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Adjust DC-DC output voltage && Two

Discussion in 'Prius PHEV Plug-In Modifications' started by overlap, Jun 5, 2010.

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  1. overlap

    overlap New Member

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    (Thanks linuxpenguin for previous answers!)

    Hi. For two+ months I have been observing my Enginer kit, ScanGauge, etc. (Source of great interest and fun!) And with the Enginer Kit OFF and observing the max and average voltage the Prius works to maintain on its own.

    According to my ScanGaugeII my 3000W converter has a (absolute and total) MAX voltage of 238v, and this is only after "charging" the NiMH bettery with the Start button "On" for lets say ~ 30 minutes, and the AMPs are something like 0.5 (less than 1).

    Is there a POT to adjust the voltage a wee bit higher? Just by inspection it seems that putting out a bit more power (amps and volts) say a full 240 or I'd like to experiment with 242 volts for example.

    2nd Question:

    I'm sure most all of you have considered running two (5000W) converters. What seems like a good idea to me is to run one at the factory 240v, and the second 5000W converter at say 220v. What seems cool about this setup is that "mostly all" of the time if there is NO EV mode and minimal amps delivered to the traction motor, then only 1 converter would be doing anything. But if in EV mode and lots of amps going to the traction motor and the voltage drops below 220v as we all see frequently, then more of the power consumed by the traction motor would be coming from the Enginer Kit. If this worked, do you think 6KW of batteries would be sufficient, or is there the expectation that 8KW would be needed?

    Thanks!
  2. dan2l

    dan2l 2014 Prius v wagon

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    Hi Overlap,
    The converter voltage will always read at the Prius HV battery voltage. I expect that your reported voltages are accurate. You should be able to run at 242v. I have done this on a 3k converter with good results.

    Who did your Install? Adjusting the converter voltage and current is an installer function. It is not easy to do and it is easy to mess it up. The process is complicated and can be dangerous. Pacific EV in Bellevue can do it for you. Or you can look at the list of installers on the Enginer Website. If you feel that you can do it yourself then you need to contact Jack for instructions.

    Note that if your ScanGauge is reading 1a then the Enginer system is putting out between 2-3a. The Prius uses more than 1a just setting with nothing on. Your converter is supplying that current plus what you see on the ScanGauge.



    I do not recommend two 5k converters on a 4kwhr system. This could be very stressful on the batteries. I have seen 85a going into my 3k converter at times. So two 5k converters could draw 200+amps. I have seen reports of people trying what you suggest using 2 3k converters.

    Also there are reports that the Prius can throw codes when the converter output goes above 14a. So you might get the best results using one 5k converter with the converter adjusted as high as possible before getting codes from the Prius.

    Thanks,
    Dan
  3. dan2l

    dan2l 2014 Prius v wagon

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    Moved here from another thread
    Originally Posted by overlap [​IMG]
    I am not getting nearly that good of mileage. I'd guess closer to 72 on average and that even requires taking extra care. I also live in the cold and puddle covered roads of Seattle. I'd sure like to get a solid 80 mpg driving mostly normally and hoping the 5000W converter can achieve that. Ideally I'd like to get 99+ but would be very happy with 90 although strongly doubting its possible making zero adjustment driving with general traffic flow. I'd also really like to bump the voltage up a bit to at least be at the full 240v or even 242 instead of the 238 max today. Anyone know if there is a potentiometer to do that? I'm also toying with the idea of two 5000W converters. I would sure hope this would achieve the constant 99+ mpg.

    Hi overlap,
    I just saw your other thread. that may a better place to discuss performance. Do you have an EV mod in addition to the Enginer switch?

    Thanks,
    Dan
  4. overlap

    overlap New Member

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    Thank you very much Dan. I installed it myself, but I have many years of auto mechanics experience working at dealerships multi-year formal training. We know when braking the voltage can climb substantially above 240v so perhaps the Enginer's converter just does not have the power to push the entire HV system (including NiMH battery) up that high. I suppose I could try to drive some external load off the two HV Enginer cables to get a very accurate reading - hmmm. Thanks for the tip about the Bellevue shop. That may be best although I'd want to know exactly how it is done and the necessary parameters to watch. I currently have 6KW of batteries which BTW with the single 3000W converter is sure nice as the voltage drop (and duration) is quite a bit less.

