whats happening here? advice please.

Discussion in 'Tech/Mech General' started by haganap, Jul 29, 2010.

  1. haganap

    haganap Funster Life Member

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    Ok, could some one please help me with some basic laymans advice please.
    I am having problems in my van with power supply for some items,

    1) I have a 300 W inverter plugged in to my 12v power source. It operates certain things such as charging my i phone, powering my sky box (but not the sky+ box for long).

    2) However there is a problem with trying to work some items, namely the laptop's getting charged, and on 1 laptop it will not power it at all, yet when I plug in in the house it powers it with no problem. Also the sky+ box has a little problem powering up as well. I know its a problem because the inverter starts squeeilng. I alway thouht that this was because there was not enough charge in the batteries, however they appear almost fully charged and yet there is still the squeeling.

    3) IS the inverter not up to the Job? I have also noticed that there was a problem with the second leisure battery. I put this in over 15 months ago and only realised today that it has not been rigged up. I put an online fuse in sittu, and today noticed that there was no fuse in it just a plastic dummy one roughly the same size:Blush::Blush::Blush::Doh::Doh: I never shecked I suppose, Or I may of checked but not actually realised it was a peice of plastic and not a proper fuse.

    So can anyone answer the problem please as to if I just need a more powerful inverter.
    The computers are toshiba's
     
  2. jhorsf

    jhorsf Read Only Funster

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  3. Wildman

    Wildman Read Only Funster

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    what current (amps) or power (Watts) does the laptop use. It is possible the startup current exceeds that allowed by the inverter.
    Is the inverter connected direct to the batteries or via a solar charge regulator as that may also complain if the startup current exceeds the limit.
     
  4. haganap

    haganap Funster Life Member

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    Im not looking at the laptop at the moment but it is wired in to my 12v socket where the TV is.
     
  5. Maurice & Val

    Maurice & Val Read Only Funster

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    Most likely not up to the job. My first was a 600w unit which was not good enough for a large 17" screen laptop. Changed it to a 1700w version and now that runs everything via 2 batteries. Next item on my shopping list - solar panel to charge the batteries. (followed by windfarm, nuclear reactor etc etc)
     
  6. MikeandCarolyn

    MikeandCarolyn Read Only Funster

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    For what it's worth,we run a 15" laptop on our 350watt inverter with no probs-usually this is for a couple of hrs in eve-by bedtime 2200ish the 110Ah battery will be at 70% but by 0900 the 2x80W solar panels will have it fully charged again.
    We also use it to charge things whilst driving-razor,laptops,cameras etc.
    Mike.
     
  7. MikeandCarolyn

    MikeandCarolyn Read Only Funster

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    Having just Googled 'laptop power requirements' I've found it seems
    that a 'worse case' scenario for laptops would be around 120W
    :BigGrin:
    Mike.
     
  8. haganap

    haganap Funster Life Member

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    so why will it not charge my laptop, but will my other laptop but both charge at home?
     
  9. lunarman

    lunarman Funster

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    The Inverter should power your laptop easily.

    The problem may be the voltage drop in the wiring to the 12v socket. This happens with mine. If I connect the inverter to the 12v socket fitted by the converter the and try to power the tele the low voltage warning in the inverter squeels and it shuts down. Powering a lower wattage devise it give no problem. The converter used a small calibre wire to connect the socket hence causing a voltage drop over the distance from the battery

    I have fitted another 12v socket connected direct to the battery (fused of course) using a heavier calibre cable and this give no problem.

    Lunarman
     
  10. Brian and Jo

    Brian and Jo Funster Life Member

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    whats happening

    hi paul,hope your are well.yes i think it is as simple as that,the inverter is not big enough to do what you are asking it to do.we have a 2000w inverter in the RV and it powers everything fine.we also have 3 110a batteries annd 2 solar panels,1 80w & 1 160w:thumb:eek:h and i forgot we have a satalitte connection to the national grid:Eeek: regards brian jo and josh
     
  11. MikeandCarolyn

    MikeandCarolyn Read Only Funster

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    I don't know :Smile: I did have a problem with an inverter not working and took it back to Sterling.They tested it and found it to be ok and said to look closer to home.I found that the guy who fitted a battery condition monitor (NASA BM-1) had wired solar panel and battery positives to wrong side of shunt. Put that right and inverter worked fine.
    I hate electrics-you can't see it like you can water-and it bites :BigGrin:

    Mike
     
  12. haganap

    haganap Funster Life Member

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    Ok let me just add this as I forgot to mention it. If I am on hook up, or the van is driving and charging the batteries, The inverter will charge the laptop., does this make a differnece to teh answers? so in essence if the batteries are being charged the laptop works.
     
  13. lunarman

    lunarman Funster

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    In that case what batteries do you have. It could point to low voltage on the batteries. When they are being charged they will be being supplied with nearly 14 volts and thus the 12v circuit will be at the same voltage. The charging source will maintain the voltage when the inverter is switched on. Hence the inverter will not detect a low voltage and thus happily power the laptop.

    Check the voltage of the batteries off charge to see if they are beginning to fail. The current drain from the may be to much for them.

    A 300w inverter should power a laptop which should be between 100 -150w. I don't think a bigger one will solve your problem

    Lunarman
     
  14. MikeandCarolyn

    MikeandCarolyn Read Only Funster

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    So-it sounds as if power will pass through your batteries and run inverter,but that batteries aren't (sometimes) holding enough charge to run inverter.
    I seem to remember reading that a pair of batteries are only as efficient as the worst one.

    Mike
     
  15. lunarman

    lunarman Funster

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    Another thought. Is there a cigarette lighter in the cab that is connected to the vehicle battery. Have you tried to run the inverter through that to prove that it works ok. or tried connecting the inverter direct to a battery to prove if the problem is the inverter.

    Lunarman
     
  16. MikeandCarolyn

    MikeandCarolyn Read Only Funster

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    +1 :Smile: Why couldn't I think of those words lol :Doh:
     
  17. Simannjo

    Simannjo Read Only Funster

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    I think Lunarmans on the right track with voltage drop...

    Closer to battery or bigger supply cables are the key.
    Try it on a standalone battery or another socket as already suggested for confirmation.

    Simannjo
     
  18. JJ

    JJ Funster

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    1.7 kilowatts for a computer? That must be one hell of a powerful machine? Are you running NASA with it? :Rofl1: :Rofl1: :Rofl1:

    JJ

    I understand that some gear deffo needs pure sine wave leccy (nice and smoooooth) and other gear doesn't care (ruffty tufffty Geordie type machines...) :Wink:
     
  19. haganap

    haganap Funster Life Member

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    thanks for all the help guys, Both Batteries are nearly new and are reading 13.6v ish, If I were to wire it up direct to the batteries, would I go to the number one battery direct? (with an in line fuse of course) but what I dont understand is why it will power lesser items with no problem?
     
  20. MikeandCarolyn

    MikeandCarolyn Read Only Funster

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    Paul-Have you read the voltage at the 12v socket? Just a thought :Smile:
    Mike
     
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