Renogy DCC50S DC-DC MPPT – Do not buy!

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Renogy has been selling a combination MPPT solar charge controller and DC-DC charger for a while now. They have both 50 amp and 30 amp units.

DO NOT BUY IT!

I have personally installed this unit in a couple vans, and do not recommend it. Here’s why:

  • The MPPT charge controller can only accept 12v-nominal panels. If you’re going to be wiring up 500 or so watts worth of solar, it really makes sense to increase efficiency and up the voltage. You can’t do that here.
  • The DC-DC charger works fineā€¦ so long as it’s night-time or you don’t have any solar hooked up. If you have solar hooked up, it will divide up the available current between the solar and DC-DC, splitting it in half between the two. So let’s say you have 400 watts of solar on the roof, but you’re only bring in 2 amps because it’s cloudy. You’re thinking, “I’ve got a 50-amp controller, I’m good!” But no, you’re not. The system will use 25 amps from the DC-DC side and your 2 amps from solar. Congrats, your 50-amp charger is now putting out 27 amps.
  • So let’s say you don’t have any solar? You should get a full 50 amps from the DC-DC then, right? Well, for a little while. I’ve recently seen the system start at 50 amps, then as time goes on (a couple hours of driving), it keeps dropping off to the point it was down to around 30 amps or less. And the lithium battery bank was not full. It just got lazy.

For all these reasons, I highly recommend going with separate components. Renogy makes some good stand-alone DC-DC chargers (20, 40, and 60 amp), go for one of those. As for solar, I like Victron controllers because they’re well-built and have bluetooth built-in, which is awesome for setup and monitoring.

The 30 and 50-amp Renogy combo units look great, until you actually start working with them. Trust me, find another solution.