    Does it really matter if error codes are logged? Does the Prius only log them historically but does not change the functionality one bit for how the car functions?
  5. dan2l

    dan2l 2014 Prius v wagon

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    The converter will easily go above 240v for the Gen1 Prius it runs at 300+v. Of course if you set the voltage higher you need to set the current lower to stay below 3000watts.

    If you set the voltage too high then you will get the Prius HV battery to go too high and the Prius will start spinning the ICE to burn off that energy. This waists the charge in the Enginer system. So ideally you want to set the voltage as high as you can get it with it never causing the Prius to go into "burn off the high charge" mode.

    My experience is that 242v is OK. 245v is marginal. 248v is too high.

    Thanks,
    Dan
  6. ericbecky

    ericbecky Hybrid Battery Hero

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    I can confirm that when the amps are too high it will make a Gen 2 Prius code. And it is the kind of code that shuts the car down and you must pull over in order to cycle the car on/off to clear the code. Or use a scangauge. I would be very careful with adjusting the amps.

    The coding is intermittent, although somewhat predictable. We have not figured out all the variables that go into making the car code. Amps of the the Enginer system is pushing, State of Charge, and temperature are some of the variables that play into the coding, but there are more, too.

    You don't want it to happen to you on a busy freeway.
  7. hobbit

    hobbit Senior Member

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    Re: Adjust DC-DC output voltage && Two

    I would like to see a decent study done on how many injected amps
    is considered "too high" by the car *under various running
    conditions*, i.e. at a standstill in READY vs. running on the
    highway with little current into or out of the stock system vs.
    heavy EV on the backroads. I'll bet the thresholds vary based
    on what's going on at the time.
    .
    Exactly what codes are set in these scenarios?
    .
    _H*
  8. mrbigh

    mrbigh Prius Absolutum Dominium

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    I would like to see a decent study done on how many injected amps
    is considered "too high" by the car *under various running
    conditions*, i.e. at a standstill in READY vs. running on the
    highway with little current into or out of the stock system vs.
    heavy EV on the backroads. I'll bet the thresholds vary based
    on what's going on at the time.
    .
    Exactly what codes are set in these scenarios?
    .
    _H*


    Still after a month of some Blah..Blah, nobody is coming forward with some real numbers to interpret.
    Trial and error seems to be the Enginer user's procedures.
  9. Flaninacupboard

    Flaninacupboard Senior Member

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    You really hate these kits, don't you?
  10. kiettyyyy

    kiettyyyy Plug-In Supply Engineer

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    He most does. Just check the previous posts he made about the kit.

    If you're going to flame a kit, please provide some empirical data supporting your claim.
  11. adric22

    adric22 Ev and Hybrid Enthusiast

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    I was under the impression that the DC-DC converter on the enginer kit barely provides any power to the battery at all, unless the car is actually consuming power. I put an amp guage on the wire coming out of my converter to the HV battery in my 2002 Prius and was able to confirm that power flow drops drastically when the car is not doing anything. In which case, when the car is pulling amps, the only thing the car can see is that the battery isn't draining as fast as it should. Which seems good to me because I would think the type of thing that would set a code would be when tons of power is pumping into the system at times the car isn't pulling any amps.
  12. dan2l

    dan2l 2014 Prius v wagon

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    Enginer DC-DC output



    Hi Adric,
    The Enginer system provides power based on the Prius HV Battery voltage, not based on the Prius consumption. So If the Prius is sitting idle but not doing anything but has the Ready light on,.. The Enginer system can still be providing full power if the Prius HV battery is low.
    I do this all the time while charging so that at the end of charge I have both the Enginer batteries and Prius batteries at full charge when I start my drive.
    Thanks,
    Dan
  13. MJFrog

    MJFrog Active Member

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    Re: Enginer DC-DC output



    Are you saying that you leave the Prius in Ready while you charge the Enginer batteries? I thought that the charger was designed so it would detect that the car was still Ready and refuse to charge.
  14. dan2l

    dan2l 2014 Prius v wagon

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    Re: Enginer DC-DC output



    Hi MJFrog,
    I am afraid that your information is not correct.

