How long will a 18650 battery last in a 400mw green laser?

Hi I got a nice 400mw Olike laser. Works great. Just wondering how long the 18650 3800ma battery will last? I know it depends on how much I use it. I'm just looking for a rough estimate (A few hours, A days, days) etc.?

It depends on the quality of the battery, If it's a cheap shit one, Not too long.

It depends on the actual mah rating of the battery and the current draw of the laser. To get a rough estimate, divide the mah rating of the battery by the current consumption of the laser.

Wrong section btw.

I got a 3800mah ultrafire battery seems to last less than a day. Anybody know how long a 1w blue running cr123's lasts?

"less than a day" is very subjective. It depends on a lot of factors such as how long and how often you use the laser, current draw, capacity and charge level of the battery, temperature, etc. Those ultrafires actually have way less capacity maybe only around 2000mah.

Please give us more details about the laser and battery.

Hmm. It's the o-like crown upgrade 400mw green laser. Here is the specs:

Wavelength:
532nm

Output Power
>350mW

Pump diode
2.0W

Dimensions:
Φ24mm×175mm

Transverse Mode:
TEM00

Operating Mode:
CW

Stability
5%

Operating Current
2A

Beam Diameter:
1.5mm(at aperture)

Beam Divergence:
<1.5mRad

Duty Cycle:
100 seconds on, 60 seconds off

Power Source:
18650 lithium Batteries ,"+" towards tail cap

Operating Temp.:
10~ 35℃

It says the operating current is 2A. So if I divide the 2A into the 3.8A of the ultrfire battery it gives me 1.9. Is that hours? Just wondering about this. The laser works great. It burns and is nice and bright. I just thought the battery would last a little longer.

As a general rule of thumb imo, whatever mAh, any kind of xxxxFire battery states, divide by two. The very best 18650 batteries currently offer no more than 3400mAh.

What are the best batteries?

AW, Panasonic, LG.

Anywhere where I'm concerned battery could be an issue, I use a quality battery...

Some stores to order, from, LarryDFW on here, lighthound, and orbtronic. There are dozens of sites that sell, but IMO those are the best places to order. Lighthound especially I love the service. Order placed on sunday night (four AW 2000mAh IMR 18650) came yesterday.

TrustFire flames are just about the best cheapo batteries you can find. You can grab them for $9 a pair on DX and they are on average 2400mAh which isn't bad for that price.

Here they are:
TrustFire Protected 18650 3.7V True 2400mAh Rechargeable Lithium Batteries (2-Pack) - Free Shipping - DealExtreme

Maybe another reason your ultrafire batteries don't last very long is because of the high current draw of 2A. These regular lithium ions cant deliver that much instantaneous current. Its be better to go with the IMR type of lithiums for high current draw.

Yes battery quality and true capacity is the most important factor...

However there are other things that will determine how long your run time will be between charges.

There are differences in efficiency for any build. Especially DPSS.

The quality and type of driver used will also affect how much current draw demand the battery will have.

As your battery drains, the voltage is dropping, if it is a quality driver that has good regulation to the pump diode, then there will often be more current demand on your battery as it drains and drops in voltage.

If the driver is not giving good regulation, then your diode output will be less as the battery drains.

Etc, etc...

You can test battery current draw with your DMM and see what current is being drawn at full charge with the laser on by touching one probe to the battery, and the other to the host bare metal.

It will probably be between 750mA's to maybe 1.5 Amps for that laser. (guessing)

If it were using exactly 1.5 Amps and stayed at that current draw, and you had a true 3000mAh's capacity, it would be about 2 hrs. run time between charges...

So you can get a good idea of a close estimate, but your true run time will have to be tested. Just check the voltage once in a while until you get a feel for how long it can go between charges...

Thanks for all the great battery info. Very useful stuff. So I measured the actual current draw of the laser with my DMM. It was 2.07 A! Wow no wonder the batteries didn't last. So my next question is what are these IMR li-ion batteries I was recommended?

As InfinitusEquitas said, go with brands like AW and Panasonic. Avoid the xxxxfire brands.

Wow, yeah IMR all the way for that kind for current. Panasonic makes ICR(same as TrustFire/UltraFire) which is not what you are looking for. Go with just about any IMR battery over ICR for that high of a current.

This battery should serve you well in this case:
AW IMR18650 1600mAh LiMN rechargeable lithium battery

EDIT: Just found an IMR Panasonic. Didn't know they made those

ApexProxy said:

Wow, yeah IMR all the way for that kind for current. Panasonic makes ICR(same as TrustFire/UltraFire) which is not what you are looking for. Go with just about any IMR battery over ICR for that high of a current.

This battery should serve you well in this case:
AW IMR18650 1600mAh LiMN rechargeable lithium battery

EDIT: Just found an IMR Panasonic. Didn't know they made those

Click to expand...

AW IMRs, iirc, are just rebranded panasonic cells . Not sure about this though.