On 30/01/18 20:01, The Natural Philosopher wrote:
> 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
>
that should be 12V,  70Ah...

> 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.'
>
>
>  >
>


--
How fortunate for governments that the people they administer don't think.

Adolf Hitler

--- SoupGate-Win32 v1.05