How is VV acheived

[degnr8]

Hey guys I'm an old modder that's been out of the loop for a while and I'm wondering how the VVs work. Is it a matter of a transformer increasing the power from a low output batt like a 3.7v or just running bigger batts through resistor discs? I wonder because obviously if it's the latter, you'd still drain the batt just as quickly at low voltage as you would at high. If the former, I have some research to do.

 

[D. Waterhouse]

It depends on the unit. Some use stacked batts to get 7.4v and drop it down by resistance or PWM (pulse width modulation), basicly flashing 7.4v on and off quickly to simulate the desired voltage. Others use a single batt and a buck booster to bring 3.7 up to the desired voltage, don't ask how, Ive got a LOT of research to do myself.

 

[degnr8]

Thanks D. Sounds like now I just need to figure out how people are doing the boosters without resorting to canibalizing it out of a battery charger

 

[DavidOck]

I"d imagine something along this line:
http://www.madvapes.com/zmax-variable-volt-pcb.html

(They have an assortment of other parts - ports, connectors, etc as well)

 

[lmp9002002]

It depends on the unit. Some use stacked batts to get 7.4v and drop it down by resistance or PWM (pulse width modulation), basicly flashing 7.4v on and off quickly to simulate the desired voltage. Others use a single batt and a buck booster to bring 3.7 up to the desired voltage, don't ask how, Ive got a LOT of research to do myself.

I'm almost certain that capacitors and Mosfets are used to bump up that 3.7V. Different types and different quality components are used in each device. Case and point being how some devices hit weaker when the battery is nearly dead, and yet the Provari seems to put out a true 6V even when the battery is at 3.3V. (Not to glorify the Provari or anything, just an example of a reason why high-dollar mods can be better in ways that arent always visible in a list of features)

 

[Dougiestyle]

Buck-boost circuits draw high amps from a high-drain battery to step-up the supplied voltage to a higher setting.

Step-down regulators draw voltage from a series of batteries to supply a voltage below and up to the supplied voltage.

The Madvapes VV regulator is a linear step-down regulator. It is less efficient than a PWM regulator.

The difference between PWM and linear regulators is that a PWM uses bursts of voltage to simulate the set output, whereas linear regulators convert a constant flow of set voltage. Linear regs are inefficient in that they produce heat as a byproduct of the regulation. The heat is wasted energy.