I've got my hands on both FlexVolt 6AH and PowerStack 5AH batteries, but I'm trying to figure out which one is better for my tool use. I don't have any 54V tools, but I do occasionally use a circular saw on hardwood and I'm keeping a big DCD1007 drill just because it's handy. I understand that both batteries can enhance the performance of my tools, but I've heard some mixed reviews about the longevity of the FlexVolt. Can anyone provide insights on which battery would be more suitable for my needs?
4 Answers
I’d go with the FlexVolt; it’s been my pick. You get more power and access to really great FlexVolt tools, which will come in handy for projects like powering your circular saw or even yard work tools.
If you're in the US, the dynamics are similar to 18V and 54V. When you use a FlexVolt battery on a FlexVolt tool, it’s like having a 2AH battery since the amp hours get divided by 3. The 6AH FlexVolt may be lightweight, but it doesn't have great runtime. I’d recommend going for a 20V option; a 6AH 20V XR would give you better performance due to its different battery chemistry compared to a 4AH or 5AH.
Why not consider using both? I've heard about reliability concerns with both types, but I haven’t faced any issues myself. The 5AH PowerStack is definitely more powerful, but if you already have FlexVolt batteries, you might find it easier to transition to FlexVolt tools later on, which are pretty impressive!
I can’t see myself justifying the cost of FlexVolt tools though; I only need tools for minor tasks. Honestly, I think I should stick with something cheaper, like Ryobi, as I expect my Dewalt tools to last a long time.
FlexVolts can be heavy, and I've heard the 6AH isn't the best choice due to lower quality cells. Personally, I prefer the 5AH PowerStack for heavy-duty tasks since it’s easier to handle. However, I noticed that the 5AH discharges faster than some traditional batteries, due to its design which allows for high power discharge throughout the cycle.

For sure, but I think the 5AH PowerStack has its benefits over the 6AH XR in some tools.