diy solar

diy solar

Expandable portable solar generator

dykdidyouknow

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Mar 5, 2021
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This build was inspired by losing power in the recent winter storm in Texas. I currently reside in an apartment, and wanted something portable, safe, and isolated. I choose this toolbox because they are modular, and there is a base box that has wheels even! The battery I chose is an Ampere Time 12V 100Ah LiFePO4 who's built-in BMS supports up to 4 connected batteries bring me to a total of 400Wh. I've got a 210W solar panel on my patio and the box is currently powering my Roomba and a pet's drinking fountain just to test a light load over a few weeks.

What do you all think?

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(the extension cable on the left and the coil for PV in the middle are just being stored there while not in use)

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Power button embedded in the lid for easy access/status

PartPurposeCost
LiFePo4 Battery100Ah of power storage, add more in parallel for greater capacity at same voltage$569
Inverter600w pure sine wave for DC -> AC$116
Solar Panels210w solar panel to charge/maintain battery$189
Solar Cables (MC4)Move power from panels to solar charge controller$17
Solar Charge ControllerMPPT charge controller for panels to charge battery (also has bluetooth to so we can change settings and check status of system)$118
Fuse BlockFuse block so we can safely draw power from the battery without worrying about damaging it$22
Mounting TapeHeavy duty double sided mounting tape to keep things from sliding around and to mount fuse block to battery$7
Extension CordSimple extension cord$19
ToolboxEverything but the solar panels will be arranged in this toolbox to make it somewhat portable if needed.$39
Wire10 AWG wire to carry power$29
Electrical connectorsTerminate ends of wires to create cables$12
Heat shrink tubingWrap the connectors$9
Total: $1,146
 
Howdy, I am new to solar and this forum. I like this build. Question, what are the advantages and disadvantages to an off the shelf unit like the $1000 Bluetti? One advantage I see if the ability to replace parts over time if they become damaged.
 
Howdy, I am new to solar and this forum. I like this build. Question, what are the advantages and disadvantages to an off the shelf unit like the $1000 Bluetti? One advantage I see if the ability to replace parts over time if they become damaged.
So my battery is ~100Ah = ~1280Wh. To compare, the closest thing I can find is the 1500Wh Bluetti. The biggest differences are the quality of components used (mine can charge and discharge at much higher amps which means way faster charging and supporting much larger loads), and I can drop up to 3 more batteries in my system to expand my storage up to 400Ah if I want to with the built in BMS in the battery I chose. It's nice to have a little pre-made box if you don't want to learn about all of it and build your own. But building your own does have some major perks for longevity and expandability/reusability, plus it's incredibly fun to tinker with if you're into that sort of thing!
 
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nice build. My question is What will it do for you in a Texas scenario? I doubt it will run your fridge. Maybe a dorm fridge.

not being negative nelly just curious. Great build
 
nice build. My question is What will it do for you in a Texas scenario? I doubt it will run your fridge. Maybe a dorm fridge.

not being negative nelly just curious. Great build
Calculating how long you can run a fridge is tricky, because it depends on many factors. Temp outside of fridge, thermal mass of stuff inside of fridge, temp you start at and temp you want to run it at (i can lower the temp to make it last longer but still keep my food safe). Personally, I can get a day or maybe 2 out of my fridge on 100Ah if I plan ahead and fill it with water jugs to add thermal mass. Most of the time if you aren't opening the fridge, it will rarely kick on to maintain temp. In the case of the winter storm, and hurricanes, we have plenty of time to prepare. This is also assuming I'm getting 0 trickle from my solar, which will give me some power even on a cloudy day. You'd be surprised!

But more important than my fridge in that situation, was warmth. I got an electric blanket that can keep me and my partner and pets warm for 90 hours of intermittent run time on 100Ah. Plus of course the negligible amount of power lost charging our phones and running a 3W LED lamp.
 
Correction from main post: 400Ah of total battery storage, not 400Wh haha. 400Ah, or ~5kWh, of power should be overkill for anything I might need it to do, so I may only add 1 more... we'll see how it works out.

The setup currently has 1 battery because I wanted to be sure that this would all work well before buying more. I will be purchasing the roller module toolbox that this one will attach to and I'll add more batteries after the system has proven itself over a few weeks.

I suspect this thing's main purpose will be providing power on camping trips, and maybe charging devices during hurricane power outages. Let's hope we don't see any more winter storms that have that effect on the state.
 
Your inverter (600W) is what concerns me about powering your fridge. Not necessarily the battery size. I like the idea of the electric blanket - I thought of that with an old portable all in one unit I have. I need to test that things ability to do the electric blanket.
 
Ah yeah, the giandel 600 /1200 peak is enough for my standing fridge/freezer. It peaks at 900w and runs at 300w
 
But more important than my fridge in that situation, was warmth. I got an electric blanket that can keep me and my partner and pets warm for 90 hours of intermittent run time on 100Ah. Plus of course the negligible amount of power lost charging our phones and running a 3W LED lamp.
Dissipating the scarce 100Ah battery energy as heat is a really bad idea.
A tiny camping gas stove and two warm water bottles will do the job MUCH efficiently, leaving your battery power for more noble purposes.


Do not underestimate the consumption of light loads. A 6W router will empty your 100Ah battery in just a couple of days.
Do not overestimate what a solar panel will deliver in emergency cases. You will very then probably NOT get an ideal sunny day, but heavy clouds and your nice 250W panel will just deliver ~30w and that for only a few hours a day. Frequently not even enough to power the MPPT controller with a positive power balance. Be happy if you can harvest 10 Ah.
 
Dissipating the scarce 100Ah battery energy as heat is a really bad idea.
A tiny camping gas stove and two warm water bottles will do the job MUCH efficiently, leaving your battery power for more noble purposes.


Do not underestimate the consumption of light loads. A 6W router will empty your 100Ah battery in just a couple of days.
Do not overestimate what a solar panel will deliver in emergency cases. You will very then probably NOT get an ideal sunny day, but heavy clouds and your nice 250W panel will just deliver ~30w and that for only a few hours a day. Frequently not even enough to power the MPPT controller with a positive power balance. Be happy if you can harvest 10 Ah.
I do not want gas or flame of any kind in my apartment, which is why I decided to go the much more expensive route of solar instead of just getting a cheap inverter generator. Keep in mind, I'm not doomsday prepping here or trying to live off grid, I just want to be able to have some warmth on a very cold powerless night, or some cold food for a couple of days during the summer. As I said, I'm also planning on adding 1 or 2 more of these batteries to the system to give me some more storage, but all of the assumptions I'm making are without the solar panel. If it does manage to recoup some power then great, but I'm not going to count on it.
 
Nice write up, I like the hyperlinks to everything.

As stated in the title it’s expandable so use it on a regular basis and see if you wish to expand the panel array, or storage or inverter capability or ........

And maybe it’s just what you need!
 
Perhaps getting a couple more solar panels to collect more if cloudy. Do you have room for that?
 
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