Blogs

08/11/2016
Battery Safety and OHM’S Law
<p class="p3"><img src="http://www.vapebattery.co.uk/image/catalog/Updatedvapingpowerchart.jpg" style="width: 1116px;"><span class="s1"><br></span></p><p class="p3"><span class="s1"><br></span></p><p class="p3"><span class="s1"><br></span></p><p class="p3"><span class="s1">So you recently purchased your first mechanical mod and then realized you had no idea that it took batteries or had no idea which batteries were going to be safe with it? First of all, congratulations on your first mech mod,&nbsp; you’re definitely on the right track now and we’ll teach you as much as we can about batteries, battery safety, ohm’s law, and how to determine how safe your coil or atomizer/clearomizer/cartomizer &nbsp;is for the battery you are using.</span></p><p><br></p><p></p><p class="p3"><span class="s1">With regards to vaping, the battery is the most important item, far more important than your coil, or multiple coils if you have them. Batteries are even more important than the debate over the superiority of wick materials (cotton, organic cotton, silica, mermaid hair – whatever). So if you are looking to get into mechanical mods, or thinking about pushing the limits of your current set-up, or are completely unaware of what your battery can even handle – then this article is definitely for you.</span></p><p class="p3"><span class="s1"><br></span></p><p class="p2"><span class="s2"><b>BATTERY SAFETY BASICS</b></span></p><p class="p2"><span class="s1"><b></b></span><br></p><p class="p3"><span class="s1"><b>Do not overcharge or over-discharge.</b></span></p><p class="p4"><span class="s1"></span><br></p><p class="p3"><span class="s1">To combat this, do not leave your batteries in any charger without supervision. Make sure that you are able to see or check on the charger every 15-30 minutes. This way when the charger indicates that the batteries have been fully charged, you can remove them from the charger. Leaving batteries in a charger all night long or longer can cause them to be overcharged, which can result in battery failure.&nbsp;Charging your battery&nbsp;over 4.25 volts&nbsp;can shorten its life-cycle and going over 4.5 volts can cause it to burst. Cease using your charger if this ever happens.</span></p><p class="p3"><span class="s1">Our recommendation on a good charger Nitecore D2&nbsp;(2 Bay) or&nbsp;Nitecore D4 (4 Bay)</span></p><p class="p4"><span class="s1"></span><br></p><p class="p3"><span class="s1"><b>Recharge batteries with a resting voltage below 3.6V as soon as possible.</b></span></p><p class="p4"><span class="s1"></span><br></p><p class="p3"><span class="s1">Leaving Li-Ion batteries in a discharged state will incur irreversible damage – creating a loss in capacity and a loss in cycles.</span></p><p class="p3"><span class="s1">Determining the exact voltage can be tricky, unless you have a multimeter. If you are delving into the world of mechanical mods and RBAs (<b>R</b>e<b>B</b>uildable <b>A</b>tomizers), or making your own coils, a multimeter is a must have device because you can use it to test your coils and your batteries. Sure, you can always use a battery tester, but the majority of battery testers are not equipped for the types of batteries that are used in mods, or even test batteries under load condition.</span></p><p class="p4"><span class="s1"><b></b></span><br></p><p class="p3"><span class="s1"><b>Do not short circuit your batteries.</b></span></p><p class="p4"><span class="s1"></span><br></p><p class="p3"><span class="s1">Short circuiting can cause a huge surge of current that will potentially burn&nbsp;out your battery, damage your mod, or even your face!</span></p><p class="p3"><span class="s1">Short circuits happen when the voltage from a battery is discharged through a low resistance wire at a discharge rate that exceeds the battery’s upper amp limit.&nbsp;Short circuiting a battery is very close to what a mechanical mod with a sub-ohm coil is doing, except you are trying to keep the resistance under the upper amp limit – there’s a fine line that you have to be careful of when sub-ohming.</span></p><p class="p4"><span class="s1"></span><br></p><p class="p3"><span class="s1"><b>Do not let your batteries touch each other or other metallic items.</b></span></p><p class="p4"><span class="s1"></span><br></p><p class="p3"><span class="s1">Keeping your batteries loose, such as in your pockets, is a good way to have your batteries fail and seriously harm you. There are battery holders and covers to keep your batteries safe. Get some – now.</span></p><p class="p4"><span class="s1"><b></b></span><br></p><p class="p3"><span class="s1"><b>Do not dispose any battery in a fire.