Product Details: 

- Model: Renogy Charge Controller - Rover 20A MPPT 12V/24V Auto-Detect LCD Display  

- Purchase Date: February 27, 2026 

Description of the Issue: 

I discovered it will not charge the battery (or initiate charging properly) if the battery voltage has discharged down to as low as 11.7 volts.  

When the battery is at or below this level:  

- The controller does not seem to recognize/start charging from solar input. 

1: Sent to Renogy Customer Support:

I bought this Renogy charge controller specifically to pair with my Renogy lithium batteries.  

When I powered it up, it refused to charge the batteries because they were sitting at 11.7 volts—which it apparently considers "too low."  

So now I'm left with a charger and batteries that simply won't charge each other. Completely defeats the purpose of buying the thing.  

This design is frustrating and feels pretty useless for real-world situations where batteries can discharge that low. Very disappointed.

2: Renogy Response:

Dear Customer,

Thank you for your message.

Please provide your order number so we can further investigate and assist you with troubleshooting.

For a 12V LiFePO4 battery, 11.7V is already considered a relatively low voltage. At this level, the battery’s BMS (Battery Management System) may trigger low-voltage protection. When this happens, the charge controller may not detect a valid battery voltage and therefore will not initiate charging.

To resolve this, we recommend using a dedicated LiFePO4 charger to briefly charge the battery and raise the voltage above 12V. Once the battery voltage recovers to a normal range, you can reconnect it to the charge controller, and it should resume normal operation.

Please let us know your order number and we’ll be happy to assist you further.

Kind regards,
Renogy

We encourage you to communicate with Customer Service through Service Center to ensure a better communication experience.

If you'd like faster support, our AI assistant is here for you anytime.

Thank you for your cooperation. 

3: Reply to Renogy:

Dear Renogy Customer Support Team,

I hope this message finds you well. I am a full-time RVer who relies entirely on off-grid/boondocking setups while traveling across the country. I am currently in DeSoto National Forest, Mississippi, with no access to shore power, grid electricity, or any external charging sources.

I recently purchased a Renogy mppt charger ( purchased via Amazon on February 27, 2026 – Order #112-1547617-1175418). Unfortunately, the charger will not activate or function properly. From my understanding and testing:

- My inverter continues to operate down to 11.5V without issue.

- My previous, lower-cost ($10) charger worked reliably even at low voltages.

- However, your Renogy charger appears to require the battery to be charged to a higher voltage threshold before it will start working.

This creates an impossible situation for me in a true boondocking environment: there is no AC power available anywhere to use an external charger to "pre-charge" the battery as suggested. Without the ability to charge from my vehicle's alternator or solar when the battery is low, the unit becomes unusable in real off-grid scenarios.

Additionally, I have been unable to register the product on your website for warranty purposes:

- When attempting to enter the order number, the field does not allow any input or submission.

- Selecting "Amazon" as the purchase source does not resolve the issue.

Order details for registration/warranty:

- Purchased from: Amazon

- Order Date: February 27, 2026

- Order #: 112-1547617-1175418

Could you please assist with the following:

1. Clarify the exact minimum input/startup voltage required for this charger model to begin charging (and any workarounds for deep-discharge boondocking situations).

2. Provide troubleshooting steps or confirm if this is a known limitation/behavior.

3. Help complete the product registration manually (or provide an alternative method for Amazon purchases), as the online form is not functioning.

4. If needed, advise on next steps for support, replacement, or refund under warranty.

Best regards,  

Dennis