Help! My light is eating batteries!

Hi,
first of all, apologies for the naivity of my situation!

My beefiest light is the first one I bought, a niwalker mm15. It's still a pretty cool light, very bright and relatively compact-however, it's just (potentially) destroyed its second lot of 4 18650 batteries. The first were panasonics and the second were samsungs...however, I don't know whether the ones I got were up to the job or not, and am very new and not very knowledgeable about this.

Any recommendations on batteries for this light, and also care guidelines-do I need to stop them draining beyond a certain point (and if so how do I know what that point is)?

Both sets of batteries worked fine, but on both sets, after the light sat around not being used for a few weeks, now won't work, even after being fully charged. The little light on the button pulses red on the light. I thought they should be ok as they actually worked, and worked well through several charging cycles. The set I got with this light wouldn't even power it up!

any help would be appreciated-I'd rather be spending my money on more lights than batteries once a year!

The design of the carrier/body is not the best as can damage the wraps fitting/removing cells. You need high drain cells ideally, flat tops to keep the length short. I removed the centre post and covered it simply with a straw(drinking). This stops the cells damaging the centre pole. When fitting/removing cells just take care as the sides catch/scrape on the edge of the thread/s. Also if the light is not being used, remove the cells from the light. So to keep use simple, just fit the cells when your going to use it. Stops any parasitic drain from being left in the light. Or check the cells every week and make sure its locked out on the switch.

If you don't have a digital voltmeter, I'd at least get an inexpensive one (like around $10 should do). That way you can check your batteries. I don't know much about this light. But if there is a parasitic drain, it would be nice to know how much. If the batteries do not have a protection circuit built in then they could potentially get drained below the 2.50v minimum requirement on lithium ion. I like to recharge at around 3.00v or higher. If a battery that has protection gets tripped, it will read around 0.00v and will have to be reset. Some chargers have trouble with doing that resetting. You can do it manually though. Having a digital voltmeter is really key piece of equipment for this hobby in my opinion. Just some thoughts.

So I wasn't far off the mark thinking that potentially parasitic drain could have led to the batteries draining below a certain amount and making them useless?
are they completely dead if that is the case? No way of bringing them back?!
oops...

Tuigali said:

So I wasn't far off the mark thinking that potentially parasitic drain could have led to the batteries draining below a certain amount and making them useless?
are they completely dead if that is the case? No way of bringing them back?!
oops...

Click to expand...

Parasitic drain is a common problem, with some lights and headlights having worse PD than other lights.

Lights with digital switches, as opposed to mechanical switches, will always have some PD just by the very nature of the switch--it's always drawing energy and in a constant 'on' state.

On some of these lights, you can unscrew the tail cap, or head and break the circuit, thereby eliminating any current draw.

Always measure your new lights over say a week, or two, just to get an idea. Always check your voltages with your DMM so you know what things are doing.

If your batteries were drained down to 2.5v, 2.0v, or 0v, for any length of time, I'd just recycle them and file this under 'Life Lesson #742'.

Chris