Question about the 18V 6/12" circular saw

[roadhog96]

Any of you guys using the DC390B with the Compact Li-On Batteries? I realize that it would work better with the more expensive 1 hr charge batteries but all I own is the compact ones. I'm interested in how long it will run before the battery will need to be recharged. Can I make 20 cross cuts on 2x6"" lumber, 30,40,50. Just a ruff idea as to how much juice these saws require. I have a chance to get a new saw and want to make sure it's going to be worth the investment. Don't want to get it and find after making 10 cuts the battery dies.

[kjones]

It is nearly impossible to give you a cut number, as the boards have so many variables. That being said, I think 20 cuts with a compact battery would be on the higher side of what I would expect.  Remember, impact drivers and drill drivers draw around 6-8 amps under load, while the circ saw, recip saw, and cut off tool draw in excess of 40 amps. Think about how fast the glass of water gets drank at that kind of speed, when it is designed to last under a much smaller draw.

[roadhog96]

It is nearly impossible to give you a cut number, as the boards have so many variables. That being said, I think 20 cuts with a compact battery would be on the higher side of what I would expect.  Remember, impact drivers and drill drivers draw around 6-8 amps under load, while the circ saw, recip saw, and cut off tool draw in excess of 40 amps. Think about how fast the glass of water gets drank at that kind of speed, when it is designed to last under a much smaller draw.

So it's really a tool that was deigned to use the larger batteries. I had no idea there was so much differences between the amp draw requirements for these tools. I've been using the 18v compact drill/driver and impact driver and those compact batteries are just fine. They last a reasonably long enough time and charge in only 30 min. For the amount time I need to use a circular saw for I would probably be better off just grabing the AC powered saw.

[kjones]

Yah, it is a huge difference in draw. The compact batteries will certainly run the tools, and are good in a pinch, but yes they are designed to really be used with the larger capacity batteries.