Inverter question

Discussion in 'Tech/Mech General' started by Road Runner, Aug 19, 2008.

  1. Road Runner

    Road Runner Read Only Funster

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    At what stage of the battery charge condition will an inverter stop operating?

    I am have trouble the minute my batteries drops lower than 12.6 volts and feel this cant be right.
     
  2. johnsandywhite

    johnsandywhite Read Only Funster

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    :Cool: How far away from the batteries is the Inverter? Is the Inverter directly wired to the Batteries or is it connected via the cigarette lighter connection? :Wink:

    The Inverter should work down to 10.9 volts (unlikely depending on current draw) more or less.
     
  3. pappajohn

    pappajohn Funster Life Member

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    what you checking your battery voltage with John.

    i think they drop out at around 11.5 volts and mine has an audible warning when it senses low battery then a few mins later it turns off.
     
  4. Road Runner

    Road Runner Read Only Funster

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    If i try running it off the RVs leisure batteries it doesn't last very long through the vehicle power sockets.

    I have a spares 110 amp battery and sit the inverter on top and last lot longer but inside the vehicle.

    Say i wired the inverter outside near the leisure batteries would i need to go out at night and turn it off?

    My current inverter is 300 watts but looking at the 600 watt maplins one for £39.
     
  5. Wildman

    Wildman Read Only Funster

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    whilst a fully charged battery is 13.8V or there abouts a reading of 12.6 is considered half charged thus a regulator will prevent further use to prevent damage to the battery. the levels are sometimes adjustable. Inverters use a lot of battery power12V does not magically become 240 or 110V, it comes at a cost and that cost is in amps. Answer is to use less mains voltage appliences when not on hook up.
     
  6. Road Runner

    Road Runner Read Only Funster

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    At present only use 240 volt on ordinary 20 inch TV and Sky box.
     
  7. johnsandywhite

    johnsandywhite Read Only Funster

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    :Cool: I currently (pun intended) have an 800 watt fitted directyly through the floor to the batteries. I also have a 1500/3000 watt 110 volt directly wired in the AGM (6x100ah) basement storage area. I intend (and you CAN too), extend the ON/OFF switch into the RV. Similar to the remote for the genny. :Wink:
     
  8. pappajohn

    pappajohn Funster Life Member

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    are you using a multi meter or the onboard volt meter to check with

    is it a CR tube tele or an LCD.

    the old tube tv's are very power hungry
     
    Last edited: Aug 19, 2008
  9. johnsandywhite

    johnsandywhite Read Only Funster

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    :RollEyes: I must make the point. In our Kontiki. The 300 watt Inverter plugged into the cigarette lighter socket beeps like crazy with JUST the laptop connected. :Eeek:

    TOO MUCH voltage drop.
     
  10. Road Runner

    Road Runner Read Only Funster

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    I was amazed to realise how much wattage a laptop takes when being used direct:Doh:
    rather than just charging, it's a real eye opener:Eek!:
     
  11. Thepips

    Thepips Trade Member

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    Hi John,
    A modern laptop won't need more than 70 watts, 6 amps but you'd need to be watching a DVD, with USB powered speakers and charging a flat laptop battery.

    Regards
    Doug
     
  12. gavel

    gavel Read Only Funster

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    inverter

    We have a 300 watt peak inverter and want to charge our disabled scooter whilst on the move. The scooter is in a trailer. Can this be done please ?
     
  13. Douglas

    Douglas Read Only Funster

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    I see a lot of figures bandied about in regards to battery voltage, the figures above I think are a typo as wildman lists his interests as Ham Radio

    First let me say that TRUE and again I say THE TRUE battery voltage can only be measured when the battery is at rest.

    To give you an example: I have 3 batteries that I keep as spares at home, they are in very good condition and even after they have been off charge for over 2 weeks they are still reading a voltage that is called surface charge IE greater than that of a fully charged battery, of course if I put a small load on them the surface charge will quickly dissipate and then read the true voltage of about 12.8 for a fully charged battery

    Please get it into your heads that you cannot measure battery voltage when it is being charged or discharged, you have to let it rest for a while and after charging apply a small discharge then let it rest first.

    Doug
     
  14. Wildman

    Wildman Read Only Funster

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    13.8V is the level at which my regulator stops charging a battery, it will of course settle after a while,l why do people have to be so pedantic about such things. I try to state general facts that can be understood by the majority of people without going into degree level explainations. The majority of readers just get confused otherwise.
     
  15. pappajohn

    pappajohn Funster Life Member

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    i would doubt it on a 300w peak inverter:Sad: chances are its only 150/200w constant output which is less than 1 amp.

    the scooter charger will take quite a bit more than that i would think!

     
  16. Douglas

    Douglas Read Only Funster

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    Roger, of course you are correct. Incorrect information is confusing. Some one who did not know better would read from your post that a fully charged battery would have a voltage of 13.8 which you and I know is not correct.

    As to being pedantic I disagree, in this instant the information is either correct or not correct and to the people who are looking for information it is VERY IMPORTANT.

    Sorry if I have upset you, but that is better than some poor guy stuck somewhere with a battery problem not understanding why his battery is not reading 13.8 when it only reads 12.something.

    Doug
     
  17. Road Runner

    Road Runner Read Only Funster

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    Caravans have a lead that charge the caravan battery on the move, could you do something along these lines?
     
  18. Losos

    Losos Read Only Funster

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    Roger, just as a matter of interest what equipment in your MH is 'mains only'

    I ask because I will shortly have to do a 'power budget' for all the equipment to be installed in my MH and I'm thinking that maybe I can get away with only the microwave being mains operated
     
  19. pappajohn

    pappajohn Funster Life Member

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    i have 6 mains powered appliances,

    aircon....occasional use, 230v only item

    microwave.....occasional use, 230v only item

    heater......mainly on gas, much warmer. 230v and gas

    water heater......mainly on gas, hotter water, 230v and gas

    fridge.....always, on hookup, 3 way unit

    charger.....always, on hookup. 230v only item

    so only 2 items always on mains.
     
  20. Tony Lee

    Tony Lee Read Only Funster

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    More on the OP's problem.

    Most likely to be caused by excessive voltage drop in the wiring supplying the inverter. Even a small 300W inverter can drag 30 amps and unless the wiring is substantial AND as short as possible, you could easily lose a volt or more.
    With the inverter loaded up, measure the battery voltage and also measure it at the inverter terminals. Less than half a volt difference is acceptable but a quarter of a volt would be better.

    If you choose to install proper wiring, make sure you include a fuse as close to the inverter as possible. A 40 amp fuse in conjunction with appropriately-sized wiring would be good.
     
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