Starter battery and winter storage

Just been out to start Baz up in advance of some maintenance I'm planning for tomorrow and the starter battery is flat
I've got it on charge now and am guessing that the radio has caused the issue as we haven't had a run out since early December.
The battery is less then 12 months old, once charged how long do you think it should last if I disconnect it?
I'm trying to work out how often I need to take him out for a run to stop this happening again.
Thanks in advance for the advice.

 

Hi, u don't say what the base vehicle is so don't know where starter battery is or how accesable it is.
I always remove my batteries and charge periodically as needed.
Search previous posts there are several threads on this subject.

 

Immobilisers are the main culprit on modern vehicles, and sometimes the radio for the central locking.

If they take (for argument's sake) 300mA or 0.3Amps, then in a 24 hour period that is 7.2AH out of your starter battery.

A week will see 50AH out and you're getting down to the battery being pretty much discharged.

To counter this discharge you need to be able to put in at least 0.3A plus an extra bit to keep the battery up on full charge, so 1.5A to 2.5A is a reasonable charger size for just maintaining the battery.

Don't forget also that the battery itself has an internal self-discharge rate that needs to be added to the 0.3A above.

On the basis above, you need to be out in it for a decent run every 4-5 days, or get a maintenance charger that you can leave hooked up and turned on.

Peter

 

Always give ours a run once a week to keep everything 'alive'

 

Thanks guys.
Baz is a 23 year old talbot so no fancy electronics to drain the battery. Having a poke around I think it's only the radio drawing charge.

 

transfer the radio feed to the leisure battery or fit a battery isolator switch.

 

A battery supplier informed me at zero degrees C a battery loses up to 50% of its power.