Build Hybrid Battery Maintenance Gear For Under $100

Discussion in 'Gen 2 Prius Main Forum' started by PriusCamper, Mar 25, 2021.

  1. fach

    fach Junior Member

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    Update!!! Maybe the RS 75-12 does not have enough juice to run the blower.
     
  2. fach

    fach Junior Member

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    The second phase is completed! I need to test now! I changed the origin 12vdc power supply (rs 75-12) for an atx computer power supply!
     

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  3. PriusCamper

    PriusCamper Senior Member

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    UPDATE: So tonight @fach stopped by to test out his new rig as well as endure my rage at my own Prius problems (Side note: have ya'll ever looked at the prices of trailer wiring kits compared to what they do? I need a cheap trailer brain part / trailer lighting system controller / build from scratch---> please help! Please send links!)

    Point of this comment is that the battery maintenance rig Fach built as explained above in his posts works. There were some loose connections as always and discussion about improving the voltage to the cooling fan / long term protection of cooling fan, but in general what he built as described above was successful in the first round of testing.
     
    #43 PriusCamper, May 12, 2021
    Last edited: May 12, 2021
  4. PriusCamper

    PriusCamper Senior Member

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    Also of note with the fan controller, we ran the battery cooling fan at a full 12v and compared it to how the prolong system by hybrid automotive would use that 12v to flip a relay inside its green box that then would slowly raise the voltage from 0v to up over 6 volts near 7 volts and fan ran much slower than at a full 12v. We also connected an old module at 7.4v on it to power the cooling fan and it ran much faster than Prolong box runs it, but much slower than direct 12v runs it.
     
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  5. alftoy

    alftoy Active Member

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    Nice progress. I've got my charger on the back burner. Spring has sprung, so its get the garden tractors and tiller going for Ma. Change winter tires. Replace water pump on Rav, oil, hydro fluid changes for garden tractors. Refurb mower decks so I can sell a couple garden tractors, CV boot on Tacoma needs changing etc etc. Minor body work for Prius, wheel bearings, brake rotors, pads before I can recertify for the road.

    What trailer wiring are you working on or require?
     
  6. Dxta

    Dxta Senior Member

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    @fach and alftoy. Can't I use any other power supplies apart from the ones referenced at the beginning of this thread?

    I have got some 48VDC with 10A output, with input of voltage of 220AC.

    I have been using about two of them connected, to give me about 92VDC that I have been using to charge my battery pack outside of my Prius. I don't use blower fan though, but just run a small PC fan, used to cool the batteries while charging.

    Here's my question:
    1. Can you provide any schematics on how one can hook up the output terminals of this charger to the hybrid battery pack while it's in the car?
    2. When connecting your charger to the hybrid battery pack in the car, should the service plug still be intact, or removed (this I know would break the circuit though)?
    3. How are you fooling the blower fan at the rear when charging the battery? Are you using a separate blower fan, or the one in the vehicle?

    Thank you.

    PS: I'm planning on getting more of those power supplies (48V), to make them up to if possible, close to 400V.
     
  7. alftoy

    alftoy Active Member

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    Instructions to hookup to hybrid battery

    2004 – 2009 Toyota Prius Plug-and-Play Car Harness Installation Instructions | Hybrid Automotive

    Video to connect charger.



    You can use atx computer power supply, lots of videos show how to rewire output 12volts to run the battery fan. Unplug the factory plug at the fan and connectthe atx power supply as Fach mentioned.

    Educate yourself, why reinvent the wheel. Olrowdy explains why charge at 350ma.

    V2-grid-charger-discharger MOD
     
    #47 alftoy, May 13, 2021
    Last edited: May 13, 2021
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  8. PriusCamper

    PriusCamper Senior Member

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    While you could in theory build a hybrid battery charger with six 10amp 48v strung together to quickly charge a hybrid pack up to 235v it would be way to high of an amp load for balancing cells in the 240v-245v range because NiMH don't like being overcharged and can quickly get damaged if you do it. That's why for balancing you need something in the 1/4 amp range because then the overcharging happens very slowly and will dissipate the overcharge as heat with minimal to no damage to modules.
     
  9. PriusCamper

    PriusCamper Senior Member

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    Once it arrives I think I finally figured out the trailer wiring solution with this 5 wire into 4 wire box for $17: United Pacific 90623 Trailer Light Converter - 4 To 5 Wires | eBay

    I think I had a bad box in my previous trailer wiring and if you try to replace stuff like this you can only find ridiculously overpriced "kits" specific to the vehicle and the more expensive the vehicle the higher the price for the "kit." Truth is all you need is the $17 part and spare wires.
     
