Battery drain - how long does yours last?

I’ve had two Supra’s and both seemed to drain the battery quicker than I recall with previous cars

I know usual suspects are radio and alarm, but is there anything else that commonly drains Supra batteries? Or do I need to adjust my thinking that three weeks without driving is enough to kill a battery in any car?

* It is not often the Supra is left stationary for this long!

My battery lasts about 2 weeks any more and it won’t turn the car over but it runs the alarm and a front facing camera that is motion sensitive

Mine was always about 2 weeks too but killed a couple of batteries because they kept going flat. Meant to fit a battery cut off switch that still allowed a small current draw to power the alarm but never got round to it

Mines the same and if it’s not used for a good 3 weeks the battery will be pretty much flat and hardly start the car! That’s why I bought a Ctec trickle charger and connect it up to that now when not using the car for long periods.

If it's cold it's particularly bad, probably 3 weeks, otherwise a month before non start, I do try in the winter to start and free up the brakes every 2-3 weeks but. So yes nothing unusual on yours!

It usually takes about 3 weeks to drop the voltage of the fully charged battery to around 10.5-11V. After the charge of the battery has been drop under of 11V it really does flat fast. Keep your car battery charged via smart charger or pull the negative terminal off to extend the battery life if the car stands unused.

Thanks all, it’s good to know that is normal behaviour, certainly saved me a few £££ to get somebody to check the electrics

It's always hard to compare these values as some Supras run 60Ah batteries but some of the facelift cars have the 45Ah smaller terminal batteries. As well as the quality and type of battery makes a big difference, any lead-acid battery will be permanantly damaged when it drops below 12.1-12.2 Volt for a longer period of time. Dry batteries like AGM or EFB(start-stop system type) can handle this better than traditional lead-acid batteries but they will prevent the car from starting as well when dropping too low.

If you have the possibility you should always connect it to a electronic charger like the CTEK units that automatically monitors and charges the battery when necessary and also shuts off when it's not. A good charger will save money in the long run. Jumpstarting the car with cables or a booster is a temporary fix as it won't save an already damaged battery when drained.