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Discussion Starter · #1 ·
So I'm looking around at all the portable power systems out there, and I'm not that impressed. I think I can do better, lighter, cheaper. End of the world or no end of the world, I gotta have my gadgets.

Now I'm not talking about running my big screen or powering up a forklift here, I only need enough to power a couple of tablets and a smartphone, and maybe charge up the old laptop once in awhile. So really, how much power do I need?

If you calculate how much energy it takes per recharge how many times a day, blah blah blah, it turns out I would like to have somewhere between 20 and 60 w/h per day. I would assume 5 hours of good sun per day in the summer, so that's between 4 and 12 panel watts in the summer, and assuming 3 solar hours a day in winter, 7 to 20 panel watts in the winter.

Seems doable, so time for some ridiculous specs and abilities.

This would be more or less a camping rig, but size and weight are important. Also important is a modular approach, so I could easily add or subtract capabilities to match how much weight I felt like carrying. The full system should weigh around 10 pounds and be able to be stripped to 5 pounds and still be worth having.

It should also fit in my new modular gear plan, so the whole kit should be 4 x 12 x 6 inches.

It should allow me to take power from many sources and store it in batteries.

It needs to be self-contained and reliable.

It should give me the ability to power phones, tablets, laptops, communications gear, and anything else that takes batteries, or be recharged.

It should have enough AC power to run the wall charger for most any device.

Looking back at this list, it's not gonna be easy. ;)
 

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Discussion Starter · #2 ·
Looking at the available small arrays out there, I'm tempted to just build my own. That is a pain in the ass though, so I'm gonna confine myself to stuff anyone can buy.

As of now, the leader is the Goal Zero Nomad 13.5M, which delivers 13.5 watts, weighs about 2 pounds, and cost about $100 a pop. I can start with one now and pick up another when I have the spare cash. Two of them would pack down to about 6 1/2 x 4 x 6, leaving about 5 1/2 inches in the case.

These panels can reach 18 volts or so, so it's probably practical to look at a 12 V battery bank. I want to use AA batteries because that's what a lot of stuff takes. If I run NiMh batteries, I will need 10 cells to make one 12 V pack, and the battery of choice is the new Gen3 Sanyo Eneloop. This battery boasts an 1800 cycle life. It has been shown that it is able to be charged to 60% after 5 years of use, which is long after most rechargeable would have died.

I can stuff 10 of these batteries into a 1 1/4 x 3 x 4 space, so they can stack 2 high and 2 wide and take up 2 1/2 x 4 x 6. These will weigh about a pound per pack. I'll start with 2 and add 2 more down the road.

Three inches of case left, what else am I gonna need? Just an inverter, charge controller, and AC/DC converter. With only 3 x 4 x 6 inches and 2 pounds left, this is gonna be hard to pull off...
 

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Discussion Starter · #3 ·
Sweet setup, but I won't spend a grand on the panel. My whole setup will probably be under $400. :)

I think I will be getting close to 100 watt/hours, which is more than enough for me.

I like the idea of splitting the batteries into 2 or 4 banks. I'll be able to recharge my radio on the move and it's alsways nice to have a little power on hand.

Oh, has anyone ever used a Lenmar NVS150U Slim 150W Inverter? It looks good to me, weighs less than half a pound, and it's tiny!
 

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I liked that kit to turn an AC delco alternator into a windmill someone posted. I and Hank are definitely looking into that one as we are partners in free energy crime.
 

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Discussion Starter · #6 ·
Well, if I was gonna pull the trigger on this right now, I would go with...

1 or 2 Goal Zero Nomad 13.5M Solar Panel(s)

2-4 Battery modules; each with; 10 - Sanyo Eneloop 3rd Gen 2000 mAh AA NiMH batteries

Lenmar NVS150U Slim 150W Inverter

Morningstar Sunkeeper SK-6 6A Solar Controller

VCT VM 80W12 5.3A 12V DC Switching Power Supply

This last item lets me plug into mains power so I can dump 12 VDC into the charge controller. It's not fussy about what you plug it into, and will take anything from 100 VAC to 260 VAC and 47 Hz to 63 Hz.

