Camera battery (2S3P 18650) in series

[tomdixo]

Hi
I'm working out ways to power my project. It includes powering at least 3 nema 17 motors - I know this isn't efficient but I have steppers laying around and don't want to pay a fortune for servos.

Anyway. Im looking at using 2 sony npf970 batteries which are each 2S3P packs of 18650 (7.4V each). Should I assume these already have a protection circuit (ie over-current, over-discharge)? I did dismantle one and found some sort of circuit but am not that familiar with protection circuits. I have attached a photo.

My idea was to simply connect these in series and plug this straight into my stepper drivers through a smoothing capacitor.

I just wanted to check to see if what I want to do is safe? Should I be using an additional protection/regulating circuit? How do I control one battery discharging more than the other etc?

Sorry for all the questions,
I would be grateful for any advice at all.

Thanks

[gilshultz]

Why not just purchase a power pack, they are inexpensive and typically use the same batteries. You are assuming correctly those electronics should be a protection system.

[tomdixo]

gilshultz:
Why not just purchase a power pack, they are inexpensive and typically use the same batteries. You are assuming correctly those electronics should be a protection system.

Thanks for the reply, I would rather not buy a power pack due to already having lots of these batteries.
On another note is it ok to use a protection circuit on already protected batteries?