Why is battery draining/going flat

[shropslad]

Hi peeps,
Had our 53 plate 1.6 petrol/lpg dynamique since new & love it. Thinking that the old original battery was dead after 4 years I decided to change it. Now I still have the same problem with a brand new battery. After 2/3 days it is completely flat,I have to re-code radio & re-programme windows every time.
I have checked & double checked all interior lights even disconnected the boot one thinking that it was that.
Any ideas what could be draining power??
Your help would be greatly appreciated. will jump start it again tommorrow.

Many thanks,
Mark

[Deano16v]

have you had the alternator checked to make sure its charging it?

[Say..."Renno"]

Had similar problem with our old clio, found that the boot switch was not turning off when closed ...does it go flat over night or if not driven every day???

Open the bonnet ,turn off everything lock the car and disconnect the battery...touch the connector on the terminal, there shouldnt be a spark...touch it a couple of times and see if the spark (if there is one) gets weaker or stays the same.

WARNING..do not remove any cell fillers (if there are any) as the spark could explode the gases...

[cactusbob]

Get one of those gauges that plug into the cigarette light socket. With the engine off it should read around 12v, with the engine running it should be around 13-16v. If ts not then your alternator may need looking at.

[shropslad]

If it was the alternator wouldn't the light illuminate on the dash while driving bit like when the fan belt is slipping.
Disconnected boot light so its not that, it normally takes 2/3 days to run flat usually, its OK if used every day.

[Say..."Renno"]

Have you had any mods done lately i.e. new radio ,sub or anything like that...or have you checked the connections at the battery itself ...

[shropslad]

As I said the problem started about 4 months ago with the old battery going flat, thought the old battery had come to the end of its life so changed it. Problem is still there could be a faulty new battery but that is very rare about 1 in 100 I have been told. will try & get it tested.
Could it be the alarm?

[cactusbob]

Wouldnt have thought it would be the alarm, gotta e something with quite a high current drain to go so quick. Your footwell lights arent staying on are they? If so check your storage compartments in the floor are closed

[davelowe]

This lark about batteries being 4 years and dead is daft. I sold my V plate Almera to my parents a couple of years ago and a fortnight or so ago, it wouldn't start. The battery has been fully discharged at least twice from new (my fault) and this significantly shortens the lifespan of them. Anyhow, I removed it from the car and noticed that the electrolyte levels were way below minimum. I bought 1 litre of de-ionised water for 52p (Wilkinsons) and topped it up and left it on charge over night. It's as good as new now.

You won't blow yourself up with a spark around a battery, but since sulphuric acid in batteries can blind you, it is best to be careful.

All you need to at least partly diagnose the fault is a multimeter (TAKE CARE THAT YOU KNOW WHAT YOU ARE DOING). Configure the thing to measure current (most will do 10A DC easily). Take of the negative terminal (with everything switched off and locked) and measure the current between connector and -VE battery terminal. It should be tiny - certainly less than 2A (about what leaving the sidelights on uses). Any more and you need to put the terminal back on and repeat the procedure with the major fuses around the battery. Failing that, the small fuses inside the car. That ought to highlight where any current is being discharged is coming from (if it is).

To test the battery itself, and the alternator/regulator, set up the multimeter to measure voltage (THIS OFTEN MEANS PLUGGING THE CONNECTORS INTO DIFFERENT SOCKETS). A fully charged battery should measure no lower than about 12.6 - 12.9V with no load (ie disconnected). If it's lower than 12.2V, it's effectively discharged. It's either knackered, or isn't being charged...

To test the alternator, get the engine started and measure the voltage across the battery. It should measure around 13.8V or higher. Generally after first starting it will be higher and then drop to about that amount (the alternator supplies a constant current which explains the difference). It should stabilise around 13-15V. If it doesn't read above 13V something is amiss with the alternator.

Bump starting your car will probably damage the catalytic converter if one is fitted. Don't do it too often!

Dave

[The Negotiator]

No battery that's 10 years old is as good as new, it's not about the levels inside, it's a lot more complex than that. A battery life of around 4-6 years is normal. Once a battery dies through it's own cycle (i.e. not left to discharge due to the user's actions or a failing in the charging circuit), it's pretty much useless. Of course you can charge it and it might look like it will work, but a few weeks later it will do the same thing to you.

Remember on the batteries used on modern cars, the batteries are maintenance free and semi-sealed, so forget it anyway.

Oh and I have been there when a battery has gone wrong under charging, it wasn't pretty and people underestimate just how dangerous they can be.

[shropslad]

tested battery today, everything looks good V strong charge when engine running & V good when not running.
I had a close look at the glove box light & could not physically see it turning off when closing the box so I have taped the switch down to keep the light permanatly off.

Will see if this is the problem,, all footwell lights etc seem OK & switch off.

Cheers all.

Mark

[davelowe]

No battery that's 10 years old is as good as new, it's not about the levels inside, it's a lot more complex than that. A battery life of around 4-6 years is normal. Once a battery dies through it's own cycle (i.e. not left to discharge due to the user's actions or a failing in the charging circuit), it's pretty much useless. Of course you can charge it and it might look like it will work, but a few weeks later it will do the same thing to you.

Remember on the batteries used on modern cars, the batteries are maintenance free and semi-sealed, so forget it anyway.

Oh and I have been there when a battery has gone wrong under charging, it wasn't pretty and people underestimate just how dangerous they can be.

As I mentioned they can be dangerous.

True, they are semi or fully sealed these days, but well made batteries do not die once they reach their 6th birthday. I have rescued many by removing the electrolyte and cleaning the plates with a chelating agent - usually sodium EDTA, filtering the lead particulates from the fluid and replacing it. Providing the plates are not physically knocked together and shorting, the battery can be as good as new (tried an old fashioned tester, glowed red hot and outperformed a brand new one). I have custom made passive electronic devices that cause minute oscillations of the plates to shake loose lead sulphate also. Either method can give one a few extra full years use.

Anyhow, hope the bulb in the glove compartment solves it.

[cactusbob]

Is it worth the hassle trying to "rescue" a battery?

[davelowe]

It depends. Tetra sodium EDTA can be bought for pennies per battery, plus the home made circuit kit cost me <£5.

If you are willing to invest a little time and effort, it beats £50+ for a new battery.

I wouldn't recommend you try the stuff I got up to in the previous post unless you have a good working knowledge of non-organic chemistry and a healthy regard for safety precautions.