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

Here is a recent user test of the Trustfire Flames 18650 from DealExtreme. These Trustfire 18650 aren't so bad as they seems. The capacity is real and after using 1 year the battery still holds the main capacity.

1-2 years Li-Ion battery tests (how Li-ion degrades over time) | BudgetLightForum.com

Blord said:

Here is a recent user test of the Trustfire Flames 18650 from DealExtreme. These Trustfire 18650 aren't so bad as they seems. The capacity is real and after using 1 year the battery still holds the main capacity.

1-2 years Li-Ion battery tests (how Li-ion degrades over time) | BudgetLightForum.com

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'Tis why I suggested them. Its the only Trustfire 18650s I use. Though he may still be better off with an IMR for that hard of a current draw because of voltage sag. Its hard to say though since the flames are pretty much half the cost of an AW IMR.

I wonder just how much voltage sag@2A the Flames really would have against an AW/Panasonic IMR. I say 2A since that probably just about the most any of us will hit. I will likely be pulling that from my latest 1W Mitsu build that I hope to power off a single 16340 and two IRON4Ds. We shall see how it does on a single 16340 Flame.

sjkuessel;

The Panasonic 3400mah cells I use have no problem at all with a ~3 amp load.

They have a low Internal Resistance.

The IMR cells will only have ~50% of the capacity at most.

You will definitely get more runtime with the Pany 3400mah cell.

LarryDFW

I have been debating dropping the cash on a set of Panasonics for a while. The 3A capability on them is quite tempting I must admit. The part that pushes me away is they are obscenely expensive... for now the flames will have to be good enough with their 2400mAh capacity.

I'm thinking the time I finally get some Panasonics is when I break down and get an HID lol.

It's a tough pill to swallow....spending so much on batteries but imo worth it. You don't want to put a cheap cell into a 3W laser, or a flashlight that needs a lot of power, and have to worry about the thing blowing in your hand.

I just spent a little over $100 on batteries less than a month ago :undecided:

Unfortunately with Panasonics $100 wouldn't get you many...

Well, they're never going to be $5 a piece if that's what you're looking for.... but check your inbox

Definately better. I wish they were $5 each. LOL I'd have a whole mess of them if that were the case XD

I will buy the li-ion batteries when I needed them. The batteries will degrades over time even if you aren't using them.

My Skylaser DPL-700 is drawing 2.0A current from the tailcap. It is measured a 800+mW green. I guest a 400mW green would use 1A.
So a real 2500mAh 18650 battery has 2.5 hours of runtime.

Blord said:

I will buy the li-ion batteries when I needed them. The batteries will degrades over time even if you aren't using them.

My Skylaser DPL-700 is drawing 2.0A current from the tailcap. It is measured a 800+mW green. I guest a 400mW green would use 1A.
So a real 2500mAh 18650 battery has 2.5 hours of runtime.

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Incredible. Suppose the averagel efficiency is like 25-30%. 2a for 700mw is quite a efficiency if they use a 2.5w or 3w 808nm diode. Afaik, 400mw532nm oftens takes 1.7a or 1.8a for that crystal assembly or structure without no active cooling. Regarding 99% of 3w 808nm we used for portables, it takes a 2.7a to be outputting 2.4-2.5w. 2a for 700mw 532nm is not much realistic. It usually happens only when the current is 2.3-2.8a and thus 808nm outputing between 2.3W and 2.8W.

Applying a 2a usually gets 400mW or 500mW. Just wondering if it was tested with an ir filter. what i'm saying might be wrong and anyway safety comes first. BTW, "near TEM00", instead of 'TEM00, is more correct for these 300mw+ greenies portables reviewed.

Speaking of 18650, i recommend the sanyo 2600mah which is at least more up-to-spec as advertised. i agreed most ultrafire 2400mah to 4200mah are no good. We tested a PL-E 500mw+ 532nm laser with each sanyo 2600mah and a 2600mah blue color ultrafire, both fully recharged. The sanyo lasts for 45mins+, the ultrafire @ only 12mins before the voltage drops to 3.4v or 3.5v tested.

I measure 2.0A at the tailcap and at the same time the LPM is giving 740mW. According to SkyLaser all DPL laser have standard IR filters so this is the green output. So this laser has an efficiency beyond 30% ?

Those Trustfire Flames are also hit or miss. They too are plagued by fakes, manufacturing problems, and bad batches. The DX forum confirms this, as well as on other forums. Unless you get your batteries from trustworthy sources (like listed above), you'll have to test the batteries yourself to see if they're worth their salt. Otherwise, just assume that you're going to get some average capacities well below the ratings on the package.

Blord said:

I measure 2.0A at the tailcap and at the same time the LPM is giving 740mW. According to SkyLaser all DPL laser have standard IR filters so this is the green output. So this laser has an efficiency beyond 30% ?

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Sorry Blord. I might have mistaken the input current for output current. what u metered is the input current(but i cannot see any beam if you are testing the current with the laser turned on...)

My understanding is that if the laser is actually ir filtered and for 2w 808nm diode, getting 700mw is rare and if a 3w 808nm diode is used, a 2.5-3a(presumably 808nm@2.8w) can produce 700mw+. Sure it depends on the diode. For example, for nlight-3.5W 808nm LD, 2.8a output - 700mw, 3w 808nm LD from most Chinese laser diode manufacturer, 2.5-2.7A- 700mW. Sure the beam quality and stability of nlight diode is a lot better.

35% or 40% of pumping efficiency is theoretically achievable but 20-25% on average for portables with active cooling. People might rather maintain the stability, beam quality or longer duty cycle than pushing the current too high. I just checked the power graph you attached and it is a lot more normal since you only tested it for 100 seconds and it rises over 700mw that short.

BTW, 40% happens often in working out tec/fan cooled lab lasers and 45%+ was also achieved in water cooling 532nms.

My Skylaser 300mW(not yet LPM tested) 532nm draws 1.45mA from a fresh charged IMR and 1.6A from my bench supply set to exactly 4.2V. It sounds like Blord's laser is quite efficient assuming mine is not insanely overspec.

@ApexProxy, most likely it will be... mine hit over 500mW peaks when I tested it briefly. tonight I will be testing to Ophir heads, and the skylasers, lasers in turn.

One can only hope bro. My laser also appears to be getting more stable with time. It mode hops far less than it used to and reaches a stable near TEM00 after around a minute as opposed to around 4 minutes like before.