This is a guest post written by Morandir835, a regular on V4L's sub forum on ECF, and an e-cig enthusiast.
A common question for new vapers is "how long will my battery last?" There are many possible answers, with many factors that come into play. V4L offers batteries (a.k.a. batts) in both manual and automatic, and in three different sizes, along with four different types. There are advantages and disadvantages to each.
Automatic vs. Manual
An auto battery best mimics using an analog, but at the cost of it being susceptible to death via juice leak (which can happen if you overfill a carto). Manual batts  provide  more control, and due to them being sealed, no need to worry about overfill killing them (unless it gets into the button which can lock up the switch). The drawback is you have to hit the button every time you vape, which means no hands-free vaping. Also due to the reduced airflow created by that seal, throat hit potential is lessened.
Generic vs. V4L  Branded One battery type is the generic KR808. These work fine, but lack all the tweaks that V4L has put into their branded batts, which includes shorter cut-off times, shorter battery life, and harder draw.  Currently, they only come in the regular-length and auto type. The Vapor King line comes in both manuals and autos, and in three different sizes. They feature better airflow, draw, and longer cut-off times than generic batts. Sizes The smaller the battery, the lower the mah (milliamps per hour). This means the shorter the battery, the more often it will need to be recharged. That doesn't tell the full story though, especially in the case of autos. Manuals are sealed, so there is little difference in the draw from size to size. Autos are unsealed and have a world of difference between each size. Shorties despite their lower mah,  pack the best punch, mimicking that of an analog best (especially on the newer series). Regular-length batts have the next best draw, with the second longest battery life, and XL's have the longest life, but a stiffer draw than the smaller batts (though the difference between that of the regular and XL is very minor). Voltage Another key part that comes into play with the different sizes is the voltage holding capabilities of each batt. The higher the voltage, the higher the watts, and the warmer the vape. V4L currently offers unregulated KR808  batts, which means they start out around 4.2 v fresh off the charger (depending on the charger and type of batt), and then work their way down below 3.6 v before needing to be recharged. The shorty batts hold their voltage longer than their brethren, XL has the next best ratio of time in use to voltage drop, followed by the regular batts. Average Life Cycle Tests In my testing of the Vapor King series (which has been collected from an average of six different batts of each size/type over a span of hundreds of charges, here are the average lifetimes in minutes with chain vaping using both CoolCarts and WOW cartos: Manuals: Shorty  - 111 minutes, Regular  - 183 minutes, XL  - 249 minutes Autos: Shorty  - 109 minutes, Regular  - 185 minutes, XL  - 244 minutes I'm a very heavy vaper (going through about 13 ml's of juice per day, most people use 3 to 5 ml's). My heavy vaping is ideal for tests like this one. Depending on your vaping habits you might see slightly shorter times (the length of your drag is a factor too), or far longer times if you don't vape nearly as heavy. Some people who can go through a single  XL batt in a day and some like myself can go through as many as 15 batts of various sizes in the same time span. Vapor Titans The final two series are both of the Vapor Titan family and are currently only available in automatic. They are the Stealth and Diamond Series, which I reference as the King Diamond batts (their original ordering name). They'll forever be KD's to me as a tribute to a certain artist by the same name. These batteries are currently the top of the line batts V4L offers, and the best generation 1 KR808's (unregulated) on the market in my opinion. They have an average of 20.7 second cut-off time, improved cell technology allowing them to not only last longer but hold their voltage longer than previous batts. The draw on these batts are simply amazing. The Stealth Series has an added bonus of longer voltage hold and time between charges due to its lack of LED. This does lead to its one drawback - the lack of a LED makes it harder to tell when the batt is dead (which after you've used them for a while you'll start to notice when they're getting to the end of charge by vapor production alone). The average times on these batts are as follows: King Diamond: Shorty - 121 minutes, Regular - 186 minutes, XL  - 259 minutes Stealth Series: Shorty - 126 minutes, Regular - 192 minutes, XL - 266 minutes The same testing method applies as before, and again your mileage may vary. Charging Cycles In a later post I'll discuss the difference between the charger types, but for now will get into charging cycles. Deep cycling is a term that describes when a battery is vaped until its end (when the LED flashes, and no longer produce vapor). This negatively affects the number of potential charges a batt can get over its lifetime. It can make the difference of over 100 charges in some cases! To get the longest life possible out of your batteries, do your best to avoid deep cycling them. My next post is about the differences between CoolCarts and WOW cartos, and their effect on the life of the batteries.   "Even Though I Nothing Learned, With Strength, I Burned." - Emperor Contact Morandir835 via e-mail at [email protected] or through his page on ECF.