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Renogy DCC30S/DCC50S, Do they boost?

Airy

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Apr 16, 2021
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Will's video review (Easy Solar Power for #vanlife and Off-grid RV Dwellers: Renogy DC to DC Charger w/ MPPT) shows the current through the DCC50S dropping to 8 amps at 9:27 into the video. Will talks about the current dying as the two batteries equalize, which implies that the DCC50S is just a buck converter and not a buck-boost converter. The Victron Buck-Boost DC-DC converter and the Sterling BB1260 won't stop charging when the two batteries are equalized, and if the input voltage drops below the output voltage, they'll move from bucking to boosting until a minimum input voltage is reached. Maybe the current dropped in Will's video because the charger stopped bulk charging and it wasn't because the two batteries were equalized in voltage? Anyways, does anybody know if the Renogy DCC50S will continue to charge if the input voltage drops below the output voltage (i.e., buck-boost converter)? If it doesn't boost, then it won't be much good with the new smart alternators where the input voltage needs to be routinely boosted to charge the coach battery.
 
Welcome to the forum.

@Will Prowse 's comments are not inline with my understanding of the unit. Given his statement that it had been a few hours, and the current had dropped to 8A, it's likely that the coach battery was at 14.5V, and the current was tapering as it does in the absorption phase, not due to equalization of their voltages.

If you check the manual, it tells you what source voltage is required for the charger to operate. It should operate as the other units you mentioned.

It can deliver a total of 50A. I believe it can source that full amount from the alternator if available; however, if solar is also input, alternator input is cut to 25A, and up to 25A can be pulled from the panels.

I've tagged Will to clarify if I am mistaken.
 
Thanks snoobler, I sent an email to Renogy earlier this week and I am hoping they get back to me and if they do, then I'll post the answer up here.
 
Welcome to the forum.

@Will Prowse 's comments are not inline with my understanding of the unit. Given his statement that it had been a few hours, and the current had dropped to 8A, it's likely that the coach battery was at 14.5V, and the current was tapering as it does in the absorption phase, not due to equalization of their voltages.

If you check the manual, it tells you what source voltage is required for the charger to operate. It should operate as the other units you mentioned.

It can deliver a total of 50A. I believe it can source that full amount from the alternator if available; however, if solar is also input, alternator input is cut to 25A, and up to 25A can be pulled from the panels.

I've tagged Will to clarify if I am mistaken.
I have one of these units and can confirm it "boosts" voltage just fine. There is a protection in the unit that prevents it to take input from a really low voltage source (battery or Alternator) - but once you hit that limit it will output as per spec (or your set voltage should you want to create a custom charging profile)
 
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