Posted on 11/08/2012 3:43:18 PM PST by virgil283
"Looking for some low-cost power backup? Given recent storms and the growing number of blackouts, you certainly have company—and perhaps fresh memories of spoiled food, a flooded basement, no heat or air conditioning and (if you have well water) no water for bathing or household chores....We found that inverters can keep at least some of your home’s essentials energized. But you’ll need to prioritize: Even the smaller, 900-watt PW900-12 was able to run a freezer, two refrigerators, two sump pumps, lights, and chargers for various electronics for our staffer at home—but not all at once. ."
Read Instapundit
I've spent 2 years living with, and one year relying on an inverter.
It's not plug and play.
/johnny
I have long been prepared with alternative power sources (four to be exact) and recommend that everyone place at least a small inverter in the emergency supplies. A 400 to 500 watt inverter can be the difference between insanity and a semblance of normalcy in a crisis. Keeping a laptop, a cell phone, or an e reader charged and possibly a modem running is critical.
One word of advice: you get what you pay for with inverters. Don’t expect a Dollar Store device to be reliable when your life may depend on it. Spend $50 and get a decent small inverter.
I tried to get one here on Long Island right after Hurricane Sandy - these was not one to be found anywhere.
You’re right Robert —Get a good one— it will pay to have a way to recharge a phone or batteries. I’ve been thinking of installing an extra battery in my truck. There’s a module that lets the vehicle charge both batteries but isolates the second battery so you can use the inverter on it but it keeps the main battery seperate so you can always start the car...
The OP doesn’t sound like he is advocating and off-grid set-up, just a simple means to power small electronics. That is easily done plug and play through a 12v cigarette outlet.
I’m with you in terms of scaling up the system. I’m running nearly 4k watts off a battery bank that is recharged by generator(C4H10, C3H8, or diesel) solar, and or wind. My cabin is completely off the grid and I’ve never struggled for electricity. A system such as this is not plug and play and not for a novice to undertake - it took me a ton of research and some trial and error to get it right. Charging a laptop in your car, on the other hand, is plug and play.
Strongly consider getting a sine wave inverter to run motors (furnace, refrigerator). Sensitive electronics may need something better yet.
I wouldn't recommend any inverter over about 1500 watts. You will not be able to power it off of your car battery without heavy cables and even then you will have to keep your engine running. If you are looking for 2500 watts or more you are better off buying a generator.
In an automobile, in addition to the isolator for the second battery (which is a great route to go!), you can also add a farad capacitor. A lot of stereo enthusiasts utilize them to stabilize power to amplifiers when the draw spikes. A decent capacitor can be found on Amazon for $100 and will assist with peak and start-up load through the inverter. Good luck, you’re on the right track! Always be prepared.
what is that?
Although a small 400 watt inverter will not power much, it has bailed my ass out more than once.
I have one under my car seat with two 12v outlets.
Runs computers, vacuums, cell phones, battery chargers, etc.
Love it. Saves me a lot if hassle. When a device gets low on power and I’m on the road I just plug it into the outlet and keep on going while it’s charging.
I have two more for the other cars but I almost never drive them so I haven’t felt the need to install. I’ll use the other cars as backup if need be.
The inductive load on startup of a motor like that can fry a small inverter.
Even one of the little 450 watt units like I have here in the house for easy access requires that you know what your load is, how it starts up, and what effect it has on your equipment.
You can't run a radio off of a square wave inverter very well. ;)
Get an inverter, sure, and practice with it. You can kill batteries, kill inverters, and kill appliances. Sometimes, if you are really lucky, you can do all three, and still leave your brother-in-law alive.
/johnny
What, they don't junk X-Ray machines anymore? I think that's where my last 2 large caps came from. ;)
/johnny
I agree, I would never put a sump pump on a small inverter. The best rule of thumb is to double your start-up power (IMO). I have a well pump that I run at my cabin that has one heck of a start up draw - fortunately, I don’t use it as a pressurized system (I use it to fill a tank in the beams of my cabin and allow gravity to pressurize my lines).
Why just go buy $129 900 watt gas generator at Harbor Freight or Home Depot?
We built a gadget that would handle the startup (duplicating the soft-start circuit, but we didn't know that) and decided, to heck with it, go for a bigger hammer.
/johnny
stand up refrigerators are horribly inefficient whether propane or electric.
They beat trying to store ice form a lake all season.
Goal Zero is the acknowledged leader in personal solar power systems. Most (some?) of their systems com with inverters.
Thinking of getting a medium system for when anarchy comes knocking.
I have a small 100w inverter I keep in my laptop bag to run it in a vehicle.
I got a 12v socket “pigtail” that attached to the battery with round terminals. Plugged the inverter in, and plugged the 26W CFL lamp in in the living room during last week’s power outage. According to the numbers on the battery and lamp, this could have powered the lamp for around 75 hours, or about 12 days running it only from 6PM-midnight. I ran it for two evenings and it showed no sign of going dead.
