The There Are No Stupid Questions Thread

I will give it another read when the tools arrives. Thanks for the long write up. It deserves its own thread.

Considering safety, you should be nearby so as to monitor the cells as they charge. A slow charger might take several hours. No one really wants to sit there for that long and monitor charging cells. I watch YouTube videos while they charge and my cell’s usually only take 1 to 1.5 hours (26650 and 21700). A strong USB based charger might make the difference from taking 8 hours to charge a battery to only 3 hours. So at least give those little USB chargers the power they need.

Charging slowly does reduce degradation, but for most people it’s not an issue. If you charge a particular cell everyday it will reduce capacity quicker, but most folks don’t charge that often. I charge once a week and I use a fast charger. I don’t really care if it degrades faster. It should still last several years. By then newer, better cells might have came out and I’d want to replace my older ones anyway. So don’t covet a battery as being precious. They are a disposable commodity. One accidental discharge too low and they are junk anyway.

It definitely helps to have a good charger. I switched to the Miboxer C4-12 when it came out. It can do a wide range of charging levels up to 3A x 4. It’s great for charging bigger, high drain cells quickly. Theres lots of other good chargers out there as well. I’d at least get one that’s 4 slots and can do 2A x 4.

You can find the safe charging levels of a particular battery by looking up its data sheet. For instance, a Samsung 30Q has a nominal charge rate of 1.5A (180 minutes) and a max charge rate of 4A (70 minutes). A good charger can give you the flexibility to charge at whatever rate you want. I would normally charge a 30Q at 2A, but if I’m in a hurry I can go 3A. No big deal. My high drain 26650 cells I always do at 3A otherwise it takes forever. They can easily handle that. Certain high capacity or older chemistry cells tend to have a lower max charge rate. Like the old Sanyo/Panasonic NCR18650B has a max charge rate of only 1.6A. I don’t even bother buying older cells. I stick to newer chemistries and not so high capacity. Those tend to have higher charge rates.

Here is the link to HKJ battery and charger tests. Lots of good info there.
https://lygte-info.dk/info/indexBatteriesAndChargers%20UK.html

Also online battery data sheets.

No risk, just slower (and less taxing for the battery).

Unless it has been upgraded at some point, or replaced by a newer model, that single-slot Sofirn/Thorfire charger they bundle with their kits only has a 5W (1A) input, and 750mA output.

It’s not demanding, and plugging it into a higher output adapter will not make any difference.

I have a Nitecore charger (UM2) and when I had a weak USB A/C adapter powering it, the UI didn’t behave properly… So, problems like that can happen. UM2 charger input 5V/2A 9V/2A, 18W (MAX). Anyway, always good to have a power adapter with surplus capability in case of future needs.

Does anyone feel like they have had to "break in" a flashlight? I purchased something new from a reputable company that should shoot 10,000 plus lumens. It was just crashing to sub 1,000 in under 30 seconds. I just kept using it, now it seems to be getting a bit better at holding on to lumens as long as i don't start at turbo...

??

Depending on heat transfer material between board and shelf, some need a few heat cycles for optimal performance eg arctic silver, mx-4

ok, cool thanks. that seems to make sense.

More sales are happening now. Currently we see Amutorch and RovyVon competing for our money. Olight has a “big sale” once a month (ending today). Nothing so exciting about it.

A question for BLF veterans: What is the most awaited brand sale during the Black Friday in late November?

We are going into the holiday sales period for China (Sept-Dec). This is when they are shipping the most products. So on one hand, you can save a bit of money. On the other hand, you can expect the longest delays, shipping times and most lost packages. I personally try not to buy anything during the holiday season. I wait for things to calm down and buy in the off season. If money is really tight and you don’t mind the wait, the 11/11 sale is a great one.

As far as a specific brand, I don’t know. It depends on the brand. Some companies don’t have sales at all and other companies will have coupon codes all year long. I don’t think there is a “most awaited brand sale”. If there is a certain brand your interested in, you should try to find out when they plan to have a sale.

What type of driver is this?

Had this in an Amutorch YooToo SD3 and transferred it to an SD2 with an SST40. But it doesn’t give the lumens: ~930.
Draws 3.5 Amps – should push 1400lm, perhaps loss at tail switch?

Specifically, can I boost it by piggybacking some 330 mΩ atop the existing 250 mΩ ones? (to draw ~6 Amps)

Direct drive with current limiting resistor and a lousy SO-8 6.5A max FET ( Datasheet )

Yeah you could decrease the resistance a bit.

So I’m good with a couple of 330 mΩ?

Should bring this to 6.15 A

What is considered low or dead voltage for 3V coin cells such as cr2032?

This is a case where it really depends on the device they’re used in (i.e. the load that it demands from the cell, not necessarily just the voltage). I’ve had them be “useless” at as little as 2.9v with a plain multimeter reading (no load applied) and some that read 2.6v (from very low drain applications). The ones in my digital calipers come out around 2.7v but clearly can’t do their job correctly a bit before that point.

I think most battery testers use a small 50mA load to test batteries but often that will separate good from bad even if they have nearly the same simple voltage reading.

Btw, this is also where the huge difference usually is in the cheap-cheap lithium cells vs. quality big name brand ones…ability to sustain and deliver current. Often the cheapies are just no good at all, but depends on the device.

From the news, isn’t R Kelly the guy who went around pissing on people?

I don’t follow the pop thing, but he sounds familiar. And I think I remember a Chappelle skit about him.

Yep

I guess the next perhaps obvious question is… why?

Marking his territory?

Ha! Of course it’s out there…

Oh, the wonder that is Duh Innernet…

If you get 3.5A with a full cell then the total circuit resistance must be quite high, about 350mΩ, see my DD calculator .

To get 6A you must bring it down to ~130mΩ, which will be difficult since the mosfet is already arround 60mΩ at 4V drive voltage, and a 40T is something like 12mΩ, plus spring, contact, switch, wire… etc resistance.

You can start by bridging the resistors, but that would only remove 125mΩ.

You think they are not already bridged? I assumed they were already making 0.125 ohm.