order to close the 110V relay and allow power to the charger.

    But, I think you knew that.
     
  4. dan2l

    dan2l 2014 Prius v wagon

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    Hu Doax,
    My error, I was thinking that you put the relay onto the 48 volt lines at the grey Anderson connector.

    Thanks,
    Dan
     
  5. banshee08

    banshee08 Member

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    Would be a bad idea to have no load on a charger with it turned on. I know some of the high powered EV car chargers specifically say "DO NOT TURN CHARGER ON WITHOUT A LOAD ATTACHED".. To turn off the charger correctly you will need to cut the AC power.
     
  6. Daox

    Daox Member

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    Yeah, my electronically minded friend warned me not to disconnect the pack from the charger, but rather the 110V from the charger. He knows a lot more than I do about that stuff, so I just listened. :) He also suggested using the normal power switch signal to power down the dc to dc converter. Its always better to work with low voltage/amperage stuff anyways.
     
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  7. Daox

    Daox Member

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    I tested out the VOX circuit tonight. It works well, but will need a little tweaking. I shot some low quality video of how it works. Comments and questions are welcome.

    BTW, one of the members on Ecomodder thought it was funny how I was basically making a clapper for my Prius. :)

     
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  8. Huibin

    Huibin Junior Member

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    Please see the email replied by Jack:

    Huibin,
    You will have the latest Mottcell batteries which has overcharge protection built-in. You shouldn't have to monitor charging any more with this battery cells.

    Jack Chen
     
  9. Daox

    Daox Member

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    Has he provided any additional information on this? Cutoff voltages? Its great that the NEW cells have this, but what about everyone else? How new is new? A lot of us recently purchased our kits too. Could you get some of this info for us?
     
  10. Daox

    Daox Member

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    Can anyone verify that the 12V 'ready wire' is actually the activation wire for the OEM high voltage pack's relays? I looked in my pictures last night and I couldn't tell. I'm pretty sure it is. There really isn't a reason to send 12V since most logic signals are 5V.
     
  11. dan2l

    dan2l 2014 Prius v wagon

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    Hi Doax,
    I may be miss-understanding your question, but if you you are wanting to verify when the prius battery is connected to the Enginer system, you can pull the blue connectors apart. With the car off you will get 0v. With it in accessory mode you will get 0v. With the car in having the Ready light on you will get 180v-240v, jumping around a little. Be careful, this is high voltage. I set up my volt meter so it was connected and could be seen from the drivers seat and was all insulated. Then I turned the car on and off without touching the DVM or wires.

    Then if you connect the DVM to the 12v lead you should see it on and off at the same settings.

    This would verify the operation of the OEM high voltage pack's relays.

    Thanks,
    Dan
     
  12. Daox

    Daox Member

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    The reason I'd like to know is because I am tapping into the ready wire to get power for the arduino and relay. Its possible, although unlikely, that the ECU's ready wire (mainly the chip in the ECU) may not be capable of powering up these devices. If that is the case, I might fry the chip in the HV ECU, not good! However, if the ready wire is actually being used to power the contactors, I know there is plenty of overhead for me to steal a little power for the arduino and relay.

    I know how I can test it, I just was hoping someone already knew. I don't really want to take apart the back end of my car AGAIN. :)
     
  13. Daox

    Daox Member

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    This weekend was an EV build day for our local EV club. I went and shared what I was doing with the Prius and got some help with modifying the VOX circuit. We were able to remove the on delay that the circuit had built into it. However, we could not get the VOX circuit to trigger well off of the balancer alarm. It was much more sensitive to us just talking in the room. We figured that the circuit was more sensitive to lower frequencies than the higher frequency of the beeper. At this point, the option was to try and find a high pass filter that only allows higher frequencies through, or to dump the VOX all together. In the end, we decided to dump the VOX.

    So, as a few here have suggested, we open up a balancer and looked at the signal going to the beeper. It should be usable, but I'm going to have to reprogram the arduino for this new situation. The beeper acts a bit oddly. Nothing that can't be programmed around though.
     
  14. pbui

    pbui Member

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    I was told that the DB8 buzzer is driven by AC voltage and the frequency is internally generated.
     
  15. MJFrog

    MJFrog Active Member

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    Unless the DB8 converts DC to AC, you were told wrong. There is no AC input to the DB8.
     
  16. pbui

    pbui Member

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    it was in an email from Chargery, the AC is internally generated, probably by the sequencer; after all, there is a round robin cycling to monitor each cell.

    I intent to put a scope on one; but haven't the chance yet.
     
  17. TheForce

    TheForce Stop War! Lets Rave! Make Love!

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    I stumbled on to a device called the MiniBMS wheile I was researching LiFePO4 batteries. I'm just wondering if something like the MiniBMS would be better for the Enginer kit? It looks like it can do everything you need. Here is a link to it.

    MiniBMS

    From what I understand it can do high voltage cutoff, low voltage cutoff, and shunt balancing. Has all kinds of features so you can do bottom balancing or top balancing and also have the charger turn off when the batteries are fully charged.

    It costs $12 per cell and $30 for the main board but if this could work and make the Enginer kit pretty much plug and play I think the price would be worth it.
     
  18. ericbecky

    ericbecky Hybrid Battery Hero

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    So 32 cells times $12 per cell is $384 plus the $30 equals $414.
    I wonder if people are really willing to spend the additional few hundred bucks?
     
  19. TheForce

    TheForce Stop War! Lets Rave! Make Love!

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    Well if this system would work better than the supplied BMS maybe you could order the kit without the supplied BMS and save some money? Or maybe Enginer could start using the MiniBMS instead of the current one and charge a little more or whatever the difference would be. I'm sure if they could buy in bulk the price would come down a little.

    From what I have been reading its better to spend a little more on a good BMS than to get a cheap BMS and have to replace cells. Unless you dont mind baby sitting the cells during charge and discharging. From what I understand and from what I have read the MiniBMS seems to be the one BMS that protects the cells the most. There might be other BMS out there that do the same or better. I just have not seen them. Of course I really have not been searching all that hard either.

    I'm just throwing this idea out there to try to make the Enginer kit better while still being cheaper than any other PHEV kit.
     
  20. dan2l

    dan2l 2014 Prius v wagon

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    Hello Eric and TheForce,
    Thanks to TheForce for finding this. Yes, this looks like it will work. What is most important is the 0.75amp shunt level for balancing. The would help a lot compared to the DB8. Although it looks like the shunt current only happens at 3.8v.

    If buddy cells are used it should be $12*16+$30=$222. This is pretty close to the cost of the origional 4 DB8 balancers. Also, Jack should be able to beat this price in volume.

    Jack says he has already got an improved balancer that does control the Charger. The real question is if this new design would also shut off the converter at low voltages.

    Thanks,
    Dan Lander