[Flexvolt with 20v blower?]

Thanks, both.  I think I will just shave off that ridge with a Dremel and use it.  

[Flexvolt with 20v blower?]

I have a 20v Dewalt blower (DCBL720P1) that works great.  I just bought a trimmer that came with a 9Ah Flexvolt battery.  I assumed I would be able to use this in my blower as well.  However the FV battery does not fit inside the battery housing on the blower.  There are two small (1-2mm) rails on the bottom of the battery guard / tool rest that get in the way (see picture).  My question - is there a reason for this, or was it just a design oversight?  Could I trim down those rails a bit to allow the battery to fit, or am I asking for trouble if I do that?  The only potential issue I can think of is that the battery would extend beyond the "foot" a couple of millimeters so when you set down the tool it would rest on the battery.  I have not been able to find a compatibility chart that addresses this.