There is every type of battery packs in the numerous online stores. If custom made battery packs is what you are looking for, go to www.euroenergy.co.uk. Here there is a wide variety of the most recent battery packs. The branded battery packs come with a good warranty that will give you the worth of every dollar that you will spend. They will last for as long as you want to use the device. You can go up to 10 years without budgeting for a replacement.