Choosing FPV radios & batteries starts with separating two very different jobs: adding an ExpressLRS receiver to a model or choosing a battery for a Tiny Whoop-style quad. The three RadioMaster items are receivers with different channel and signal-feature profiles, while the Ovonic item is a four-battery pack. That makes the buying decision less about picking one universal winner and more about matching the hardware to the build.
Quick take
- For a compact model needing four PWM channels: RadioMaster ER4.
- For fixed-wing control with eight servos: RadioMaster ER8.
- For antenna diversity and receiver-focused signal features: RadioMaster RP3 V2.
- For a 65mm FPV or Tiny Whoop battery need: 4X Ovonic 100C 850mAh 3.8V HV LiPo BT2.0.
The first three belong in a receiver comparison; the Ovonic item belongs in a battery comparison. Use the price table to see how the listed costs relate, then narrow the choice by model type and required hardware.
Listed-price comparison
| Product | Listed price | Relative price bar |
|---|---|---|
| RadioMaster ER4 ExpressLRS 4-Channel Receiver | USD 17.49 | |
| RadioMaster ER8 ExpressLRS 8-Channel Receiver | USD 40.99 | |
| RadioMaster RP3 V2 ExpressLRS Receiver | USD 22.49 | |
| 4X Ovonic 100C 850mAh 3.8V HV LiPo BT2.0 | USD 22.99 |
Decision matrix
- Receiver or battery? Choose the ER4, ER8, or RP3 V2 for ExpressLRS receiver hardware. Choose the Ovonic pack when the immediate need is a LiPo battery with a BT2.0 discharge plug.
- Small model control: The ER4 description covers small aircraft, boats, cars, and other models requiring four PWM channels.
- Fixed-wing servo setup: The ER8 is the receiver specifically described for fixed-wing users and eight servos.
- Signal-feature priority: The RP3 V2 lists antenna diversity, a built-in TCXO, and WiFi firmware updates.
- Tiny Whoop battery fit: The Ovonic battery description names 65mm FPV drones and several Tiny Whoop-style applications.
Product notes
RadioMaster ER4 ExpressLRS (ELRS) 2.4GHz 4-Channel Receiver [RM-HP0157.RX-ER4
At USD 17.49, the RadioMaster ER4 is the straightforward receiver choice when a model calls for four simultaneous PWM channels. Its ExpressLRS 2.4GHz format and compact-design description point toward small aircraft, boats, cars, and other models where a four-channel receiver fits the job. The reason to choose it is clear channel coverage at the lowest listed price. The limitation is equally clear: four channels do not cover the eight-servo scope described for the ER8, so it is not the natural pick for a setup built around eight servos. It is also a receiver, not the battery portion of an FPV build.
RadioMaster ER8 ExpressLRS (ELRS) 2.4GHz 8 Channel Receiver [RM-HP0157.RX-ER8
At USD 40.99, the RadioMaster ER8 is aimed at fixed-wing users and supports eight servos. Choose it when channel count is the deciding requirement and the build needs an eight-channel format. The 20cm high-sensitivity antenna, DC 4.5-8.4V supply range, 16.5g weight, and 43×30×15mm size provide concrete setup parameters. Its limitation is price: it has the highest listed price in this comparison. The ER8 also solves a receiver need only, so it cannot stand in for the BT2.0 battery pack in a Tiny Whoop-oriented setup. Its role is clearest when fixed-wing servo control matters more than battery selection.
RadioMaster RP3 V2 ExpressLRS (ELRS) 2.4Ghz Receiver [RM-HP0157.RX-RP3-V2
At USD 22.49, the RadioMaster RP3 V2 centers the decision on receiver features rather than channel count. Choose it when antenna diversity, a built-in TCXO, and WiFi firmware updates matter to the setup. The 2.404-2.479GHz frequency range and 500Hz/F1000Hz maximum receive refresh specification give a builder concrete numbers to match with the rest of the system, without treating the numbers as a quality ranking. Its limitation is role and power requirement: the listed working voltage is DC 5V, and RP3 V2 remains a receiver rather than a battery. It suits signal-feature selection, not a Tiny Whoop battery replacement.
4X Ovonic 100C 850mah 3.8V HV Lipo battery BT2.0 For Beta FPV Tiny Whoop drone
At USD 22.99, the 4X Ovonic 100C 850mAh 3.8V HV LiPo BT2.0 pack is the battery-focused choice in this comparison. Its listed 1S, 850mAh, 3.8V LiPo format and BT2.0 discharge plug align with the described 65mm FPV and Tiny Whoop applications. Choose it when the immediate need is flight batteries rather than radio control hardware. The limitation is its defined format: the item is a four-pack of 1S batteries, so it addresses a Tiny Whoop-style battery need, not ExpressLRS receiver selection, channel count, or antenna features. Its 61.7×15.3×7.6mm dimensions and 14g net weight are also relevant setup specifications.
Final recommendations by use case
- Compact aircraft, boat, car, or other small-model receiver: Choose the ER4 for its four-PWM-channel description and receiver-specific role.
- Fixed-wing build with multiple servos: Choose the ER8 because its title and description identify an eight-channel, eight-servo use case.
- Receiver decision led by antenna and firmware features: Choose the RP3 V2 for its antenna diversity, TCXO, and WiFi update details.
- 65mm FPV or Tiny Whoop battery purchase: Choose the Ovonic pack for its 1S 3.8V LiPo format and BT2.0 plug.
The key takeaway is simple: the RadioMaster models solve receiver-selection questions, while the Ovonic pack solves a battery-format question. Once that split is clear, channel count, fixed-wing use, signal features, or Tiny Whoop fit point to the appropriate item.
