Power and Portability

System · June 2011

Folks I am a noobie, just getting started learning to build a solar/wind off grid system that would give me a good deal of power and some portability (be able to load it up in the bed of my truck) Given that I have no idea even where to start, other than I know I need panels, charge controller, deep cycle batts and an inverter.

I suppose it would be a good idea to hit as many of my known requirements before I ask you for recommendations...

Potential devices to power:

Laptop w/90watt adapter

LED Rope lights

a coleman electric cooler

3 USB devices

I know I am leaving some stuff off but this hits the high points, Okay...

Can you please help me with some design ideas, recommendations, risks etc.

My background... well my friends nicknamed me "Sparky" once because my (then) wife, now ex, plugged in my 100' extension cord in over around the side of the house, while I was in the backyard, cutting the dog chewed end off to replace it, thereby proving that electricity burns blue at least when its in the form of a fireball between your hands (ya like every picture of Merlin the magician you have ever seen...) cooked my hands pretty black, pretty fast... ya not much of an electrician...

I would really appreciate your thoughts

Thanks
Ryan

Cariboocoot · June 2011

Re: Power and Portability

Welcome to the forum, "Sparky".

I suppose your looking for a little camping power with this set-up? It helps if we know the actual purpose of the application. You'd be surprised how many different ways there are to achieve the same ends.

Forget the wind. It's not very reliable and even less portable.

As you've already surmised, all off-grid systems are based on loads. A lot easier to determine how much power you need and figure out how to get it than to throw a bunch of stuff together and agonize over how it doesn't meet the needs.

The missing bit of data: time.
We could probably surmise how much total Watts there are in your equipment list, but only you know how long you'll want to use it for. There's the two numbers needed to start with: total Watts and total Watt hours. Type of load is important, and will this be all DC or is there going to be an inverter involved? It's amazing what you can accomplish with a 12 VDC system for a camping application. Otherwise for 120 VAC loads you can get a Kill-A-Watt meter and actually measure the power usage before you design the system, providing you already have the devices you plan to run.

So a few details about the application and I think some suggestions as to design will be forthcoming.

mike95490 · June 2011

Re: Power and Portability

Generally, ICE will be a better way to keep the cooler cold. electric is not effficient for camping situations. The other stuff will be easy.

RCinFLA · June 2011

Re: Power and Portability

The 12 vdc Peltier coolers are not very efficient. For close to 100 watts of consumption you don't get much cooling.

A small refrig on an inverter will draw about 110 watts and give you much better cooling capacity. It will likely have a lower run time duty cycle so overall consumption is less then the Peltier cooler.

Either one is going to take some large PV panels to supply power for.

System2 · June 2011

Re: Power and Portability

Awesome guys thanks for the fast response, okay ice is better, i understand the logic there, my concern too was "time", if we ended up doing a week or more out in BFE, I assumed that even though it would be a big time consumption issue that it could make up for the waste by being much easier than ice if for no other reason than it would be a pain to either refresh ice often enough to keep cold stuff cold. Also was thinking in terms of "Bug In/Out" if we had a disaster and had to go without the grid for a couple of weeks, what would we need to support that if we basically limited the use to a "Camping" type of solution? I had hopes that we could utilize the gear for all situations, and assumed that if I went with extra storage capacity that it could counter the consumption by a mini-fridge (ditching the "cooler" idea) along with LED lighting and what not. In addition to the ice refresh issue there is some consideration to take in concerning availability of ice in a disaster situation

I suppose that our typical use would be 4 day weekends, every now and then we go and the girls stick around the camp and me and a couple of the brothers in-law go off trail for a couple of days on a loop and extend the stay to a week or so.

There were some assumptions on my part that it would be relatively onerous to haul the gear (Heavy and bulky) given the requirements, which I hope to offset with the convenience of having access to suitable power out in the boonies.

So... yes ill develop the requirements a lot tighter ASAP and post what I think is a solid set, thanks again for taking the time to help a noob try to figure it all out!

all the best,
-Ryan

techntrek · June 2011

Re: Power and Portability

The best way to achieve cold food storage long-term is via a propane-powered fridge. All campers have them, and you can buy full-sized stand-alone units but they aren't cheap. Camper fridges sip LPG, you can go 3-4 weeks on one 20 pound tank.

Power and Portability

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