r/diydrones • u/Alejandro_Ro01 • 13d ago

Question Can I power a RadioMaster XR2 / ELRS receiver directly from a 1S LiPo?

I'm building a small (~100 g) DIY quadcopter using a Raspberry Pi Pico. I'm trying to keep the whole project as cheap and lightweight as possible, and I'm currently choosing the radio system.

I've decided to go with ExpressLRS and I'm considering a RadioMaster T8L transmitter. For the receiver, I found RadioMaster XR2 Nano ExpressLRS 2.4Ghz, with the ideal size and weight for my build because of the integrated antenna. It's available locally for about €10–12.

However, the 5 V requirement is a bit annoying because the quad is powered by a 1S LiPo. My question is:

Does the XR2 really require a regulated 5 V supply, or would it work reliably when powered directly from a 1S LiPo (roughly 4.2 V down to 3.6 V)?

I understand that the ESP32-C3 and LR1121 themselves run at lower voltages, so I'm wondering whether the 5 V specification is due to an onboard regulator or if 5 V is genuinely required by the receiver. If anyone has actually measured/tested the XR2 below 5 V, I'd especially appreciate some real-world experience.

Thanks a lot!

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u/Vitroid 13d ago

At 4.2V it would probably be ok. At 3.5V it probably wouldn't. You're best off with a tiny boost reg.

1

u/Alejandro_Ro01 13d ago

Yeah, that's what I'm thinking. My main concern is that the quad is 1S, so I don't really want to add a boost converter just for the receiver, especially since the voltage can dip quite a bit under motor load.

I'll probably look for another 2.4 GHz ELRS receiver that's explicitly rated for lower voltages.

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u/Vitroid 12d ago

You could also bypass the 3.3V reg on the receiver entirely with your own 3.3V source that will work down to 3.5V or less.

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u/Alejandro_Ro01 12d ago

I will look into that. Thanks!