I was finding the battery was not holding charge for very long. A few wks and it was getting flat. I think that is a problem of the alarm or something though and maybe not the battery. It was cranking slow on old wiring that I also thought was battery's fault. Now it's transformed so I should get a better idea of the battery's performance. It was about £50 off eBay from memory. Iv had it just over a yr so still going strong after a charge anyway