hi all,

another prob iv been having recently is my battery is going flat daily!!

 

i have jump started her twice, then as that failed i gave the battery a full charge for 20hrs, still it went flat within a day.

 

the car has a clifford alarm and im guessing this is draining it, but even saying that, the last four days i have left the car unlocked and with the alarm off to see if the battery will still hold charge, yet again, come the morning its flat again :(

 

how can i check my alternator is working, or how can i check the battery is still good or not????

 

thanks,

 

dan

Understanding battery charging, discharging, float charging, and deep cycling would be a lengthy proccess so will not go into it fully here except surfice to say a completely discharged battery will NOT fully charge in 20 hours with a normal diy charger, all you get is a plate surface float charge,.

 

When the battery was new it was deep cycle charged which is a process of charging and discharging which then gives it a strong chemical basis from where it can now charge and discharge without damaging cells, once this deep charge is lost usually from letting the battery go completely dead any further charging from diy charges will just not cut it and in time actually harms the battery and ultimately kills individial cells.

 

There are some much better electronic conditioning chargers on the market that use electronic switching and internal resistance to mimic deep charging but as they tend to be more expensive are often overlooked but given the cost of replaceing batteries over your lifetime ownership of cars the conditioning charger makes more sense.

 

All of the above relies on the fact the battery is in good order and the plates are not sulphated and there are no dead cells, of course if there is then nothing will make the battery work correctly again and its time for a new one.

 

 

Of course there could be an issue with your car such as current drain on a circuit, faulty earths, faulty alternator and all of these need checking first, assuming all is ok then a good way to check the battery is to charge it the best you can and NOT refit to the car for at least a week and then refit it and see if is dead or alive, a dead battery will mean it cannot hold charge a battery that starts the car could be saved by the aformentioned charger

 

 

Jeff TT

Edited August 16, 200916 yr by JeffTT

is there an easy way of checking the alternator is doing its job charging the battery???

is there an easy way of checking the alternator is doing its job charging the battery???

 

A small volt tester can be used to see what the battery voltage is with the engine running, depending upon battery state the voltage should read anywhere between 13.0 and 14.5 volts anything less than 13 volts would point to an alternator / charging fault.

 

Jeff TT

A simple way if you don't own a multimeter is to wait til dark and see if the headlights get brighter when you rev the engine and dim again when the engine idles.

 

Ideally for an accurate reading then the above method should be used.