Battery and charger advice for Fenix Bike Lights

Hi All,

Bit of a newbie when it comes to 18650 batteries.

I have recently upgraded my lights to these:
https://www.fenix-store.com/fenix-bc30-v2-0-bike-light/
https://www.fenixlighting.com/product/fenix-bc21r-v2-bike-light/&nbsp

Subsequent to purchase I have found out about the dangers of the 18650 from some of the horror stories on here and elsewhere.

As such I am re-thinking using some old mediafire batteries that I have had lying around from an old laser pen (maybe I should just recycle them if they are dangerous?) and have bought some LG battery to use:
https://www.fogstar.co.uk/products/lg-mj1

I have read that we should use "good chargers" to charge these batteries to minimise dangers of failure and keep the battery cells healthy.

These lights are designed to charge the batteries, would the circuitry in them be considered a good charger to keep them healthy? are they ok for occasional charge use?

or if they are not good enough to keep the batteries healthy in the long term, would this be good enough:

https://www.fogstar.co.uk/products/xtar-pb2s

The review from Lygate (who seems to be the authority on this matter) seems to be good, and I will buy this either way as I think it looks good (unless anyone knows of a good 4 battery one!).

Or would something like this be better for the batteries, and if so why?
https://www.fogstar.co.uk/products/xtar-vc2-charger-2-bay

I will be using these lights for long distance bikepacking trips so would like to keep weight of the setup to a minimum. So I assume that I would be able to at least charge the batteries in the lights or power bank charger while away and train them in the good charger?

Thanks for your help everyone

Paris

Its hard to tell from the picture how fenix electronics works and if use of unprotected batteries could be dangerous. I personally always prefer protected - if done properly, they do not have lower capacity than bare cells. They are just little more expensive. Fenix BC probably uses step-down electronics (my best guess) so its safe, because when the battery is completely discharged (2.5V), LED wont shine bright or maybe even not at all. If the electronics is step-up it can drain cells to virtually 0V and destroy them, such scenario wouldnt be dangerous, just the batteries would be dead.

Charging can pose more dangers. I would charge them with quality charger and all time supervised - not over the night! If done this way, I think there is nothing wrong with it.

Hi Sirpetr,

Thanks for your help and advice!

The Fenix lights definitely seem to have the step down circuitry you describe as they start off powerful and end very weak / dim as the battery depletes.

Also I am sorry the links did not work, here is another try with the manual which details the runtimes etc.

Fenix BC21R v2.0:
https://www.fenixlighting.com/product/fenix-bc21r-v2-bike-light/

Fenix BC30 v2.0:
https://www.myfenix.co.uk/fenix-bc30-v2-0-wireless-control-bike-light


So I will follow your advice to get a proper charger.

I think I will order the Xtar charger / Power bank as the reviews seem good and it displays information for charging and has battery management?

https://www.xtar.cc/product/XTAR-PB2S-Charger-122.html

https://lygte-info.dk/review/Review Charger Xtar PB2S UK.html


Or is this missing some features to be my only charger?


Also, I will just get rid of the unprotected batteries I have - I just don't think the risk is worth it. I now have 6 of the LG MJ1 protected batteries now which seem to be far more reputable than the mediafires...

Thanks again for your help

Paris