First Post

[DAM650]

Hello from Central TX.

We are currently building out a 16 x 16 x 10 shed, converting into a tiny house with a loft space.

As of now we have the electrical 120 volt roughed in, and spray foam closed cell insulation with 3 inch on the metal roof, and two inch on the walls.

I wanted to ask how I can correctly size an offgrid system to power up EG4 12000 BTU mini split, small fridge, dual burner induction top, instant water heater (should I do propane for the water heater and stove? I think yes), laptops, DC lighting, fart fan for a composting toilet to run constantly, and power for tv and soundbar and laptops, wifi booster. Anything else I have neglected to mention for tiny house living

I have zero experience with electric and building battery systems, other that watching tons of videos on batteries, and diy systems. For whatever reason electricity make my brain lock up.

Any formulas, advice, you have to offer is very welcome.

Thanks in advance

Darren

 

[SamDeleted]

Hi Darren what space have you got for panels ?

 

[DAM650]

Hi Darren what space have you got for panels ?

i was planning to roof mount, but there is room on the ground too if necessary

 

[MisterSandals]

I wanted to ask how I can correctly size an offgrid system to power

You absolutely NEED to do an energy audit of everything you are using or plan to use. If you can figure daily watt hours and max AC load (for sizing inverter), its pretty easy to determine needed array and battery.

 

[Ryujin]

I'm definitely new to this, But I've been running our 12 V water pump and the 12 V composting toilet fan (24/7) from a 3 year old marine battery that I literally left discharged for 2 years, including multiple days of freezing in colorado winter. Currently I charge it with a cheap PWM charge controller about 1 day a week and then disconnect it and it runs both of those fine for another week.
I wroe off the battery as dead but since it continues to work I will keep using it to draw less energy form our other batteries.

 

[50ShadesOfDirt]

Is the whole site off-grid, or just this shed?

Never to late to get into the planning ... but, as you are past, or going past, the appliance acquisition stage, I'd suggest the following:

- do the power audit ... see what your choices at this stage are/will do to you
- see if you can rework the appliances (propane/nat-gas cooktop, instead of induction), etc.

Realize that any energy "saved" is a potential reduction in solar gear sizing & costs, right at the start. Then, run thru your design calcs to see what the sizing of components might be. The design steps:

1. Go here, and enter in each appliance's values (watts, hours/day you want to run it, etc.):
unboundsolar.com/solar-information/offgrid-calculator

2. Go here, using numbers from above, and fiddle with various entries/components, and you'll see in real-time what your system component (inverter, mppt, panel) sizing is:
www.altestore.com/store/calculators/off_grid_calculator

There are many similar website pages/calculators, but these two pages should help you get through most of the necessary calculations. This helps you quickly decide if you can do what you want to do, and you can vary component choices for what-if scenarios.

This is off-grid, so a small, standalone system would likely consist of an AIO inverter, a battery-bank (most likely LiFePO4, or LFP for short), and solar panels, along with connecting bit & bobs (cables, fuses, etc.); generator would be a backup to recharge battery-bank if solar not cooperating, or if powering large occasional loads. System reference voltage would be your choice of 12v, 24v, or 48v (most components must match the reference voltage you ultimately choose).

Once your initial calcs are done, you can see Will's videos & diagrams for example systems, under "DIY Solar ..." drop-down list at top of this forum.

Post what you come up with, and folks can help further!

Hope this helps ...

 

[DAM650]

You absolutely NEED to do an energy audit of everything you are using or plan to use. If you can figure daily watt hours and max AC load (for sizing inverter), its pretty easy to determine needed array and battery.

Thanks for those links, that is gonna make this much easier. I don't math so good....

I looked on the spec sheet for the EG4 Hybrid but did not find max AC load listed.. Still searching

 

[Rednecktek]

Do a search for "Blurb time" under my username, that'll help point you in the right direction.

 

[DAM650]

Hello all, I got my eg4 mini split yesterday.
The deeper I get into this, the more i find out that my ignorance in this field of knowledge is deeper than i had imagined.
wanted to see if anyone could look over my inputs on the energy audit and see what i might be missing.

Thanks again for all the advice

Darren

 

[MisterSandals]

look over my inputs on the energy audit and see what i might be missing.

I do not see a number of hours for "air con" so it is excluded from your usage (Wh) totals.

 

[DAM650]

I'll fix that