Battery becomes flat........
 

Would very much appreciate some hints on the following problem I have. Have been searching a bit, but I am still curious....:


Twice during the last two weeks my battery (1-2 years old) has become flat.

Checking with a voltmeter (with engine off) the battery reads approx 12.5 volts, (with engine running) it reads 14.0 volts (and increases a little while measuring).

When the engine is running and I switch on the headlights, the voltage reading decreases slightly. Voltage increases again when the lights are off.

After recharging everything has been OK, but after driving for maybe nearly one hour battery is weak once again. The battery also seems to become weak if the car is left for a week or so.

Alternator brushes bad, or grounding problems?

Any hints appreciated!

Regards from Norway

Wankelviking

Well the battery has either died and 2will no longer hold a charge or you have a draw some where.

The stock alarm is known for killing off batteries.

A battery can still have voltage but not enough amps some times.

Have both your alternator and battery tested (by a reputable shop...make sure the battery is FULLY CHARGED before the test). Odds are both will fail a load test.

Well the voltage sounds good.
Stationary it's 12.5 and running 14v.

Although a tester can check other stuff like amperage too.

Two years is about the average lifetime for a standard battery.
Unless you bought one of those "premium" models, go buy another one.
Wal*Mart's sells the EverStart(?) batteries for like $40.


-Ted

Re: Battery becomes flat........
 

everything here is normal...

what do you mean it becomes "weak" ??

i just replaced a battery.. you checked the alternator to battery voltage right? use a multimeter to check alternator to + voltage.. it should be 14.. if its not 14, theres a short, or your battery is bad.

my battery was corroded, so even tho my alternator was putting out 14 volts at the dash, the battery was only accepting like 12 or something.. so it wasnt charging.. basically the battery was corroded.. its been in there for about a year. i guess these 7's eat batteries too?

rule #1 get your battery tested

Battery Death
According to the Battery Council International (BCI), as many as 85% of the 70 million new lead-acid batteries sold each year will go dead before their approximate 5-year design life. The primary reasons: vibration, lack of maintenance, improper charging and incorrect application.

Vibration can jar a battery's internals loose. Once the lead plates start to move, they can touch, causing a short. Because a battery is only as good as its worst cell, one loose plate can spoil a whole battery. Many of the more expensive batteries use epoxy paste material to secure the lead plates. These pastes are formulated for the optimal balance between internal resistance (to be as non-intrusive to electron transfer as possible) and durability. These "plate-lock" adhesives can degrade over time, but this technology generally extends battery life compared to units that lack it.

Improper maintenance and charging promote battery failure through sulfation. This is a byproduct of discharging: During discharge, the chemical reaction causes lead sulfate to form on the plates. If the battery isn't recharged within a few days, the lead sulfate will harden and crystallize, diminishing the battery's ability to accept a charge. Low water level in the cell will also cause sulfation.

In addition to stimulating sulfation, improper charging damages batteries in other ways. Overcharging causes heat damage and excessive gassing (and can be caused by a faulty alternator/regulator). Undercharging makes a battery more likely to freeze in cold weather.

Routine maintenance will extend battery life. Any corrosion should be cleaned regularly, vent caps should be kept tight, and electrolyte should be kept at the bottom of the splash band. Finally, stored batteries should be kept in a cold location that doesn't consistently get below 32 degrees F, and their state of charge should be checked every two months.

Temperature
A standard (maintenance-required) lead-acid battery is designed to produce 100% of its rated capacity at 80 degrees F. Output diminishes to 65% at 32 degrees F and 40% at 0 degrees F. If the battery isn't fully charged to begin with, capacity suffers even more.

Oil viscosity also affects the battery's ability to start the engine. If an engine's cranking-power requirement is 100% at 80 degrees F with 10W-30 oil, that same engine will require 155% of said cranking power at 32 degrees F and 210% at 0 degrees. Using SAE 20 oil, that same engine would need 250%—2 1/2 times—the cranking power to start at 0 degrees F that it would to fire at 80 degrees F with 10W30 oil.

Furthermore, wet-cell batteries can actually freeze at low temperatures. In worst-case scenarios, they become bombs: Their polypropylene cases become icy shells, and the cells emit high-pressure gasses when a charge is introduced. Something has to give.

Re: Re: Battery becomes flat........
 

Thank you for your replies!

By "weak" I mean that the starter turns slower than normal.


I will get a new battery today. Should I check the brushes as well ?


Oivind

Weird things happening
 

With a fully charged battery I started the car this morning.

Neither the side blinkers nor the servosteering did work.
The warning blinkers ("idiot lights") did work.

Maybe this could give someone a clew for a solution here.....

Oivind

Sorry, being a foreigner, I had some language trouble in my last posting:

I have now installed a new battery. Same problem occurs.

The power steering does not work (no warning beeps either)

The blinkers do not work, but the exterior "warning" blinkers work.


Must be a shortcut somewhere ?


Oivind

Problem partly solved........
 

The weird problem with power steering and blinkers is solved.

They are connected on the same fuse. Unfortunately I did not notice that the fuse was gone until I had a second look.




sorry...