Figuring Out Solar Power

Macy M1 comment6891 views

Power has never been my forte! Nothing has changed with that. We did work our way through figuring out our solar power set up for the tiny house over the weekend though. I think! We’re least invested $2,744.61 into the guess that we are right!

This is what we got

Our system

We went with a 24 Volt system to save some money over the straight 12V set up. We’ll start with 8 panels (overkill) which will be wired in series and in parallel to work with the selected charge controller. Our hope is that we can generate more than enough power for those short winter days.

We’re starting with 6 AGM batteries (underkill), wired in series and parallel as well for a 300Ah battery bank. Because we’re using AGM batteries we’ll aim for a max of 50% depletion so we don’t damage the batteries. That ives us an actual battery bank of about 150Ah. We added up our worst case scenario (shorter winter days with supplemental heat) and our estimate says we should have about 287 Ah battery bank. We’ll set it up so it can grow but we may be totally overshooting our needs. So we undershot our first try knowing we can add to it.

We will likely add wind power into this system at a later date. We tried to keep that in mind though we will mostly just have to figure that out when it’s time.

Our Resources

The internet is full of great resources on this. Almost too much of it! The easiest to understand for me is

If you’re more comfortable with hard copy info and want a good book we love Off Grid Power by Chris Haynes of

I won’t pretend to know more than I do

In reality, James is the brains behind this bunch but I wanted to post as a check in to how much solar actually costs. If we were to buy this in a kit it cost’s upwards of $7,500-$9,000 (without panels!). Since we are piecing together this system ourselves and using recycled panels, we’re spending a total of $2,750 (with panels!). This system should provide all of our power for the next 5-7 years. After that we will likely need to replace our batteries.

At that point we may upgrade to lithium ion batteries. They cost about 5 times as much but you need half as many (because you can deplete them fully without damage). They also last 2-3 times as long. I imagine technology will have advanced even further by then and they may even become more economical by the time we’re in the market for new batteries.

I would love to hear feedback

Do you see any holes in our set up? We won’t actually install it for about 2 more weeks and would love to hear if you can see any problems we run into. I’ll update how it goes once we have it running. Do you have a different system you like, I would love to hear what it is!

Follow up

Thank you for the feedback! It’s been pointed out that we are missing a charger to hook our generator up in the case of a few cloudy days. We had intended just using our existing Honda Generator which has a 12V connection. Then we realized that won’t work for our 24V system! We are adding a charger so we can just step down the 110 V which we hear is much more efficient anyway.


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