</b></span></p><p class="p4"><span class="s1"></span><br></p><p class="p3"><span class="s1">This is just common sense people. There are dangerous chemicals in batteries. If you try to burn your batteries they’ll release dangerous fumes and will probably explode. Do yourself, and the rest of the world, a favor by taking your old batteries to a battery recycling center.</span></p><p class="p2"><span class="s1"><b></b></span><br></p><p class="p1"><span class="s1"><b>WHAT’S IN A NAME?</b></span></p><p class="p2"><span class="s1"><b></b></span><br></p><p class="p3"><span class="s1">Let’s take a look at the specifications of AW IMR batteries for a moment:</span></p><p class="p4"><span class="s1"><b></b></span><br></p><p class="p3"><span class="s1"><b>IMR16340 Specifications:</b></span></p><p class="p3"><span class="s1">Nominal Voltage : 3.7V</span></p><p class="p3"><span class="s1">Capacity : 550mAH</span></p><p class="p3"><span class="s1">Lowest Discharge Voltage : 2.50V</span></p><p class="p3"><span class="s1">Standard Charge : CC/CV ( max. charging rate 1.5A )</span></p><p class="p3"><span class="s1">Cycle Life : &gt; 500 cycles</span></p><p class="p3"><span class="s1">Max. continuous discharge rate : 4A</span></p><p class="p3"><span class="s1">Operating Discharge Temperature : -10 – 60 Degree Celsius</span></p><p class="p4"><span class="s1"><b></b></span><br></p><p class="p3"><span class="s1"><b>IMR14500 Specifications:</b></span></p><p class="p3"><span class="s1">Nominal Voltage : 3.7V</span></p><p class="p3"><span class="s1">Capacity : 600mAH</span></p><p class="p3"><span class="s1">Lowest Discharge Voltage : 2.50V</span></p><p class="p3"><span class="s1">Standard Charge : CC/CV ( max. charging rate 1.5A )</span></p><p class="p3"><span class="s1">Cycle Life : &gt; 500 cycles</span></p><p class="p3"><span class="s1">Max. continuous discharge rate : 4A</span></p><p class="p3"><span class="s1">Operating Discharge Temperature : -10 – 60 Degree Celsius</span></p><p class="p4"><span class="s1"><b></b></span><br></p><p class="p3"><span class="s1"><b>IMR18350 Specifications:</b></span></p><p class="p3"><span class="s1">Nominal Voltage : 3.7V</span></p><p class="p3"><span class="s1">Capacity : 700mAH</span></p><p class="p3"><span class="s1">Lowest Discharge Voltage : 2.50V</span></p><p class="p3"><span class="s1">Standard Charge : CC/CV ( max. charging rate 2A )</span></p><p class="p3"><span class="s1">Cycle Life : &gt; 500 cycles</span></p><p class="p3"><span class="s1">Max. continuous discharge rate : 6A</span></p><p class="p3"><span class="s1">Operating Discharge Temperature : -10 – 60 Degree Celsius</span></p><p class="p4"><span class="s1"><b></b></span><br></p><p class="p3"><span class="s1"><b>IMR18490 Specifications<br> </b></span></p><p class="p3"><span class="s1">Nominal Voltage : 3.7V</span></p><p class="p3"><span class="s1">Capacity : 1100mAH</span></p><p class="p3"><span class="s1">Lowest Discharge Voltage : 2.50V</span></p><p class="p3"><span class="s1">Standard Charge : CC/CV ( max. charging rate 3A )</span></p><p class="p3"><span class="s1">Cycle Life : &gt; 500 cycles</span></p><p class="p3"><span class="s1">Max. continuous discharge rate : 15C</span></p><p class="p3"><span class="s1">Operating Discharge Temperature : -10 – 60 Degree Celsius</span></p><p class="p4"><span class="s1"><b></b></span><br></p><p class="p3"><span class="s1"><b>IMR18650-1600 Specifications:<br> </b></span></p><p class="p3"><span class="s1">Nominal Voltage : 3.7V</span></p><p class="p3"><span class="s1">Capacity : 1600mAH</span></p><p class="p3"><span class="s1">Lowest Discharge Voltage : 2.50V</span></p><p class="p3"><span class="s1">Standard Charge : CC/CV ( max. charging rate 4.5A )</span></p><p class="p3"><span class="s1">Cycle Life : &gt; 500 cycles</span></p><p class="p3"><span class="s1">Max. continuous discharge rate : 15C</span></p><p class="p3"><span class="s1">Operating Discharge Temperature : -10 – 60 Degree Celsius</span></p><p class="p4"><span class="s1"><b></b></span><br></p><p class="p3"><span class="s1"><b>IMR18650 -2000 Specifications:<br> </b></span></p><p class="p3"><span class="s1">Nominal Voltage : 3.7V</span></p><p class="p3"><span class="s1">Capacity : 2000mAH</span></p><p class="p3"><span class="s1">Lowest Discharge Voltage : 2.50V</span></p><p class="p3"><span class="s1">Standard Charge : CC/CV ( max. charging rate 2A )</span></p><p class="p3"><span class="s1">Cycle Life : &gt; 500 cycles</span></p><p class="p3"><span class="s1">Max. continuous discharge rate : 10A</span></p><p class="p3"><span class="s1">Operating Discharge Temperature : -10 – 60 Degree Celsius</span></p><p class="p4"><span class="s1"><b></b></span><br></p><p class="p3"><span class="s1"><b>Determining Your Maximum Discharge Rate</b></span></p><p class="p4"><span class="s1"></span><br></p><p class="p3"><span class="s1">The most important specification to pay attention to is the “Max. continuous discharge rate” for each battery. Each battery has a number and a letter, either measured as&nbsp;A or C (30 Amps or 15C). Look at the IMR18650-1600&nbsp;for example. If your battery has a maximum continuous discharge rate of 15C, this&nbsp;means the battery is rated for 15 times the capacity of the battery measured in amps. So&nbsp;a&nbsp;battery that sits at 1600mAh, which equals 1.6Ah will have a max continuous discharge rate of 15 X 1.6 = 24A. There is a chart below which has the max continuous discharge rate in Amps of some common batteries.