NCR18650B and Solarforce K3

Hi guys,
I understand a little about electronics but am a bit baffled by flashlight talk

I have a Solarforce L2P with the extender to take two 18650 batts
It is fitted with a K3 5.5-13v head
I use two Panasonic NCR18650B batteries charged by a Nitecore i2

Are my batteries protected ? If not what care do I need to take when charging and using the light ?

Pics below for battery identification. Thanks for all advice
Mike.

It is protected, read more here: http://lygte-info.dk/info/isMyBatteryProtected UK.html

That copper strip under the gold colored tape is the lead for the protection circuit. The black piece on the bottom is the protection circuit.

The Panasonic 18650B cells with a button top using this protection circuit tend to be close to 70mm in length. On some lights where the cells are stacked, they are too long to screw the tail cap on. The other issue is that the company that is supplying the circuit is using an additional clear over wrap covering the cell that can make the cell a little large in diameter for some lights.

Typical protected button top cell is 68.5mm in length.

Thans guys, so I take it I can just trust the charger to do its job and use the light without any worries. Sounds good to me ... I will order a couple of spares then
Mike.

mikehill said:

Thans guys, so I take it I can just trust the charger to do its job and use the light without any worries. Sounds good to me ...

Click to expand...

Whoa, not so fast there cowboy.

An informed user can be a safer user, so all I want to point out is that in any multi-cell light where cells are in series you have the potential for problems if the cells are significantly imbalanced.

Provided you use cells of the same vintage, charge them together, use them together, you'll likely have years of trouble free service.

However if you pop a discharged cell in by accident along side a fully charged cell, you now have an unsafe situation. I'm not trying to strike fear, just adding a note of caution that you still need to take care. The protection circuit in each cell helps add to safety but isn't a guarantee.

If you don't already own a Digital Multi Meter it might be worth getting even an inexpensive model. They can be handy around the home and will allow you to do a sanity check on your cells - a quick voltage test of each before you put them in will confirm for you that the cells are at roughly the same state of charge, which is what you want.

You could probably get by safely for some time simply by using your Nitecore i2's multi-bar LED display - be sure you always install fully charged cells into the light. That said as cells age it is possible one will age faster than the others and over time an imbalance starts to develop; having a voltmeter handy allows you to check for this and remove a potential source of problem and worry.

Personally I find that removing a source of worry is beneficial all in itself.

Thanks Tandem, I have a Fluke DMM and understand about balancing the voltage as they are multi-cell in series. I just wasn't sure on the protection and current draw issues. Always pays to warn if in doubt though :thumbsup:
Mike.