Comparison: Renogy DCC50S vs RBC50 DC DC solar + alternator charging

Renogy has launched an updated 50A combo DC-DC/MPPT unit, the RBC series. Renogy’s input on this video’s comment section sheds light on the RBC’s behavior and even a bit about the DCC’s.

We use the 50A versions for examples below although the same logic applies to 30A versions. We also assume the bank can accept whatever charging is offered and that the alternator can output 50A.

DCC50S alternator + solar behavior

• 25v input limit
• The DCC will charge at ≤50A from either source
• if both sources are active it will charge at ≤25A solar + ≤25A alternator. I will call this a 50/50 split.

In DCC logic active solar means Vpanel ≥15v. Since this can be true and still yield nearly no power, the combined charging floor of the DCC is 25A (~0A solar + 25A alternator).

RBC50 alternator + solar behavior

• 50v input limit
• The RBC will charge at ≤50A from either source
• the combined charging “split” is unknown other than the floor discussed below.

With the RBC active solar means ≥7A solar harvest.

Worst-case scenario (likely, IMO) If the split is 50/50 like the DCC then the combined charging floor of the DCC is 32A (≥7A solar + 25A alternator).

Best-case scenario (unlikely, IMO) If there are no defined split limits then the floor might be 50A (≥7A solar + ≤43A alternator).