Basic question on max MPPT capacity to batteries

Yes, they’re Rolls 210 ah batteries. 132 lbs each! 4 would be pushing the limits of what I would be comfortable with from weight perspective... I would have to swap out the inverter too, that would be pricey.

Sure you don't want to go 24V battery bank?
It'll double the solar watts your Rogue can handle
It's what I did when my Rogue was maxed out.

But maybe not if you've already invested in a fancy 12V inverter, otherwise ... it's pretty simple and makes high watt wiring easier/cheaper. Get a 24-12V converter (I got a 40A Victron).

Heck, I think that Rogue will work with a 48V battery bank ...

EDIT: OOPS, nevermind. Just saw you have 3x12V batteries. Those are big 12V batteries to give you 630Ah.
EDIT2: Maybe if you bought another one, then 24V or 48V would be easy :)

Just set both controllers to the same Vabs and time at Vabs and same Float voltage.

With two separate solar sets you have the option of splitting the bank to put your inverter on one and run the rest of the rig on the other like I have posted about elsewhere--if it is any use to you of course. I do have to choose which bank the Trimetric is reading though. ( I have a shunt on each and swap the display as needed, so I don't need two displays the way I do things--YMMV)

Easiest to just put both controllers on the one bank--both controller negs go on the one shunt same as all the other negs.

With different controller to battery wires, they will have different voltage drops and their controller displays will show slightly different voltages, so they won't be exactly in synch for when they think they reach Vabs, but will be "close enough" if you use fat wire for each.

Can’t get the same 250 panels, they are discontinued. Have plenty of space for the panels, so 60 cell vs 72 isn’t a space equation.
I have the old Rogue 3024 MPPT from my previous trailer that I can hook the 250w panel up to that, was trying to avoid 2 wire runs from roof to front if possible.

phemens wrote:
I have a total of 630 ah of batteries (3x 12v). My plan was to wire up 3 solar panels 1 existing 250w plus 2 new 300w panels) at 24v to a Victron Blue Solar 50A MPPT controller. I spoke to the guy selling me the panels, he tells me that my first limitation in the max wattage the batteries can accept from the controller at 12v (manual says 700w at 12v or 1400w at 24). After that point he says that the MPPT will cap the output anyways.
He says I’m better off putting 2 x 72 cell 335w panels on the Victron 50A MMPT (670w total) and adding a separate controller for the 250w panel wired separately to the batteries.à
Is this correct?

The controller can accept up to 100 volts. This will dictate if you wire series, you need to make sure you dont go over that.

Whatever watt panels you get if you go over the 700 watts the controller will just cap the amps. 700/12v = 58 amps.

72 cell panels are big.

If as you suggest your 850 watts of panels, you will not actually get that out of them during full sun. maybe 700??

Id rather have more solar and let the controller limit the power, then not enough. Again up to the 100 volt the controller is rated at.

Dont know where you are installing these. But to save on splitters and such, I would do your 3 panels in series for a 60 plus volt total. I would get matching panels with what you have. 3-250 watt panels.

But the two 72 cell panels will have the higher volts. ( probably 36 v short circuit) So in series 70 plus volts to controller.

So 3- 250watt or two 335watt on a voltage perspective are really the same. Its only an 80 watt difference.

So it comes down to how much real estate you have to mount panels.

phemens wrote:
I have a total of 630 ah of batteries (3x 12v). My plan was to wire up 3 solar panels 1 existing 250w plus 2 new 300w panels) at 24v to a Victron Blue Solar 50A MPPT controller. I spoke to the guy selling me the panels, he tells me that my first limitation in the max wattage the batteries can accept from the controller at 12v (manual says 700w at 12v or 1400w at 24). After that point he says that the MPPT will cap the output anyways.
He says I’m better off putting 2 x 72 cell 335w panels on the Victron 50A MMPT (670w total) and adding a separate controller for the 250w panel wired separately to the batteries.à
Is this correct?

The batteries will accept 30% charging rate no problem, but not worth going higher than that ( except with certain batteries) So your 630AH bank can accept 190 amps no sweat.

However, the MPPT controller will cap its amps to its rated "size" in amps. Eg my Tracer 20 amper will do that and no more even if it is on a bigger panel (in watts) than it is rated for (260w)

So you need a 20 amper for that 250w you have now. Add a pair of 300s you need about 25 each? So that 50 amper looks about right.

So the guy is right that you need both controllers in parallel on the one big battery bank, but you will not go over what the bank will accept in total amps.

If the 335s are a good price and the 50 amper will do it, sounds good.

You can go a bit over on panel watts (as often recommended with MPPT) anyway, because most of the day you will be under the max watts and be getting more AH haul, but 250w over is way too much IMO.

You can easily get 50 amps into those batteries when low on charge. If you expect to actually get 50 amps your panels would have to actually produce 700 watts. Reality is with sun angles, clouds and temperature etc your 850 watt rated panels may only produce 50% to 90% depending on conditions.

Need more info on the 250 & 300 panels to decide if it is better to have separate controllers. Basically if the cell counts (60 or 72) are the same they should work fine in parallel feeding a single controller. Yes it is best to have same panels that match so if you have a good controller for the 250 consider leaving that in place.