Why does the ProVari need to use high drain batteries (the full technical answer)?
The ProVari uses an internal DC/DC converter that continuously monitors the output to the atomizer load and maintains a constant voltage with an output current limit of 2.5 amps ( each unit is tested to this limit in production, most exceed this limit by .1 to .2 amps). This output voltage is usually higher than the input battery voltage, depending on what the ProVari is adjusted to.
Battery output current is NOT the same as ProVari output current.
Here is an example that shows why. When the ProVari is putting out 5.0 volts at 2.5 amps into an atomizer load, that calculates to be 12.5 watts.
That means the battery has to supply 12.5 watts to the ProVari, at a minimum. In reality it is more because nothing is 100% efficient.
If the battery voltage is 3.7 volts it will need to supply 12.5 watts / 3.7 volts or 3.378 amps minimum. Because nothing is 100% efficient, let's add that in. Most ProVari devices are 90% to 95% efficient. Picking the worst case, 90%, the battery current must now need to be 3.378 amps/ .9 = 3.75 amps. That is a more realistic current draw, but it could be even higher.
WHY?
Let's take a look at what happens when the battery voltage droops lower than 3.7 volts. At 3.5 volts the battery current goes up to 3.968 amps.
But it can be even higher still when the battery droops to near end of charge, say 3.2 volts. The battery output current now goes to 4.34 amps. And we have to keep in mind that this is ONLY the average current. Because the ProVari converter is a pulsing device, the pulsed battery current can be a factor of 2 higher than the average current.
The battery needs to supply pulsed currents of over 8 amps. These engineering calculations show why you need a high quality, Low Internal resistance battery to supply what the ProVari converter needs.
Where does the internal resistance come into play? According to ohms law, when you are drawing 1 amp out of the battery , the battery voltage will droop .1 volts for every .1 ohms of battery internal resistance.
At 4 amps this means the battery voltage is no longer 3.7 volts but 3.3 volts.
If it won't match up to the demands of the converter in the ProVari , We won't sell it. This is why we recommend using AW red high drain
batteries only!.
They have passed all our tests and are rated to work with the full range of voltages that the ProVari can offer.
