The start of my solar pilgrimage

System · July 2005

I am a 74 year old rank amateur who is technically impaired; however, I have been reading up on solar. My goals are simple: to be able to live off the grid in case of a natural or unnatural disaster.

I have started by buying a 12W panel with a Sunsaver 6 controller included on eBay. It is mounted on a portable, adjustable worktable that I picked up cheap. I also purchased a Xantrex XPower Powerpack 300 which, for anyone not familiar with it, has a 21 AH AGM battery, a 300W inverter and DC and AC charging cables. It self regulates. One must use the AC/DC ports to charge it or to use its power.

The wire from the panel to the controller is 18 AWG and is 18' long. Since it came from the factory with that wiring, I suppose (?) it is OK. What do you all think? My new el cheapo multimeter shows 13+ volts going thru the controller to the battery. Advertised to put out one (1) amp, but I am getting only .60 amps max. I can't get a reading on the amps going from the controller to the powerpack, although volts give a reading which is the same as that going from the panel to the controller.

Am thinking of cutting the panel lead down to 4', using a barrel connector and bypassing the controller and going straight to the powerpack.Does this sound feasible?

This whole thing I am doing is a practice run for when I decide to go to a larger system. I would appreciate anyone's thoughts.

By the way, I should have said this first, but this is the best newsgroup I have ever visited. No flaming! Everyone is civil, and the knowledge level of your resident gurus seems very high indeed.

Thanks again.

dilly

niel · July 2005

Re: The start of my solar pilgrimage

very good on your getting started with this. the system you are getting is simple and small. you will not run much for very long with it, but hopefully you won't have to until you are ready to expand it. it will probably run a light or 2 with a very small tv for a short period of time. the wires are probably fine for the little current you are passing through it. if you wish to shorten it it will cut down on your voltage drop some. i wouldn't cut more than half of it as you may need the extra wire length later. this may give you some more current, but many of us don't see the full ratings of our pvs except once in a great while. typically much less will be seen so don't worry.
niel

System2 · June 2006

Re: The start of my solar pilgrimage

I agree that this is a terrific source- thank you all.

I am also looking at solar, probably for the same reasons. I am also tech/elec challenged and am gathering infor SLOWLY!!

I live in an apartment without a great deal of direct sunlight. I want to be able to run a PC, a few lights, a refrigerator and, and, if possible, short bursts from a microwave, possibly for a long term outage.

The Xantrex 1500 suggests that a 40 W BP solar panel will do this, and more. It is pricey ($750 package), but portable (on wheels) and plug 'n play.

1) Is this likely to be accurate?
2) Is there a better (cost, efficiency, smaller, etc.) way to go?
3) Is Xantrex acceptable?
4) Will 80 W be better -(Duh!) The 40w plug 'n play package is appealing.
5) Suggestions?

Thanks for any and all feedback.

crewzer · June 2006

Re: The start of my solar pilgrimage

The Xantrex 1500 Powerpack contains a 60 Ah AGM battery. Assuming that the battery is healthy and fully charged, that the ambient temperature is ~77 F, that discharge current from the battery is 3 A (C/20), a severe 80% discharge (48 Ah) and 90% inverter efficiency, it can supply 32 W at 120 VAC for ~16 hours, or ~518 Whr of energy.

Heavier loads will reduce the battery’s useable capacity. Using my desktop PC (Dell 3000 w/ LCD monitor) as an example, it draws 130 W from a true sine wave inverter. Let’s make that 150 W from the Powerpack’s MSW inverter, and factoring in the inverter’s 90% efficiency estimate, that would be 167 W from the 12 V battery, or ~14 A. A healthy and fully charged 60 Ah AGM battery will sustain a 14 A load for ~3 hours before hitting a 20% SOC (80 % DOD).

This type of discharge is severe and should not be done very often. A 50% max DOD is a good rule of thumb.

So, I think the Powerpack could run a typical modern PC only for about three hours as a backup power source. You can run similar calculations for other small loads, but the battery in the Powerpack could not possibly sustain a typical fridge compressor’s start-up surge.

Assuming a 40 W PV module, a small controller (i.e., a Morningstar SunSaver) and the equivalent of 5 hours per day of insolation, it would take ~4-5 days to recharge the Powerpack’s battery from an 80% discharge.

HTH,
Jim / crewzer

rplarry · June 2006

Re: The start of my solar pilgrimage

Also the msw inverter will eventually burn up the compressor in the frige.

System2 · June 2006

Re: The start of my solar pilgrimage

Thank you all.
Are there suggestions to build my own?

What size battery would I need to run the PC a few hours/day, with lights, fridg and a few extras? How many watts to keep it charged?

Would a laptop for internet connections be a better alternative to the PC and have battery run and charge the laptop battery? If so, can I use the smaller panel and apply the cost difference toward a used laptop?

Thanks, again,
Tony

BB. · June 2006

Re: The start of my solar pilgrimage

First, think about how long and what loads...

