about to wire up 2x mpp 2424, lifepo4, solaredge autotransformer and 4.5kw of panels. sanity check?


Solar Addict
Nov 30, 2019
N Alabama
so a year ago I decided to build a small (2kw) system for my RV

that turned into me reselling about 200 solar panels to fund a larger system.

in the process we bought land that had grid power already, so I've been able to take my time.


things I have on hand:

2x mpp lv2424-msd off-grid units and parallel kits for each

24x 250w 60cell santan panels

solaredge autotransformer

3x 24v120ah lifepo4 banks with chargery BMS's and relays on each.

------ info on the AC power wiring ----

I have a main breaker at the meter. I fed that to another grid-only 200a panel in the house.

the grid only panel will feed both of the mpp units, the mpp units will feed a 200a sub panel

the sub panel also feeds the garage, which is fed with 4/0

there are two RV hookups -- a 30a pedestal in the main driveway for guests and a 50a for our motorhome

-------------- goals -------------

wire up both of the mpp lv2424-msd's in parallel for 4+kw of 120vac

wire up autotransformer to provide split phase 240

get and install manual transfer switch for garage power, so it can be ran on the grid if necessary

---------- concerns ---------

my panels have a 38vOC -- the DC wiring run will be fairly long, can the mpp units handle 3s?

how much overpanneling will they tolerate? if I have to do 2s I'll want to do two 2s5p arrays for 2500w on each controller

autotransformer - how much current can I pull from it at 240v on the regular? should I add extra cooling? how is it going to handle resistive electric loads like water heaters and dryers?


shoutouts to santan solar, watts247, signature solar, temco and many many other retailers for being awesome.


Solar Addict
Dec 17, 2020
Elgin, Texas
how much over-paneling will they tolerate? if I have to do 2s I'll want to do two 2s5p arrays for 2500w on each controller
I am running mine 3S3P (2250w) no issues. That's all I can add as the rest of your plan is outside my experience.