Has anyone installed the enginer PHEV?

Discussion in 'Prius PHEV Plug-In Modifications' started by alevinemi, May 28, 2009.

  1. Flying White Dutchman

    Flying White Dutchman Senior Member

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    some new one's

    - wy not combine 2 dc - dc converters and get 24amps
    what is good for easy eV mode driving.

    -maybe this is becaus the HV wire;s from the kit do not go to the current sensor? and wy not? easy installation?

    -wy not cell the battery's next to the DIY kit for people wanting only the battery's?

    -i see a controller en dc- dc converter butno charger? of is the controller box the charger.. but where is the controller box then?

    -the onlu picture you use is from a gen 1 prius.. wy not make one including a video from the gen2?

    -wy not sell 63 battery's and charger with a BMS+ from hybrid interfaces?
     
  2. miscrms

    miscrms Plug Envious Member

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    Sounds too good to be true, but who knows? This basically appears to be a simplified version of the cal-cars setup (basically a battery in parallel with a big switch) or Manzanita Micro setup (basically a battery in parallel through a DC to DC converter). The simplification is basically leaving out the CAN bus monitor.

    My biggest concern is how do you protect the OEM battery if you don't monitor the CAN data? It _seems_ to me like this unit may still try to charge the battery under conditions when CCL is set to 0 by the controller to keep the battery from charging to protect it. That could include conditions where SOC is high, or battery temperature is out of range for example. If they use a DC output voltage on the converter that is low enough to protect the battery, they probably won't be able to trigger SOC drift. Since the PHEV current has to be run outside the battery current sensor (to avoid a current imbalance error that shuts down the hybrid system) the only way for the coulomb counter in the battery controller to recognize the extra charge coming in and adjust the SOC up is for the Voltage to get high enough to trigger the recalibration routine. If the controller never raises SOC up to >70%, the Prius won't make any special effort use more electric drive than usual, and mileage won't be significantly improved.

    I could be wrong here, but the reason the cal-cars conversion (which set out to develop the simplest possible effective open source conversion) got as complicated as it did was because there are a lot of issues that came up with regards to protecting the internal OEM battery and/or convincing the prius HV system to actually use the extra charge tha was available to it.

    Look forward to seeing what folks find out!

    Rob
     
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  3. SageBrush

    SageBrush Senior Member

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    Man that was a useful post. Thanks! Do you know the min and max SOC of the extra battery; that is, how much of the rated pack is useable ?

    I wildly guess that I average 5 kW in city driving, so this pack will blend in 50% electric. If it is reliable it is a *great* buy.
     
  4. mrbigh

    mrbigh Prius Absolutum Dominium

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    It will be reliable as the batteries last, we do not know yet the constant discharge rate to be used,1C, 2C, 3C or up to 4C
    You have to realize that the sixteen 40AH LiFePO4 Battery Cells do power only a low voltage input (48VDC) DC/DC converter up to 240 VDC.
    This extra power source directly attached to the HSD converter side of the OEM NiMh battery pack doesn't go through the current sensor (so no Coulomb counting), the Battery Management System of the Prius never see an extra power source, but being that the Enginer DC/DC converter provides a constantly 240 VDC (while the LiFePO4 40AH juice last) at such a higher voltage the ICE turns on less often at speeds above the 34 MPH mark.
    The Enginer system is not meant for purely EV driving, so far I understud by their advertising, is a high speed enhancer that will minimize fuel consumption. Another way of PHEV.
    So far, I still like the BMS+ system
     
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  5. SageBrush

    SageBrush Senior Member

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    MrBigh,
    Please correct me if I am looking at this system the wrong way -- I just think of it as an average 2.5 kW assist for the useable capacity of the extra battery. In city driving I average about 40 kph, which requires about 5 kW. That means about a 50% electric blend.

    This might be the first sub $25k, 100 mpg city car.
     
