I had trouble with a brand new battery on a Bandit, when the battery was fitted by the shop, it was not charged by them, if you rely on the bikes charging system to fully charge a new battery, it will never reach its full storage capacity. The battery gradually becomes lazy and a cell gives up. (it was only 2 months old).
!2 volt batteries must show 12.7 volts, when fully charged, or they are not any good, it needs a full charge, which is 12 hours at a 1 amp rate, you then need to put a voltmeter across the terminals and leave it there for a while, observing if any drop in reading is happening, if there is, it is not holding charge.
You may not be getting 14v at 3000rpm, (which is the usual figure), because of the battery condition.

Hmm that could be the case, one note though: when i received the battery, i followed the instructions and charged it up before connecting it to the bike. So i don't think it would be a case of initial charging issue. It might be a duff battery though... I wonder if there is any guarantee that applies on these things.

It's this battery i bought:

http://www.ebay.co.uk/itm/Yamaha-XP-500 ... 2316eeba49

It says 6 months warranty, and i bought in 16 january so i'm out of warranty period i'm afraid...

halfabusa wrote:
It says 6 months warranty, and i bought in 16 january so i'm out of warranty period i'm afraid...

No you're not. A six month warranty does not comply with the sale of goods act. You must get a minimum of a year I believe. Next time though, you might be better spending a wee bit more on a brand name such as Yuasa.

oh well... i'll learn from my mistakes...

Batteries can be a bit problematic with warranty, a bit like clutches and brakes. Most oem's are only six months these day even on a new car or bike. Being consumable items, these are exempt from the eu 6 year warranty thingy and also the Sale of Goods Act is a difficult area when dealing with batteries, bulbs, clutches etc unless it's a result of some other item on the bike or car causing it/them to fail. However, having said that, many dealers will still exchange it if you are a good customer. It's different if you buy a new battery that states it has a 12 month warranty though, clearly. In your case it's worth trying to claim but they will possibly want evidence your bike is ok and charging correctly. Give it a go. SOG almost certainly wont be of any help, I say that through many years of dealing with problems like that in the trade.

Son Of God, why would He help?

Cause i pray