Renogy Solar Charge Controller: “E3”
warning RV solar charge controller error codes
What it means
The controller reports a battery under-voltage condition: battery voltage is below normal operating range but typically not yet at the full over-discharge cutoff. It is an early warning that the battery is running low.
Most likely causes
- Insufficient solar charging relative to the loads being drawn most likely
- Weak, aged, or partially discharged battery common
- Voltage drop from undersized or loose battery wiring less common
Safe checks you can do yourself
- Measure resting battery voltage with a multimeter to confirm the reading.
- Reduce loads and allow solar to recharge the bank.
- Check wiring gauge and terminal tightness between battery and controller.
How to reset / clear E3
- Let the battery recharge above the warning threshold; the warning typically clears on its own as voltage rises.
- If it persists at a properly charged voltage, power-cycle the controller (battery off, then on).
When to call a technician
If the battery shows under-voltage even shortly after charging, have it capacity-tested or replaced by a qualified person.
Applies to
Renogy Rover 20A/30A/40A · Renogy Rover Li 20A/30A/40A
FAQ
What does Renogy Solar Charge Controller code "E3" mean?
The controller reports a battery under-voltage condition: battery voltage is below normal operating range but typically not yet at the full over-discharge cutoff. It is an early warning that the battery is running low.
How do I reset Renogy Solar Charge Controller E3?
Let the battery recharge above the warning threshold; the warning typically clears on its own as voltage rises. If it persists at a properly charged voltage, power-cycle the controller (battery off, then on).
What is the most common cause of E3 on a Renogy Solar Charge Controller?
The most likely cause is insufficient solar charging relative to the loads being drawn.
Related · Renogy solar charge controller
The controller has detected that the battery is over-dischar… E2
The controller has detected battery over-voltage: the batter… E4
Load short circuit: the controller detected a short across i… E5
Load overload: the current drawn through the controller's lo… E6
Controller over-temperature: the controller's internal tempe… E8
PV (solar) input over-current: the current coming from the s…
Sources
- Renogy Rover 40A Manual - System Status Troubleshooting (Page 21) — Rover 40A manual, Error Code table, E3 Battery under-voltage (ManualsLib / Renogy)
Note: Confirmed on the Rover 40A manual table. The Wanderer manual does not list E03 as a separate code.
● Last verified 2026-06-29 · compiled from manufacturer documentation. Codes can vary by model year — always cross-check your unit’s manual.