  6. SageBrush

    SageBrush Senior Member

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    Somewhat off-topic --

    Any ideas how efficient the charging is from the wall ?
     
  7. NWPriusPlus

    NWPriusPlus Junior Member

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    Having read the Enginer documents (thanks to everyone for the links), I am impressed with the apparent quality and completeness of the package (automatic fire extinguishers no less!), but there is one aspect that is especially puzzling.

    Everything that I have read online since 2007 leads me to believe that any PHEV battery current must be inserted into the Toyota system inside the Hall sensor next to the Battery Energy Control Module, or else the current being measured by the BECM sensor will not match the current being read at the MG1 and MG2 inverters, and DTC's will be set. According to the 2006 repair manual, the MIL will illuminate and the car may or may not drive normally, depending on which DTC is set.

    Since the Enginer documents and photos clearly show their connection to the Toyota HV cables are to be made outside the Hall sensor (as mrbigh has pointed out), I must be mistaken about the DTC. Could someone comment please? Thanks.

    NW BMS+ Driver
     
  8. mrbigh

    mrbigh Prius Absolutum Dominium

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    We do not have any facts yet from anyone who had install the Enginer system, no even data from the manufacturer, in order to have a relevant testimonial of range/use.
    We will see the posts of the "Enginer's" adventurers in a short while I guess.
     
  9. mrbigh

    mrbigh Prius Absolutum Dominium

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    I think that we had crossed our path in the past............besides being your first post at PC.
    Apparently, the constant 240VDC applied to the HSD will not trigger any DCTs but, if this source will start turning on and off constantly (probably because of a DC/DC converter malfunction), believe me that the vehicle will start throwing DCTs all the time do to a Voltage imbalance at the input of the HSD monitoring system.
     
  10. miscrms

    miscrms Plug Envious Member

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    A few more thoughts:

    - This appears to be a system designed in China, the office in Michigan seems to just be a US distributor. Not necessarily bad, I just point that out as I think there was some confusion.

    - Diagram posted previously from the EAA PHEV site clearly shows an included 48V pack charger, again there seemed to be some confusion:
    Enginer - EAA-PHEV

    - Diagram shows 3/4kW DC : DC converter. I assume 3kW for the 2kWh pack, 4kW for the 4kWh pack? At 240V, that should be capable of 12.5A max output for the 2kW or 16.67A max output for the 4kWh pack. That sounds pretty lean to me for being able to stay in EV or stealth mode much. For comparison the Manzanita Micro DC : DC converter used in the PiPrius conversions was a 4kW power factor corrected unit that cost ~$2,500 by itself. Even combining this unit with a CAN bus controller and using the Prius HV system data to control the converter states it seems they struggled to get the MPG averaging much over 60mpg. IMHO this is likely because the dc:dc converter just can't really put out enough current to keep the ICE from lighting frequently, or offset a lot of gas at high speeds. From what I recall the Cal-Cars pack is putting out 40-60A cruising at 50-60mph (supplementing the ICE and running at 80-100mpg) and up to 100A during EV acceleration.

    - When the 2kW pack is putting out 12.5A @240V, the draw from the battery should be about 62.5A, plus a bit for conversion efficiency. If they are using a 16 series pack of 40Ah batteries, the discharge rate would be ~1.6C. Probably ok, but depends greatly on the batteries. The OEM NimH batteries are capable of well over 10C in bursts (100A from 6.5Ah batteries), but they are quite exceptional. Many cheap NimH or Li-ion batteries are unhappy about anything over 1C.

    - From what I've heard a series string like this without a BMS is a pretty bad idea. I don't see any indication of BMS in their diagrams, and at this price point I'd be very surprised if it had one. Maybe with only 16 cells it will be ok. For comparison, our local dealer sells Chinese Thundersky LiFePO batteries 16x40Ah with charger intended for electric scooters for $1270. The BMS they offer would add ~$1500. An off the shelf 4kW dc:dc converter would probably be $1-2k.

