10,000+ Lumen Lithium Ion Scuba Torch Lights
Recreational and sport diving typically warrants high output lights with heavy scatter. The difference is incredible, as it means looking at a tiny lit up spot with smaller output lights vs lighting up the whole scene.
Available Options
All of these are rated by their manufacturers for depths of 80m (262ft) or more, although I'd take that with a grain of salt. Most of these are made and shipped directly from Chinese manufacturers and although these are sturdy, the depth was probably never tested. They all take four 18650 lithium ion batteries. When you pick one out, double check whether they need button top or flat top; these are all button top. When you look around at US retail options, you'll instantly notice the price tag skyrocket. If you're buying from a reputable brand, the most common thing they've done is get someone else to test and certify the light you're getting lights up properly and doesn't leak, or they tested it themselves. Those extra costs have to be baked into the price which is why the prices are significantly higher, but the likelihood you get a dud light is significantly lower. If you buy one of these Chinese manufacturer units, you'll want to test it in your bathtub, pool, or a bucket of water within the return period, so make sure you pick up proper batteries and a charger.
Dave Lo, ScubaTerra Founder:
This is the dive light I have. I picked it up on recommendation from some tec divers who have used them in Silfra and other locations. I've only used it a few times but it works great. I'm a little paranoid about leaks though, and I double reinforced the threading at both ends of the canister with silicone grout and grease. This uses button top batteries.
Dave Lo, ScubaTerra Founder:
I have not tested this one, but it has high reviews on Amazon.
Dave Lo, ScubaTerra Founder:
Avoid this light. I'm only including this unit for reference as multiple resellers offer it on multiple sites, and it has multiple bad reviews that you should know about from multiple people who have purchased this. This has the same light configuration as the previous unit (10x white LEDs in a ring, with a row of red LEDs and a row of blue LEDs). However, the canister is visibly different. This only has one review on Amazon at the time of writing, and is calling the seller out for relisting the light after the other listing received multiple bad reviews. Many of these lights are white-labeled, meaning the manufacturer sells it to someone who resells it brandless or under their own brand without modification.
Dave Lo, ScubaTerra Founder:
Avoid this light. I'm only including this unit for reference as multiple resellers offer it on multiple sites, and it has multiple bad reviews that you should know about from multiple people who have purchased this. Not only do buyers complain about it not working, there's a problem with the seller's claim of 28,800 lumens. For perspective, the professional photographer scuba canisters that run at 30,000 lumens typically have a battery canister roughly 3x larger by volume with 2-4 hours of dive time on a single charge (depending on whether you run it at full 30,000 lumens or at a lower setting). So either the claimed 28,800 lumens are overstated, or the duration at which you can use this will be painfully short.Build Quality
Getting a high build quality is difficult under such requirements though. High reliability canister light setups can cost easily over 1000 USD. There are many significantly cheaper options with lower reliability in build quality. It's important to avoid leaks because the batteries used are typically lithium ion. Not only can an underwater short be dangerous, if the water seeps into the battery, lithium reacts very violently with water.
Typically these canister lights have a screw cap at the end, or the lamp head screws onto the canister. There should be a high quality O-ring where they meet, or the canister is likely to leak. Some people like to coat any exposed sections of wiring, boards, or seams, to prevent water from displacing air inside the canister.
Sealing with Grease
One suggestion is to insert the batteries into the canister and then fill any empty cracks inside the canister with grease. The grease should be non-conductive to not cause a problem with the batteries, and now water can't get in because there's no space for the water to fill. The problem with this technique is that it makes a huge mess every time you're changing the batteries. They're covered in grease, and you have to poke down into the canister and rub any grease off the terminals before adding fresh batteries so that conductive contacts can still be made.
Sealing with Silicone
Another common suggestion is to seal the batteries and lamp electronics with silicone.
One variant of this is that you can cluster the batteries together as they'd be inserted, and then seal the entire cluster in silicone with wax paper and rubber bands. When you do this, you're effectively filling in any possible air pockets. Water can't get in if there's no air to displace. And unlike grease, the silicone just peels away when you need to change the batteries.
Lamp Testing
One common problem in testing such high output lamps is that they can overheat when tested out of water. These lamps are typically made with a set of LEDs connected to a circuit board with a controller which manages power levels. Many of these lamps are not designed to dissipate heat fast enough when in air... only when in water. When testing above water, make sure your lamp isn't overheating.
Another problem that you'll have to consciously prevent... many people have the rim and face of the lamp in their view when turning it on. These lamps are incredibly bright, so when you do that, it will hurt your eyes. Aim it away from yourself and all other living things, and then turn it on.
Batteries
You'll want 8+ batteries in size 18650 while you travel in case any cells go bad, or you're not able to quickly charge overnight. Remember that the light can go in checked luggage, but the batteries must go in carry-on when you're flying. Some airlines will require batteries to be encased separately from the device they'll be used in, and some airlines even require the batteries are in a fire-resistant bag labeled "LiPo safe".
When purchasing batteries, you'll see many claiming to be rated for over 3000 mAh. Ignore these. There are tons of videos online of 18650 tests, and most claiming over 2000 mAh are outright frauds. There are only a few manufacturers who sell genuine units in the 2600-3000 mAh range into consumer channels. You can't even tell quality by price -- many of the people who have shared tests show that the price per battery is often completely disconnected with the quality of the battery.
Finally, make sure your 18650s are the right top for your light. There are two types of tops -- flat tops and button tops. Button tops are a little taller. Most of the lights above are button tops. Some have a microUSB port built in directly for charging, but this reduces the amount of space they can use for the actual power storage chemicals.