DIY: Mini Solar 'generator'

tx2sturgis · May 24, 2018

I slapped this together, we'll see how well it works out in the sticks.

Parts I used:

20-size EverStart AGM motorcycle battery, roughly 10ah (I already had this)
Morningstar Sunguard Charge Controller, 4.5a max
Aleko 20w Solar Panel
Dual cigarette lighter plug
Inline ATC fuse holder and 15a fuse
Small cheap plastic ammo box (I already had this also)
misc wire, bolts, nuts, connectors and couple of foam pads

If buying all new, total cost would be just under $150.

I mounted the controller inside the box and mounted the power ports on the lid.

Then hooked up everything up with a fuse inline between the power port and the battery.

Then did some testing with my laptop:

The laptop charger (car charger style) pulls about 3 amps when charging.

This 20 watt panel provides about 1.2 amps when in full sun.

Which means that if the laptop takes 2 hours to charge, it will take about 6-8 hours of full sun to replace that energy, or less if charging while in full sunlight.

I expect it will easily charge a smartphone or tablet, several times on a full charge.

I plan to use it at the campsite, away from the rig, maybe sitting at a picnic table or under a tree, with the panel in full sun.

I will let ya'll know how it works out.

John61CT · May 24, 2018

Nice portable powerpack.

tx2sturgis · May 24, 2018

Yes, I knew the term 'generator' would set the 'clickbait'.

I previously built a large version of this, with a larger battery and more bells and whistles, quite awhile back, but it was HEAVY.

I wanted one that can easily be toted with one hand to a picnic table or some shade under a tree.

Plus, I want to use this one for my 12v AT&T Mobley hotspot. I will be able to test it fully in a few days, hopefully.

highdesertranger · May 24, 2018

I built a similar unit much the same way you did. works great for small loads. somewhere on here I have a write up about it. I use mine to run small gold clean up equipment. thanks for sharing. highdesertranger

John61CT · May 24, 2018

For both light portability and high AH capacity LFP is the way to go. Not cheap even DIY, but still much better value than the OTS units.

tx2sturgis · May 24, 2018

Some people are willing to shell out $500 to $1500 for the mass-market solar 'generators', and some of those don't even come with a solar panel. You are expected to plug it in at 'home'...wherever that may be.

Of course, those units have a lot of pretty lights and digital displays, inverters, LED lanterns, some even have air compressors.

We get tons of questions about them. And for some folks, they are just what the doctor ordered.

But I dont need all that.

I just want a simple, reliable, cheap, solar powered, way to charge my phone at the picnic table, or power the wifi hotspot and run my laptop without being 'tied' to my rig.

John61CT · May 24, 2018

Exactly, with OTS units you are rarely getting the various components sized to meet your specific needs.

And usually grossly overpaying.

What really floors me is when there's no option for swapping out the battery once it's worn out.

Some of these chemistries will only last a couple hundred cycles, you're supposed to just buy a whole new unit when the actual battery component might be worth only 5% of what you paid for the whole thing?

They just don't want you to realize that if they identified what's actually inside.

tx2sturgis · May 24, 2018

It's called 'Planned Obsolescence'...

And it works almost every time.

tx2sturgis · Jun 9, 2018

Out here for a radio event, the mini power pack is working well.

It is currently charging itself of course, and a small battery pack, and/or cellphone, and a laptop, and powering the Mobley.

Holding 13.6 volts with a 20 watt solar panel in full sun. Its been running fine for 2 days.

So far, so good.

highdesertranger · Jun 9, 2018

cool thanks for the report. highdesertranger

RVTravel · Jun 9, 2018

Very cool tx2sturgis.

tx2sturgis · Jun 9, 2018

Update:

For the last couple of hours the voltage has been holding at 12.8. There are no indicators or readouts so this is measured at the battery terminals with a digital meter.

I am typing on the laptop powered by this pack, along with the Mobley and the small Anker pack still charging.

Will update as the evening progresses.

tx2sturgis · Jun 9, 2018

Here is a voltage reading:

And here is the approximate amperage being drawn by the laptop, plus Mobley, plus the Anker pack:

This reading was taken inline at the fuse.

This 20 watt panel will provide about 1.1 amps, more or less, so apparently my load and my input are approximately balanced. As soon as I disconnect any of the three devices it should begin to replenish the main battery.

becida · Jun 10, 2018

tx2sturgis said:
Out here for a radio event, the mini power pack is working well.

It is currently charging itself of course, and a small battery pack, and/or cellphone, and a laptop, and powering the Mobley.

Holding 13.6 volts with a 20 watt solar panel in full sun. Its been running fine for 2 days.

So far, so good.

An excellent report on a system that's doing the job!

jimindenver · Jun 10, 2018

Nice!

It shows solar does not have to be huge or expensive to be functional.

tx2sturgis · Jun 10, 2018

Thanks, just a DIY solution to keep a couple of low power devices going. It wont run a fridge, microwave, or power tools, but it seems to work for the smaller stuff.

Mainly I wanted to demonstrate how easy it is to cobble up something that will work, for much less money than the expensive solar 'generators' that have all the bells and whistles....and non-replaceable batteries.

John61CT · Jun 10, 2018

Nice job too, so many drink the Yeti / Kodiak koolaid.

Be interesting to see if 50W is enough when in suboptimal conditions.

I would go straight to 100+ myself.

A $40 AH counter would help show when the income and outgo are more or less balanced, but not worth it financially unless you had a more expensive battery at risk.

tx2sturgis · Jun 10, 2018

As I type this, it's out there on the picnic table at this campsite, running the 12v Mobley, holding 13.8 volts.

So its more of an 'internet generator'!

That panel is just 20 watts....this is a small, cheap, portable system you can literally carry in one hand.

I have much more solar and generator power in the truck and cargo trailer, this little go-pack is for setting up on a table or under a tree to charge a phone or power a normal laptop away from the main rig.

You could scale it up of course, and I also built a larger portable pack (actually several over the years) but they tend to be heavy and cumbersome. This one is easy to tote around and move as the needs arise at the campsite.

highdesertranger · Jun 10, 2018

I recharge mine off of a 50 watt panel, so far so good. mine is very similar to Texas's. great minds think alike. here's mine,

https://vanlivingforum.com/showthread.php?tid=14389

highdesertranger

dklassen · Jun 12, 2018

"so many drink the Yeti / Kodiak koolaid."

Is it that you can't afford one or you just need something to complain about? You seem to get bent when someone uses the term "solar generator" yet when you do a google search that's how 95% of them are referred to, DIY or otherwise. So given I and others have a Kodiak or other and really like them, we're Kool-Aid drinkers? My Kodiak works great for our application and for many others as well. It's my assumption you've never actually owned one so calling people Kool-Aid drinkers is a little uninformed.

DIY: Mini Solar 'generator'

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