Building 7.4 v pack

[Star Bird]

Would wiring 2 Panasonic Protected 18650 3.7V 3400mAh cells in series make a Protected 7.4v battery pack?

Or are there problems with wiring it this way?, as apposed 2 unprotected cells and wiring a PCB for 7.2V Li-ion battery packs.(which is out of stock)

Just really wanting some long runtime for cons..

[Bark]

I think the cons are that the cell with the higher charge will potentially shutoff the recharger when it maxes out, which means the other cell won't be maxed out, limiting battery run-time life. Also, the cell with the lower charge will drain below the minimum threshold resulting in the battery needing recharged sooner, even though the other cell would still have some juice. Basically, the window of battery run-time usability will be narrowed, in terms of when the battery needs a recharge and when the recharger says, "all charged."

I Googled this very issue a while ago. No one really wants to say, "It's perfectly fine," in definitive terms. Honestly though, the above is all I came across. Maybe a good mitigating strategy is to charge both 3.7v cells before joining them together?

Also, any time I found this topic, they always said to use the same make and model cells too.

[Silver Serpent]

You can use 2 protected cells in series for a 7.4v pack, but you don't want to charge them that way. You need the PCB to charge the cells properly.

[Star Bird]

I guess that I should wait for the PCB to get back in stock or the 7.4v 2600 mAh battery