They are safe, but I got a 2400mah one from amazon (https://www.amazon.co.uk/Replacement-Battery-pack-2400MAh-Slim/dp/B003N2JG34/ref=sr_1_1?ie=UTF8&qid=1514661963&sr=8-1&keywords=2400mah+psp+2000+battery) and battery lasts about 10 hours playing COD RTV. that one says 3600mah on the battery but 2400mah on the amazon page.