13650 with 1W laser... Why not to do it.

[Weegidy]

I made my first laser build with a small flashlight that originally used 3AAA batteries. The pack that held the batteries was terrible, and my laser was putting out less than 500mW.

I ripped out the pack and installed a 13650 pack in the handle, thinking that could handle the power. After less than 1 minute the laser started flashing on and off more and more rapidly.

In science class today (where I am now) I used one of out logger pro sensors to measure the voltage of the laser over time. I did not have a current probe, but my ammeter seemed to stabilize around 1.8amps.

I don't know the internal impedance of the battery I used, but it was an UltraFire cell [link]. I was confused as to what is happening at first, but after looking at the graph below I realized that the voltage was dropping exponentially as the temperature of the battery increased and the internal impedance rose. Once the voltage dropped to 3volt the drivers circuitry cut off the voltage until the resistance of the battery fell and the light came back on. This cycle continued.

I hope this helps some people figure out which cells to use.

Here is the driver I am using. I can not longer find it online, I bought it a year ago. I think it was something like "Micro FLX" or something. Its range is 3-5volt. I think that is very common for all drivers, so it doesn't just apply to this one.

 

[ApexProxy]

It looks like the top left most resistor has some issues. Also, the solder blobs look a little excessively large. it could be possible that something was shorted out by solder or that there is something up with the oddball resistor.

I have never run a flex drive before but it is my understanding that they are buck and boost drivers. It may also be possible that your batteries are not giving sufficient power and the flashing is the driver struggling to run. If the batteries are getting hot then its likely you have some shorting going on and that would explain the lack of power getting to your driver.

 

[Weegidy]

It looks like the top left most resistor has some issues. Also, the solder blobs look a little excessively large. it could be possible that something was shorted out by solder or that there is something up with the oddball resistor.

I have never run a flex drive before but it is my understanding that they are buck and boost drivers. It may also be possible that your batteries are not giving sufficient power and the flashing is the driver struggling to run. If the batteries are getting hot then its likely you have some shorting going on and that would explain the lack of power getting to your driver.

Indeed I used a lot of solder, but the problem is not in the resistor or the wires. And there is no short - the battery itself does not get warm. I would really like to find an ammeter I can use to plot current vs time so I can see what the internal resistance of the battery is doing.

 

[Cyparagon]

Your biggest problem is you're using ultrafire, and a half-dead one at that.

 

[ApexProxy]

First off, I run my lasers mostly off Ultrafire blues since they are so scary cheap I can get a whole mess of them. So far they beat the hell out of the IMRs I have for runtime and I notice no difference in output. I will confirm the output with an LPM as soon as I get mine though.

Based on the numbers you show for voltage your battery was at or below half dead when you started your test so you may want to try it again at full charge. A full charge is 4.2V but it will very quickly drop to 4V and then more slowly drop after about 3.9V or so. Also, do you own only one single 13650? If not swap it out and try with different batteries. It is quite possible you received a dud battery.

 

[Weegidy]

First off, I run my lasers mostly off Ultrafire blues since they are so scary cheap I can get a whole mess of them. So far they beat the hell out of the IMRs I have for runtime and I notice no difference in output. I will confirm the output with an LPM as soon as I get mine though.

Based on the numbers you show for voltage your battery was at or below half dead when you started your test so you may want to try it again at full charge. A full charge is 4.2V but it will very quickly drop to 4V and then more slowly drop after about 3.9V or so. Also, do you own only one single 13650? If not swap it out and try with different batteries. It is quite possible you received a dud battery.

I have a ton of 13650s, I have 4 ultrafire blue ones, 4 ultrafire protected, and 4 AW protected. I get the same result with all of the ultrafire cells, I havent used the AW with my laser though.

 

[Cyparagon]

I run my lasers mostly off Ultrafire blues since they are so scary cheap I can get a whole mess of them.

Does your diet consist of ramen? Why not? Ramen is scary cheap and you can get a whole mess of it.

So far they beat the hell out of the IMRs I have for runtime

That, sir, is weapons-grade bologna.

 

[BShanahan14rulz]

How much current is your laser trying to pull?

I don't trust ultrafire. I've only bought two ultrafire cells. One was DOA, the other had very low capacity. At the time, though, my light only accepted <17mm.

Apex doesn't say anything about how he uses his cells, so I'd take his statement about Ultrafires being better than LiMn chemistry cells with some salt. If I had a sepic, I'd go for IMR.

 

[ApexProxy]

I'm not saying the chemistry is better at all. My statement was that My Ultrafires seemed better than my IMRs and they do. They were tested out to be on average 800-900mAh(the 16340s) while my IMRs are only 500mAh so their real life runtime is about 1.5x what I timed my IMRs at. I have only gotten one DOA ever of an UltraFire or TrustFire and I have 24 16340s and 12 18650s of varying types. I hook up all my new batteries individually to a large USB fan I have that runs at 1.65A and let them run down to 3V and charge them up to make sure they work and take a charge.

