Car Stereo - Making Battery go flat - how to figure out whats going on

Forums › Gadgets, robotics, home automation, electronics (including wearables) › Car Stereo - Making Battery go flat - how to figure out whats going on

Morgenmuffel

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#177410 1-Aug-2015 16:31

Ok

I installed a Head unit thingie in SWMBOs car back in April and since then the battery is going flat in a couple of days of non use, I used Iso Connectors to connect the stereo to the cars wiring, so i am not sure why it would be doing this.

Whilst i don't have a clue about Cars or Stereos i have previously replaced a head unit using ISO connectors with no problems.

What can i do to test whats is causing this, or should I just give up and take it to an installer?

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Mad Scientist
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#1356691 1-Aug-2015 17:03

I think your battery has reached end of life. Get an auto sparky to confirm that

johnr

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#1356694 1-Aug-2015 17:05

Have you had the battery load tested at full charge?

k1w1k1d

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#1356698 1-Aug-2015 17:11

My suggestion would be to take it to your local friendly auto electrician.
Should only take them a few minutes to diagnose if the fault is caused by the stereo, an installation error, or something else that happened at the same time by coincidence.

Probably pay to check that things like the glove box light, boot light, or a courtesy light under the dash is not staying on.

jpoc

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#1357527 3-Aug-2015 09:21

Morgenmuffel: Ok

I installed a Head unit thingie in SWMBOs car back in April and since then the battery is going flat in a couple of days of non use, I used Iso Connectors to connect the stereo to the cars wiring, so i am not sure why it would be doing this.

Whilst i don't have a clue about Cars or Stereos i have previously replaced a head unit using ISO connectors with no problems.

What can i do to test whats is causing this, or should I just give up and take it to an installer?

One pin of the ISO connector carries power that is always present unless a fuse has blown. It is normal for this to draw a small amount of current all the time. Unless there is a fault with the head unit, it should never be able to draw enough power to drain the battery even over a couple of weeks.

As others have pointed out, it is much more likely that your battery is on its last legs and that the tiny extra draw of the new head unit is tipping it over the edge.

How can you test this?

If you have something like [url=http://www.aliexpress.com/item/New-Portable-HYELEC-Digital-Clamp-Meter-Multimeter-AC-DC-Current-Volt-Tester-Hot/32387604473.html]this you can check to see how much is being drained from your battery and then you can decide if you need a new battery or a anew head unit.

Mattmannz

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#1357543 3-Aug-2015 09:34

If you have a basic multi meter you can measure current draw at rest. It should be very low. Disconnect the positive lead on the battery and put the meter in between. This will show you the current draw of all circuits in the car. Now pull the stereo fuse and see if it drops much.

dickytim

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#1357705 3-Aug-2015 12:24

Often the OEM adaptors have the constant power and acc power around the wrong way, this happens on a lot of the ones for VT-VZ commodores.

Not an uncommon problem it seems. Changing the pins around can be fiddly but can be done.

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scuwp

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#1357708 3-Aug-2015 12:33

My vote is this is a coincidence. More than likely that the battery and/or charging system has decided to give up the ghost. I would be eliminating that first. Either call the AA out if you are a member, or call into any battery place they can normally test it for you on the spot.

Lazy is such an ugly word, I prefer to call it selective participation

wasabi2k

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#1357735 3-Aug-2015 13:01

repco will also hook up a battery meter for nothing.

While they have a terrible reputation, my local one is pretty good.

Talkiet

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#1357744 3-Aug-2015 13:11

I was going to suggest testing the parasitic draw on the battery as well...

http://www.batterystuff.com/kb/articles/charging-articles/testing-your-battery-for-parasitic-load.html

REMOVE YOUR WATCH FIRST. Car batteries are big enough to kill you. If done correctly it's safe but there's a staggering amount of energy in them.

DON'T attempt to start the car with this setup in place.

Cheers - N

Please note all comments are from my own brain and don't necessarily represent the position or opinions of my employer, previous employers, colleagues, friends or pets.

lxsw20

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#1357767 3-Aug-2015 13:46

You could always just disconnect the stereo for a couple of days and see if it's still an issue.

Jaxson

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#1357810 3-Aug-2015 14:27

Are you sure you've got the ACC setup right?

Can you use the stereo with the key right out of the ignition?

Without the key, the stereo should be essentially completely off.

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shk292

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#1357818 3-Aug-2015 14:34

REMOVE YOUR WATCH FIRST. Car batteries are big enough to kill you. If done correctly it's safe but there's a staggering amount of energy in them.

Cheers - N

Maybe if someone drops one on your head from a great height, but there is no way that 12v dc is going to push enough current through your body to kill you

Talkiet

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#1357829 3-Aug-2015 14:45

shk292:

REMOVE YOUR WATCH FIRST. Car batteries are big enough to kill you. If done correctly it's safe but there's a staggering amount of energy in them.

Cheers - N

Maybe if someone drops one on your head from a great height, but there is no way that 12v dc is going to push enough current through your body to kill you

Fair enough I guess... But it could weld a metal watch to your arm still :-)

But yeah, you're right - pure electrocution won't kill you*

Cheers - N

*Probably, YMMV

Please note all comments are from my own brain and don't necessarily represent the position or opinions of my employer, previous employers, colleagues, friends or pets.

lxsw20

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#1357832 3-Aug-2015 14:46

No but you can give your self a nasty burn with the amount of current a car battery can put out. If you got your watch between the chassis and + terminal you would certainly know about it.

jpoc

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#1357984 3-Aug-2015 16:49

Jaxson: Are you sure you've got the ACC setup right?

Can you use the stereo with the key right out of the ignition?

Without the key, the stereo should be essentially completely off.

I believe that all variants of the ISO connector have one pin that is always live irrespective of the position of the ignition key.

When they key is out, the radio is still allowed to draw current to maintain the clock and other functions such as preset frequencies for the tuner etc.

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