Master life.....
 

Any idea how long it takes before the battery dies if the masters left on with nothing else on..........?

Well,
Get a piece of string, double it and take every inch as equalling 5 mins. Now, divide the string by feet equalling the temp in degrees C and you have the time before the battery dies. For a 12 volt battery this time needs to be doubled:ugh:
Unless the aircraft is facing North in which event the battery lasts 50 % longer!:E
You plonka:cool:

An honest question!
Don't be bullied by pra**ts
If the master switch is left on then maybe some electrics will drain even if all instruments,radios etc are switched off.
There will probably be a small leak to earth somewhere,so maybe the battery will last between several days or possibly weeks,even months but it will definitely drain down.
On my race cars there is a master switch which is always off when not running,even so the batteries lose charge over a few months.
Lister:)

Thanks Lister,
Just wondered, cos I left ours on a for bit before realising - but it wasn`t in the hours or days range....more like minutes!

Still think my answer was a hell of a lot more accurate given the facts we had to work with:ugh:

several days to even months, gosh that precise:D

Tee hee, your go:p

I'd suggest even 'hours', depending on the state of your battery to begin with.
I've lost count of the number of times I've had to use external power to get someone's aircraft started because they left the master switch on and then went off for an afternoon's shopping/sightseeing, whatever.
A few minutes isn't going to hurt it though.

Presumably you could wire a decent ammeter in circuit with the battery, turn everything off but leave the master on, observe the current drain and then based on your battery's fully charged rating, work out how long it would take to drain appreciably. However, trying to work out how far it has to drain to the point you can't start the engine is back in string-measuring territory.

If I left the master switch on on my C172 it would be running 2 electric giros and the beacon so I would not expect more that 1 to 2 hrs battery life


shy_one

30 minutes in a healthy 172, I know from bitter experience, never did that again. The only thing on was the gyros.

Engineering was closed but luckily the airfield bum handswung it for me and insisted on charging me $1. I didn't think he would be able to do it and I gave him $10 when he did. What a hero.

Its one argument to hardwire the beacon on with the master switch.

An IFR equipped aircraft battery, in good condition is required to last 30 minutes. I wouldn't expect any more than that.

I agree about the sentiment of the anti-coll light, I never switch mine off if I'm doing stuff outside the aircraft with the battery on (such as refuelling to a fuel gauge total). That way, I'll spot it during my "last look back" before I walk away.... ;)

Should last longer if you have everything turned off, not sure what needs to be on for the 30min requirement but I think it is more than just gyros.