Sorry, forgot to post the results of the test on the OEM Canon LP-E6 battery. I tested this battery twice, it was charged both times with the canon battery charger. This battery is 3 years old and NEW it should have a rating of 1800mAh. The results were: Test 1 -- 1561mAh. Test 2 -- 1572mAh. So given the results being so close togeter i am confident that this battery after 3 years is sitting at about 87% of capacity. Cheers. Simon.