Thought I'd share my setup. I only have one Osmo Action battery and I needed to record all day around Disneyland. This was my solution and it lasted ALL day! It's not pretty but it works.

Parts:

• Aurora PowerXND Mark II 128 52mm Variable ND Filter
• Anker Powercore 13000 mAh
• SmallRig Osmo Action Cage
• SmallRig Battery Holder
• SmallRig 1/4 Double End Adapter
• Manfrotto tripod
• GoPro 1/4 Tripod Adapter
  

"It's not pretty but it works."

Not at all, that's quite an elegant solution, and you've answered everybodies questions they might have regarding using external power source.

Thanks for showing your rig and for the links.  I did not know there were variable ND filters (not polarizer???) and which one since I see on B&H a range of options and PRICES!

edited to add:  What I'd like to know about the Smallrig cage:  Can you have what I'll call the gopro adapter on the bottom and still fit a tripod mount next to it in one of the screw holes?   I'd like to just attach the gopro thingie (so no lose parts and screws) but possible just screw in a tripod at the same time.

Hi, thanks for sharing your set up with our Osmo Action. Cheers!

ff22 Posted at 7-3 14:34
Thanks for showing your rig and for the links.  I did not know there were variable ND filters (not polarizer???) and which one since I see on B&H a range of options and PRICES!

edited to add:  What I'd like to know about the Smallrig cage:  Can you have what I'll call the gopro adapter on the bottom and still fit a tripod mount next to it in one of the screw holes?   I'd like to just attach the gopro thingie (so no lose parts and screws) but possible just screw in a tripod at the same time.

There are variable ND filters. Be careful there are plenty of bad ones that give the "X effect", where one corner is darker than the rest of the frame if pushed to the limit. I use Aurora PowerXND Mark II 1-7 stops

I don't quite follow what you're trying to do but I added more picture so you can really see how it is attached. I did use a GoPro tripod mount. Nothing is loose.

davesantos Posted at 7-3 15:16
There are variable ND filters. Be careful there are plenty of bad ones that give the "X effect", where one corner is darker than the rest of the frame if pushed to the limit. I use Aurora PowerXND Mark II 1-7 stops

I don't quite follow what you're trying to do but I added more picture so you can really see how it is attached. I did use a GoPro tripod mount. Nothing is loose.

I've taken your picture and added some highlights and included one I did the other day.  Just using the immediate gopro (finger thingie), it looks as if there is room to actually screw in a tripod.  The "loose" item is the part I've outlined in blue.  I don't want to futz with it and its two screws but leave it attached but till maybe screw in a tripod mount to its left or right, as outlined in red.  

You are right, I'm making it more complex than necessary (g)

Oh, how long did it take for your item to ship?

ff22 Posted at 7-3 15:41
I've taken your picture and added some highlights and included one I did the other day.  Just using the immediate gopro (finger thingie), it looks as if there is room to actually screw in a tripod.  The "loose" item is the part I've outlined in blue.  I don't want to futz with it and its two screws but leave it attached but till maybe screw in a tripod mount to its left or right, as outlined in red.  

You are right, I'm making it more complex than necessary (g)

You can fit a mini tripod, I just tried my Manfrotto. It's tight but there is enough clearance. The cage took a little less than 14 days to arrive.

davesantos Posted at 7-3 19:25
You can fit a mini tripod, I just tried my Manfrotto. It's tight but there is enough clearance. The cage took a little less than 14 days to arrive.

Thanks.

Hope I'm not too trying...

What about that filter.  Expected delivery:   Wed. Jul. 17 and Mon. Sep. 2

ff22 Posted at 7-3 19:47
Thanks.

Hope I'm not too trying...

No worries.

The filter came quick. It came the next week after ordering. The listing says it ships from China but it actually shipped from Irvine, CA.

davesantos Posted at 7-3 20:07
No worries.

The filter came quick. It came the next week after ordering. The listing says it ships from China but it actually shipped from Irvine, CA.

I'm still trying to justify the cost of that cage but I like the fact you can change the battery and open the usb door without having to remove it from the cage.   I presume you can get a pretty standard plastic lens protector for the 52mm "lens" contraption?