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MPPT for truck, alternator/solar

Discussion in 'Power Electronics' started by Blackout, May 21, 2018.

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  1. Blackout

    Blackout

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    May 21, 2018
    I am wanting to hook a mppt to my truck and have a camp or hurricane setup. I have 105ah deap cycle to run my fridge, Camp lights, fan, shower, etc. I would like to know if I can us this for the alternator for when the truck is running and solar when the truck is not? Do I need a fuse for whatever the charge control is rated for Plus a battery isolator? I would like to DIY this installation and not have to buy the red Arc bcdc charge controller for $800+. I will ultimately have 2 100w panels on the roof rack and 2 105ah batteries.
    Thanks for the help, Jack.
     
  2. Bluejets

    Bluejets

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    Oct 5, 2014
    Solar controller is a separate unit.
    Vehicle alternators regulate their own output.
    2 panels @100w for at best 5-6 hours a day is 1-1.2kw.(at best)
    Is that enough for your daily use?
    You've listed quite a few loads but no data on current draw so we have no idea of total loading or voltage ( inverter?) efficiency requirement also.
     
  3. Blackout

    Blackout

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    May 21, 2018
    I have the
    Wynter 62dz fridge/freezer @4.5A+- 12V
    2 USB 3w 5V lights that plug into my current pwm charge controller.
    Water pump (haven't chosen one yet) should be 12V 4A, but will only be ran once a day for 20 minutes or so long enough to wash my kids. I'm hoping to get quite a bit of charge from driving via the alternator. I was hoping that the two solar panels would be able to support the batteries and just the fridge if we were were away from the truck for the day or two. Thanks for your reply.
     
  4. Blackout

    Blackout

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    May 21, 2018
    I guess I'm asking if I can connect the trucks alternator to the wind turbine inputs on a 30A wind and solar(dual input) charge controller without an isolator relay? I would need a 30A fuse of course, but wouldn't the charge controller have a built-in isolator relay to prevent back charge into the cranking battery? My porch solar project works well for a few days without sun, 2 panels, 1 105ah battery, and 2 lights. We had water preasure during and after hurricane Mathew 2016, and hurricane Erma 2017. I could heat up water and cook with the Colman stove. The one thing that made it a pleasure was the fridge/freezer and if the battery got low, I had to use the generator to power the fridge and let the battery charge with solar. I now want it mobile for this season and have my ice cream and eat it too!
     
    Last edited: May 22, 2018
  5. kellys_eye

    kellys_eye

    4,282
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    Jun 25, 2010
    Connect 'any' source to the battery via isolation diodes. This will prevent back-feeding from any one to any other and allows whichever source is the most 'prominent' to do the charging.

    Low forward-voltage drop and over-rated current handling values should be considered for safety and longevity.

    There may be some consideration for voltage measurement (feedback to controllers) to be taken into account i.e. some people adjust their alternator output to be slightly higher to compensate for the diode volt-drop. Not essential, but without knowing how your system is configured I can't comment any further.
     
  6. Blackout

    Blackout

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    May 21, 2018
    Diodes? Ok, I thought that the charge controller has the ability to discern which voltage is greater?
    Back feeding to the cranking battery through the isolator is possible? Or is it cheaper/easier to put in fuses and diodes?
    My alternator will never get to 14.5-14.8V, which actually doesn't charge over 13.4V(2016 Tacoma), and mppt "smart charger" increased volts to 14.8. 20V is very attainable for the solar panels, so unless I'm driving at night, the panels will do most of the work, or does it go by amps? Can you draw a schematic from cranking battery/alternator to the deap cycle? Everything is a question because I'm just learning. Thanks
     
  7. kellys_eye

    kellys_eye

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    Jun 25, 2010
    I wouldn't know - you don't post any details of the make/model....
     
  8. Blackout

    Blackout

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    May 21, 2018
    My apologies
    I found this on Amazon
    MarsRock 1400W 12V/24V Off Grid MPPT Wind Solar Hybrid Charge Controller Design for Max 800W Wind with Max 600W Solar Panel with Booster Function
    1. [​IMG]
    2. [​IMG]
    3. [​IMG]
    4. [​IMG]
    5. [​IMG]
    6. [​IMG]
    but am open to suggestions. My budget is $200 for the charge control, I already have 1 Walmart 105ah battery, 2 100w grape solar panels.
     
  9. Blackout

    Blackout

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    May 21, 2018
    BTW, the fridge, battery, pannels and controller is almost 2 yrs old, I bought them b4 hurricane Mathew.
     
  10. kellys_eye

    kellys_eye

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    Jun 25, 2010
    A diode from the output of the alternator to the positive of the battery will suffice. Diode should be rated at twice the current capacity of the alternator.
     
    Blackout likes this.
  11. Blackout

    Blackout

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    May 21, 2018
    Ok, so around 300 amp since alternator is 140. Would I separate the alternator and solar with two different pwm charge controllers? Or would I go from 300 amp diode into wind input on mppt dual input?
     
  12. Blackout

    Blackout

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    May 21, 2018
  13. kellys_eye

    kellys_eye

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    Jun 25, 2010
    The alternator will connect straight to your battery (via the diode). Everything else will be connected as per the last of your pictures.

    The wind and/or solar will charge the battery or, when the motor is running, the alternator will do it.

    Fuses should be used in the battery and alternator lines.
     
    Blackout likes this.
  14. Blackout

    Blackout

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    May 21, 2018
    So I really don't need a dual input wind and solar charge controller. Because, you would suggest to run from the alternator to a ?amp fuse to the diode and straight to the battery, bypassing the charge controller all together. I do appreciate all your help. Thank you for your time and patience.
     
  15. Bluejets

    Bluejets

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    Oct 5, 2014
    Just watch that your alternator has some form of regulator. Some are external ( usually older units) and later models have it internal.
     
    Blackout likes this.
  16. Blackout

    Blackout

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    May 21, 2018
    Yeah, I think the regulator is keeping my voltage down. I was hoping to get voltage up to 14.8 (what the pwm solar charger does). But if that is not possible without buying the Redarc dcdc charger, then I will just have to save up the money for a reliable trustworthy component.
     
  17. Bluejets

    Bluejets

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    Oct 5, 2014
    Fairly standard to have 13.8v on 12v system alternator output.

    As far as the extra diode on the alternator, I don't really see the need for it. There is no external diode on a standard alternator install and it remains connected to the battery during engine shutdown with no ill effect.
     
    Blackout likes this.
  18. Blackout

    Blackout

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    May 21, 2018
    I cannot have the cranking battery for my truck die. It's either an isolator or diode to prevent ANY discharge leaving me stranded in the middle of Ocala National Forest. I will use this truck to camp with the family, to the beach, and still drive to work and park in a secure lot(hospital).
    I'm not optimizing the charge of the battery if the alternator only puts out 13.9, this is why I thought I could use a mppt charge controllerto bump up the volts to 14.8 .
     
  19. debe

    debe

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    71
    Oct 15, 2011
    The most efficient way to charge your battery from the altenator on the vehicle is to use a Redarc isolator. It automaticly connects the battery when the altenator voltage rises. It automaticly switches off when the voltage drops to around 13V. This is what most campers here in Australia use. REDARC ISOLATOR.jpg
     
    Blackout likes this.
  20. debe

    debe

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    Oct 15, 2011
    The diode option is not as efficient due to voltage drop across the diode. This is one of 6, 150A diodes I salvaged from a scraped MIG welder at a scrap yard. They are not small. DIODE 140A.1.JPG DIODE 140A.2.JPG DIODE 140A.3.JPG
     
    Blackout likes this.
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