Where would the ITP SA1 Eluma and Shiningbeam I-mini (both single cell aa lights) fall into this?
I think you are using the word "regulation" in a different meaning than I do.
This graph shows you the typical runtime off a typical well known P60 XM-L drop-in:
While there is decent regulation for minute 0-55... the end of the discharge curve is not regulated at all and the driver isn't able to keep the current up to the previous level. That's what you typically get from budget circuits. (read the majority) On dual aa/14500 driver it is true that regulation often is better (on 14500 batts) than 18650 lights... due to the buck boost nature of the driver... resulting in a sharper drop-off at the and a better (true) regulation over the whole runtime.
picture stolen from HKJ.
The comment that most (budget) flashlights are regulated or well regulated over the whole runtime is simply not true ... mine sure aren't.
So essentially what I'm trying to say here is this.... know thy discharge curve/behavior on depleting cells... and often measuring isn't necessary. I wouldn't go so far to say that protection circuits aren't necessary on cells that are used with a light with a "soft" drop-off at the end.... but there is a tendency.
Would make a nice game show .... estimating the voltage just be looking at the brightness on high.
kreisler instead of argue about how many angels can dance in the head of a pin take your trueRMS DMM and test it from the wires connected to the led star, go to do your asperger homeworks boy :P
i still dont know what trueRMS means. hehe.
the DMM and the C9000 were my best purchases in the past 3 months! :p
lazy ass
Vectrex. Some good info your putting out there. I'm curious to your references to "Budget Lights" when taking about these circuits. Can you list some examples of Budget Lights vs non Budget Lights? I mean where is the point on when a light is no longer a Budget light? Is it just above a certain price point?
Phew that is asking a lot.... I would have to condense all the test I read over a period of 2 years into one post... not easily doable... the next problem is that I don't actually own 14500s and 16340 LiIons... so my advices would be purely theoretical and with no first hand experience. I only use 18650 ( with HiMax 2400/Xtar 2600) lights and my smaller lights run eneloops (AA/AAA) exclusively. So my view on AA/14500 lights is very eneloop-based... and a thread about 14500 batteries is probably not the time nor the place to give advice about lights driven on NiMHs. I do lend me some trustfire protected 14500 flames from time to time from a friend, to check if I should change my attidude towards the smaller LiIon based cells, but 14500 lights often just exchange brightness for runtime... and most 14500 cells don't store more overall energy than the average NiMH battery. If you want a general advise on drivers... look for current regulated drivers and not PWM regulated ones. Every light I own above the $30 mark has one. I am leaning towards spending some money on a super compact 1x18650 light with full on regulation these days.
So I guess every manufacturer has their own "Budget Light" versions.
No there are some manufacturer that don't do "real" budget... the tricky part for me lately is to find lights with premium attributes for a budget price ($25-40)... shiningbeam lights and the lower end Klarus/Jetbeam/Xeno lights seem to offer that. But it is true that you have to look at individual models to distinguish good/bad lights or good value for the money paid. There are some good lights out there from high class brands that are overpriced and on the other side there are true gems in budget lights land. Also the production quality fluctuation in Budget lights is something that puts some people off. I always have a better feeling recommending well known brands like Fenix(E21)/Klarus(P1A/2A)/Xeno(E03) to beginners since the chances of getting a good one is higher, than the typical budget light brand like Ultrafire/Trustfire etc. . It depends a bit on your exceptions... If you are looking for stellar machining and anodized threads it will cost you a bit.
How about ITP? Like say the SA1 Eluma?
ITP is also good but just a step under the aforementioned in build quality judging from my ITP A3s. The SA1 is too big for a AA/14500 imho ... you can get 18650 lights that are smaller (or at least thinner) and ramping isn't nearly as useful in reality as it sounds in theory, take that from an UF H2B owner.
What are the issues of charging an unprotected 14500 below 2.75 volts? The reason I ask is I just did it. My first 14500 and I waited too long when it was in the flashlight. It went to about 2.2 volts and after letting it set for about 10 minutes it went up to about 2.54 volts. I went ahead and charged it and it took the charge and is now 4.15 volts. I know this is not a good practice cause from what I've read, if it goes below 2.75 volts you are just supposed to throw it away. Is that really necessary? Has there really been much experimenting to see how low these batteries can go and still take a charge?
what's your flashlight?
2.54V remaining offline voltage at rest (or short "2.54V resting voltage" haha) sounds low. i wouldnt mind charging it SLOWLY in my charger but always checking the cell's temperature (with hand/touch). if the cells becomes warm or hot, then the cell will explode hee. (so you should stop the charge process). if the cells stays cool, then nothing will happen.
I heard the advice that one shouldnt LEAVE the underdischarged cell too long in this state. Days/weeks at 2.54V could damage the cell and THEN the recharge process gets hazardous.
God save the queen
The flashlight I was using for my rookie 14500 testing was a cheap Duramax single AA (single mode) that can be had at Autozone for $13. Surprisingly good light especially for the price. Battery was a cheapo Ultrafire 900 mAh. Battery never got hot during this charge.
This whole experience tells me I have to check the battery voltage a lot more often than I thought I was going to have to. I didn't even use the light much before the voltage took a huge dump. I don't even think I ever had it one for more than a minute at a time. Seems just turning it off and on for short bursts takes a lot of juice out of the battery. Did a big brightness increase but short on the staying power. Lots of wow factor but not much in usability. More for tweakers.
i didnt know that Duramax flashlights run on 14500. Good for you!
yes, when you look at battery discharge curves, the parameter is always amperage. And at some point the voltage would take a huge dump.
Eneloops, for example, take their dump at exactly 1.2000V (and resting voltage of 1.2000V is considered as "cell: empty" .. although it isnt).
As you can see, recharging underdischarged cells doesnt lead to poof if you hurry up with getting the cell back to your UF charger.
Well the Duramax sure didn't advertise to run on 14500 but for $13 it was my guinea pig. Turned out it liked the extra brightness just fine. Light is pretty much all throw and it reaches out there pretty well with that 14500 in it. Never got hot either (but I never really had it on very long). Just looking at that Duramax, it looks and feels pretty well made (sure looks more expensive than $13). Even has momentary (half press) on clicky.
i also looked once into buying the eluma but i am glad that i didnt. way too big for 1x AA. i like compact sized torches:
http://eagletac.com/html/d25am/specs.html
also check out the 4Sevens lights with cpf discount (10% off):
Quarks are very versatile and *bright*, even with Eneloops. The tint is very greenish but nature is green too! All happiness!! :D
I have the same opinion as Budgeteer and Don on overdischarging. Here a longer thread if you want to dig deeper into that matter.
+ 1
that's where i got my info from too. hehe.
okay but now it's time for heia (whaddabou-u Vectrex? ;) )
Made the mistake to take a nap in the evening... now I can't sleep.