Amplifier Drains The Battery Even When The Ignition Is Off

Mete Goktepe

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hello dear friends,

I bought a factory amplifier for my 850.. I already upgraded the speakers with Jbl power series in 4 doors and the rear deck.the amplifier is HA 7240 which originally comes with C70 volvo but because it was bought from e-bay as used I noticed that the amplifier rapidly drains the car battery. especially if you listen to music for 45 mins with the engine not running the car fails to start unless you jump start it. if you dont drive the car for 2 days the car will not start again. but if the amplifier is disconnected and the audio system is used without the amplifier there are no problems..

it seems like this amplifier is leaking voltage even when the car ignition key is removed.. normally the DIN cable should stop supplying the voltage when the audio system is turned off.

does anyone have any idea to test the amplifier if its leaking voltage?

my cars headunit is the SC-815 headunit.

any help and advice will be appreciated..

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If you're amp is connected straight to the battery, it will continue to drain it even after the car has been turned off. A in friend of mine simply installed a switch in the line, so that he can cut the power when he turns the truck off.

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I thank everyone for the answers.. how should be the installation of this amplifier? I mean I connected it straight to the battery.ground was taken from the body not from the battery.I tought when I turn the headunit off it wouldnt drain the battery..(normally the din cable was supposed to cut the voltage to the amp when the headunit is off) am I wrong?. but it does in two days... also I noticed if I run the stereo when the car is not running the battery drains in less than 1 hour.. is this normal? maybe it is because the amp is powerful and uses too much power? the questions may sound dumb sorry for my lack of knowledge about audio systems..

how should be the best connection method? any recommendations?

for example our friend R Moose says connect the remote wire (blue) to something that shuts off when you shut the car off. what should be this "something"?


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If you have a high wattage amp,it is normal for the battery to die if you play the stereo without the car being on.

You might want to invest in a capacitor.If you have an aftermarket HU,connect the remote wire from the amp to the blue wire on the back of the HU.

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This all sounds a little familiar.

What is the remote turn on lead for the amp connected to?

Got any pictures of your installation? At the radio and the amp?

Have you checked the battery lead's current draw with an ammeter ?

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Hello again,

the amplifier's positive cable was connected directly to the positive cable of the battery and the negative was connected to the car body. the Din cable was used to turn the amp on but I have to say the din cable wasnt original.but its working properly because I tested it. I was thinking when the Headunit is turned off(its a SC-815) the amp wouldnt drain the battery but it did. my solution was connecting the amps positive cable to the headunits positive cable so it would turn off with the headunit.

the amplifier is(factory C70 amp(HA-7240) 4x100w) I bought it from E-bay so maybe I should take it to my friend who is an expert in electronics so maybe he can test the amp.(maybe amp is faulty I dont know)

my speakers are Jbl's p552 series in front and rear doors which have 60watts rms and rear deck speakers is also Jbl Gto with 60 watts rms. the dash speakers are oem volvo and they receive their power from the hu...

can I still connect a capacitor to the original Headunit? or its only good with aftermarket headunits? or replacing the existing 60ah battery with a higher one would help?

the amp is diconnected since a week and there is no draing problem.

I know I asked many questions but help is really appreciated.

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