Recently taken delivery of a cycle light with li-on battery pack (6 batteries wrapped in blue plastic). Battery then sits in a small Velcro bag.
Just wondering how to prevent water from causing the light to malfunction?
The plastic connections seem to be a tight fit.

slip the battery in a condom (use a small zip tie at the cable end) – stick it back in the velcro bag.

C & B seen by any chance, i wrapped mine using waterproof gorilla tape, you could sit in a basin of water and it would still work fine

I fully taped mine using electrical tape then put a couple of latex gloves over for good measure. No issues and it gets regularly soaked being in Cumbria.

Clingfilmed mine following a broken condom incident. Works well, but I’ve got millions of watch batteries under the stairs now!

I found some “Liquid Rubber” at B&Q, used for repairing shed roofs. I’ve given the battery three coats (just dip it in the tin, hang up to dry, repeat) and its totally waterproof. Seems very durable, and more permanent than a balloon or tape.

Plasti-kote is the best thing to use

http://www.amazon.co.uk/Plasti-kote-400ml-Super-Gloss-Spray/dp/B000TRL4SQ/ref=cm_cr_pr_product_top

food bag from the missus’s stash in the kitchen and a zip tie does the trick for me. suppose you could double bag it for extra protection

Clingfilmed mine… Though tbh my mates haven’t bothered and never seem to have any problems with theirs.

I put mine in a road inner-tube and zip tied the ends.

does the battery actually need protection?

Plasti dip on mine, works a treat, use some sugru where the lead exits the pack otherwise the flexing of the lead will split the coating.

Plastidip

Plastidip looks the same as Plastikote

Yes, li-ion definitely need protecting from getting wet

Li-ion cells don’t get hot when charging or discharging, if they do then there’s a problem which could kill you or worse.