Solar charge controller for portable mini-system

[wintomatic]

I am making a portable mini-system panel that I can move between my Ice fishing house and boat. System needs: 12v and 24 volt configuration (12v in fish house/camping, 24v in boat. Very low power consumption-Will only be powering 12v lighting, 27” lcd tv, radio, and phone/laptop charger…small enough so the energy vampire neighbors can’t plug their coffee makers into it! (Actually doing this until Victron release of 120v multiplus 500va-1600va compact units in 1-2 years)
So far I have Victron Phoenix 250 inverter, victron IP65 12v/15a charger with wall mount, and two 12v/100ah lithium batteries.
Question is about Victron smartsolar mppt charge controller:
1) which one? (75/10 or 75/15) for 2 small solar panels in series
2) “load” terminal on solar charge control: Is there Power to it from the battery when no solar panels are connected?
If there is, can I connect 12v fish house wiring to the “load” with an inline fuse and use a fused cable on positive battery cable lead to charge controller without using a fuse panel at all?
Terrible Idea?

 

[mikefitz]

The 75/15 is only slightly more expensive than the 75/10 and will allow full output in a 12v system of the two100 watt panels under ideal conditions.
The load terminal power is from the battery and a low battery protection voltage can be set. It's short circuit protected at 15 amps, but an external fuse would be best practice. A master fuse at the battery positive is a good safety technique.

Once the Victron solar controller has been used on a 12v or 24 volt system it 'remebers' the voltage. Where its used an a system with a different voltage, this needs to be manually changed via the app.

Mike

 

[wintomatic]

The 75/15 is only slightly more expensive than the 75/10 and will allow full output in a 12v system of the two100 watt panels under ideal conditions.
The load terminal power is from the battery and a low battery protection voltage can be set. It's short circuit protected at 15 amps, but an external fuse would be best practice. A master fuse at the battery positive is a good safety technique.

Once the Victron solar controller has been used on a 12v or 24 volt system it 'remebers' the voltage. Where its used an a system with a different voltage, this needs to be manually changed via the app.

Mike

Thank you, so to sum it up:
1)There is power from battery to the “load” terminal of charge controller even when solar panels are disconnected.
2) I can wire my 12v fish house wiring, which is definitely less than 5 amps total draw, to the “load” terminals without issues.
3) the Victron 75/15 controller with two 100 watt panels in series would be the best setup for me and allow me to get the most out of my panels in ideal conditions. (I said I had two 12v 100ah batteries, but I was going to ask about panels as well).
4) I don’t need a fuse panel if I wire it this way.
Does this all sound right?

What about in non-ideal conditions? (Like on the flat roof of a fish house in Minnesota, from December through February). Would your recommendations change at all based on that?