Battery life

[Surfer]

I wish this would get posted as a sticky! How long will my 110 amp battery last if I am powering a colour Tv at 65 watt and a satellite receiver at about 30 watt. If some one can post the calculation it would be appreciated. Thanks.

 

[Willy_5041515]

Hi Ian, Power (Watts) = Current (Amps) X Voltage (Volts), according to Mr Watt (he was a Scotsman so it's bound to be correct!). So Watts = Amps and Volts. In your case you are using a total of 95 Watts at a battery voltage of 12 V. So the Amps will be Watts divided by Volts = 95/12 = 8 amps. Your battery can supply 110 Amps for 1 hour so, theoretically, it can supply 8 Amps for 110/8 = 13.75 hours. Sadly, it doesn't actually work like this. The ampere/hour rating of a battery is only a comparitive indication. How long a given current can be drawn continuously depends on the battery construction. But if you take 75% of the answer you won't be far off, i.e. 10 hours (if your lucky!). However, batteries do recover to some extent so you may get more than 5, 2 hour sessions. Enough to keep East Enders going for a week at least.

 

[Pete4]

Bang on Bill, one thing you forgot to mention though is that the higher the amps being drawn off the battery the less efficiant it is. This means that if you draw 1 amp out of a 100 amp hour battery, you should get 100 hours worth but if you draw 2 amps, you get less than 50 hours.

Pete

 

[D@ve]

The other thing that gets forgotten is that as the voltage drops some items (TV's certainly) will stop working long before things like lights etc

 

[sharpy]

we get about 4 days worth from a 110 amp battery. thats using water pump whenever its required, a fair bit of lighting and lots of telly; although sometimes just a weekend will pretty much put the needle well into the red. so i guess 'trial and error' seems to be the rule!

 

[Surfer]

Thanks for the help but if you take sky with you there is no ways you are going to be watching some soap like Eastenders. Can't stand it any way as it is so false it is unbelievable. Star Trek or similar is probably more realistic than Eastenders!

 

[ericcaravanning4u]

Sheesh I woud just plug it in Ha Ha