Using Unprotected Batteries in the Thrunite TN40S

I'm trying to figure out the best batteries to use in the new Thrunite TN40S.

The TN40S takes 4 18650's and I'm trying to figure out if unprotected batteries can be used in the light.

I'd like to assume that the light itself is protected so you can use unprotected cells like the Samsung 35E 18650 3500mAh 10A Flat Top Battery, but I don't want to turn the thing into a grenade. Thanks for any info/cell suggestions.

Quality cells without PCB are still protected against overdischarge/heat and venting

high drain cells like Samsung 18650-30Q can easyly handle 15A without any heat issues

in the picture below you see 8A rated cells terminate with the mechanical bimetal cut off because of overdischarge
high drain cells keep a higher voltage on high currents and their capacity doent get lower much

I use unprotected Samsung 25R INR cells in a thrunite TN32UTvn. I was nervous as hell when first using it but was reassured by a more experienced cpfer (ven)
As long as they're matched cells purchased and used together. And you keep watchful eye not to run them too low on voltage keeping them balanced you should avoid issues.

Keep an eye for any damage to the cells.

Also don't run the light for long term in very low settings as it's easy to run to low voltages without noticing any dimming of the light.

Thanks for that info!

If you were going to get a set of cells for this light, which would you get?

In maukka's review of the Marauder X7 (which also requires high drain cells) it looks like the Samsung 35E cells did better than the Samsung 30Q (graph).

Would you expect to see the same performance difference between those cells in the TN40S?

I'm wondering because the Marauder X7 steps down from 9000L to 1800L after only 1.5 min where the TN40S I believe doesn't step down from 4450L, it just stays on full blast.

Does the TN40S shut off through its own protection when the voltage drops below a certain voltage or does it wait for the bimetal regulator to trip at 2.8 Volts?

TN40S arrived yesterday, way sooner than the Dec 12th shipping date they promised (yeah!)

The battery carrier has springs and metal buttons in the carrier so you can use flat top batteries.

Decided to go with some Samsung 30Q's because the Sony VTC6's are double the cost and perform almost identically according to Mooch's testing.

The test at http://lygte-info.dk/review/batteries2012/Common18650comparator.php seems to indicate that the 30Q's maintain a higher voltage than the 35E's for a long period and then cross at around 3.2 volts at 2.500 Amp hours. I'm not sure how low the voltage can go before the light will turn itself off or what the effective range is for this light.

Thrunite's site says: Working Voltage: 5.5V - 8.4V

So maybe the 35E's would have been a better choice for this light?

Samsung 30Q's are on sale right now for $4.70 ea with free shipping if you get 10 and use their Cyber Monday code CYBER2016
http://www.batteryjunction.com/samsung-30q-18650-3000-flat.html

Using the same code for 4 30Q's comes out to $5.68 ea which includes shipping.

I tried using some 3400 Olight 18650's (non high output) and the light shut off in Turbo mode in 1 second. But it runs fine on High mode, and its bright as hell.

Spotlighted some howling coyotes around some cows at about 900 meters, waved my hand in front of the light for movement and they took off running.

Seems the TN40S is now on sale for only $151.96 on their Thrunite site with the use of their code: xmas

Which is $18.99 less than the discounted price I paid for buying it early and waiting over a month for it to arrive.

Time to have a talk with them