Inverters - Anyone Know about These?

• 

  outlander on 04/05/2018 - 01:13

  +1

  I know a little about it.

  Far as I know, there's no real way to tell without running it through an oscilloscope and watching the power signal. You could make a guess that because its only $140, and its being sold by catch, that its not a very unit, but that would be just that - a guess.

  Goods is a subjective term anyway. It might be able to handle one load fine while fail on another one more sensitive to variation.

  What is it your trying to run? 600w is pretty beefy. Is it a projector?

• 

  MishyMoo on 04/05/2018 - 02:31

  Thanks outlander.

  A Nutribullet (blender). 650w.

  I guess one of the things that could happen is I'd blow a fuse (hopefully not blow up the blender). From what I've read, some inverters have an internal fuse (would need to pay someone to fix it. WallCann said $50 to fix), some have have external (which I could prob fix myself). I've seen some advertised with spare fuses, so I'm guessing that's something that happens.

  I could end up needing a b&m store for this type of item… Not sure what Catch's returns policy is these days…I haven't bought from them for about 3 yrs). They used to be good.

  Inverters are a lot cheaper on eBay also. I'm just not inverter-educated enough to know what I'm buying yet..

  • 

    outlander on 04/05/2018 - 12:54

    Hmmm… You might want to go for double the capacity then (a 1.5kw inverter)

    The good news is that a blender doesn't require a perfectly clean wave to run, so you can get away with cheaper units that aren't as sophisticated in their inversion.
    The bad news is that a blender is basically a large inductor, and will draw a large surge current at startup, much more than 650w. If your using the blender like many people, pulsing it on and off, it probably will break.

    When it comes to things like this, weight is a good indication for quality. The heavier it is, the more heatsink material is there and the less likely it is to overheat (heat is the main killer of electronics). What I like to do is find an expensive item, see how much it weighs, and try and find a cheap unit that weighs as close to that as I can.

    Another good tip for ebay in particular is the site feedbackselector.com
    It allows you to search feedback by title, so you can get feedback on just that item

    • 

      MishyMoo on 04/10/2018 - 13:32

      I just read back over this.
      Thanks Outlander.
      This info is really useful

• 

  chiron on 04/05/2018 - 08:17

  +2

  For most appliances there wouldn't be much difference between modified and pure sine wave. You can always add extra filtering to a modified sine inverter.
  More importantly, it's the VA rating that matters; the VA dictates how much power is required to deliver the Watts, so a 600W appliance might have a 900VA rating which means that 900W is required to deliver the 600W to the appliance (600W used by the appliance and 300W returned to the grid). The difference between VA and Watts is what's called the 'power factor'.
  So basically, you need to meet or exceed the VA rating rather than the Watt rating. Most inverters can handle an overload for a short amount of time. Something like a blender has a motor which takes a lot of current when starting up, but takes considerably less when running. So a 600W inverter is probably fine for such an appliance because the 600W would only occur for a short amount of time while the motor starts (assuming the VA's match too).
  For reliability though, get an inverter at least 40-50% over-rated, otherwise they'll run hot and be more likely to fail.

  • 

    MishyMoo on 04/05/2018 - 09:10

    Thanks Chiron. This is valuable info.

    Do you know how I can tell if an inverter is a good one from an online description?
    Are there 'brands' or is an inverter simply just an inverter wherever I buy, so one that is inexpensive is just my good luck in finding it?
    … Or is there a shop or website that has a particularly good reputation for inverters?

    • 

      Euphemistic on 04/05/2018 - 11:40

      +1

      You cant' tell a good anything from an online description. You need to find reputable reviews (and that might not be easy).

      • 

        MishyMoo on 04/05/2018 - 15:26

        Thank you for that reminder, Euphemistic. I'm starting to make a few 'buying rules' around this now.

• 

  [Deactivated] on 04/05/2018 - 11:50

  +1

  My hippy friends that live off grid have always told me buy the best inverter you can afford. Deep cycle golf cart battery do well for storage.

• 

  MishyMoo on 04/05/2018 - 19:02

  Thanks stormii
  Much appreciated!

• 

  Euphemistic on 06/05/2018 - 07:22

  +1

  Caravanning forums and sites are pretty informative on this stuff. They use off grid power systems a lot.

  • 

    MishyMoo on 06/05/2018 - 14:36

    Thank you. great idea 😊

• 

  MikeKulls on 05/10/2018 - 11:13

  I bought a cheapo eBay inverter (1000W) and its been running for years. I've overloaded and run it with low voltage and it hasn't caused an issue. Inverters are cheap now. The expensive part is the batteries and solar to run it. It depends how long you want to run it and how long you'll be off grid as to how much you need to spend on batteries. If you will have your car there then just pop the bonnet and run it off the car battery with the engine running.

• 

  MikeKulls on 05/10/2018 - 11:16

  One thing to look for is the standby amps on the inverter. Mine uses 0.6 amps just doing nothing. Some bigger units use 1.5 amps. If you plan to only turn it on as required then no big deal.

  The other thing I would add is your batteries will need to be in tip top condition. I tried running just a 100W bar fridge on mine. It was fine when batteries were new but after they got just slightly old they wouldn't start the fridge. The startup current is huge for electric motors.

  • 

    MikeKulls on 05/10/2018 - 11:18

    Or slightly flat the fridge wouldn't start. Running off the car with the engine running would get around that.