3.3kw Off Grid Ground Mount Tiny Home Array help needed

[GSteinenduro]

Hey crew, first time posting so I appreciate any help up front.

I'm going to be building a small 3-4kw ground mounted solar array for a tiny house I own. It's going to ideally be set up in a way that everything is self contained away from the home, for space constraint and safety reasons. I'm going to build out an insulated box to house the inverter, batteries, and charge controller. Ideally I don't want to mess with having to tie directly into the breaker box, but instead I'd like to run a 30amp RV power chord from my system into my existing plug in on the tiny. I'm struggling to find a solution though. It seems you can run a 15amp adapter off the inverter, but I'm not confident that will work if we're running multiple loads at at time. What options do I have to run such a power chord from the array to the home? Thanks!

 

[rodrick]

Hey crew, first time posting so I appreciate any help up front.

I'm going to be building a small 3-4kw ground mounted solar array for a tiny house I own. It's going to ideally be set up in a way that everything is self contained away from the home, for space constraint and safety reasons. I'm going to build out an insulated box to house the inverter, batteries, and charge controller. Ideally I don't want to mess with having to tie directly into the breaker box, but instead I'd like to run a 30amp RV power chord from my system into my existing plug in on the tiny. I'm struggling to find a solution though. It seems you can run a 15amp adapter off the inverter, but I'm not confident that will work if we're running multiple loads at at time. What options do I have to run such a power chord from the array to the home? Thanks!

What inverter do you have most of the larger ones have a place for a cable with lugs to be connected besides the outlets

 

[GSteinenduro]

Haven't settled on one yet, waiting to figure out the best solution for the fit before purchase. Do you know if they'd be rated for a 30amp power chord?

 

[JimP]

Lots of generator cords out there rated for 30 amps, for 120 or 240. In an ideal world, you'd have a generator input on your house. Put the opposite on the power shed.

Honestly though, you will be far better off using direct burial or conduit cable between the buildings. It _sounds_ like you are thinking about essentially having a heavy duty extension cord laying on the ground between the buildings. That is going to cause problems.

 

[rodrick]

First off you need to decide on a voltage which normally is determined by expected loads so you need to determine your total loads including startup loads which can be 3 to 5 times running load required amps

most of your cheaper inverters will claim a surge rating double the constant rating ie 2000/4000 this surge is mili seconds so don’t count on that

your larger inverters have terminals on them you can hook your cable to but as previously mentioned hard wiring is a better option

one option is a aio inverter there are several that are not much more than a basic inverter but will do much more and by the time you get the other required items normally this is a cheaper alternative, the one drawback is no load self consumption is typically higher

so to start with figure you loads so you can decide what inverter capacity is required to do this get the power requirements for everything you will have in the house lights,frig,microwave ect and this will tell you your size of inverter needed

 

[glandpuck]

A 30 amp RV plug configuration is for 120 volts only. Not 240 volts. A NEMA 14-30 is the style on a generator and an electric dryer. They are 240 volts. A NEMA 14-50 is the style popular for level II EV charging. Requires a 50 amp breaker circuit at 240 volts.

Remember that PV output is lowest in the short days of winter, highest in April/May/June and not as high in the summer with very hot days.

Most lithium batteries can be safely installed outdoors in a NEMA 3R rated cabinet and the manufacturer will specify the operating temperatures.

The inverter itself will need to be well ventilated, whether indoors or outdoors. Some inverters are cooled only by convection with large heat sinks. This is referred to as passive cooling. Many inverters use electric fans as singles or multiples and this is referred to as active cooling.

Running a breaker box is fairly easy You can look into DIN rail mounted boxes, breakers, disconnects and solar fuse holders. Make sure youir system is well grounded at the array and near the inverter and install lightening arrestors for DC at the array.

Good luck.