IMR chemistry may be superior but so far I almost never see IMRs with capacities as high as I see standard Ultrafires test to. I may not have found very good suppliers for IMRs or something but I usually see most 16340 IMRs at about 500mAh which is sadly small. Also, while IMR chemistry may be superior when is it going to matter when the draw of even a 2.2W 445nm is only 1.5A? That means each 16340 is being drained at 750mA each which also means they are running at less than 1C and usually get their peak possible capacity. The lower current on each battery is also a giant reason why I never ever run anything off a single battery.

Basically my point is, IMR chemistry may be superior but when the batteries are low capacity due to cheap suppliers and the current you require most of the time is less than 1A, when is an IMR actually better? That question is not sarcastic by the way, I am seriously asking because I am honestly not quite sure why everyone says they are so much better.

 

[BShanahan14rulz]

It depends on your driver. I only own one IMR, and only use it with one device, because that's the device that needs it. And it's not about the ability of the cell either. You could probably draw 10A from a 16340 if you wanted to, but you might do damage either to the cell's internals or to your own externals.

Also, you keep comparing different chemistries' capacities when that isn't a valid comparison. IMRs just have lower capacities than ICR. That's just the way it is. But you can't draw no 10A from an ICR.

Oh, and for small cells, my rule of thumb is discharge at max 1C, maybe 1.5C if you trust it. 1.5A is kind of a lot to be drawing from an icr16340.

Also, curious, what drivers do you use in your 2.2W devices?

The reason why IMRs are better is that they don't have as much voltage sag under load as ICRs, hence able to keep voltage up longer. They also are capable of higher discharge currents, which can come in handy towards the end of a discharge cycle into a sepic.

 

[ApexProxy]

I know that the number of cells you use is dependent directly on the driver. This is the reason I never use boost drives so all my lasers run on two cells. Less current on each cell improves runtime and preserves cells for more cycles. This goes for any cell chemistry.

All my 445s run buck drivers, most of which are X-Drives or buck drivers from SL.

Basically this is what I gather in the case of duel cell bucking setups:
-you are running far more voltage than the diode can take anyway so sag doesn't matter thus making IMR voltage advantage not beneficial
-most of the time draw is 1C or less so IMRs don't benefit
-by chemistry IMRs have lower capacity so ICRs are better for this

It sounds to me like IMRs are pretty much useful where you require voltage to be held up longer and high current drain situations. So basically, IMRs are for single cell situations where their benefits matter and for linear setups where you have to deal with voltage drop through the driver.

This means my use of ICR(Ultrafire) cells is actually totally legitimate and actually superior to IMRs right? Unless I am missing something else?

I also only ever use my IMRs in my single cell 300mW 532nm Skylaser because I was taking into account the draw was too much for ICRs.

 

[BShanahan14rulz]

Yep, you got it :wave:

The main problem with Ultrafires is that they aren't always what they say they are on the label, and if you don't test them ahead of time and just assume that they are what they say they are, you might inadvertently abuse a cell so much that it decides to abuse you back. If you are aware of the discharge characteristics of the cells and can match them into somewhat matched pairs, then no point in worrying.

AWs are good for noobs, just say "AW IMR" or "AW Protected" and you can feel confident that you didn't just advise them to buy something that they would accidentally kill themselves with.

I made it a point to only own lights/lasers that run on alkaline/nimh AA size, or 18650 sized Li-ion, this way I can easily source name-brand cells. I've wanted a 16340/cr123a/18340 light for a while, but just can't bring myself to buy off-brand again. I still consider AW an off brand, just because he doesn't actually manufacture the cells himself.

 

[Weegidy]

AWs are good for noobs, just say "AW IMR" or "AW Protected" and you can feel confident that you didn't just advise them to buy something that they would accidentally kill themselves with.

Haha, well I am not so much of a noob when it comes to batteries, but I haven't found any RCRs that have longer life than AWs. In my books they're the best 16350s.

I made it a point to only own lights/lasers that run on alkaline/nimh AA size, or 18650 sized Li-ion, this way I can easily source name-brand cells. I've wanted a 16340/cr123a/18340 light for a while, but just can't bring myself to buy off-brand again. I still consider AW an off brand, just because he doesn't actually manufacture the cells himself.

And that is a good idea, but I'm already loaded with 16350s because of all my flashlights. For non-standard builds I use LiPo batteries - you can buy a good LiPo 3 cell (re-wire it so they are in parallel) and it will deliver like non-other.

 

[Cyparagon]

My Ultrafires... were tested out to be on average 800-900mAh(the 16340s)

When you say "tested," I think you actually meant to say "I looked at the label and took their word for it."

 

[ApexProxy]

When you say "tested," I think you actually meant to say "I looked at the label and took their word for it."

Yet again another useless post that's a direct assault on your perceived level of my intelligence.

For your information when I said "tested" I meant what I said. As unbelievable as it may sound I actually know what that means. There are several methods of testing cells from using hobby lithium cell chargers that actually measure the capacity through charges and discharges to the simple method of running a battery on a constant measurable load and timing its runtime and then using that to get the capacity.

But again, thank you for assuming I'm an idiot.