Good explanation! If I want to get the same amount of lumens as the old incandescent flashlight, there is no need for heat sink then?
Generally, yes… because incandescents are horribly inefficient compared to LED. Incans waste so much energy in the form of heat versus photons. You can seriously burn your hand on the head of some high power halogen/xenon incan flashlights.
Yes. For instance, I used to use a 2 D cell Maglite with 1.2v NiMh cells and a 2v bulb to get extra output. When led bulbs came out I was able to get even more lumens and batteries lasted much longer. The original setup produced no noticeable heat and the led setup probably ran even cooler. It’s very easy to get more lumens with led. Modern flashlights are many times brighter than older incandescent to the point that they can get hot and need cooling. You can take a modern led flashlight and run it at a lower setting and be brighter than incandescent and it won’t heat up much at all.
My charger does 500mA and shows me the voltage of the battery as it reaches 4.20 I just need a ballpark number e.g. listed 2500 battery, is it really 1200 or is it 2300? That would be enough.
Can I guestimate true capacity of a cell by noting how long does it take to say go from 4.00 to 4.20 in minutes? I am assuming voltage increase is linear and inversely proportional to the battery capacity.
I don’t think you can use that method since most li-ion chargers start in constant current mode and finish in constant voltage mode. So it will stay at 4.2v for maybe 20 minutes until the current goes to zero, but the time can vary a lot.
The only way I know is to use a battery charger that shows you the milliamphours as its charging. Since it’s usually measured from 2.5v-2.6v to fully charged, I tend to start around 2.8v-3.0v and if it charges 2300mAh I’ll add a little more and say it’s about 2500mAh. So even using a charger that measures it, is not exact. It’s only pretty close, assuming the charger model has been tested and shown to measure pretty accurately.
There's totally such thing as a stupid question...and I've asked lots of them since I've joined the forum...lol. with that said..you're not stupid if you ask a stupid question...but you cannot get upset for being clowned for said stupid question. Trust me, im living it every day. Lol.
Nope. Go to a gas station and put down 10bux worth.
It’ll fill at top speed ’til it gets to about 8bux then will slow down some.
When it gets to 9bux it’ll slow down even farther.
By the time it gets to like 9.70, it’ll just be a trickle, incrementing by pennies ’til it hits 10.00 and then stops.
Same way Li cells are charged. CC is full-tilt at the rated current up to when the “pushing” voltage hits 4.20V, and then it switches to CV mode, just applies that 4.20V and lets the cell sip more and more slowly as it “catches up” on its own until the difference between “pushing” and “battery” voltage is small enough that the current drops to whatever percentage of the CC rate determines it should cut off.
Then how about this one? Just look at the time taken to say from 3.90 to 4.10 (assuming this is being done on CC part of the charging curve). Isn’t that part of the graph assumed to be linear? If it takes 20 minutes at 0.5A to raise 0.2V on one cell vs another one where it took 30 minutes, can’t I claim that other cell has 50% more capacity?
There are other factors that your not taking into consideration. Different cells have different amounts of internal resistance. This can effect the charge times. Even temperature can effect how well a cell can take a charge.
You can try all kinds of techniques, but who knows what results you’ll get. Like I was saying earlier, even with a known charger that can measure the mAh going into a cell its still only going to be a ballpark estimate of the cell capacity. To get better accuracy you need a dedicated testing rig thats calibrated and you need to know how the manufacturer tested the capacity. Some might start at 2.5v, some might start at 2.65v. The test might be done at different room temperatures. They may measure it at a certain charge rate. All these factors go into their cell capacity rating.
The types of measurements your suggesting are way more variable than even the basic battery charger capacity tests (which aren’t very accurate).
I’m not sure what your trying to accomplish. If your just trying to see which of two cells has a higher capacity you can do a load test. Put it under a set load like a flashlight at a brightness that won’t over heat it and measure how long it takes before the low voltage protection kicks in. Thats real world results there.
What batteries do you have?
Has anyone tested those models before?
How many amps will 4 XP-L HI emitters pull in a D4SV2? Looking for a suitable 26650
The black Shockli ones are solid
Thanks! Looks like I can at least obtain those in a reasonable manner.
I have ordered a 26800 tube for the light but I don’t know where I am going to get a 26800. I’m not paying $20 for a single unit from an unknown Aliexpress seller. I’m halfway considering picking up the Convoy L8 just for the cell and charging capability. The thing is, I would much rather have the L7 or the L6 so it sucks to spend $90 that way.
$8 for a 26800 here. Not in stock at the moment but you can get alerted.
I’m not holding my breath. I’ve been on that site off and on for weeks lol
Thanks for looking though
Hi all, I made 2 silly mistakes when tapping into my cars wire a few years back. I removed a bit of the insulation and soldered to the wire using plumbers flux and it was really close to the connector socket at the back of the audio unit. Currently the solder connection looks corroded due to improper flux. My question is can I just resolder with proper flux and this will stop the corrosion? I know replacing that portion is the best option but I don’t have much length to work with. Hopefully the corrosion did not travel to the end.
Ewww, acid-core solder.
If it’s already corroded, it might have already been “used up”. If not, wet paper-towels might “wash” any residue.
Yeah, you can go over it again with new solder, maybe to build up any etched metal, but it might not be necessary.
Yeah I know lesson learned. Are you saying I may have lucked out and to leave it alone. So far I havent lost any signal or function.
Yeah, I’d leave it. Like drain-cleaner, it gets “used up” as it eats stuff, so…
Thanks for answering.
If it were on wiring to sensors or modules I’d tell you to go through the trouble of replacing the wire entirely or at least a good portion of it, but since audio isn’t crucial if it fails and you’re still getting a good signal apparently, may as well leave it be…been a few years already so you’re not likely to see it worsen (it could, but it’s unlikely at this point). If it’s easy-ish to access, it wouldn’t hurt to remove the harness and closely inspect the connectors for corrosion on both sides, if you feel the joint was close enough to them. A nylon or fine brass brush at low speed in a dremel can clean up light corrosion without damage if you’re careful…would certainly be fine on din pins and the various snap-in harness connectors can be replaced fairly easily if needed. Probably fine, though.
Plumbing and welding stuff is generally destructive to electronics. Normal tin/lead general purpose solder is good to have around, or even a little handy-tube of cheap rosin core silver solder.