Sofirn Q8 group buy (gb closed, but try PM to Sofirn for discount)

Just ordered some from that ebay link thanks.

Tried to order on AE. First with request to adjust price in message field in my cart.
Later same question to Sofirn in the message center in “my” AE.
Same response: none whatsoever. Well: two can sing that song. Consider me out of this buy

Maybe I just got stuck between two bits in their answering bot. IDK, but I’m done with Sofirn.

This is my first soda can light and wow, in catching up, the discussions are many!

Well, I got lucky and was able to work at home, which somehow(?) coincided with delivery day ;)!

It occurred to me that I don't have 4 same brand/model button tops so tonight, I loaded it with 2x 35Es, 1x blue 25R and a Nitenumen 3400 protected (Nu 188). I was a little concerned for the 25R, being it was 'higher drain capable' than the others. To my surprise, they all only dropped to 3.92V.

This Q8 is heavy and I didn't want to secure it with just my hand so I used an old, heavy duty rechargeable drill lanyard and attached it to the 1/4" mounting hole with a socket head screw. It got back to the house without incident although my high torque labrador jerked me everywhere till he wore out. We found all the jackrabbits in the nonbuilt-out neighborhood phases with no lack of light or throw! Can't wait to explore Lost Maples SNA, Hill Country SNA, Kickapoo Caverns...!

So you ordered from AE back when the group buy was still active, but they never adjusted the price for you?

They didn’t. But never mind. I will find myself another light for my four spare 30Q batteries.
Already un-subscribed the thread.

Mixing cells is dangerous. Putting four different cells in, especially at different voltages, can easily cause problems. They will equalize their charge as quickly as the cells can manage, with some cells basically charging others at a rate far higher than they are intended to be charged. This can melt the springs or damage the batteries or make it overheat.

Get four identical cells and treat them as a set, like they’re a single unit. Married, basically. They charge together and discharge together and always go in the same light at the same time.

Hi TK... we are up late! They were all at 4.2V when I started but I'll definitely have a matched set, soon. I should be putting in an order with Mountain Electronics soon! Thank you!

She doesn’t mean just the voltage. The cells have different characteristics and resistance so while you run the light the “worst” cell will be over stressed trying to balance out to the rest of them. In the meantime, just run the 2x 35E’s (and leave 2 slots open) and you shouldn’t even notice an output difference.

Actually, running different cells in parallel is pretty safe (if all start at the same voltage). If you run a strong battery like a 30Q and an old laptop pull 2000mah, they will work together. Under load the 30Q will draw more power to compensate for the weaker battery, but their voltages will always be the same. There is no chance of one battery voltage getting too low.

It’s when the batteries are in series that you need a matched and married set.

Still, it is a good idea to run 4 of the same batteries.

+1 …. BROODMASTER…… Great advice from TK & contactcr, I hope you heed it. :+1:

Your ’playing with fire’ doing it how you mentioned you were. :open_mouth:

TLDR: If you want to put in cells in parallel, always check their voltages/SOC.

No, it was fine. They were all fully charged and at 4.2 volt.

People mix all different battery sizes in parallel setups.

It’s in series that you need all them to be identical.

Like with the BLF GT. You can put 4 identical 3500mah in one carrier and 4 identical 2000mah in the other carrier. This will work fine as the carriers are in parallel.

The 4 battaries in each carrier are in series, so those 4 need to be identical and matched up.

When batteries are in series the voltages can vary and the low voltage protection only sees the total voltage. So you could have 3 cells at 3.2v and one at 2.4v and the lvp would see 3v total and think it’s fine, but really one battery has gone much too low. This can ruin that battery and make it dangerous to continue using.

Nope, the strongest cell will be stressed the most, not the weakest.

Ok…… but ’I’ am still not gonna do it. :wink:

I’m with teacher, won’t catch me mixing cells like that.

I got my Sofirn Q8 today from Amazon. Charged up 4 30Q cells with a solder blob on the otherwise flat top, straight away right out of the box it makes 5775.3 lumens.

Do solder blobs perform much better than button tops or is it negligible? 30Q’s and the 10A Panasonic/Sanyo are easy to find in BT but seems like almost nothing else is readily available.

I just charged four new 30Q button tops to 4.1V and they ended up from 4.080 to 4.091V. Is the spread in voltage safe enough to use in parallel in my Q8?

Yes, it’s safe

Is there some type of maximum difference in voltage before batteries should be charged again until they are closer before using in parallel?