# 5 mile green laser pen advice please & 18650 4000mah battery advice



## buckyball (Mar 18, 2014)

hi ive spotted a laser pen on ebay claiming it can point a 5 mile beam see http://www.ebay.co.uk/itm/5Miles-Ra...61189758953?pt=UK_Gadgets&hash=item2587a887e9 is this possible ? its £8.29 does that seem ok ? or can you get a laser that points even further for around that price ? then it says i need 1 x 18650 4000mah battery, ive looked that up to discover its size ( its bigger than AA) so next question would be whats the best 18650 battery to buy..what make ? and remember the laser pen says i need a 4000mah one, many thanks for any advice


ps i did find this thread using google which is why i registered on this forum but im totally new to understanding any info on batterys so please be gentle : ) http://www.candlepowerforums.com/vb/showthread.php?330236-2012-Battery-test-review-summary i dont see a conclusion on that thread all i want to know is what are the best 4000mah 18650 batterys and why( name the brand and model) and if u can give a rough idea of shop price that would be awesome too

also ill need a charger for this size of battery (i have a charger for aaa/aa/c/d/9v already) so just need 1 to handle 18650 batterys so can you recommend one or should i just go for a cheap one on ebay


thanks
dave


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## Arilou (Mar 18, 2014)

I have no experience with this particular seller, but I've bought several cheap green lasers from ebay, and they were around 30-50mW. The claim that you could see it from 5 miles away is plausible.


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## caddylover (Mar 18, 2014)

green goes the farthest. you need to ask "tmack" on here, he is a laser builder and I own one of his lasers.


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## bshanahan14rulz (Mar 19, 2014)

That is all marketing hype, from the 5 mile claim, to the 4000mAh 18650. You can see a green laser from 5 miles away if it is pointed at you, but you won't have a laser dot at 5 miles away with a laser pointer. All hobby portable lasers use the same sized optics. You would need a beam expander to keep the beam divergence low. 

And no, you won't see the beam 5 miles away.

Do you have an actual need for a handheld laser pointer that can point at objects 5 miles away? Distance isn't really the best measure of a laser. I've a laser that can shoot photons to pluto if I pointed it that way. Doesn't mean anything. 

Regarding 18650 and other Li-ion sizes, I'd avoid getting into lithium ion unless you really have to. Get a green pen laser that doesn't claim to be a death ray, and use those rechargable AA or AAAs that you already own. You will find that you don't actually need a laser capable of throwing a beam 5 miles or a l aser that uses a potentially more dangerous power supply like a Li-ion.

Google for a laser pointer forum, sign up, read up on safety, legality, etc., and once you feel that you understand the dangers, both physical and potentially legal, you can contact the builders there. They can build anything that is possible to do as a hobbyist. TMack, whom caddylover referenced above, is one of many builders there who is extremely helpful in helping folks understand what they need and what is possible.

Keep in mind that with a low power laser, you don't have to be so paranoid about lasing specular surfaces or shining it outside, while still being able to enjoy the unique monochromatic wavelength and even sharing the experience with friends without worrying about inadvertently frying their retinas.


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## StarHalo (Mar 19, 2014)

bshanahan14rulz said:


> I've a laser that can shoot photons to pluto if I pointed it that way.



Fun fact: You'd have to wait _five hours_ for your photons to arrive there.


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## bshanahan14rulz (Mar 19, 2014)

Yeah, I guess you'd have to "lead" the planet by a short distance ;-) Even more mind boggling considering we're a decent distance from the sun, but light emitted by the sun only takes 8 minutes to get to us.

Did we kick Pluto out from the solar system, or are we now just denying its existence? ;-) Poor pluto :-(


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## buckyball (Mar 19, 2014)

thanks i own a green laser pen bought on ebay a few years ago it can point a beamabout 1000metres using 2 aaa batterys which it uses up pretty quickly, i guess no1 needs a 5mile beam but i do point at stars so the longer the beam the better, it would be cool to be able to touch say a tree top with the laser from a long way away to scare a few crows !! ive just bought a red laser pen too for £2.12 on ebay but i may take a chance and get this 5mile green laser just for fun thanks for advice



bshanahan14rulz said:


> That is all marketing hype, from the 5 mile claim, to the 4000mAh 18650. You can see a green laser from 5 miles away if it is pointed at you, but you won't have a laser dot at 5 miles away with a laser pointer. All hobby portable lasers use the same sized optics. You would need a beam expander to keep the beam divergence low.
> 
> And no, you won't see the beam 5 miles away.
> 
> ...


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## CyclingSalmon14 (Mar 19, 2014)

4000MAh batterys....I wish.


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## maquinista24 (Apr 4, 2014)

The most powerfull 18650 batteries in the world are the panasonic 18650ncrb with 3400mah. 4000 mah 18650 doesn't exist, is a fake.


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## monkeyboy (Apr 4, 2014)

I'm guessing you're from the UK, as you're quoting prices in £.
If you check the ebay regulations, it's illegal for them to sell a laser pointer over 1mW to UK or Australia (5mW for US), this is obviously way more powerful than that.

Legal issues aside, you should never buy a cheap high powered laser pointer, as they can put out dangerous amounts of invisible IR laser light and not necessarily in the same direction as the visible light. This can damage your eyes without you even knowing.


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## Arilou (Apr 4, 2014)

monkeyboy said:


> I'm guessing you're from the UK, as you're quoting prices in £.
> If you check the ebay regulations, it's illegal for them to sell a laser pointer over 1mW to UK or Australia (5mW for US), this is obviously way more powerful than that.



