This  is a guest post written by Morandir835, a regular on V4L's  sub forum on ECF, and an e-cig enthusiast. V4L offers three types of chargers: Vapor King Wall Charger, Vapor King USB Charger, and Vapor King Slim Wall Charger. Wall Charger The VK  Wall Charger is V4L's first version. It plugs into any wall outlet. It's the most bulky  of chargers, but is the only one that doesn't pose compatibility issues. They charge batteries to about 4.25 volts  €˜off load'. They also have the highest average charge times of all the V4L chargers. I have tested all 3 lengths using the wall charger. The average charge times are as follows: Shorties - 82 minutes, Regulars - 128 minutes, and Xls - 176 minutes. Occasionally while charging Vapor King automatic batteries using a USB charger, the light won't turn red or blue, just purple and the battery will refuse to charge. When that same battery is plugged  into a wall charger, it will read either green (if fully charged) or red (if it needs to be charged) and will complete its charge cycle. When you attach a carto to the battery it is  €˜on load.' When this happens, the battery voltage drops. When a Vapor King battery is  €˜off load' you'll see 4.25 volts on a multimeter, but once a carto is attached  it will drop down to about 4.2 volts. This is a normal function and nothing to worry about. What does make a difference is this slight overcharge. Overcharging a battery will hurt it in the long run, which I will explain later. USB Charger The VK  USB Charger  pulls 300 ma from a USB port, which is not an issue on any standard USB 2.0 connection. The charger lights up  red to indicate the battery is charging and blue when it's fully charged. The blue light will flash as the battery is charging. The shorter the intervals between flashes, the closer it is to being fully charged. These charge faster than the wall chargers and will usually put the battery at about 4.25 volts when complete. The drawback of USB chargers is they have the highest potential for overcharging (of all the chargers I've tested). One day I left a battery on its USB charger for 13 hours, and when I took it off it read 4.29 volts  €˜off load.' These chargers should never be used with the new manual Original Vapor King Diamond and Stealth batteries. These batteries will come out at 4.26 - 4.27 volts 'off load' if taken off the charger as soon as the light turns blue. The average charge times are: Shorties - 79 minutes, Regulars - 123 minutes, and Xls - 166 minutes. Slim Wall Charger The newest charger is built  to UL standards, has a smaller footprint, and will easily fit 5 or 6 plugged into a power strip. These are the fastest of the chargers, and safest against overcharging. A Vapor King battery will come in at 4.21 volts  €˜off load' in all my tests, while a Vapor Titan line battery is about 4.23 volts. Technically, the batteries won't last as long using these chargers, but the loss is minimal (5-10 minutes maximum). The worst overcharge I've gotten using these was 4.25 volts after 14 hours of charging, which places it right at the same level of the previous chargers when they came hot off the charger. Most importantly, the Slim Chargers are the only chargers that should be used to charge the new manual Diamond and Stealth batteries. The newer cells on these batteries are far more susceptible to overcharging then the older automatic Diamond and Stealth batteries. I highly suggest picking up at least one Slim Wall Charger when you order the new batteries. The average charge times are: Shorties - 66 minutes, Regulars - 97 minutes, and Xls - 138 minutes. How Charging Affects Batteries Overcharging a battery greatly reduces its life span, sometimes to the point of killing it. I have purposely killed a battery by leaving in on a charger for more than 24 hours. I suggest never leaving a battery on a charger longer than 12 hours, especially when using a USB charger. Deep cycling occurs when the entire battery charge is depleted, until it flashes and/or no longer produces vapor. This equally damages the battery cell. I've done a number of tests showing you can gain as many as 100 extra recharges out of a battery by simply charging it right around the time you notice a significant decrease in vapor production. For those who are just starting to vape, this will be harder to tell, but with time you'll be able to decipher exactly when it's time to stop without any flashes from your battery. The new manual line will make it easier to tell when the battery needs recharging. My good friend SnowDragon  put it best by saying they have two gears. Batteries stay in high gear for a majority of their life, then drop dramatically. As soon as you feel the change, its time to recharge the batteries. In my opinion, the safest and fastest charger is the Slim Charger. What charger do you prefer and why? Let me know in the comment section below. Contact Morandir835 via e-mail at [email protected] or through his page on ECF. "Even Though I Nothing Learned, With Strength I Burned." - Emperor