On 30/01/18 15:54, Ahem A Rivet's Shot wrote:
> On Mon, 29 Jan 2018 19:43:02 +1200
> nospam.Richard.Miles@f24.n3634.z1.binkp.net (Richard Miles) wrote:
>
>> Probably going to see if I can get hold of a UPS hat over here pretty
>> soon. I am getting ready to start a car pi project and I have been
>> concerned about how to elegantly shut down when I power down the car.
>
>  There are permanently on rails in all cars, you'll find one feeding
> the radio (as well as a switched rail that only comes on with the
> instruments). Keeping a pi running won't matter to a car battery.
> That depends. I had an alarm destroy the battery in a car after 2 months
off road.

12V, 20Ah. say 5V 140Ah. 2 months is 60 x 24 hours = 1440 hours

So 100mA draw at  5V is enough to flatten a car battery in 2 months

Pi's draw beween 100 and 500 mA whgen idle  depending on model


Its amazing what the Abilitry To Do Simple Sums can tell you when faced
with handwavey statements like 'Keeping a pi running won't matter to a
car battery.'


 >

--
Karl Marx said religion is the opium of the people.
But Marxism is the crack cocaine.

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