Am i Charging a car battery correctly?

Ebenezer_Scrooge_2

I have removed a flat battery from my golf as it has been sat for around a month.

The battery is 85amp hour? but my 4amp charger says it should only be used with batteries upto 70 amp hour?

Anyway its been on charge for around 12 hours and the battery is not charged and only reading 11.27 volts?

will it charge with my charger, and how long will it take?

DatabaseError

check the fluid level (unscrew the caps) fluid should be just covering the ribs/gubbins in the battery, if it is low fill with de-ionised water, supermarkets sell it for about £1/litre, then recharge if necessary

Ebenezer_Scrooge_2

Thanks Tony
says it is maintenance free though.

fwor

Yes, it should charge your battery Ok, though - depending on the design, it may get slightly hotter than intended.

It will obviously take a bit longer, but it's difficult to say how long, as it depends to a very large extent on the condition of the battery. In simplistic terms it should take more than 20 hours to charge, but in practice it could be longer if the charger cannot maintain a high charge current as the battery voltage rises.

More likely though, as it has been standing discharged for a month, is that it has built up sulphate deposits on the plates and will not successfully charge. Some chargers - such as those by CTEK - have a special charging cycle that can overcome this, but they are fairly expensive - starting at around £50.

Ebenezer_Scrooge_2

my charger was a chepo from wilkinson only cost me £10

spud17

I have removed a flat battery from my golf as it has been sat for around a month.

Unfortunately, if the battery is starting to show is age, and has been left flat for some time, it is very likely that it will not hold a charge.

The charger should be O.K. but in a situation where the charger is working flat out I'd give it a rest after a few hours. This allows the charger to cool and also reduces the chances of over heating the cells.

Are there any signs of bubbling (hydrogen) in the cells?

Re maintenance free, you can usually get the top off, and after a while there WILL be water loss.

BritBrat

Losen any caps and start charging.

Do it in a well aired/ventilated place and do not create a spark just after charging is done.

The gas given off is hydrogen.

Ebenezer_Scrooge_2

Cant see that the top will come off, it is a big varta with sticker acrooss the top

amonra

Charging voltage should be 14.7 volts but your charger is probably struggling with a totally flat battery, so just give it time. Hopefully it will come up to 14 volts. As others have commented earlier, perhaps it has been left TOO long. If you are not in a desperate panic, try discharging it by fitting it back in the car and leaving the headlights on, then re-charge it again. Try this two or three times to see if it improves. If not, then it's a trip to a motor factor. Good luck.

unrich

Deep discharging starter/heavy batteries (letting them go really flat) can damage cells.
If you have had it on charge and off charge it is not registering above 12.9V or so after a couple of hours then its probably faulty.
If it keeps going back to the same voltage you may have a faulty cell in the battery.

Avoriaz

spud17 wrote: »

..Re maintenance free, you can usually get the top off, and after a while there WILL be water loss.

I’m not sure that is very safe advice.

Forcing a maintenance free battery open could potentially be very dangerous if sulphuric acid splashes all over your face or hands.

There is also the problem of how to properly seal it afterwards.

It is not something I would attempt lightly.