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"yes but is the beer still cold?"

No, I drank it all before it got warm

Quote: Originally posted by MudIark on 14/5/2007

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Quote: Originally posted by J_Clarkson on 14/5/2007

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Quote: Originally posted by MudIark on 14/5/2007

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Quote: Originally posted by J_Clarkson on 13/5/2007

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....... but in answer to your question, the fridge draws approx 10A and your battery is rated at 110Ah so in theory if the battery is fully charged it will run the fridge for 110/10h = 11hours.

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This is true only while the battery contains 12 volts, once it goes below the fridge will draw more current dropping the voltage quicker and increasing the amperage and so on. Therefore the 11 hours very soon becomes a lot less hence the reason the battery will flatten overnight

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Actually it won't. As the voltage drops so too will the current, its ohms law.

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Ohms Law yes you are right BUT......


120 watt fridge at 12v draws 10 amps (120/12=10)

the same 120 watt fridge now with 10 volt supply (120/10=12) - now drawing 12 amps

At 8 volts (120/8=15) - now drawing 15 amps

at 6 volts (120/6=20) - a massive 20 amps

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Wrong ...

The stated wattage applies only at the stated nominal voltage, and anyway, when a leisure battery voltage drops below about 11.8v the current will be practically nothing so it will never be running at your stated 10v anyway.

As I said before, take the voltage below about 11.5 and the battery becomes a door stop.

Quote: Originally posted by J_Clarkson on 15/5/2007

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Quote: Originally posted by MudIark on 14/5/2007

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Quote: Originally posted by J_Clarkson on 14/5/2007

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Quote: Originally posted by MudIark on 14/5/2007

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Quote: Originally posted by J_Clarkson on 13/5/2007

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....... but in answer to your question, the fridge draws approx 10A and your battery is rated at 110Ah so in theory if the battery is fully charged it will run the fridge for 110/10h = 11hours.

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This is true only while the battery contains 12 volts, once it goes below the fridge will draw more current dropping the voltage quicker and increasing the amperage and so on. Therefore the 11 hours very soon becomes a lot less hence the reason the battery will flatten overnight

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Actually it won't. As the voltage drops so too will the current, its ohms law.

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Ohms Law yes you are right BUT......


120 watt fridge at 12v draws 10 amps (120/12=10)

the same 120 watt fridge now with 10 volt supply (120/10=12) - now drawing 12 amps

At 8 volts (120/8=15) - now drawing 15 amps

at 6 volts (120/6=20) - a massive 20 amps

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Wrong ...

The stated wattage applies only at the stated nominal voltage, and anyway, when a leisure battery voltage drops below about 11.8v the current will be practically nothing so it will never be running at your stated 10v anyway.

As I said before, take the voltage below about 11.5 and the battery becomes a door stop.

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Dont worry about, I have been an electronics engineer for 20+ years after finishing my degree in Electrical and Electronic eng.

If you don't believe me then try it, just hook a battery with an ammeter in series across the grey plug and watch the current fall over a few hours but don't ruin your battery.

Quote: Originally posted by lunarjon on 13/5/2007

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there was acheap generator on ebay this morn for 35 and 10 delivery id sugest using one

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Quote: Originally posted by Flandersfields on 18/5/2007

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Quote: Originally posted by lunarjon on 13/5/2007

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there was acheap generator on ebay this morn for 35 and 10 delivery id sugest using one

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This generator sold for £47.00 plus £10.00 delivery, my local B&Q have exactly the same for £39.99!

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Dont buy one for use with a caravan. Its almost certain to blow up your battery charger/psu.