Reddit reviews CBconcept 10XG412V20W G4 JC Halogen Light Bulb,20-Watt,12-Volt, 10 Bulbs

Well doesn't really guarantee you that, tips of wires oxidize and stop being conductive.

Eg after 3 days in salt water:
https://youtu.be/E0dBCeOPw4c?t=212

Reads ~1v out of water, cleans contacts and reads ~3v, puts nail through and you can see it venting.. probably not enough energy to ignite though so maybe good enough.

FWIW for $5 I just bought a box of these: https://amzn.com/7542904760 Can stick them on XT60, or can discharge half a pack at a time using balance lead: http://i.imgur.com/L3Rwe63.jpg Typically its like damage pack, put bulb on end of xt60, leave it on front/back patio (it'll be bring and slowly dim, even when its no longer making any light current is still flowing), next day go get it verify its discharged <1v with multimeter (check pack and each cell w/balance lead), cut off connector and short wires together and add it to pile of dead lipos to bring to recycling place.

Those halogen bulbs draw a lot of power. Example bulb.

So you plug your battery in and these six bulbs will light up and empty the battery relatively quickly. The fan will keep things cool because those bulbs get hot.

If you plug it into a charger/discharger it will take like an hour or more as most charger/dischargers can really discharge at very low wattage.