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Hi, could one of you electrical experts please help with something obvious? If I am wild camping and using my leisure battery, how long will it last? Do the amp hour rating by the total power being consumed?

ie if I am running a 12V telly that consumes 15W and have a fully charged 85amphour battery, should it last 85/15 hours , i.e 5 and a bit.

thanks

John

i would not try to run my battery down to less than 50%,
lights, 8w over the cooker/sink is normal.
8-10w main lights.
spot lights are 15-21w.
they use lots of power.

to work out what your using:

15w tv = 1.4 amp, aprox      so 10 hours of tv 14 amp from your battery.

dont forget pump for water and light you use in the loo.

i am changing over to LED blubs, 18w output = 150mili amp with LED.

hope that helps.

floppy

Hi Floppy,

sorry for being dense but how does 15W convert to 1.4amp?

And then how did you get that 1.4 amp = 10 hours from an 84 amp hour battery?

thanks

John

p.s just reread and I guess you are saying 10 hours = 14 amps leaving 70 amps? but still dont know how to convert watts to ampshours

Quote: Originally posted by firruk on 30/10/2007

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Hi Floppy,

sorry for being dense but how does 15W convert to 1.4amp?

And then how did you get that 1.4 amp = 10 hours from an 84 amp hour battery?

thanks

John

p.s just reread and I guess you are saying 10 hours = 14 amps leaving 70 amps? but still dont know how to convert watts to ampshours

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ok, 15w /12v = 1.25 amp hours, but nothing is perfect, so would go for 1.4 ah to be safe.

so its, w / v.     18w /12v = 1.5 amp hours, that 1.5 amps from your battery every hour. does that help any.

floppy

Thanks,

suddenly that physics comes rushing back, but its a long time ago!!

regards

John

Volts X Amps is Watts

Watts divided by Amps is Volts

Watts divided by Volts is Amps