The AW IMR high drain
batteries that come with the starter kit are considered one of the best battery brands available, and is what Provape strongly recommends be used in the ProVari.
The Tenergy battery charger is a decent charger, but there certainly are better chargers available. The ProVari is a high end mod and certainly deserves to have the better batteries and charger available. ProVape offers the Pila charger in the accessory section, one of the top two chargers available.
Best Rechargeable Battery Chargers: Pila Battery Charger & Pila Charger
Any of the Xtar or Nitecore Intellicharger battery chargers offered at RTD Vapor are a major upgrade to the Tenergy charger sold by Provape.
Battery Chargers
Although higher-end battery chargers have an auto turn-off after completion of a full charge, it not considered safe battery practice to leave a battery on a charger overnight. They should be removed soon after completing a charge. Statistically the most common battery incidences occur while charging batteries. Don't trust electronics to work every time; be safe and remove batteries soon after being fully charged. And never leave your home while batteries are being charged.