I’m asked quite a lot about battery life…”How long will that eGo 650mAh last me between charges?” It’s a great question, obviously…and one that depends on a few variables. However, certain aspects are immutable. So let’s take a look at this question and see what we come up with, shall we? This may get a little technical, but don’t worry…it’s not so hard and afterwards you’ll be able to easily figure out all kinds of useful info about your devices!
For the sake of this example, I’m going to use a standard eGo type 650mAh battery as our reference. I have a bunch of these battery types lying around, and I’ve metered most of them at about 3.4 volts, even though they are rated at 3.3v; so I’m going to go with the manufacturers claim of 3.3 volts. In addition, I’m going to use a Kanger T3 as a load for the battery. A standard resistance T3 is approximately 2.5 ohms, so we’ll use that figure.
Next we need to know what 650mAh (milliAmphour) actually means. Essentially it means that, if you have a load applied to a battery and hit the switch, it will deliver up to 650 milliAmps of current for one hour. So…what is the amount of current our example setup will really deliver and for how long?
Using Ohm’s Law (where in a direct current circuit the current draw is equal to voltage divided by resistance), we can calculate that a 3.3 volt battery with a 2.5 ohm load will draw about 1.32 amps (or 1320 millAmps) of current. So, since our battery is rated to deliver 650milliAmps amps of current for one hour, we can simply divide 650 mA by 1320 mA to determine the amount of time our eGo can deliver that amount of juice. In this case it’s about 0.49 of an hour, or about 29 minutes.
Now for the variables part. To turn that 29 minutes into a useful indicator of vaping time, we need to know a couple of things; one is how long are your “toots” (nod to Nick “Grimm”Green) and how many of ’em do you suck down? So let’s just use my typical vape pace as an example; you can plug your own figures in here for your own situation.
When I vape, I tend to have the button pressed for about 5 seconds for each blast. I also tend, on average, to take about 40 draws an hour. So every hour I’m “using” 3 minutes and 20 seconds of my original 29 minutes (5*40=200, 200/60=3.3). With this handy-dandy bit o’ knowledge, I can determine that, on a fully charged battery, I’m golden for about 8 hours (29/3.3). Now, if you do the math, you’ll see that the figure is actually 8 hours and 46 minutes; however the eGo will shut down before the current supply is fully depleted to protect the battery from being fully drained.
So there you go…if you vape at my pace with my type of setup, you can get about 8 hours from a charge on an eGo 650mAh. Note, however, that after some period of time that will change as the battery ages. After a few months, that 650mAh may become 475mAh and less as it gets “older”).
You can figure out your battery “life” regardless of the battery if you know the voltage of the battery and the resistance of the device you’re using by plugging your figures into the above equations. Have fun!