Battery Guardian (3S Version)
Know Which Pack Is Dying Before It Takes Your Plane With It
Every Battery Guardian is hand-built, bench-tested, and backed by our 30-day money-back guarantee from the day it arrives. If it doesn't change how you think about your battery bag, send it back.
The Problem With How We All Check Packs
A resting voltage reading tells you almost nothing. A pack can sit at a perfect 11.4V and still sag off a cliff the second you go to full throttle.
Puffing shows up late. By the time you can see it, that pack has been getting worse for months.
Cheap IR meters inject a tiny AC signal and estimate. That number has little to do with what happens under real flight current.
Even when you get a good reading, you have nothing to compare it to. One number, no context, no trend.
Packs get shuffled in the bag. You know one of them is weak. You don't know which one.
So most of us fly the whole bag and hope, or we retire packs way too early and throw away money.
What Battery Guardian Actually Does
You connect a pack, press the button, and it pulls a real DC load through the battery while measuring each cell individually. Not an estimate. An actual load test, the same kind of stress your motor puts on the pack, measured across a precision shunt.
Real DC load testing. Battery Guardian draws genuine current and measures voltage sag under that load. This is the difference between guessing at internal resistance and measuring it.
Per-cell resolution. It reads every cell through the balance lead, so a single failing cell in an otherwise healthy-looking pack has nowhere to hide. That one cell is what kills packs and starts fires.
History that follows the pack. This is the part no other tester does. Every Battery Guardian ships with pre-printed battery tags. Scan a tag, and every test you ever run on that pack is stored against that specific battery. You stop looking at one number and start looking at a trend line. A pack whose IR has climbed 40% over six months is telling you something a single reading never could.
Honest readouts. The display tells you what it measured, not a made-up health percentage. No "SAFE TO FLY" badge. You get the numbers and clear observations, and you make the call.
Chemistry aware. LiPo, LiPo HV, and LiFe each get tested against their own correct voltage floors, so your LiFe packs stop getting judged by LiPo rules.
Powered by the pack under test. No wall wart, no batteries, no USB cable. Plug in the pack and it runs.
Your data stays yours. The companion Android app stores everything locally on your phone. No account, no cloud, no subscription. The release build ships with the internet permission stripped out entirely, so the app physically cannot phone home. You can verify that yourself.
What Battery Guardian Is Not
We would rather you know this before you buy than after.
This is a bench and pre-flight tester, not a monitor. It does not watch your pack while it charges, it does not live in your plane, and it has no temperature sensor. You bring a pack to it, it runs an on-demand test, and it remembers what it found. That's the whole job. It's designed to catch a failing cell on the bench, in your shop, with the pack in your hand, which is exactly where you want to find that news.
Fit and Compatibility, Stated Plainly
This version is 3S only. It tests three-cell packs. It is not a 4S or 6S tester, and we are not going to pretend otherwise. Higher cell counts are in development.
Whatever connector your packs are on, we include the adapter. Battery Guardian's main lead is EC3, and every unit ships with XT60, Deans, and EC5 adapters in the box. Cell readings come through the standard JST-XH balance connector every 3S pack already has. Open the box, plug in, test. No hunting for a pigtail, no order delay, no surprise. About The App
The Android app is free and available right now at flyingtigerrc.com/battery-guardian-app, along with the full user manual.
We are working toward a Google Play listing, and Google requires a group of real testers to run the app before they will let us publish it publicly. If you would like to be one of those testers, reach out and we will get you set up. You get the app either way. Joining the test group just helps us get it into the Play Store faster for everyone else.
An iOS version is coming. It is not available yet.
Who This Is For
If you have more than a few hundred dollars sitting in your battery bag, this pays for itself the first time it catches a pack you were about to launch on. It's for the pilot flying expensive airframes, the club member who charges packs in an attached garage, and anyone who has ever had that quiet moment of wondering whether the pack in the plane is the good one or the one they meant to retire.
What You Get
Battery Guardian bench tester, assembled and bench-tested by hand
EC3 main lead plus XT60, Deans, and EC5 adapters, so any 3S pack connects out of the box
30 pre-printed battery tags for pack history tracking
Free Android companion app with the full user manual built in
Free shipping
30-day money-back guarantee from the day it arrives
Pre-Order Now At Early Bird Pricing
Regular price is $119.99. Pre-order today for $89.99 with free shipping. Units ship within 3 weeks of your order.
This is the first production run, built by hand, one at a time. Pre-order pricing ends when the run ships.