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MiniBMS unreliable charger shut off

Discussion in 'Prius PHEV Plug-In Modifications' started by cproaudio, Jun 2, 2011.

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  1. cproaudio

    cproaudio Speedlock Overrider

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    I recently installed MiniBMS into my system. There are many mornings where I had to unplug the charger because the MiniBMS was beeping and the charger was still charging. Red LEDs are on. Sometimes the charger would shut off then a few seconds later turns back on. I've checked the voltage on the cells with red leds and they were between 3.8 and 3.9V So far no cells are damaged. My kit still functions to its full capacity. The HVC is wired up properly. I've seen it shut off the charger many times. The ignition wire to the BMS is also working properly.
     
    #1 cproaudio, Jun 2, 2011
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  2. Flaninacupboard

    Flaninacupboard Senior Member

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    What are you using to disconnect the charger? a solid state relay for the AC input, or a smaller relay on the DC output of the charger?

    Also, you should have all the red LED's coming on at the almost the same time on miniBMS, if it has been running overnight there shouldn't be some cells red (shunting) and some cells not. did you manually balance the pack before adding the miniBMS?
     
    #2 Flaninacupboard, Jun 2, 2011
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  3. stefano5777

    stefano5777 Member

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    Should have gone with pacificev Bms cp almost 1 month no issues at all I get almost 56V charge everytime
     
    #3 stefano5777, Jun 2, 2011
  4. cproaudio

    cproaudio Speedlock Overrider

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    I'm using a regular SPDT relay to disconnect the AC to the charger. The MiniBMS sends out the HVC signal so it's not the relay. I was under the impression that once HVC occurs it wont reset until the ignition is turned on again.

    I manually balanced the pack after adding the MiniBMS. I over discharge a couple of cells during manual balancing but all the red LEDs come on within 1 minute of each other. By over discharge I mean instead of draining the cells 8 hours at .6 amps I let it sat for 16 hours.
    C12 and C14 trigger the LVC. C11 triggers the HVC. After the LVC, C12 and C14 measured 2.8v while rest of the pack measures 3.2v. I just bought a Mastech 0-60V 0-3A power supply to fully balance the pack.
     
    #4 cproaudio, Jun 2, 2011
  5. cproaudio

    cproaudio Speedlock Overrider

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    I got the MiniBMS before I found out about the PacificEV's BMS
     
    #5 cproaudio, Jun 2, 2011
  6. stefano5777

    stefano5777 Member

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    Well that sucks. You should sell it to some unsuspecting Enginer user in enginers forum and buy the PacificEv bms :)
     
    #6 stefano5777, Jun 2, 2011
  7. Flaninacupboard

    Flaninacupboard Senior Member

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    That's the way it should be. I suspect the contact in your relay is stuck on. i've you've ever plugged in the enginer charger while the AC was hot you'll have noticed it generates a sizable spark. If that happens inside a relay (or a mechanical timer, as happened to me) it will get stuck in the "on" position. i'd reccomend you either use a solid-state relay for the AC input, or connect your relay to the DC output of the charger (that is how the 16D works, i suspect for that very reason).
     
    #7 Flaninacupboard, Jun 2, 2011
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  8. cproaudio

    cproaudio Speedlock Overrider

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    It's not a stuck relay. A stuck relay does not cycle on and off. Mine does. The MiniBMS's HVC output is cycling the charger on and off.
     
    #8 cproaudio, Jun 2, 2011
  9. mrbigh

    mrbigh Prius Absolutum Dominium

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    This is a subject well worth keeping an eye on.
     
    #9 mrbigh, Jun 3, 2011
  10. Flaninacupboard

    Flaninacupboard Senior Member

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    Did you connect directly to the 12V battery, or somewhere else? Where did you ground it? MiniBMS is usually pretty resilient against noise, but there could be a problem there. Have you sent any queries to cleanpowerauto?
     
    #10 Flaninacupboard, Jun 4, 2011
  11. cproaudio

    cproaudio Speedlock Overrider

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    Power straight to battery, ground at HV battery cover. IGN from a relay energized by the "READY" wire. I've even tried disconnecting the ready wire but sometimes I would wake up to a beeping BMS. I have emailed cleanpowerauto and they said that it could be a noisy ready wire but I dont think so because the ready wire is from a relay that get its 12V from battery. I have since wired up my own HVC activated by the buzzer output from the BMS and resets with the ready signal. I may check into it when I clean up the installation on the kit.
     
    #11 cproaudio, Jun 5, 2011
  12. subdewd

    subdewd Junior Member

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    Actually a coil relay can still actuate while the contacts are stuck,
     
    #12 subdewd, Jun 6, 2011
  13. lopezjm2001

    lopezjm2001 Senior Member

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    I cannot understand why you are using a relay energized by the ready signal. You should connect the 13.1 volts ready signal directly to the ignition input of the miniBMS. The miniBMS manual has the following warning"Do NOT leave the ignition key on or unattended while charging, it will disable BMS ability to turn off the charger when the first cell reaches HVC event". If this relay you are using becomes faulty or is incorrectly wired then this could be your problem.

