Hi Steve,
As said earlier I would recommend that you only use OEM batteries on high risk equipment like this. If you need to find out whether the 3rd party batteries are any good, buy some and test them in your workshop to see how they perform. Obviously if the batteries turn up without the dimple in the end then they will be incompatible and will not charge the cap in the specified time. Although the batteries are rated the same voltage and amp hour, better quality cells are used bu OEM suppliers in my experience. If you test/inspect the 3rd party batteries and find no difference in performance then you will have to complete a risk assessment to quantify buying these instead of the OEM ones.
