External Regulator Conversion Kit for Sprinter Revel by Agile Offroad

This is a Revel MUST HAVE! 2021-2023 Revels with 2x 125ah batteries are a fantastic improvement over older AGM battery Revels, but the power systems have some flaws. One of the biggest flaws is Xantrex’s implementation of a second alternator in this van. The Xantrex alternator is internally regulated, and they rely on a switch (called a combiner module) to attempt to turn the alternator off before the batteries are overcharged.

Every single Revel with a Xantrex combiner module (regardless of the revision) has inherent limitations of alternator charging. Some versions undercharge the batteries (they may indicate 100%, but it is not a true 100% due to state of charge drift). Some versions overcharge the batteries which can damage them and cause the fan to beep and reset. Some versions will charge the batteries fully once, and then will not attempt to charge them again until they have been depleted to zero.

This kit will add a proper external regulator to the existing Revel alternator so that the alternator and regulator system are capable of charging your batteries to full and then maintaining them at full while the engine is running.

Installation is possible by a competent DIYer. See the installation instructions below.

We also recommend pairing this with our 3rd battery kit for a transformation of your power system on a budget.

Additional Information

In some versions of this combiner module, the batteries will be chronically undercharged to prevent overcharging. Winnebago goes as far as to tell customers that they must plug their van in every few weeks to fully charge it, admitting that the batteries cannot be fully charged with the alternator.

If you have batteries that are undercharged, the symptoms are usually obvious in that your batteries won’t charge to 100%. There are other non-obvious symptoms with undercharging related to battery state of charge drift

In other versions of this combiner module, the batteries will be chronically overcharged. When the batteries are constantly overcharged, it can damage the MOSFETs in the BMS modules inside the batteries to the point where the batteries no longer work and need to be repaired or replaced. Symptoms of overcharging could be realized as rapidly blinking blue lights on the control panel when driving or repeated beeping from the fan. The fan beeps every time it is powered up. As the batteries are overcharged and shut down, the fan will beep when they turn back on. You can confirm overcharging by looking at the battery trouble codes visible in your Lithionics battery app while the symptom is present.