  10. fach

    fach Junior Member

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    Howdy @Dxta ! As @alftoy said, follow the schematics from Olrowdy! The only thing that I change was the power supply for the fan. The RS 75-12 did not work for me, and the ATX power supply is giving the juice that I need for the car fan and A tiny addon that I am working on adding that is not necessary, but I think nice to get.
    About connecting the charger to the hybrid battery, please read the top of the link that alftoy share with you:

    "WARNING! (Now that I have your attention, please read the next sentences carefully.)
    There are dangerous high voltages inside the charger and IPU. You can be KILLED if you are careless and don't follow the safety instructions while building the charger and when installing the charging harness. At the same time, if the IMA battery breaker switch is OFF and you follow the warnings given in this article and in installing the charging harness from installation instructions given from the web, it is quite safe to work on this high voltage system. If you are not comfortable working around high voltage, try to enlist the help of someone that knows what to do. (Or just wear latex gloves).”

    We did remove the services plug to install the cable and then reinstalled the service plug when I completed the installation. About the fan, like alftoy said, I unplug the factory plug, and I connect the power from the ATX. During our test @PriusCamper believes that running full power the fan will kill the fan faster (we do not want that), and we were thinking of adding a PWM motor speed controller to reduce the speed of the fan motor and, in this way, mimic the slow fan speed of another system.

    pictures of my cable for reference.
     

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  11. PriusCamper

    PriusCamper Senior Member

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    Update: @fach and I were texting yesterday about the idea having this charger build automatically switch from discharging to charging and then back again via an Arduino. We might try to use some spare relays from an old battery pack for this. Anyone ever put much research into re-purposing the battery pack relays?
     
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  12. Dxta

    Dxta Senior Member

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    Hi @fach . Isn't it possible for me to incorporate a 50ohm resistor in my charger circuit, to bring the current down to 1-2A, since my charger outputs 10.0A of current?

    Here's how I got the proposed resistor value:
    My charger info;
    96.0V with 10.0A outputs.
    V=IR
    R=96/10
    R~9.6ohms

    New resistance value (R1)to reduce current to 2.0A(I1) becomes,
    R1=IR/I1
    Where R1 & I1 are new resistance and current values for the charger.
    Therefore,
    R1=10.0*9.6/2.0
    R=48.0 ohms
    ~ 50.0ohms.

    From my estimates, I know that a 50.0 ohm resistor may work to bring the current down to 2.0A that would be safe for the batteries. What do you think?
     
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  13. PriusCamper

    PriusCamper Senior Member

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    For best results you want to bring the signal down to 1/3 of an amp for the balancing portion of the charging process... And 10amp of charging is fine but switch to 1/3 of an amp once you get into the 230v range...
     
  14. Dxta

    Dxta Senior Member

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    Any ideas how that can be achieved? Are you guys having a separate discharger, how?
    If I'm using 10A, that implies that my HV cabling to the battery pack would be thicker, and not of a less thicker size like you guys have with a less than 1.0A current. So bolting it to the module stud 8mm would be a problem.
     
    #54 Dxta, Jun 13, 2021
    Last edited: Jun 13, 2021
  15. PriusCamper

    PriusCamper Senior Member

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    The problem is only once the battery pack reaches full charge... You could charge the pack at 50 amps if you wanted. But once you get to full charge it's the nature of NiMH to be damaged by over charging, which is why balancing all modules/cells (aka: full charge) needs to be done at a 1/3amp or less, which is why we're using the specific equipment mentioned in this thread.
     
  16. PriusPatrick

    PriusPatrick New Member

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    Prius Camper....this write up is awesome on the battery grid charger......and while i love the idea of building this and rehabbing the battery on my 2008 Gen 2 Prius, my wife will kill me with another project. That being said, i read somewhere in here you service the old Priuses for a pretty decent fee. Is this still the case??? I am in the vancouver/portland area and would to entertain your services.....let me know!!! Thanks in advance.

    Patrick.

     
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  17. PriusCamper

    PriusCamper Senior Member

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    Just sent you a private message...
     
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  18. tangerino

    tangerino Junior Member

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    I'm in a similar position as PriusPatrick and would also be interested :) I'm in south Seattle
     
  19. Dxta

    Dxta Senior Member

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    Do you think, the voltage sense wires, and all that, can cope with the 10.0A current flow, without those getting hot?
    I know during normal driving conditions, the vehicle sees more current draws from the pack than this.
    What do you think?

    Dxta
     
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