    - From a functional perspective, I really wonder how much the car is going to be able to use the power from the extra battery. From the early days of PHEV conversion people tried just increasing the capacity of the built in battery and charging it externally, and found they got almost no benefit. This was due to the Battery controller not recognizing the extra charge and there fore not using it. Since Voltage is a poor indicator of state of charge for NimH batteries, the battery controller uses a coulomb counter to measure the amount of current going into and out of the battery. It doesn't particularly care how big the battery is, because it knows how big its supposed to be. It doesn't care what the level of charge is, because it knows what its supposed to be. It was soon discovered that by raising the system voltage above 242V, you could trick the battery controller into thinking the battery might be over charged and running a calibration routine to adjust the SOC upwards (frequently referred to as SOC drift). It was also quickly discovered that leaving the system voltage at >242V for too long would quickly raise the SOC above the point where the car makes efficient use of electric drive and actually hurt mileage. Leaving it at >242V for too long also will eventually overcharge the original battery potentially reducing its lifespan. From there it was determined that a means of dynamically connecting and disconnecting the >242V pack was needed, and that the SOC range over which the car would make efficient use of the extra battery energy available was really quite slim, maybe only a few percent in the vicinity of 72% SOC. Because the margin was so slight and the changes occur so quickly, it was determined that this could really only be accomplished by a dedicated micro controller. This controller would monitor the CAN bus for SOC, as well as a number of other parameters and decide on the fly when to connect and disconnect the extra battery to maintain optimal performance. This system worked quite well under controlled circumstances, resulting in the early fleet of 100mpg+ capable cal-cars conversions. From these cars, it became clear that while this system worked, it had flaws. The ideal SOC depends on a number of factors, including temperatures and driving conditions, to name a few. While these vehicles made excellent demonstrations, it was quite tricky to maintain these results in real world day to day conditions. A big part of the problem was the inherent clunkiness of dragging the real battery SOC around to different values, combined with the fairly simple controller used which basically used a series of relays to do very basic logic. This gave rise to the SOC spoofing controllers used today in most conversions. This has the advantage of just letting the OEM battery be maintained at its ideal SOC (~60%), while the controller tells the system that the SOC is something else. This allows much greater precision, reaction time, and flexibility, allowing these conversions to really get the most use out of the external pack possible. Even with all these smarts, it still takes a concerted effort on the part of the driver to maximize efficiency. Its been pretty well documented that your average fleet monkey can manage to get only 50-60mpg out of these cars, while a careful driver can get well over 100mpg. Without all that technology, I'm pretty skeptical that this product will do much for your mileage, but maybe they've come up with something clever that has alluded everyone else.

    - As I indicated above, my biggest concern is that in addition to potentially not working very well this pack might damage your OEM battery. As most know the Prius only uses about 40% of its batteries capacity, from about 40-80% SOC. This is one of the keys to making the battery last a very long time. The portions of the charge/discharge curve that occur below 40% and above 80% are much harder on the battery and will shorten its life. While it uses coulomb counting to keep track of SOC, there are numerous other safeguards including temperature and voltage monitors to make sure it stays in this range. Preferentially the Prius tries to maintain the pack at about 60% SOC, or somewhere in the neighborhood of 225V. From the table I've seen 45% is in the neighborhood of 215V, and 81% is around 238V. The voltage can go well outside these ranges for short times under heavy load (down to 180V or so) and heavy regen (up to 280V maybe), but these are dynamic voltages not related to the steady state SOC of the battery. Its the same reason the lead battery in a regular car can ready 14 Volts when the alternator is running, but has a real resting voltage at 100% SOC somewhere around 12.5V. Lead acid are also much more tolerant of overcharging (and in some respects actually need periodic overcharging), and alternator voltage regulators as a result are often pretty sloppy. NimH and Li-ion are very mush less tolerant of overcharging. Anyway, if the external pack voltage is >242V anytime the battery current is near zero or discharging, and 81% SOC is ~238V, it would seem to me that this system has a distinct possibility of regularly charging the OEM battery beyond its 80% SOC limit. This is potentially bad for battery life, but also bad for MPGs. As anyone who has come down a mountain grade and gotten full green bars part way down may have discovered, when SOC goes over ~80% the car goes into a mode similar to B mode, where it dumps energy out of the battery by spinning the ICE with the electric motors. This is its last line of defense to stop the battery charging more and potentially damaging it. Its been found that once you get into the high 70s or so, efficiency takes a big hit as the car just wants to get rid of charge and doesn't care about using it efficiently. There are other protections on the built in battery as well, that are enforced by the CDL (current discharge limit) and CCL (current charge limit). Anyone who has played around with EV mode is probably familiar with the seemingly random behavior that sometimes dictates whether you can or can't get into EV mode, and how long you can stay in it or how hard you can accelerate in it. SOC is only one piece of the puzzle in a very complicated algorithm that keeps the battery safe. By not having access to the CAN bus, I would be concerned that this pack can't know the status of CCL, and will go ahead and dump charge into the pack when the controller says its unsafe to do so.