    I see lots of statements like this where people that do not own and operate a particular system make incorrect statements about it. So I would suggest that we all need to be careful that we only pass on valid information.

    Thanks,
    Dan Lander
  15. Flaninacupboard

    Flaninacupboard Senior Member

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    Wnginer specifically state it can charge while in ready, and suggest you could put a solar panel on your roof to charge while you drive (not too sure on that one) and pre-charge/warm-up as Dan does.
  16. MJFrog

    MJFrog Active Member

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    This is good to know.

    Last night I put the car in Ready while charging and ran the SOC up to 76% before I shut the car off.

    Strange thing during my commute this morning...about 7-8 miles into the commute, my SOC dropped rapidly from ~63% to ~54% level. I saw this happen one time previously. During this time, my Scangauge indicated a -nn BTA reading so I know there wasn't any actual massive charge drain from the HV pack. I can only speculate that the ECU was recalibrating the SOC level. I will keep a close eye out to see if it happens again.
  17. JeffreyDV

    JeffreyDV New Member

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    I have had that happen to me couple of times also. According to the BMS+ website, it is normal for the computer to recalbrate the SOC reading.
  18. Flaninacupboard

    Flaninacupboard Senior Member

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    yes the rationale being that our 40% SOC window doesn't always live between 40% and 80% DOD, but may wander round between 10 and 90% DOD, with some recalibration happening every now and them
  19. skschoch

    skschoch New Member

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    SOC Measurement

    As I understand from reading this forum, the Prius calculates the SOC of the traction battery by measuring the current going in and coming out of it. Its computer then integrates the current difference over time to get the SOC.

    I also understand that for various reasons, this method, while being more precise, can get "off", so in certain conditions, the Prius will "recalibrate" the SOC by measuring the voltage.

    I still don't know when the Prius will do this "recalibration". Anybody know?

    I have the Enginer 4kWh system in my 2004, and I am very familiar with the way it's hooked up, which is actually very simple. The 48V battery pack is connected to both the charger and the DC-DC converter. The only other thing that connects to the charger is the power plug - there is no signaling between the DC-DC converter and the charger. The charger charges the 48V battery pack when you plug it in, and, at least in the model I have, it stops charging when the battery pack reaches its "fully charged" voltage.

    The DC-DC converter is connected to the 48V battery pack, the HV traction battery, and a switch and lights mounted on the dash. The switch is in turn connected to a wire that goes to 12V when the car is "Ready". Thus, the only things the DC-DC converter can use to change its behavior are:

    1. If the car is "Ready" AND the PHEV switch is ON;
    2. The voltage of the traction battery;
    3. The voltage of the 48V battery pack;
    4. The temperature of the DC-DC converter.
    As I understand it, the connection to the traction battery is done such that the current from the DC-DC converter is not measured by the circuits in the Prius. I understand it is this way because the Prius will show a fault if the current from the battery doesn't match the current going to the motor/generators. Thus, the Enginer system is a "stealth charger" that slips current to the traction battery that is not noticed by the Prius until it does a "recalibration".

    I have the model with the 3kW DC-DC converter, so the current is limited to 3000W/240V = 12.5A. I understand the new Enginer systems are shipping with a 5kW DC-DC converter, which can push more current to the traction battery, at the price of using up the charge in the PHEV battery pack faster.

    If I have any of this wrong, please correct me.
    2 people like this.
  20. dan2l

    dan2l 2014 Prius v wagon

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    Re: SOC Measurement



    Yes, I think you are correct and have done a good job describing the Enginer system in simple terms.



    I am not a Prius expert, but I have read somewhere that one of the triggers for the recalibration is if the Prius computer gets a signal that the Prius HV battery is above 242v. This would happen if the Enginer system combined with Regenerative braking got the Prius HV Battery up to its full charge.

    I have my converter set to 242v. I generally charge the Prius to 75%SOC. At that point the converter is putting out about 5a. Then after I drive one mile I go down a big hill that has a 300ft elevation drop. At 75% all works normally, but if I was at 80% then the car seems to do a recalibration that causes some anomalies.

    Thanks,
    Dan
    2 people like this.
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