Can you drain battery completely by listening to stereo?

[anewman]

Just wondering if sitting listening to the stereo (having recently installed a subwoofer) could drain the battery. I am guessing this is a stupid question and the answer is a big yes, but the thought crossed my mind that all you would need to do to prevent this is have the central electrics control unit switch off terminal 86s (the one that's live till you remove the key) when the voltage reaches a pre-set level. The computer is certainly able to monitor voltage and record a fault code when the battery goes below a certain level.

Have upgraded the battery anyway from a 063 to a 096 anyway, so should have more reserve capacity - and will try work out how much power my stereo is likely to use when turned on later, in terms of amp hours.

[Dave100]

Yes it can drain your battery, especially if you have sub, amps etc.

I know as a mate has done it, he was listening for just over an hour with the engine off. You can imagine what happened next.

[mannyo]

With the stereo and sub on the battery will go flat surprisingly quickly. I reckon an hour at most with an older battery, perhaps longer with a good newer one before you start to have problems. The stereo will still be running at this point but the battery will not have enough juice to turn over the engine.

[gadgetman]

You can buy kits to kill radio and amps at certain battery levels.

Killed several cars this way, even with factory kit. Mondeo routinely gives me low battery message at 50 minutes.

[jamesrbeaumont]

or buy a red or yellow top battery at about 200 plus each, even they wont last forever

[TeflonTom]

Yeah quite a lot of the marine electrics places sell those battery guard devices that you can set to switch off when the battery reaches a preset level but tbh it's probably not worth fitting one to a car, just get a massive battery instead, like one from a big diesel engined car.

[Simonbt]

Recently been on a two week holiday camping and I've had the car sat with its stereo running for a good couple of hours without any noticable difference in battery strength when started - but with amps and subs you'll probably run into problems/

[Fabia DMG]

Yes you can drain battery and very easy. I where cleaning my Furby at home listening radio with keys in and battery went flat in probably 40min. Try to started but only with click noise from engine. I have to call recovery, lucky I have one including home start. So didn't cost any think is in my premium.

[Sonner]

i thought only single women called recovery for a flat battery on there own drive way, most people just knock on a neighbours door and ask for start... assuming that you or someone in your neighbour hood has jump leads.

i live on the seafront, when my MR2 used to get a flat battery i used to push along the seafront myself, hop in when built up enough speed and jump it into life in 2nd, FYI the seafront is flat.

[dano989]

ive fun my battery flat at a show.

[E11HES]

ran mine all night with a sub on at VW Fest in august, lasted ages. Luckily i was camping with a mate who had some leads, seemed to go flat quicker after that too so i try not to do it as much now, dont fancy paying for a new battery, just an extra expence

[Fabia DMG]

i thought only single women called recovery for a flat battery on there own drive way, most people just knock on a neighbours door and ask for start... assuming that you or someone in your neighbour hood has jump leads.

i live on the seafront, when my MR2 used to get a flat battery i used to push along the seafront myself, hop in when built up enough speed and jump it into life in 2nd, FYI the seafront is flat.

for your information none of my neighbors have one I did try before I call recovery. Pushing car to start is the stupidest idea you can do

[gadgetman]

for your information none of my neighbors have one I did try before I call recovery. Pushing car to start is the stupidest idea you can do

Why is it stupid? I've push started many a car.

[Beancounter1980]

After we had fitted an aftermarket headunit i noticed the car would be difficult to start after it had been left in overnight.

Having changed the battery we suffer no such problems.

Although i do ponder whether it is having a detrimental effect on the new battery????

Even though the car starts first time every time after the new battey...

[Beancounter1980]

for your information none of my neighbors have one I did try before I call recovery. Pushing car to start is the stupidest idea you can do

I've Push started loads of cars :wonder:

[anewman]

I once found my Fabia flat and thought push starting would be easier than farting about with leads. Asked my GF to push and she was struggling, I thought she was being a weakling. I got out and pushed and found the same. Difficult to push, although where I park my car there is a very slight incline upwards. Ended up using leads.