PC on Internet--probably won't be any cable modems working more than a few hours after a major power failure... You may or may not have telephone/local ISP access... A laptop is a good choice--much less power than a desktop.

Fridge--without lots of sun and panels, you are not going to be able to power it... Microwave, not without a couple good size batteries...

So, what do you need? In order of need (in my humble opinion): Air (>3 minutes without, you die; Water [missing from original post] >3-7 days without, you die; >14-21 days without food, you die). 1 day without Internet--priceless

Your basic needs should be to survive 3-5 days before help arrives.

Water... 0.5 - 1 gallon of drinkable water per day. Filter, disinfectant, water storage container, another container to gather water. If you have a water heater for your unit (closet/garage), make sure that you can open the drain valve and have something to catch the water and a simple filter.

Enough prescription medicine to last you a couple weeks. (for my Mom, I always order her refiles 2-3 weeks in advance (90 day supply).

Food. Anything that will keep for 3-5 days--canned foods are nice--rotate through them every year or so (get things you like to eat anyways). Freeze dried is nice an light if you have to leave your home--can eat dry, but nice to have water. Little packages from camping store will last five years. Metal cans will last 30+ years.

http://www.mountainhouse.com/ (freeze dried food manufacturer)

The rest of the items would be pretty much the same things that I would plan for a camping trip:

A little stove (I like Coleman fuel stoves--gallon of fuel is cheap--propane is easy, alcohol fires are easy to put out with water). You can get a nice multi-fuel stove too (runs on many types of fuel/gasoline/etc.)...

Sleeping bag, tarp, tent (if you live in a bad weather area or earthquake zone that can make your place unlivable), matches/lighter, aspirin, Tylenol (if bleeding, avoid aspirin), rope, cook gear, plastic bags (big and small), good shoes, axe, knife, toilet paper, towel, clothing (in layers--for your climate), hat, sun screen, bug spray, first aid, and any other "survival" gear that is appropriate for your area.

You would like your most important items to fit in a regular napsack. Medicine, some water, a bit of food (coast guard life-boat rations or candy/energy bars), ... The bigger backpack can have the rest of the bug-out gear... A couple nice LED flash lights, cheap radio with head phones (little radio on headphones with 2x AA batteries will last for week or two if used eight hours a day).

Couple of places/links to look around:

am/fm/sw radio (150 hours 40% volume/70 hours LED light x 2AA bats)
http://www.countycomm.com/gp4light.htm

1 watt LED flash light, 1x AA bat for 4 hours (good walking around light). Too bright for reading/close-in work
http://www.countycomm.com/FENIXAA.htm

small LED flash light 1xAA bat--great for reading, small jobs and getting around the house. 25-100 hours per bat.
http://www.brightguy.com/detail_int.php?Sku=GER2280011

I will stop here for now... I too like the idea of having something that can power a TV, a few lights, and even a fridge/freezer... And eventhough I have 3,500 watts of solar panels on my home, they are part of a Grid-Tied system (connected to Utility power, no batteries or backup capability--useless in a power failure)... So far, everything I have seen point me to small LED's, propane/Coleman fuel stoves, (like I am camping) and an efficient gasoline generator (Honda eu2000i was my choice--but I have a shed to store this stuff in)... If I was in an apartment, I would have to dump the generator (no safe place to store gasoline and run generator--although a Honda eu1000i is small and you could try syphoning gas from your car)... Otherwise, I am not sure what I could do with a few 10's of watts of solar panels other than charging AA/AAA rechargeable batteries). But, if I choose items (AA LED lights/radio) that don't use much power--a brick of batteries (24 or 48) will last me for several months and I don't have to watch for stolen solar panels/generators. A large battery and inverter just does not store enough power to be very useful without a large set of panels to back it up.

-Bill

System2 · June 2006

Re: The start of my solar pilgrimage

Thanks, Bill, for your time and effort!

I have done most that you have suggested.
Disappointed that the 1500 may not be viable. I'll keep looking.

I am concerned that 3-5 days for help to arrive is too optimistic.
Water will be a problem. I have purification, but ... .
There may also be a fuel shortage (propane, gas) for cookers. Tuna and oatmeal!

ASP

System2 · June 2006

Re: The start of my solar pilgrimage

Tony wrote:

I live in an apartment without a great deal of direct sunlight. I want to be able to run a PC, a few lights, a refrigerator and, and, if possible, short bursts from a microwave, possibly for a long term outage.
The Xantrex 1500 suggests that a 40 W BP solar panel will do this, and more. It is pricey ($750

It's very unfortunate that some suppliers are spreading wrong information like this. People believe it, purchase it and when it won't do as advertised, come to the conclusion that Solar won't work / is no good. I've talked, or should I say listened to people who have swallowed the line, bought similar systems, believing that it would run their full sized fridge for the next six weeks and are astonished when it will only do so for six minutes. If indeed it will even start the fridge, which by the way, tends to be one of the biggest energy pigs in the house.
Check out the thread on "Chest Fridges.
Wayne

The start of my solar pilgrimage

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