I know bike batteries aren't very good at holding a charge but mine has gone nearly flat in a week.
Normally i have a trickle charge plugged in, but not this week.
So what could be the possible causes, and is there a way of finding the problem.
Thanks in advance.
Brad.

Does it normally hold its charge in a week?

ETA - how old is it?

[Edited on 21-7-09 by speedyxjs]

The battery was only fitted in May. The old one lost it's charge and would re-charge, so it was replaced. I just presumed it was the old battery.

Get a multimeter and set it up for the 10 amp dc range.
Remove the +ve battery terminal and then connect the meter leads between the break
i.e 1 lead to the battery post and 1 lead to the cable you removed.
You'll then see what the drain is in amps.
remove you're fuses one by one to see if the drain disappears that way you'll find the circuit.

Did what you said Gary and i got a reading of 0.05 amps. Then i disconnected the fuses one at a time and i always got the same reading until i pulled the starter relay fuse which is separate to the rest.
Should this be normal or do i need to remedy this.

0.05 amps is VERY small and would take quite some time to flatten a battery.
Don't know what the ratings on a bike battery are but lets say it's a 60 amp hour battery for arguments sake.
So you'd get 60 amps for 1 hour before it's flat or 1 amp for 60 hours or 0.05 amps for 1200 hours ( or 50 days).

Ok so it's a generalisation and obviously not on a constant scale but you get the idea.

I doubt it's that that is flattening the battery to be honest.

Edited to add
You did have the probes in the correct holes to do the test didn't you??
You normally have to move the +ve lead from the volts/ohms socket into the amps socket ( If you get my drift)

[Edited on 21/7/09 by omega 24 v6]

I'm sure bike batteries are around 4ah

You could just fit a master switch but it would also be an idea to do some more investgation to trace where the current is leaking to.via the relay.

ok so a quick search shows a cycle battery of around 12 amp hours which would be flat in 10 days at that drain rate.
So you'd prob need to look into it and see why/where the leakage is. i.e trace it down the line unplugging as you go untill you narrow it down. It could even just be dampness/salt doing it.

[Edited on 21/7/09 by omega 24 v6]

Yes i did move the +ve lead.
And i would say that the battery might have been a bit low previously.

I will have a noisey and do as you say mate, i have an incling that it could be the CDI unit , the problem there is if i isolate it , then i have mess about unplugging it to try and get the engine to start.
Cheers anyway fellas.
Brad.

For a bike battery you will need to fix due to the low capacity. I would guess this is what killed you last battery they don't like being discharged more than about 50%, and if the voltage goes under around 11/10V you will be lucky to recharge it...

Basically lead acid batteries sulphate when the voltage across each cell drops bellow a critical level.. They also self discharge at around 1 to 4% of there capacity per week, not a problem if you use the car frequently..

I would find the fault but until then disconnect the battery when not in use/leave on an automatic charger..

Dan