Jump to content

Zombie battery


Waynebaby
 Share

Recommended Posts

Hi All,

I've always considered auto-electrics to be some form of black magic, but this weekend I realised it was Voodoo, when my battery turned zombie.

The car started perfectly on it's hi-torque starter on Sunday morning before I took it for a quick drive of 15 minutes, after which I parked up on the drive. An hour later I went to start it and was rewarded with silence when I turned the key, punctuated with intermittent clicking from the solenoid. The first thing I checked was the battery, which was showing ~13V across the terminals, but to be certain I hooked up the trickle charger and this showed "full" after about 10 minutes. Not the battery then. Next I checked all the earths and the continuity looked good. Not wanting to believe it might be the starter, I decided the problem was the solenoid and duly ordered a new one. Needless to say the new solenoid didn't fix it.

I was resigned to having to get the hi-torque starter off when I decided to test the old Lucas starter motor using jump leads directly from the battery - nothing doing. Now, I knew the old starter motor was good when I put it away and so I re-checked the battery. It was still showing ~13V and was still happily taking a charge, but I was starting to have my suspicions. A quick trip for a new battery and normal starting service was resumed.

I can't figure out the old battery, which seems to have turned into a galvanic version of the living dead over the course of an hour on Sunday morning. To all intents and purposes it looks alive, but in reality it can hardly produce enough power to properly energise the starter solenoid, let alone turn the starter motor. All my previous batteries have either faded away slowly over weeks or died quickly and completely overnight. Has anybody else had a battery turn zombie? Is there another test I could have done with a multi-meter which would have revealed the problem sooner?

Wayne

Link to comment
Share on other sites

The problem is you can't test a batteries condition by just measuring it's voltage. You have to place a load on the battery and then measure the voltage. All batteries have an internal resistance. When new this will be very small. As the battery ages this will increase and reduce the capacity of the battery. In other words the internal fault only becomes apparent when you try to draw a lot of power out of the battery.

A good test is on a charged battery is to put the headlights on and then measure the voltage. It should around 12.5volts and after a couple of minutes will drop to around 12volts. If it is around 9volts then you could have a problem,

Dave    

Link to comment
Share on other sites

Guys

An old trick i was shown to test a battery.  get an assistant to hold the ignition key in the start position.  Whilst he or she is doing this look in the top of the battery (If not a sealed type) see if there are bubbles in the electrolyte (Acid).  if there are that cell is dead as the other cells are trying to make up for that one dead cell.  For those of you who don't know a 12 volt battery is made up of 6 times 2 volt cells.  A wet battery will only produce  2 volts per cell, it is purely that way with physics as a chemical reaction.  The power of the battery is in the acid and water mix which is called electrolyte. not in the lead plates. 

 

Regards

Andrew     

Link to comment
Share on other sites

"look in the top of the battery"   That's with the filler caps off - and so with nothing between strong sulfuric acid and your eye.

NOT recommended!  Or if you must, with goggles or a visor, or a mirror and torch, although what appears to be air above the acid is an explosive mixture of oxygen and hydrogen, electrolysed from the water.

Dont mess with batteries!

John

Link to comment
Share on other sites

Andrew,

Don't want to be picky, but it's 2.1 volts per cell :lol:. You can revive a battery by reverse charging it, it won't last long thereafter but, there is a short improvement. My son-in-law accidentally reversed charged my nearly new battery, took 6 hours on full beam to flatten it! 

Doug

Link to comment
Share on other sites

John D

of course use goggles that is just common sense.  It is not only sufficient acid it is a mixture of 10% sulfuric acid and 90% water, and that is called electrolyte.

 

Doug

it is actually 2.45 per cell when on charge as the overcharge factor is needed.  This will then fall to 2.10. This should be across al cells as wet batteries Need what is known as a equisation charge.  

You cannot revive an battery at the end of its life no matter what claims are made.  Active material falls of the lead plates ever time a charge is applied.  This material will fall to the bottom of the battery into what is know as the mud space.  This. Will then short across the negative and positive plates resulting in a dead battery end of story

regards

Andrew

 

Link to comment
Share on other sites

Andrew,

What is  the"overcharge factor"? What is the "equisation charge"? What is the "mud space"? I can find not internet reference.

And, I'm sorry but I've seen my Uncle revive a battery by reverse charging it. "Knocks the crude of the plates" was his explaination.

 

Doug

Link to comment
Share on other sites

I bought a Ctech battery charger a couple of years ago and have recovered a couple of batteries that appeared dead and that I would have normally disposed of. My old start & charge, charger confirmed they were unchargeable, but the Ctech was able to bring them back to life, also gives you an indication of condition. Makes me wonder how many batteries I have premeturely retired in the past.  Batteries do wear out eventually and not a lot you can do. Biggest killer in my experience is not enough use, so now I periodically recharge as a matter of course.

Mark

Link to comment
Share on other sites

2 hours ago, dougbgt6 said:

Mark,

Yes, some battery chargers won't charge a stone dead flat battery. I have one of those :angry: and another that will! :lol:

Doug

Doug it may be due to the waveform left after rectification because what you get out of a charger is not pure DC. If there is any charge still in the battery this will smooth the waveform to produce true DC and should improve the charge. A flat battery will not do this. The waveform can vary with the design of the charger. e.g. full wave or half wave rectification. A 2000 MFD 50VDC  capacitor across the charger leads may help. 

Dave

Link to comment
Share on other sites

7 minutes ago, Pete Lewis said:

 Wave Form    ................dont wave at Doug he's just been appointed as AO ,,feel sorry instead  

Pete

As an ex AO, well done Doug. I am sure Pete will tell you all the info on being an AO.

We are looking for a new AO for Newbury Area as Lloyd our present is on the move.

Dave

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...