Exchange of Sofirn batteries for Molicel P45B

Hey Guys
I thought I could swap out the Sofirn batteries that come supplied with the Sofirn Q8 Plus, to get a bit more lumens - on average from 16K to 20 or 21K.
But, I just read this on reddit:
“it does gives a bit of extra punch, but the newer q8+ models have a plastic protector to try to prevent said batteries from being used since they removed the spring bypass:((.”

And one of the replies says:
“Oh thats very easily removable. Heck, mine didn’t even come with one, and it’s was bought after they started putting it! Also I think they only has the spring bypass on a couple of early units.”

I received the torch a few days ago, so I would imagine it has the plastic they mention.
So, please I wanted to ask :
1 Where is that plastic?
2 How do I remove it?
3 And finally: why can’t I install the Molicel directly?

If it would be possible to upload a picture or diagram because I don’t know much about the technical terminology.

The spring bypass isn’t (standard) on the Q8 Plus for a (long) while now; it was only on a few early (review) units I believe and on the model (the EC06) that Sofirn made for Astrolux at first. A spring bypass is easy to do though, if you have a bit of experience with soldering.

In regard to the “plastic protector” I have no idea what kind of that is. I recieved my Q8 Plus in March and it didn’t have a ‘plastic protector’ in it.

What you do need to take into consideration is that you (most likely) need an ‘adapter’ for the Molicell P45B, since they are flat tops and might not make a good contact with the brass ‘positive-ring’ on the driver.

Soldering a ‘blob’ (or “button”) on top of them is an option, but I would rather recommend to go with one of the 2 options that Convoy offers:

PCB button for a 21700 battery; use some (kapton) tape to fix it in place on the battery:


A 3x 21700 adapter, which you have to sand of a bit of the plastic edges to fit into the Q8 Plus:

Personally I use the plastic adapter, but I have also tried the ‘PCB adapter’ and that also worked fine.

When you recieve your Q8 Plus, you can maybe take a picture of the inside, which maybe shows the “plastic protector”, so I/we can better help you with that.

Hello Wingman,
Thank you for replying, because you have cleared up the last doubt I had about the use of the Molicel P45B in the Sofirn Plus.

  1. I have just received an email from Sofirn, where they confirm that it is not necessary to make a by pass.

  2. The black plastic protector (which in the end I will not remove) can be seen here in this link, there are two photos, the second photo you have to scroll to the right. You can clearly see the difference. I don’t know how to upload pictures, that’s why I show you this way.
    3 After a lot of searching, -as I said- the ideal is not to remove the plastic part but to use those flat batteries with adapters.
    4 I still had the last unsolved problem and thanks to your contribution, I have solved it. I was afraid that the PCB buttons could be displaced when screwing the torch in. Well, that won’t happen with the flat to top, -which I didn’t know about- because it’s clearly seen that it’s a single body that fits in the hole for the three batteries, so they stay in position even if you turn it when screwing it in. I’ll sand them if necessary, but I’m not worried about that.
    As soon as I get the flat to top plastic ones from China and try the new batteries I’ll let you know how it turned out.
    Thanks again for your clear and valuable input.

I just checked and my Q8 Plus also has the black plastic protector in it! In my mind/memory it didn’t have one, but my memory clearly failed me… :sweat_smile:

So yeah, the Convoy 3x 21700 adapter clearly works well, even with the ‘plastic protector’. The reason you have to sand/grind down the outer edge of the adapter, is that the internal diameter of the Q8 Plus is slightly smaller than the adapter is. With a ‘dremel’ (or other rotary tool) and a grinding wheel/bit, it’s just a few minutes of work.

A spring bypass is not necessary, unless you want the absolute maximum output. I read in that thread on Reddit you linked to, that there were a few reports of people ‘frying’ their springs with high drain batteries. If that is the case, it could be usefull to have a spring bypass, since the current will then go through the bypass and not the spring, preventing the springs from heating up to much.
You will push the rest of the flashlight a bit harder though, with the risk of components being pushed (closer) to their limits.

Currently I’m using Samsung 40T (40T5) batteries in my Q8, since at the time the P45B weren’t available yet. I’m still thinking of swapping them for P45B’s though, although I’m not sure if I want to spend another 20 euros (+ shipping), just to have a small gain. The Samsung 40T is already a good and reliable high drain cell, so it’s a shame not to use it.

I’m glad I could help and if you have anymore questions, just ask!