Vex V5 Battery Extension Methods

Hey there. I’m looking at using the VEX v5 platform for an educational autonomous robotics application (NOT competition). I’m finding the battery life of a single V5 battery is too short and for my purposes just changing out the battery when it runs low is not feasible.
Does anyone have any experience with extending the battery on the V5? Can the cells from multiple batteries be connected? Can a larger capacity battery of the same voltage and current outputs be substituted for the v5 battery?

Personal note sent rather than open worm can here


If you’re OK with being tethered to the wall, you could just have a battery charging while it’s also powering the brain - as long as the robot isn’t pulling more current than the charger is putting in, that should power things indefinitely.

There has also been talk of a power supply that connects directly to a V5 brain (for use with the new “smart field control” system) but I don’t think it’s available for purchase yet.


You can use the charger input and have the wall charge the battery that powers the brain.

The battery packs are smart, the brain and the cpu on the battery talk. There isn’t a way of connecting them in parallel to increase the power.


It depends on what kind of mobility/power you need. For stationary and low power, as foster and john mentioned, just plug in the battery to the charger. However if you need more power and/or you want the robot to be able to move around, then you could replace the V5 battery with any suitable 12V ish battery of a capacity of your choosing. Obviously, doing so carries the responsibility of creating your own connections and of not starting a fire, but it is doable because the battery-brain communication is not actually required for the brain to power up and do its thing.


Glad someone mentioned the battery charger isn’t actually designed to charge the battery as fast as it discharges. Custom battery is the way to go if this is something you need. Or a higher rated power tether system.

Also BNS did this a few years ago


I’m actually looking information on this too. In my project I need the robot to be running on its own and not being tethered to a wall. One of the solutions my team was thinking of is taking 2 of the batteries and wire them in parallel making the voltage the same 12v but more milliamp hours. A concern that occurred was that we were worried if something would damage the micro.

Is this a safe option or is it better to just go with a third party 12v battery

Given Foster’s posting earlier in the thread indicating that there’s not a mechanism for parallel battery, I wouldn’t recommend trying that.

Because these are smart batteries, they require communication between the battery and the brain, and wiring in parallel would likely cause that communication to fail, and could lead to unintended consequences.