Flat battery again

hneel · **January 02, 2016, 15:41:32**

I bought my i30 somewhere in november. A couple of days later I had a flat battery, which I blamed on the navigation which had crashed.
The guy who helped me with it said that the battery was still rather new.

Now I'm having the same problem again.
I can't think of what could have caused this. All lights were out. Dascam was not connected. What else?
I haven't used the car for more than a week, because of the holiday season, but a battery should not drain that fast.

Is this a common problem with this type of car? Or should I get a new battery after all?

Asterix · **Reply #1: January 02, 2016, 16:12:25**

If you want to know if the battery is ok you need to have it tested with the right equipment

That will require the battery to be fully charged and then tested according to the spec of the battery.

What you can do yourself without tools is to take off the negative lead and then slowly approach the lead to the battery again. If a spark shows when getting close to the battery then there is a power usage. Remove 1 fuse at a time until there's no spark anymore, and find out what that specific fuse is for.

asathorny · **Reply #2: January 02, 2016, 18:35:49**

In the six years that I have owned my i30 I have only suffered from flat battery twice and on both occasions it was automatic lights not switching off, once with the hatch and once with the passenger map light in the visor.

obviously something is draining the battery, good luck finding it

Shambles · **Reply #3: January 02, 2016, 18:51:04**

There's always this possibility...

Blat Fattery

nzenigma · **Reply #4: January 02, 2016, 21:36:47**

Quote from: Asterix on January 02, 2016, 16:12:25

What you can do yourself without tools is to take off the negative lead and then slowly approach the lead to the battery again. If a spark shows when getting close to the battery then there is a power usage. Remove 1 fuse at a time until there's no spark anymore, and find out what that specific fuse is for.

That is a quick side of the road test that can be of assistance. However, it can be misleading, you would be looking for a large spark. The modern car, in good order, is always drawing a small current. Generally, the internal action of a good battery will make up for the loss. For example, if you crank a motor over until the battery is totally dead, then try again a few hours later the battery will have developed enough energy to turn the starter motor a bit more.
Shambles possible solution is interesting.
Occasionally, the alternator can be the culprit. A faulty internal rectifier (diode) may not stop the alternator from charging the battery but will 'leak' current from the battery when the ignition is switched off.

The Gonz · **Reply #5: January 03, 2016, 02:46:42**

Quite true. The rectifier diodes are arranged to oppose AC current flowing in the undesired direction, diverting it towards providing more DC in the correct 'charging' direction. It may be more likely to develop an open circuit than a short but could happen. For this to be tested at home in the easiest way, use a charger on your battery while still fully connected in your car and then with one of its leads off and note the charging current reading difference.

This will give a clue to overall system current 'leakage'. Then test again with alternator lead removed. If you don't have even a cheap Arlec style battery charger, you really should get one.

The Gonz · **Reply #6: January 03, 2016, 03:03:31**

Here you go, the ammeter on the panel is a useful diagnostic tool in its own right.
"ns"

Having said that, you might have a multimeter already which you could use to measure resistances around the system.

hneel · **Reply #7: January 03, 2016, 11:56:14**

I noticed that the navigation device was connected to what appears to be a GPS unit, mounted beneath the radio. Could it be that this is permanently powered? Perhaps I'd better unplug it.
On the other hand, if this was the cause more people would have a problem with it.

The Gonz · **Reply #8: January 03, 2016, 16:08:40**

GPS units are receivers only and don't consume much power. Every phone or tablet has one.

beerman · **Reply #9: January 04, 2016, 02:17:09**

I was told that in a modern CRDI engine, if you run the battery down enough, it never truly recovers.

Enough that when we had an i30 at work and ran the battery flat, even though it jump started, they replaced it, and they are cheap arses and wouldn't do something that dosent need to be done

Dazzler · **Reply #10: January 04, 2016, 06:37:58**

Quote from: beerman on January 04, 2016, 02:17:09

I was told that in a modern CRDI engine, if you run the battery down enough, it never truly recovers.

Enough that when we had an i30 at work and ran the battery flat, even though it jump started, they replaced it, and they are cheap arses and wouldn't do something that dosent need to be done

Might be related to the fact that they are a special type of battery that needs a specific charger. If people use a standard charger they wouldn't get enough charge.

