hi everyone question is this alarm unit rechargeable. if it is where does it recharge from? any info would be appreciated 

It has an internal battery in the siren and is wired so i presume charged from the normal electrics

As above, pretty sure it should charge from the car.

 

They have a service life of 5-6 years. At this point the entire alarm siren needs to be replaced as the battery is not a user serviceable component.

 

Some people have split the alarm siren to remove and replace the battery depending on the condition of the PCB

thanks for replies car will be 8 years old in Feb. 34.000 miles from New. I assume that if the batt won't charge. it won't sound alarm or beep when locking the vehicle.  I'll know it then needs replacement. no point in buying  2nd hand off ebay as I see those adverts don't seem to indicate age of them.