TRAXXAS Temperature & Voltage Telemetry Sensor (Long), Black, 6521

Can now see the temperature of my rc motor and voltage of my battery which is super helpful to know and prevent damage to expensive components

Works accurately and fit perfectly.

This Traxxas temperature and voltage sensor worked exactly as I hoped. Installation was straightforward, and the long cable made it easy to position where I needed it in my RC. The readings in my telemetry system have been accurate and helpful for monitoring battery voltage and motor temperature during runs. It’s been a useful upgrade that helps me keep better track of performance and avoid overheating.

I am using this in my TRX4 G-500 crawler. I think the temperature is very useful for heavy duty trailing or rock crawling, especially using 3s batteries. The voltage telemetry is an absolute necessity when you are using LiPo; especially when using the rig in such a way that the low-voltage feature of the Traxxas ESC may not be immediately obvious. The temperature probe installation is very easy - simply zip tie the flatter sensor part of the black hooped wire directly to the motor (any motor, Traxxas or otherwise). The readings are quick to transmit and seem accurate thus far. The wire length is just about perfect for the TRX4 chassis, with enough slack to route as desired, but not so much that you have to be creative zip tying the excess wire. The voltage installation will take some basic knowledge in electronics. Traxxas saw fit to fit the voltage wire with a JR male plug with a single wire to be attached to the positive power source. Using the Traxxas battery adapter is not possible without modification of the TRX4 ESC battery connector (which I am unwilling to do on a new rig). Many folks simply solder the red wire to the positive terminal of the ESC connector, and this is fine. However I prefer a plug/unplug option that doesn't require modification or soldering of the TRX4's connection. Because the xl-5 hv ESC comes with a full-voltage takeoff that runs straight to the battery (as confirmed by multimeter measurements using 3 different batteries), I decided to use that as my source for telemetry. However, the takeoff uses a JST male connector. So I simply built a JST female to JR female connector by soldering 2 red 20AWG wires attached to the respective terminals. I completely removed the black wire and the terminals originally attached to the stock connectors. I made the length long enough to feed under the battery tray, but not be too slack. Before attaching to the telemetry connector, I ensured perfect continuity from the red ESC battery connector to the final plug. Out of curiosity I plugged the telemetry unit and checked its continuity, and found that a 9.05Ohm resistor is wired into the unit. That same resistance was present without anything plugged into the telemetry cable... which explains how it works in the receiver box. The later model TRX4s (including the G-500) have BEC voltage going to the receiver. As a result, the telemetry picks up on this steady voltage and reports it to the transmitter *even when the voltage telemetry wire is not connected to the battery*. I would *not* trust this for good battery voltage reporting as it will mask the actual voltage coming from the battery. When I plugged the battery to the telemetry terminal, I could tell I was obtaining real-time voltage -- prior to connection, there was no momentary drop of voltage when I quickly throttled up the motor; post connection, the telemetry showed the momentary voltage dip one would expect from a quick throttle up. Getting the telemetry unit to fit in the receiver box was a bit tedious, but not hard really. I do wish there was perhaps 2-4mm of red wire to make it a little easier. So, save the money on the half-useless Traxxas adapter, buy some bulk connectors with cables and solder your own JR female - JST female adapter. $3 for the temperature mount is silly in my opinion since I connected mine with a zip tie for effectively less than 10 cents.

makes it easy to watch for temperature increases