    - If they are using a system voltage of 238V or less, they should be ok from a battery safety perspective (assuming they also have built in temperature monitors and other sensors to try and guess what the CCL limit is). However, as mentioned above at 238V you can't get into SOC drift, which means the battery controller will never adjust the SOC upwards to reflect the extra charge added. This gets you into a screwy operating range where the batteries real SOC is higher than the battery controller things it is. This means the controller will try to add charge to the battery when it doesn't need it. For example if the controller thinks the battery is at 60%, but its really near 80%, at the next stop the controller will try and charge up the battery more. This should raise the voltage and eventually trigger an SOC drift, but I'm not exactly sure how this will work. As I said above the voltage at the battery can I believe temporarily get up to 260 or 280V under heavy regen, so I would guess the battery controller knows to ignore high voltages during braking. It might not figure out its overcharged the battery until after the regen is done and the battery is resting again at too high a voltage. Now the SOC gets adjusted upward to well over 80% and the car dumps charge by whatever means available, regardless of efficiency. All in all that sounds very inefficient as far as getting the system to use supplemental pack charge, and doesn't sound very healthy for the OEM pack either.

    As I said above, I look forward to seeing what more people find out. If this simple system actaully works somehow, it could revolutionize PHEV conversions by bringing them into a much more reasonable price range.

    Rob
     
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  11. miscrms

    miscrms Plug Envious Member

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    As I recall the DTC problem occurs if you _do_ put the supplemental pack current through the hall effect sensor. This was tried initially, as it would be very desirable for the BMS to measure the current from the supplemental pack and register the real SOC in real time w/o having to SOC drift. This unfortunately causes a DTC though that shuts down the system. When the system is idle, but the pack is in parallel it would see current coming into the battery through the hall effect sensor, but none of the downstream current sensors would be showing any current output, so DTC and shut down the system. Under electric drive, with the supplemental pack in parallel, the supplemental pack would be dumping current into the HV lines headed toward the inverter motors directly w/o it going through the hall effect sensor. This would reduce the amount of current put out by the oem battery through the hall effect sensor. Now the current out of the battery does not equal the current showing up at the inverter/motors, must be an error DTC and shut down.

    By putting the supplemental pack current directly onto the oem battery without going through the sensor both conditions are fixed. At idle, current flows into the pack and charges it without registering any current on the sensor. no mismatch equals not DTC. Unfortunately also means BMS does not register the charge. Under electric drive, the current from the supplemental pack adds to the current from the oem pack, and both pass through the hall effect sensor together. Now all the current from both batteries is accounted for, and matches the current measured at the other end so again no error.

