get on fleabay type in 12v 18ah you will get a seller up called UPS, I bought a battery off of them £26 delivered, there all fresh stock take a full charge and will last for ages, I have bought two off of other companys and they have been sh*te and got a few off of other sources and they havn't been very fresh and havn't lasted long, you will get a few people on here to tell you to go to scrapyards and get them out the bins, if they got good batterys then good luck to them, but if your serious about lamping and want to stay out for a good amount of time and not for a half hour shine try what