I'll be taking a closer look at these components over the next week or so to make sure they will work well together. Stay tuned...
 

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Impel-2 lithium ion 145 watt/hours power storage @ 2 lbs 10 oz.
Solaris 62 CIG solar panel 62 watts @ 3.4 lbs
So the total portable power system is around 6 lbs.

No other battery comes close to lithium batteries in a SHTF situation. See what your output on ni/mh batteries are in cold weather.
Yes it is a fairly expensive set up but basicly the same as a system the Army uses.


I am always looking for better set up and for right now this seems to be the most efficient portable system I could find, but if anyone knows of anything better I would like to know about it when I do another up grading of my equipment.
 

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Discussion Starter · #8 ·
It all depends how one defines "better" I guess. The system you put together has more capacity than the one I am designing, no doubt about it. The one I am building will have far more capability.

My design goal is to create a small, relatively light system that will meet all of my portable electrical needs. I will be able to store electrical energy from the sun, from any AC source (100-260 VAC, 47-63 Hz) or from any 5-30 VDC source. By having a small inverter, I will be able to charge any handheld by using it's standard wall charger.

My system's modular battery bank will allow me to, for example, have 2 modules being solar charged back at camp while using the third to power my communication gear and the 4th to power the base radio.

The individual batteries from my battery modules are easily removed in order to use the batteries in other devices. The AA sized batteries can also be put into C or D cell "spacers" and used anywhere C or D cells are required.

My system will cost about $400 - $450 and provide about 100 watt/hours of storage and 27 watts of solar. I could build 3 such systems for what you spent on your system and end up with 300 watt/hours of storage and 81 watts of solar. Three of these would be a lot heavier, but also be a lot more flexible and capable.
 

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What I said was better is lithium battery storage is better that ni mh batteries for storage.
Lithium batteries weigh about half what a ni mh battery weighs for the same power output.
Lithium will hold a charge many times longer tha ni ma batteries.
Lithium batteries will work at lower temperatures.

For portability I see no need for an inveter, everything can run directly from the powere source. I think that maybe your ideal and mine of what we call portable is different where I probably put the most emphasis on power/weight ratio. You look like you want a fairly light unit that can power as many things as possible and put more emphasis on cost than weight. Both ideals have there place and which is better depends on the indivisuals needs.
 

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Discussion Starter · #10 ·
Yeah, different "mission," different gear.

I was thinking lithium batteries until I came across the new Sanyo cells. To me, the idea of lasting 1800+ cycles is more important than the weight, at least for this project. Until ZAF releases their new zinc-air battery technology, the Sanyo Eneloops are the best way to go, in my opinion.

As I said before, you have a sweet system.

Cost, weight, capacity, and capabilities are all important. In any system design, you will be forced to make trade-offs and compromises. I'm trying to detail my design process in hopes that it will help others to better create a system that will meet their own needs.
 

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Discussion Starter · #11 · (Edited)
system diagram.png

Basic system diagram.

As it now stands, this system would be able to use it's own solar panels, or any 5-30 VDC source, or any 100 - 260 VAC source. All of these inputs would go through the charge controller.

The system will store in its custom 12 x 4 x 6 case, which will have built-in wiring. There will be 4 battery pack stations, each switchable to either "charge" or "output" modes. The 4 battery packs will each store 2000 mAh at 12 V, and could be taken out of the system and used as portable power if needed. The input section (charge controller) and output section (inverter) will also plug into the bag's wiring harness using high capacity RC connectors.

The output section will feature a 120 VAC socket (150W max) for charging virtually anything that has a charger or standard plug. There will also be 2 USB ports for charging USB devices and a regulated 12 VDC plug.

The DC power supply is mainly a convenience item, allowing me to charge the battery packs from my normal house current. I'm now looking at switchable "universal" supplies that would output a variety of voltages and come with an assortment of tips to adapt to many different devices. In a "power out" situation, I would be able to plug this into the system's inverter and directly charge stuff from battery reserves.
 

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