Confused by solar charger sizing

[alderotes]

I'm hoping to set up a simple battery charger for my LifePO4 batteries. I'm charging 1 battery at a time. I have both 12v and 24v 100AH. I have a Victron 75 15 (12/24v) charger and 2 BougeRV N-Type 200w solar panels. The solar panels are 36.4v VOC and 6.3imp (amps). I know I can't wire the two panels in series because that would be 72.8 volts which is too close to the Victron's limit of 75. The Victron manuals says the nominal wattage is 220w at 12v and 440w at 24v.

So, if I wire the panels in parallel (400w), I can charge the 24v batteries but have to unplug one solar panel when charging 12v batteries because of the nominal wattage limit on the Victron charge controller? All the videos I've watched say you have to watch the voltage but can have excess amperage . . . apparently not because of the Victron's wattage limit.

I'm guessing I need a more capable solar controller but need to understand this so I don't buy another throw away.

Thank you!

 

[time2roll]

Most MPPT will limit power to the rated wattage. Basically it will be 15 amps maximum regardless of the battery. Yes connect the panels in parallel.

If switching between batteries it is generally best to disconnect the solar input power first, disconnect controller from the battery second. Opposite when connecting with the controller to the battery first and then add the solar.

Could get a second same controller and just leave one controller and one panel connected to each battery.

 

[KnobCountry]

The current limit on the victron is for reverse polarity. You can use parallel if you want. The victron will pull current up to its limit, the extra will just be wasted (clipped).

 

[Suijkerbuijk]

No you can not use a switch .
A mppt is normal program for on type volt .
For 12 or 24 volt.
If you use a switch than you can have a problem that the mppt can set 24 volt on a 12 volt battery.

Best solution is use 2 mppt and charge the battery on its own mppt charger

Than the 75/15
That 75 means the max volt input from the solar panels not your battery .
The 75/15 can only do 12 or 24 volt out put.
You can set 75 volt input with a 12 volt out put .
So you not need to change that if you like to charge 12 or 24 volt .
Is only that a high volt solar input on a 12 volt battery its not optimal to use.

So again go for 2 seperate systeem for charging.

A good charge is a
Epever itracer-nd
It have a 120/150 volt input for solar .
You can go for a victron or epever other type those have a 100 volt input .
Like a victron 100/15 and up.

You solar panels you use now can over volt the 75/15 .

 

[alderotes]

Thank you everyone for the helpful answers. I have multiple batteries, so the plan is to connect one in the morning, let it charge all day, and then remove it and connect one the next morning. The Victron is supposed to be able to sense whether a 12 or 24v battery is connected. I have pigtails on the batteries and the Victron, so I appreciate the advice as to which order to unplug the solar panels and batteries!