Battery Charger as Source of Power for Victron Controller

AnOldUR · February 2022

Rather than use the controller that normally comes with a Renogy solar suitcase I mounted an MPPT 75|15 controller in the box on the front of my T@B. I added an SAE port to the side of the box to connect the solar panel. Works great!

I recently purchased a small 900/700W generator only for the purpose of charging my batteries when not enough sun is available. It’s too small to really power the trailer. Could a 12V/5A NOCO GENIUS5 smart charger be plugged into the generator and the 12V output from the smart charger be plugged into my SAE solar port? In other words, is a 12V/5A battery charger an acceptable source of power to pass through the MPPT 75|15 controller for the purpose of charging a battery? I’d like to avoid bypassing the controller and think the data from the Victron app might be helpful, but don’t want to destroy the controller.

I asked this question at the end of a generator thread, but hoped it would get a better response on its own. Sorry for the duplicate.

ChanW · February 2022

I'm not sure where your other thread is, so I hope I'm not duplicating answers....

I'd be concerned with the 'smartness' of your Noco conflicting with the smartness of the Victron controller.

My Noco has an inbuilt controller, that you can see, when looking at the graph put out by the battery monitor, looks pretty specific with its charging curve.

Perhaps using a simpler charger would work better?

If it were me, I'd hold off til I had a professional opinion....

Noco Genius charge/desulfation curve:

pthomas745 · February 2022

Your SAE port is connected directly to the battery?

Your Victron is connected directly to the battery?

Plug your NOCO into the SAE port, and the Victron will simply monitor the battery state of charge. It will just register the charge coming in, however.

(I discovered that NOCO has a proprietary cable for the SAE port, so I find it much easier just to use battey clamps directly to the battery....but I rarely use the NOCO for charging.)

ChanW · February 2022

@pthomas745, I had the impression that he was going to put the charge through the Victron controller as he is the solar panel connection.

@AnOldUR, Keep in mind too, the in the Victron settings, the controller has a specific 'charge profile' set up for the solar panel charge curve. You need to set up a separate profile for the generator/charger (if indeed it would work) and then remember to switch profiles when you switch power sources.

AnOldUR · February 2022

@ChanW you are correct. I was hoping to go through the Victron controller, not directly to the battery since the port is already wired that way.

I am aware of settings for battery type, but haven't seen any settings for the input side. I'll have to look into that. The Renogy solar suitcase has a maximum operating voltage of 17.6V and a maximum operating current of 5.68A. That sounds like it's in line with what the NOCO puts out, but don't know if or how that equates to this situation?

ChanW · February 2022

I'd try to contact Noco, and/or Victron. They're the pros, and maybe they actually have a customer tech support department....

CrabTab · February 2022

@AnOldUR Why not just add a second SAE connection that's wired directly to the battery bank from the generator 12V output?

Towhee · February 2022

@CrabTab. I like this idea. I use my noco through the SAE port ( with a gender changer) wired directly to the battery. Works perfectly.

pthomas745 · February 2022

How is the Victron wired to the panel?

Grumpy_G · February 2022

Two issues: The NOCO expects to "see" a battery not the input of a charge controller. There is a good chance it's not even going to turn on charging voltage. Then, the charger is only 5A vs the 10 or more amps that the converter puts out. So charging would be faster with the generator connected to the regular AC input of the trailer.

AnOldUR · February 2022

CrabTab said:

@AnOldUR Why not just add a second SAE connection that's wired directly to the battery bank from the generator 12V output?

That's something to consider, but wonder what damage I'd do if mistakenly plugged my solar suitcase into the port without the controller?

@pthomas745. The solar panel is wired to an SAE port on the side of our box with the controller in the box wired to the battery.

CrabTab · February 2022

AnOldUR said:

That's something to consider, but wonder what damage I'd do if mistakenly plugged my solar suitcase into the port without the controller?

,,, then use an Anderson Power Pole or Furrion connector for the second port.

Dutch061 · February 2022

As posted in the other thread.

If you look at the manual for the MPPT75/15 Solar Charge Controller, it clearly states as follows under section 3.3

● The controller will operate only if the PV voltage exceeds battery voltage (Vbat).
● PV voltage must exceed Vbat + 5V for the controller to start. Thereafter minimum PV voltage is Vbat + 1V.

The answer is NO, it will not work. It will not damage anything, but it will never charge either because you will not exceed the battery voltage by 5 volts for the MPPT to turn on.

Brad

AnOldUR · February 2022

Dutch061 said:

● The controller will operate only if the PV voltage exceeds battery voltage (Vbat).
● PV voltage must exceed Vbat + 5V for the controller to start. Thereafter minimum PV voltage is Vbat + 1V.

From this and your reply in the other thread @Dutch061, I now know I'll have to bypass the Victron if going with the NOCO. I just need to decide which options will work best for me. Thanks for bringing your info to this thread.

AnOldUR · February 2022

CrabTab said:,,, then use an Anderson Power Pole or Furrion connector for the second port.

I had wired a cigarette lighter connection directly to the battery into my box for a Coleman 12V cooler. NOCO has a cigarette lighter adapter that might be the easiest way for me to bypass the Victron controller.

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Battery Charger as Source of Power for Victron Controller

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