24v or 48v for travel trailer?

[compass]

Planning to upgrade my trailer. Trying to decide which voltage system I should go, 24v or 48v?
* I have 2x 220w solar panel (19.7v 11A, https://lumerasolar.com/product/220w-bifacial-12v-solar-panel-canadian-made/). I'm planning to get 4 additional same ones. This will be the max I can fit on my roof.
* Planning to get all in one system like MPP 3048lv-mk.
* Have one 12v 100Ah LiFePo4 battery, but planning to get larger battery and repurpose the 12v battery for other use.
* Trailer is 2022 model and came pre-wired for solar.
* I can get very good price on solar panel and MPP 3048lv-mk.
* I'm also planning to get a connection to my house from the trailer. So when the trailer is not being used, I can still take advantage of the system in the house.

If I go with 48v and 6S configuration, the voltage will over the max for MPP 3048LV-MK (115v). For 3S2P configuration, the voltage will below the min voltage (60v).
Also given it is a travel trailer and will be parked in the campsite which may have shade quite often, should I go with 2S3P configuration for more redundancy? Then I will have to do a 24v system.

Any suggestion? Thanks!

 

[#40Fan]

Since you haven't bought the new panels, why not get 4 with 40V+ ratings? Wire them in 3s2p with your old panels. Then stick with your 48 volt plan.

 

[compass]

4 40v panel would be larger and probably will not fit my roof. Plus the current panel price is really good.

 

[Rocketman]

For RV’s the best idea on solar panels is go with as much in parallel as possible- shade issues.

If you want to go 48v that would be 3s2p. Really the battery voltage is your decision. There will always be times that the other voltage will be “better” - just go with what you think will be best overall.

Is your rig setup for 50a power connection? Or just 30a?

If it’s 50a make sure you know your inverter will handle going from 50a 240v split phase power to 30a 120a single phase power on both legs.

Also can your inverter dial down the input current limit? - so you can just plug an extension cord in 15a or 10a or 8a - depending on the cord and the distance.

Pre-wired for solar usually means a 10awg wire. That will be fine for the 2p - but 3p will be 33a which may be overloading the wire. Need to verify the wire size.

 

[HRTKD]

My panels are in series. My experience has been that if one panel is in shade, so are the rest. For those situations, I use a set of ground deployed panels outside the shade zone. 12 volt works just fine for my setup, but I have only one air conditioner.

A bifacial panel on a trailer does not conform to the bifacial installation instructions that I've seen that require 1 meter of distance between the panel and the reflecting surface.

Be very careful with buying components for a 48 volt system. Many parts are rated up to 48 volts, not beyond that. Your system will live almost it's entire live well above 48 volts. This is especially true of switches and breakers.

 

[compass]

After some research, I'm leaning toward 24v system. It seems more flexible. So I have options to use 2s3p or 3s2p configuration (MPPT range 30v to 80v). My rig is on 30amp and 1 AC. I'm also not planning to use AC very often. I may just add a fan for air circulation inside the rig. So the efficiency gain for 48v system may not be that significant. Too bad the battery I have in hand is Renogy 12v 100ah, so I can't just get another one in series. So I'll need to get another 24v battery.

I'm trying to decided between MPP HYBRID LV2424 and 2424LV-MSD. Similar price and spec.

 

[Rocketman]

Put that one 12v battery in you house bank, then get 24v batteries for the inverter bank. Make sure you can read the cell voltage somehow (usually via Bluetooth).

Good Luck!