    You can see from the cal-cars schematic below that they apply the supplemtal pack directly to the battery, not through the hall effect sensor:
    http://www.eaa-phev.org/images/4/4a/EAA-PHEV-PRIUS-HighPowerSchematic.png

    Rob
     
  12. miscrms

    miscrms Plug Envious Member

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    A few more thoughts after finding the ebay ad:

    - it does appear that they have some sort of BMS as they claim battery balancing. That should be good news for cell life.

    - battery max discharge is ~3C, so ~1.6C shouldn't be too bad. Not quite as cushy as the 0.3C that they measure cycle life at, but probably not too much worse.

    - It would seem like all they would need would be an "on/off" digital input to simulate the contactor used in cal-cars conversions. That would give you the option to use this with either a CAN-View or Chris Ewert's SOC spoofing controller. For an extra ~$500 I would think that would give you a much more capable system. I guess you'd need the ability to turn it up over 240V to, if that is the voltage they are running. Many dc:dc converters are adjustable and externally triggerable. It would almost be worth getting one of these just to play with, it seems quite a bit cheaper than you could buy all the components for.
     
  13. NWPriusPlus

    NWPriusPlus Junior Member

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    Thanks to both mrbigh and miscrms for their prompt replies to my question. I have printed out miscrms summary of the Plug-in Prius conversion saga that has stretched on for so many years and across so many mail-lists. What a treat to have it all so well expressed and in one place.

    I apologize for not making myself clear before. By "inside the Hall sensor" I meant that the parallel packs should be tied directly to main Prius battery, as you have explained, to avoid the current mismatch DTC’s. (I was mentally picturing the way my BMS+ parallel packs are connected, “inside†of the sensor, i.e. on the battery side, but did not express myself clearly).

    So mrbigh’s explanation that a constant input on the HSD side may not trigger the problem must be the reason the Enginer system could work. It will be interesting to see how it turns out!

    NW BMS+ Driver
     
  14. miscrms

    miscrms Plug Envious Member

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    I haven't seen the install pdf yet, anyone have a link? The link at EAA PHEV didn't seem to be working for me earlier....

    I do believe that some people were successful putting relatively small currents through the sensor, but sooner or later they all ran into issues as I recall.

    How do you like your BMS+? I like the idea of Norm's setup alot. My only concern with it is how well the stock batteries will hold up to cycling. There had been some reports back a while that people had tried using the Prius cells in full EVs with disappointing results, but I don't think they had a BMS. I haven't had much time to keep up with PHEV events lately, so I haven't heard much about how the BMS+ is working out.

    Rob
     
  15. eddiem

    eddiem New Member

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    I will install the 4KW kit this Tuesday; can a ScanGauge II show if the stock battery is being overcharged by the Enginer kit?
     
  16. toddwking

    toddwking Average Joe

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    Did you get it installed? I think you'd be the first of us. I'll have it installed tomorrow, but won't personally be able to drive it for a few more weeks.
     
  17. eddiem

    eddiem New Member

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  18. SageBrush

    SageBrush Senior Member

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    Thanks for the posts, miscrms. Very useful for laypeople like me. At a minimum, I'm happy to see that battery costs are not outrageous anymore; as for the electronics prices, they are much more a function of sales volumes.
     
  19. NWPriusPlus

    NWPriusPlus Junior Member

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    The link for the installation manual at EAA PHEV as given in post 51 above seems to work ok, at least right now.

    How do i like our BMS+ so far? I love it. We'll see how the batteries do, but it has been one year to date and they seem to be exactly as they always have been, at least as far as I can measure. I have a rather long review that may not be quite ready for prime-time, but since you asked I will try to post it later on today (new thread in this forum). It contains photos, so I have to wait to get 5 posts up before the links will work!

    NW BMS+ Driver
     
  20. miscrms

    miscrms Plug Envious Member

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    Based on info here, it looks like scan gauge can monitor SOC, HV Volts, and HV Amps.

    http://www.scangauge.com/support/pdfs/XGAUGE.pdf
     
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