Yeah, right. Every seller on ebay claims to be selling "5 mW" lasers. I've bought several of those and they were around 50 mW.



monkeyboy said:


> Legal issues aside, you should never buy a cheap high powered laser pointer, as they can put out dangerous amounts of invisible IR laser light and not necessarily in the same direction as the visible light. This can damage your eyes without you even knowing.



You'll know a few hours later when you've got a choroid burn and detached retina. And for the next 6 months or so until it heals.

BTW the 808 nm "infrared" light isn't totally invisible, but it is hard to see. It wasn't the 808nm from a green laser that I injured my eye with. It was a cheap 650nm red laser, which is a lot brighter than it looks.


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## monkeyboy (Apr 5, 2014)

Arilou said:


> You'll know a few hours later when you've got a choroid burn and detached retina. And for the next 6 months or so until it heals.
> 
> BTW the 808 nm "infrared" light isn't totally invisible, but it is hard to see. It wasn't the 808nm from a green laser that I injured my eye with. It was a cheap 650nm red laser, which is a lot brighter than it looks.



Sorry to hear about your eye damage but what's your point here?
Are you trying to say that you shouldn't worry about eye damage unless it's so severe that your retina detaches?
That's not the best advice.


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## Arilou (Apr 5, 2014)

monkeyboy said:


> Sorry to hear about your eye damage but what's your point here?
> Are you trying to say that you shouldn't worry about eye damage unless it's so severe that your retina detaches?
> That's not the best advice.



I was confirming what you said about red/infrared light causing damage without you even knowing. It is true that you may not notice initially. A burn can cause swelling and fluid build up under the retina which will not be apparent until some time later.


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## maquinista24 (Apr 5, 2014)

Arilou said:


> I was confirming what you said about red/infrared light causing damage without you even knowing. It is true that you may not notice initially. A burn can cause swelling and fluid build up under the retina which will not be apparent until some time later.



Yes, this is true. You can damage your eyes without your knowledge. I know the case from the brother of a friend, that was playing with a cheap chinese laser and he knows the damage the next day when he has a "black point" in her vision and then go to the doctor and say that the retina fall...


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## bshanahan14rulz (Apr 7, 2014)

Rhetorical question: Why didn't their goggles protect their eyes? Because they were not wearing them


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## Arilou (Apr 7, 2014)

bshanahan14rulz said:


> Rhetorical question: Why didn't their goggles protect their eyes? Because they were not wearing them


 This is true. It was a cheap made-in-china 650nm laser pointer. 650nm doesn't look all that bright. Because it didn't look extremely bright, I wasn't being as careful with it as I should have been.


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## WILSON (May 10, 2014)

maquinista24 said:


> The most powerfull 18650 batteries in the world are the panasonic 18650ncrb with 3400mah. 4000 mah 18650 doesn't exist, is a fake.


This.

I have to use (unprotected) Panasonic 3400mah mah's and 30-Amp Sony 18650 VTC5's everyday. Any company (with the possible exception of NASA) claiming their 18650's are rated at _"4000 mAh"_ is lying.


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## buckyball (May 10, 2014)

thanks for the advice, after waiting a month for some to arrive from china id ordered on ebay i contacted seller and they refunded me seeing as theyve not arrived, i couldnt wait any longer so bought 4 ultrafire brc 18650 4000mAh 3,7v li-ion batterys on amazon uk for £10.99 with free postage, the laser works well and has a novelty attachment on it to produce hundreds of light dots on a ceiling etc for fun and if i take that bit off ive also got a bright green laser beam for pointing out stars to people..i will keep a log of how many charges i get out of these batterys




WILSON said:


> This.
> 
> I have to use (unprotected) Panasonic 3400mah mah's and 30-Amp Sony 18650 VTC5's everyday. Any company (with the possible exception of NASA) claiming their 18650's are rated at _"4000 mAh"_ is lying.


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## WILSON (May 10, 2014)

buckyball said:


> thanks for the advice, after waiting a month for some to arrive from china id ordered on ebay i contacted seller and they refunded me seeing as theyve not arrived, i couldnt wait any longer so bought 4 ultrafire brc 18650 4000mAh 3,7v li-ion batterys on amazon uk for £10.99 with free postage, the laser works well and has a novelty attachment on it to produce hundreds of light dots on a ceiling etc for fun and if i take that bit off ive also got a bright green laser beam for pointing out stars to people..i will keep a log of how many charges i get out of these batterys



The Panasonics, Sonys, and Sanyos are good for at least 5, or 600 charges ... as long as you don't keep draining the heck out of 'em (read: Under 3.2V). 

I'm not sure about Ultrafires. I've _used_ them,... but that was long before I heard the saying "Never buy a barrel with the word _WOLF_ in the name, or a battery with the word _FIRE_ in the name".


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## buckyball (May 11, 2014)

christ dont say that ! i seriously hope 18650 batterys dont catch fire when being charged...which leads me to think if they are that risky should i put a metal tin/tray on ground under where the charger would be plugged in on wall to try to catch any dripping debris should it catch fire ?? ( so hopefully carpet doesnt go up in flames and i could throw tin out the window !!! ) seriously hope my missing ebay purchase wasnt on that mh370 missing malaysian plane !!




WILSON said:


> The Panasonics, Sonys, and Sanyos are good for at least 5, or 600 charges ... as long as you don't keep draining the heck out of 'em (read: Under 3.2V).
> 
> I'm not sure about Ultrafires. I've _used_ them,... but that was long before I heard the saying "Never buy a barrel with the word _WOLF_ in the name, or a battery with the word _FIRE_ in the name".


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## FRITZHID (May 12, 2014)

http://www.candlepowerforums.com/vb...d-Close-Calls-The-dangerous-side-of-batteries


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