New Car Battery Voltage
From time to time you may notice that your car battery sometimes struggles to start your engine. This may be the result of a failing battery or simply a weak battery which would benefit from charging. One method to check the battery’s condition is to measure the voltage when under a no load condition then compare the voltage reading to a loaded condition. (Loaded condition is when the battery is powering a circuit such as your headlights) By perfoming this simple test you are looking for a voltage drop between the two conditions, a huge voltage drop would imply the battery is weak and may require charging with a mains battery charger. Here is a new Bosch battery which I have purchased to replace an old worn out battery in a Ford Fiesta. This particular battery has a Cold Cranking rating of 360A and can provide a 41aH rating.
The higher the load, the greater the voltage drop but if a light load such as only your sidelights brings the voltage down to 12.00v there is a high chance that your battery is weak. This may require charging or replacement depending on the battery condition / age. The sidelights in a Ford Fiesta are rated at 5 watts each, 2 front, 2 rear and 2 number plate bulbs = 30W. This is around 2.5A which for a 41Ah battery is a very small load. If your battery is completely drained, you may find that the voltage reading is well below 12.00V even without a load. (If you battery voltage is quite low such as this one, the chances are it requires replacement)
After checking / topping the cells I did give this battery an 8 hour charge with a mains charger but sadly it didn’t last long, less than a week. Sometimes it is just a question of charging but if the battery is dying it will drain fairly rapidly after being charged so your only alternative is a replacement.
Bosch Wiper Blades Ford Fiesta MK4 1.4 Zetec Front Wheel Hub Removal