Battery worries

[carl8190]

Im using 18650 in my lights due to it being cheaper in the long run, I know you should stop using 18650 when they get to 3.7v or its dangerous to recharge if they drop below this. This is a problem because im always worried to use my light incase it drop below 3.7 volts so how can I get round this as keep checking the voltage does my head in, Also i never seem to get 18650 runtimes out of my torches do these 3 hours runtimes on 18650's mean if you run a 18650 completly flat?

 

[Hondo]

Re: Battery worrys

This all depends on the type of battery and regulation of the light. First, if you use protected 18650's (I don't) the protection circuit gives you a decent security against over-discharge. It should open the circuit if the voltage drops to low. It also should protect against over charging and short circuits.

Second, if your light is not boost regulated, you will get a visual brightness drop before the battery gets too low. Most of mine do this. If you have a light like an HDS or Novatac (with the appropriate 18650 tube), it has built-in protection that will cause the light to step down in brightness as it reaches depletion, and give you warning.

If you have a fully boost/buck regulated light, without built in warning, and are using non-protected 18650's, you either need to learn your battery's discharge characteristics and charge before it is sub-3.6-ish volts, or be prepared to kill a battery or two. The good news is that running a Li-Ion all the way down, with a single cell light, is not likely to hurt anything or anyone other than the cell. I use old laptop batteries, so I don't worry much about losing one, though I never have. Also, browse a bit in the "flashlight electronics - batteries included" sub-forum, there is a lot of good info like this on there. Your thread might actually end up moved there by a mod.

 

[carl8190]

Re: Battery worrys

My torches I run 18650 in are Jetbeam RRT2 and Fenix TK11 R5, I am unsure how they would react on a 18650 if it got to 3.7v

 

[Kestrel]

Re: Battery worrys

Moving to /Batteries-Electronics/ ...

 

[tre]

Re: Battery worrys

My torches I run 18650 in are Jetbeam RRT2 and Fenix TK11 R5, I am unsure how they would react on a 18650 if it got to 3.7v

I'm not sure about the TK11 but the RRT-2 will blink and drop one brightness level when the battery starts to get low. Don't rely on the protection circuit in the battery. Most seen to kick in between 2.4 and 2.75 volts which is too low.

 

[kaptain_zero]

The correct manner to use LiIon batteries is to leave the house with a freshly charged battery. Check the voltage when you get back after a nights worth of use, then you'll know how much you have depleted your battery.

It's good to remember that frequent, light, refresh charges on a frequently used light is best as it causes the least wear on your LiIon battery. If your battery will go unused for a significant amount of time, leave it partly discharged and simply top up the charge just before it's next use. Full discharge/recharge cycles are hard on the LiIon cells.

I always drop my CRC123 cell in the charger for my HDS before going out for the evening, and while that cell is charging, I plunk the backup cell that I have in my holster into my light and place the freshly charged cell into the holster as backup. The following day I do exactly the same, so each cell gets used in rotation, keeping the wear and tear even on both cells. I almost never need my backup battery during the evening, but that varies from day to day... so I DO carry a spare. As mentioned, the HDS will step down, giving a heads up that the battery is starting to run down. I swap as soon as I see that happen.

Regards

Christian