Welcome to POTV's new Sub Ohm & Cloud Chasing forum. Please use the forum to discuss all things related to this activity and keep all other stuff in the appropriate forums. Sub Ohm vaping is for experienced vapers and while you will find good advice from our great members there are some simple things that you need to be aware of. Batteries and Chargers. Modern, IMR batteries with a high maximum discharge make vaping with low resistance coils relatively safe, but it is still important to take care. Make sure that you buy good batteries from a reputable vendor if you are intending to sub ohm vape. Some recommended batteries are: Sony VTC range which have a 30A limit Purple Efest line with 30/35A limit MNKE batteries with 30A limit Always remember, that just because your battery has a 30A limit, it does not mean that you should be pushing them to this limit. The high amp limit allows you headroom. Please leave yourself some. While there are reputable dealers on eBay, unless you are 100% sure of the provenance of a particular battery, we would recommend using a specialised vendor. Check the marketplace or use your regular vaping retailer. Don't scrimp on your charger. If you are pushing your batteries to the limit, then you want a reliable charger to ensure that you don't have any issues. Bear in mind that if you are using a low resistance coil, you may find yourself having to recharge your batteries more frequently. Chargers from Nitecore, Xtar and Efest are often recommended. Ohm's Law and Coil Building. It goes without saying that before you attempt to sub ohm, you MUST have a good grasp of Ohm's Law. Google is your friend in learning about this, but essentially, it will tell you how many watts you are pushing through your coil and how many amps you are drawing from your battery. A simple calculator can be found here. Ohm's Law Calculator Using a base of 4.2v for a freshly charged 18650 battery, this will give you a rough guide to the amount of headroom you have with your battery as well as the amount of power you are pushing through your coil. If you are at this point, we have to assume that you are confident and competent at building your own coils. It still needs to be said that no matter how experienced you are you should always test your builds with a multimeter or Ohm checker before you fire them up on a your device. Possible Issues. It is possible that, due to the higher temperature that you are using in a sub ohm build and the increased amount of vapour that you are inhaling, there may be an increased risk of the production of carcinogens. Whilst this has not been medically proven or disproven, we feel that it is important that you are aware of this possibility. For the reasons outlined in the previous paragraph, it is very important when using low resistance builds to know exactly what is in the liquid you are vaping. There have been numerous reports of issues regarding certain flavours containing Diacetyl. It is highly recommended that you avoid using any liquids that may contain additives from the same molecular group as Diacetyl, (buttery/creamy flavours), when sub ohm vaping. For more info on this see here : Diacetyl - Planet of the Vapes Wiki General Stuff. You need to be aware that the majority of devices on the market are designed for higher resistance vaping. This means that you often are pushing things beyond their intended use. The manufacturer's warranty may be invalidated if you cause damage by vaping at a sub ohm level. You may also cause injury to yourself or people around you if you push your devices too far. While sub ohm vaping is not inherently dangerous, it is not without risk. This short introduction has been designed to give you a few important things to remember if you plan on going down this route, but it is by no means to be considered a comprehensive or complete guide. Take every precaution that you can and make your cloud chasing experience as safe as possible.