</span></p><p class="p3"><span class="s1">You should always determine what your max continuous discharge rate is in Amps (which many of the new and popular batteries have already) to keep your math consistent and mind at ease.</span></p><p class="p2"><span class="s1"><b></b></span><br></p><p class="p1"><span class="s1"><b>HOW TO USE THIS INFORMATION EFFECTIVELY</b></span></p><p class="p2"><span class="s1"><b></b></span><br></p><p class="p3"><span class="s1"><b>Knowing the max discharge rate in amps is only half the battle.</b></span></p><p class="p4"><span class="s1"></span><br></p><p class="p3"><span class="s1">How do you know if your coil or atomizer/clearomizer/cartomizer won’t short circuit your battery? Simple, use this equation: <b>battery volts / the ohms resistance of your coil = your actual discharge rate</b>.</span></p><p class="p3"><span class="s1">If your actual discharge rate is less than the maximum discharge rate you calculated earlier, you’re in the clear. If it’s not, you need to suck it up and rebuild a higher resistance coil.</span></p><p class="p3"><span class="s1">Let’s take a closer look using the 18650 1600mAh battery again (for the sake of continuity). If you took a freshly charged 18650 1600mAh battery and tossed it in your mechanical mod with a very limited voltage drop, and put a .2 Ohm coil on top, you’d be running at 20 amps. To figure out this math you take the voltage running to your coil from your battery, which lets say after a full charge, the multimeter shows that the battery is sitting at 4 volts. Now, divide by the ohms of your coil. The number you get is your total amps. In this case our math is 4/0.2 = 20. So we now know that running this exact setup will push our battery to 20 amps, just 4 amps under its max discharge rate. If you were using a different battery capable of less power under the same circumstances, you would be asking for complete battery failure and the chance of possibly hurting yourself.</span></p><p class="p4"><span class="s1"><b></b></span><br></p><p class="p3"><span class="s1"><b>Safety PSA</b>: Resistance in coils can have a variance of 0.2 Ohms in either direction, or +/- .2 Ohms. This means that if you build a 0.2 Ohm coil, you have to account for that +/- 0.2 Ohm variance. The coil in the above example at .2 Ohms is an incredibly unsafe coil, and I would not use nor suggest that anyone use such a coil. Because of this, I would not recommend anything lower than a 0.4 Ohm coil for 18650 1600mAh battery.</span></p><p class="p4"><span class="s1"><b></b></span><br></p><p class="p3"><span class="s1"><b>Equation Recap</b></span></p><p class="p3"><span class="s1">Let’s take a look at everything you’ll have to calculate in order to determine your coils safety in order.</span></p><p class="p3"><span class="s1"><b>1. Calculate your battery’s capacity in amps: </b>capacity in mAh / 1000 = capacity in amps</span></p><p class="p3"><span class="s1"><b>2. Calculate the maximum discharge rate if measured in C:</b>&nbsp;maximum discharge rate = (battery capacity in amps) x (continuous discharge rate)</span></p><p class="p3"><span class="s1"><b>2. Measure your battery’s volts</b> with a&nbsp;multimeter.</span></p><p class="p3"><span class="s1"><b>3. Measure the Ohms</b> <b>of your coil&nbsp;and subtract .2</b> to account for the +/- .2 variance.</span></p><p class="p3"><span class="s1"><b>3. Calculate the discharge rate you’ll have with the coil you’ve built</b>: &nbsp;battery volts / Ohms = your actual discharge rate</span></p><p> <style type="text/css"> p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 30.0px Helvetica; color: #303a44; -webkit-text-stroke: #303a44} p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 30.0px Helvetica; color: #303a44; -webkit-text-stroke: #303a44; min-height: 36.0px} p.p3 {margin: 0.0px 0.0px 0.0px 0.0px; font: 17.0px Helvetica; color: #272727; -webkit-text-stroke: #272727} p.p4 {margin: 0.0px 0.0px 0.0px 0.0px; font: 17.0px Helvetica; color: #272727; -webkit-text-stroke: #272727; min-height: 20.0px} span.s1 {font-kerning: none} </style> </p><p class="p3"><span class="s1"><b>4. Check to make sure that the actual discharge rate is LOWER</b> than your battery’s maximum discharge rate.</span></p>