    The problem with AC relays is that when they go faulty they faulter in the on position indefinitely.If this happened, a battery cell could become overcharged and damaged. Try using a normal car relay to isolate the charger output instead of using a AC relay to isolate the charger input. AC relays can be unreliable and this has been my experience as an electrician, they are susceptable to faulter when exposed to high frequency noise which in Enginer's case high frequency noise is emitted by the DC converter. This is another reason why I did not use a AC relay in my wiring diagram.

    My main reason for not using an AC relay was that user's who are not licenced to work with 120Vac or 240Vac and who are not knowledgeble in this area and have no formal training could end up killing themselves. The same reason why Jack keeps all the voltages in the Enginer box at 48Vdc only, with the exception of the DC converter output.
     
    #13 lopezjm2001, Jun 6, 2011
  14. cproaudio

    cproaudio Speedlock Overrider

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    I use the ready wire to energize a relay to take the load off the factory ready wire. The ECU does not provide much current on the ready wire. Any additional load could overload the ECU and fry the output. As it is, the ready wire is switching on the converter and the Enginer BMS. Adding on another device could overload the output. If all these components overload the ready wire and fried the output, Toyota will not warranty it because damage is by overloading. Normally, this wire rests at ground but since I'm using a relay, there's no ground at rest. I don't see the relevance of having the ready wire rests at ground when the IGN is triggered with +12V.
    It switches the Enginer kit on with no problems. It cuts out the converter during LVC with no problem. I heard the buzzard beeped then the red LED on the switch lit up so I know the MiniBMS's LVC is working properly.
    I'm not using A/C relays. All the relays that I'm using are standard potter brumfield 12v automotive relays with the exception of a few DPDT and 4PDT relays. Those are also made for automotive use well as the coils are rated at 12V. I chose to switch off the A/C input to the charger because it's bad to leave the charger on with no load.

    Anyway, I have wired up my own HVC using a SPDT and a DPDT relay with ready wire activating the charger and the buzzard turning off the charger. This is just the band-aid to an existing problem. So far it's working flawlessly. I just got a Mastech adjustable 0-60V 0-3A linear power supply to further balance all the cells. That's why I also installed a switch on the IGN by the BMS to reactivate the charger without power on the car.

    Once my packs are fully balanced, I will wire up the IGN directly to the ready wire with cleanpowerauto's recommended cap and resister to filter out the EMI. I doubt this will fix the problem as the MiniBMS is the component that sends the electrical output to cut off the relay I used to cut off the charger.
     
    #14 cproaudio, Jun 9, 2011
  15. mrbigh

    mrbigh Prius Absolutum Dominium

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    CPROaudio
    The acronym that you are referring to Alternating Current is AC and not A/C. The latest being used referring to Air Conditioning.
    I hope you don't mind the correction. ;)
     
    #15 mrbigh, Jun 9, 2011
  16. cproaudio

    cproaudio Speedlock Overrider

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    I typed too fast.
     
    #16 cproaudio, Jun 10, 2011
  17. lopezjm2001

    lopezjm2001 Senior Member

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    Hi CPR,

    It sounds very strange, the HVC relay signal from my miniBMS operates every single charge causing my charger to stop. My charger never gets a chance to finish charging on its own due to having a low HVC setting of 3.6 volts. My charger goes into constant voltage mode for about 5 seconds before the HVC event occurs.

    A well balance Enginer battery has the charger finishing the charge without a HVC event using the BMS16D because it has a HVC of 3.8 volts (instead of 3.6 volts). I have never seen this happen to me but I have been informed that this is suppose to happen this way.

    I think that you should try using the HVC relay to isolate the charger output, just try it. This is what Enginer does and it is what I am doing and it works every time. If it does not work then go back to isolating the input. It is possible that the Enginer charger needs to see an output current of 0 amps to latch in the off position and stay disconnected after only getting a momentary pulse. It cannot latch if you isolate the input and it will start charging again.

    I doubt that EMI is a problem unless you are using the converter whilst charging, I doubt it.

    Good luck
     
    #17 lopezjm2001, Jun 10, 2011
  18. cproaudio

    cproaudio Speedlock Overrider

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    I ordered the 3.6V version but the HVC occurs between 3.6 and 3.85v Cleanpowerauto does not recommend cutting the charger output. They recommend cutting the AC input instead. Once the cell is fully charged, it raises from 3.5v to HVC in a few seconds. The I have measured the high cell and cutoff happens between 3.65v-3.85v
     
    #18 cproaudio, Jun 11, 2011
  19. lopezjm2001

    lopezjm2001 Senior Member

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    The miniBMS was designed for EV applications, it was never designed to be used with an Enginer kit for a PHEV.
     
    #19 lopezjm2001, Jun 11, 2011
  20. lopezjm2001

    lopezjm2001 Senior Member

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    The miniBMS was designed for EV applications, it was never designed to be used with an Enginer kit for a PHEV. So the instructions applies for an EV and does not necessarily apply for a PHEV with an Enginer kit.
     
    #20 lopezjm2001, Jun 11, 2011
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