Probably the most overlooked tasks when using 1S batteries in micro RC aircraft and multirotors is checking voltage after flights, before parallel charging and during battery storage. Checking voltage allows you to maximize flight times, keep an eye on battery condition, and assure (cell) voltage is within spec for parallel charging, just to name a few. Up until recently there hasn’t been many good stand-alone voltage checkers that were capable of reading down to 3.7V, and if so, they were big and bulky being designed for multi-cell batteries. I’ve been using a Junsi CellLog 8M battery monitor with an adapter to measure 1S batteries even though its specs say 2-8S. The CellLog measures down to about 3.5V. Now, Ready Made RC has an awesome little checker that fits the bill perfectly!
The RMRC 1S Voltage Checker is a very small stand-alone LiPo battery voltmeter that accurately and consistently measures down to 2.79V. Voltage is displayed on a relatively large and bright 3-digit blue LED display. The RMRC 1S battery voltage meter incorporates two connectors: Molex 1.25mm (Inductrix, UMX aircraft) and 2.0mm pitch JST-PH (mCPX heli, Nano QX 3D quad). You could easily make an adapter for the red JST-RCY connectors if you have hopped up your 1S micro quad with better connectors. The photo below shows my adapter with the JST connector stuck to the side of the display with double-sided tape before rewrapping with a piece of transparent heat-shrink tubing.
Update: Ready Made RC now offers the JST-RCY adapters!
I compared the voltage reading of two RMRC 1S Voltage Checkers with an inexpensive digital multimeter, Junsi CellLog 8M and a trusty iCharger 308Duo. Both 1S Volt Checkers were exactly 0.03V lower than the other devices. To keep voltage readings consistent across all of my equipment, I simply adjusted the voltage on the RMRC 1S Voltage Checkers up to match. On the back of the printed circuit board is a tiny potentiometer under the heat-shrink tubing. I carefully cut a small hole to allow access. The other voltage checker is getting rewrapped so no hole was needed. DIY mod at your own risk.
If you have 1S LiPo batteries with the three types of connectors, you’ll want to get a couple RMRC 1S Voltage Checkers along with JST-RCY adapters. You could put a piece of heat-shrink tubing over the adapter connector and make it more permanent. It wouldn’t hurt to pick up more checkers just to have on hand as well. You can get these little gems direct from Ready Made RC, currently less than $5 each for the checker and less than $1 each for the adapters!
Links to Ready Made RC Website
RMRC 1S Voltage Checker Specs
- Battery types: LiPo and LiHV packs
- Connectors: Molex 1.25mm and 2.0mm pitch JST-PH
- Voltage range: ~2.79 – 23V (6S)
- Voltage cutoff: ~1.5 – 2.79V
- LED Color: Blue
- Weight: 3.4g
- Dimensions: 34x10x10mm
- P/N: RMRC-1S-VCK
Close-ups, Feedback and Reviews
To be more mobile friendly, photos on TazRC are limited in size. I would be happy to post any close-up photos on request. Just leave a comment below. Also, feel free to leave your feedback or personal review on the RMRC 1S Voltage Checker. Registration not required.