Got a bit of a problem with the old polo!

Difficulty starting when left overnight, battery basically doesn't have enough to turn over although it is only a year old. But if the car is ran for a bit, and leave it for a few hours then try start it it starts fine. And this sounds like the battery not very good although its not that old.

But i tested my alternator charging and it 12.7 which is bad, should be 13.5-14volt from what iv read, so i think it could be that

Not sure if i should buy a new alternator or a new battery, anyone able to clear this up?

You'll only get 13.5+ if all the electrics are turned off, also is your alternator belt tight enough?

Having a similar problem with mine, gonna check all the earths and electrical connections, clean and coat them with some water repellant grease. Then see how it goes, not sure how old my battery is but have a fully charged spare on standby!

new alternator. might be worth fitting some new brushes and voltage regulator to the old one 1st though, as they arent expensive. has the battery light been flickering at all?

Also if the alt is covered in oil, then that could be the cause of it not working (they are prone to getting killed this way due to the common leak point on the cam cover gasket)

I was thinking of just trying some brushes, battery light inside the car hasn't flicked at all though. Hasn't oil or water on it at all either.

Where can u buy brushes and voltage regulators from?

Will check the earth and connections, what grease do use on the connections?

Edited 4 December, 201015 yr by maherjack

hi,

sounds like your battery needs a top up and a good charge, typical in cold weather, all my cars have the same thing.

as long as its not a maintenance free one that is.

to check if it needs a top up, undo the 6 caps on the top of the battery it might be under a cover but read the label first, if it says anything like maintenance free then don't go trying to rip the top off - it will only end in tears...

if you find the caps i find its best to use a 2pence piece. once you've got them off have a look inside and you should see the electrolyte solution (water) and plates running down each side of each hole (left and right), the solution should be just over the top of each plate. itis probably 1 or 2mm under in your case.

you can top it up with normal water from the kettle that has been boiled, don't ask why this works - it just does.

if you have a battery charger either remove the battery or disconnect it and charge it on a low setting for a hour or so. while its off, clean the terminal with sand paper, both on the battery and on the car and make sure when its refitted it has a good connection by pushing the connectors to the bottom of the battery post and tightening well.

hope this helps

- also, you can use copper grease on the earth connection as well as cleaning with sand paper.

i would not use this on the battery post, although i see no harm, however it would not make much difference and only means, when you come to remove it later, it is pretty messy.