Somebody who knows about batteries pls help?

[IsaacT]

I built a 445nm laser from a 9mm diode and have it running at 2.1A on an X-drive via DTR. I am using two 16340's right now, but it seems like a shine the laser 5 times no more than 10 seconds each time and my batteries are dead.

Now, one of my batteries is 2 years old, so that might be an issue, but even though the amp setting on the driver is more than the batteries, I wouldn't expect such short runtimes....

Any ideas as to why this is? I have some AW IMR 18350 batteries coming now....will these allow for longer runtimes? I am currently looking for a custom built 2x 18650 battery host to transfer the diode module and driver to, but for now I have to work with this....ridiculousness? I have charged my batteries 3...maybe 4?.....times today.

Thanks,
Isaac

PS-if any of you who see this thread can build 2 x 18650 host to fit an aixiz copper module please shoot me a PM, ehgemus hasn't been on for weeks.

 

[Laser Smith]

What kind of 16340's are they? If they're cheapo's they probably can't handle the draw. You gotta remember that when you run in series you only actually have the capacity of one battery

 

[IsaacT]

So I only get the Amperage of one battery with the Voltage of two?! That's not fair!!!

One is an Ultrafire and one is an AW black label. rated at 880mAh and 750mAh respectively. The batteries on their way are both AW Red Label. Dunno the rating however.

Thanks,
Isaac

 

[jeffreythe00]

Check the voltage on your batteries after you pull em off the charger and after you can't use them in your laser. In series you get twice the voltage and half the capacity. What mah are they rated?

The 18350's should handle the current better (maybe not depending on your cells) and they should have a bigger capacity (again depending on your cells)

Are the batteries warm when you pull them out?

Edit: I'm 99.9% sure your problem is capacity.

Let me explain.

In theory, A cell with 1000mah. mah = Miliamp hours.

Example. A 1000mah cell discharging at 1A/1000mA will only last about an hour or until the driver can't keep up supply.

So in your case you have aprox 750mah and you are discharging those cells at 2.1A/2100mA

Well... I'd say you wouldn't get much use out of em.

 

[IsaacT]

They are somewhat warm...I posted the specs on my batteries in particular in my second post. As for the voltage I will do that when they die again.(they have been in the charger for awhile now).

 

[jeffreythe00]

They are somewhat warm...I posted the specs on my batteries in particular in my second post. As for the voltage I will do that when they die again.(they have been in the charger for awhile now).

I edited my post a bit. I seen you posted specs after I posted.

 

[IsaacT]

And if I ran them in parallel, I wouldn't get enough voltage to supply my buck driver? So I either have enough mAh or enough V but I don't get both? Dammit. But you think the 18350 AW Red batteries I have coming could do it?

 

[jeffreythe00]

I don't know what buck driver you have and it probably couldn't run with 3.7V. Do you have specs?

You can have both voltage and capacity. Just use larger capacity cells or use a different driver.

What are the specs of the new cells?

 

[jwwilson23]

M if your batteries are in paralell the voltage is of one battery so if u had 2 3.7V batts it would put out 3.7 not 7.4 like it would in a series. For current wise if the batteries are parallel you add the capacity of both to get your capacity.but if they are in series then the total is equal to only one of the batteries currents.batteries in Parallel are great if you can achieve the right amt. Of voltage because you will get a lot more capacity with them but I don't know if this could work, search some other builds by people I think I've seen flaminpyro do a big host saik or something in 9 mm and he modded his battery holder to be parallel see what driver he used
Series could also be better in theory to I guess but it seems you are better off with using parallel if u can find the right driver
(You helped me now I'm helping you hopefully )
O yeah I hope this post was a bit meaningful as I'm on mobile and it took forever to type

 

[IsaacT]

The X-Drive requires 5.6V atleast on the input...is it possible to connect them both in series AND parallel at once? Probably not but who knows? Hopefully you... Lol. I think I'll either have to find a new host for 18650 batteries or a boost driver. Ugh I hate these crappy runtimes!!!

Thanks! If I can ill rep both of you when I get home(iPhone can't do it very well).
Isaac

 

[jeffreythe00]

Not possible with two cells. You'd need at least 4 cells to do series and parallel and even then its really not at the same time because you'd have to choose if you'd want two parallel sets wired in series with each other or two sets in series paralleled with each other.

If you get a new host and use the same driver. Make sure it can hold two 18650's or you are back to square 1 again :beer:

 

[DTR]

You should be getting about a half hour out of your 750mAh AW cells since these units draw about 1.5A on average from my observations. My bet is the crappyfire battery is your issue.

You can compare it to an 18650. Say you have a real capacity of 2800mAh and a boost driver that is drawing over 3A then you are still under an hour runtime. Now if you go to 18350's you may be about on par with the runtimes you can get with an 18650 boost driven build.:beer:

 

[IsaacT]

I bet my crapfire battery is it...it is 2 years old, has been stored in heat and shit...it's probably just ready for the LiIon graveyard.