The Gonz · **Reply #11: January 04, 2016, 08:33:36**

The charger only has to do whatever the alternator system will do to charge it, which is seen as the charging voltage. So long as the charger can supply enough current to maintain the correct voltage at all times, I'd expect it to do its job.

hneel · **Reply #12: January 04, 2016, 12:34:10**

I probably found it: I had mounted a bluetooth dongle on the OBD port, and that one seems to be permanently powered as well. I first assumed that it would only be powered when the car was switched on.
When I googled I found several other people who had run into battery problems for the same reason.

PhireSideZA · **Reply #13: January 04, 2016, 12:53:26**

Quote from: hneel on January 04, 2016, 12:34:10

I probably found it: I had mounted a bluetooth dongle on the OBD port, and that one seems to be permanently powered as well. I first assumed that it would only be powered when the car was switched on.
When I googled I found several other people who had run into battery problems for the same reason.

It actually makes sense. My OBD dongle always has power regardless if whether the car is locked, unlocked, key in or out. Glad you found the culprit!

The Gonz · **Reply #14: January 04, 2016, 15:08:42**

Good find. I keep Bluetooth turned off on my devices to save power.

Asterix · **Reply #15: January 04, 2016, 20:06:19**

Quote from: hneel on January 04, 2016, 12:34:10

I probably found it: I had mounted a bluetooth dongle on the OBD port, and that one seems to be permanently powered as well. I first assumed that it would only be powered when the car was switched on.
When I googled I found several other people who had run into battery problems for the same reason.

That was propably also the cheapest solution...

Thanks for the feedback.

hneel · **Reply #16: April 20, 2016, 18:30:10**

Unfortunately it happened again today. Just when my wife wanted to use the car.

For months it had been running fine.

A few weeks ago I had routed the power line of the OBD connector to a switched powerline (taken from the radio), just to prevent these kind of things.

I managed to start the engine again and the car is now running stationary to load up the battery. I measured the voltage and it was 14.2, which should be ok.
I think I'll soon measure the current draw from the battery and try to find the source by removing fuses.

hneel · **Reply #17: April 21, 2016, 09:42:00**

I measured the current and it turned out to be one of the fuses in the yellow holder: ROOM LP

It drew 180 mA. Isn't that a but much?
Now how could I further find the real culprit?

Phil №❶ · **Reply #18: April 21, 2016, 11:15:05**

180 thousandths of an amp isn't going to flatten the battery IMO, unless you don't start it for extended periods. I still think thee's something else going on or a bad battery. 4.32 amps in 24 hours.

However whatever it is, is not causing blown fuses or melted wires, very strange indeed

PhireSideZA · **Reply #19: April 22, 2016, 20:15:39**

Quote from: hneel on April 21, 2016, 09:42:00

I measured the current and it turned out to be one of the fuses in the yellow holder: ROOM LP

It drew 180 mA. Isn't that a but much?
Now how could I further find the real culprit?

That should be the dome lamp IIRC.

For what it's worth, I have LED bulbs in my dome light and even when off I do see some residual current and the bulbs are dimly lit. I have no idea where the parasitic current is coming from but the draw is so little that it doesn't make a difference to the starting of my car even after two weeks of standing. I am a bit relieved that you also have a slight draw

nzenigma · **Reply #20: May 09, 2016, 02:47:00**

This current is so low, it is irrelevant. As I said previously, the 'at rest' electrolysis process in the battery will make up this loss. The car's security system needs to be 'alive' so that you can open doors & so it can read your key chip.

Have you checked or better still, swapped the battery? It could have an intermittent internal connection. That is not uncommon. Intermittent short circuits in the car's system are less common. Once a component is shorting it usually stays that way, as in the previously mentioned case of alternator rectifiers.

You don't mention how long it takes to flatten your battery.??? If you are talking 'overnight', try the sniff test.

Warm wires smell.
If you are measuring the battery voltage, when flat, with a multimeter it will still read 12-14volts because the meter has negligible load.

Another thought bubble

: Could this be caused by a bad earth? An easy trap to fall into, because the symptoms appear to be similar to low +12v.

I once had to drive a car with browned out headlights. I was waiting to smell burning wires. Didn't happen. As I pulled to the side of the road, I put the clutch in; lights came up to full brightness. I drove on to the next town engaging the clutch and free-wheeling around every dark corner. The cause: an earth strap from the motor to the body had been left off by a mechanic. The engaged clutch was completing the circuit.
Good luck