240v power 'cleaner' / 12v psu to handle bad input

Discussion in 'Electronics & Electrics' started by ShadowBurger, Mar 18, 2020.

  1. ShadowBurger

    ShadowBurger Member

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    Ok really nooby title, I apologise

    I have a dirty little 2-stroke generator which works great for powering something that doesn't care at all about the state of the AC coming in, but anything even remotely sensitive will be ruined by this thing. I usually use it to power my halogen worklights in the garage as theres no power out there, but when I plugged in my new LED lights they were surging in brightness and then the transformers died within a few seconds.

    I want to be able to run my Waeco fridge off this if I need to but I'm afraid to hook it up and kill the fridge

    What can I stick on this thing to clean up the AC coming out of it? I am guessing both frequency and voltage will need work and I'm assuming that'll be expensive and complicated. I don't want to buy a new generator unless it's a diesel and I'm not ready for that kind of expense

    A 12v DC step down converter that can handle horrible input might do the job in a pinch as I have 12v work lights, I just need to know whether it can handle the disgusting input reliably. 12v 10A or so should do fine.

    What about a PC PSU?
     
  2. theSeekerr

    theSeekerr Member

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    So, the device you're looking for is called a "power conditioner", but those things are expensive, and the most common type probably won't fix the problem you have anyway.

    One reasonable approach is to buffer the output via a battery and an inverter - run a battery charger off of the output of the generator, and an inverter (or 12V appliance) off the battery. This allows you to isolate the appliance 100% from the generator if you need to.

    You could also run a hefty 12V supply directly from the generator and skip the battery - this approaches, in a roundabout way, how modern Inverter Generators work.
     
  3. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    how will I find out whether a 12v battery charger will handle the yucky input? apart from cooking my only charger by finding out the hard way that it won't :p
     
  4. rickbishop

    rickbishop Member

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    If all you're going to be running on it is some LED lights and your waeco fridge, buy a second hand house solar panel, a charge controller, and a 100ah deep cycle battery, then run your lights and waeco off 12v.

    The only expensive thing in this would be the battery. 250w panels are going for about $30 each on facebook, and a suitable charge controller should be no more than $50. YMMV on the cost for the battery.

    I assume this is a shed on a block somewhere, not just in your back yard?
     
    HSV_Enigma likes this.
  5. mAJORD

    mAJORD Member

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    Linear charger won't care.
     
  6. theSeekerr

    theSeekerr Member

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    Yeah, this is the trick - if your charger is linear (i.e. chunky, heavy, uncomplicated, and probably old) it'll definitely be fine.

    Modern switchmode devices may have more difficulties.
     
  7. aXis

    aXis Member

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    It depends on what the actual problem is with the generator output - i.e. does it have a lot of transients, or does it have poor voltage regulation and is causing over/undervoltage.

    For a cheap non-inverter generator I'd be more inclined to think poor voltage regulation. Neither a power conditioner nor double-conversion UPS would help here - the power conditioners usually don't change voltage, and the UPS will probably keep alarming and going offline. You can get a type of conditioner / UPS called an AVR (automatic voltage regulator) but they are pretty rare now.

    A simple, dumb linear 12V power supply would probably work great, with the exception of being poor efficiency. Big toroidal 12V transformer fed into a full bridge diode rectifier, some big capacitors and then a linear regulator set to 13.8V with a beefy heatsink.

    You could improve the efficiency by replacing the linear regulator with a DC-DC converter. It should handle enough swing in the DC voltage to still give a stable output.
     
  8. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    will an ATX PSU do the job?
     
  9. aXis

    aXis Member

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    Probably not, it's likely equally sensitive to crappy power or overvoltage. If you have an old/spare one that you dont mind killing, then by all means give it a go though.

    How far from your house to the shed? Can you run a power supply back at the house, and a long DC cable over to the shed. Even better, a 13.8V power supply at the house and a small car/motorbike battery in the shed as a buffer?
     
  10. merlin13

    merlin13 Member

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    Assuming that one hasn't actually got a problem with the output circuitry, think it'd be more cost effective to simply sell that one and put the coin towards a genset that'll output clean power.

    And a four-stroker as well. Unless you like dicking about with oils...
     

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