Amazing what “normal” light can do for your morale, rather than huddling around a candle or LED lamp. We were able to read, play board games, etc.
Another thing mentioned on that site, in the comments, is having an alcohol stove on hand. Safe to use indoors...no carbon monoxide, not explosive and can actually be cut with water to make it burn more evenly and last longer. In a pinch, you can even use ethyl rubbing alcohol from the drugstore (isopropyl doesn’t work so well).
Got my Trangia alcohol stove for about $18 from eBay.
I run about 75% denatured alcohol and 25% water in mine, which gives a good simulation of an electric stove set between medium and low. Higher alcohol mixtures burn hotter for boiling water and lower is better for simmering, but harder to light and keep running.
Each ounce of 75/25 mix will run the stove for about 8-10 minutes. Two ounces will run it long enough to heat up food then heat up water for washing the pan.
A gallon of alcohol can be had for around $10 and using a 75/25 mix will run the stove for about 25 hours.
Watts per day is a nonsensical measure.
Your car burns about 2 gallons of gasoline per hour, yet the alternator puts out only about 1000 watts. That's not enough to run much. This means that your battery would likely run dead, too. Then you're left with no electricity, no car, and no gasoline.
Why not buy a cheap 1000 watt generator. They cost about the same as an equivalent power inverter, and only burn a quart, or so per hour.
Watts per day (considering voltage & amperage) is an important calculation, for me. I use watt hours and determine the daily average. When determining how long my battery bank could power which items and for how long in the absence of my charging methods, it was crucial. Assuming that anyone building such a system is familiar enough with electricity knowing that a watt is a joule/second and has the ability to determine kw*hr.
ping of possible interest...Using inverters for emergency power
My 4L V6 Dakota burns ~.35gal/hr @ idle
I have a 1500W inverter and an Optima yellow top battery in my Jeep. Before we got a generator we lived in one room for 3 days using it to power some essentials. One other advantage is having portable AC. I do a lot of pruning with Sawzall.
You got to keep the engine going with those huge inverters, which will otherwise suck the battery down within minutes. So basically you’ve made your car double as a generator. Why not just get a generator. It’s more fuel efficient.
That’s at idle, but idle won’t keep 900 watts going.
Back around 1998/1999 at the old ham club, we pooled an bought a gadget that you could plug in (like a shunt, with fancy electronics) that would give you detailed information about whatever you were powering, including start-up cycles, all the majikal trig stuff, and average power consumption over time, etc...
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
I bought the device detailed in the link below. I was astounded at the specs: real power, apparent power, power factor, and other stuff. The accuracy is stated as around 1%. The device is $30 at home depot. This would be a good investment for anyone trying to size an inverter, generator, or other power source. One can understand the loads of their furnace, refrigerator, or other device.
bkmk
It looks like there is a large cap in my old microwave. I'm still afraid to stick something in there to give it a final discharge before disassembly.
I have an older version of that. Had to replace a fuse inside after attempting to check out my microwave.
/johnny
It remains an attractive nuisance, but now I know I should just leave it intact (except for cutting off the external cord) and keep a laptop and some other electronics in there in case Iran comes after us.
Please treat the transformer/capacitor from a microwave oven with extreme respect. The energy from that system is most unforgiving and would be instantly fatal in many scenarios.
Please treat the transformer/capacitor from a microwave oven with extreme respect. The energy from that system is most unforgiving and would be instantly fatal in many scenarios.
Sure, the panels put out 96VDC @ 2A. I read that as 8 amps. One hour of that is 192 AH (less line loss and conversion loss) into the batts, since everything relies on the batteries.
Watts are derivative. If I have to do something like that I prefer to use KVA.
That has worked for me on large and small systems. I've got some small stand-alone systems fielded now that have done great for 2 years with minimal mainenance except PM.
/johnny
Even during the ~8 years since it's been out of service, I haven't bothered to take a second look inside the power section.
I built my HW-101 later that year. And got rid of the ARC-5 transmitter and old Hallicrafter receiver I had been using.
I built the power supply for the HW-101 because I couldn't afford to buy the one heathkit provided.
That transformer was given to me by an Elmer. I had to figure out primaries (yes, plural) and secondaries.
Got heater, B- and all those special voltages out of it, rectified, and smooth as a kitten. Life lesson in inductance and capacitance.
I've been playing with 'lektrikity for a long, long time.
What I talk my brother-in-laws into doing is my business. ;)
/johnny
I love dangerous high voltages as much as the next guy.
I used to keep an old microwave out in the garage just to put strange stuff into, to see what would happen. My favorite was loosely wadded bronze wool. (steel wool burns). This in addition to many high voltage, high power electronic and mechanical projects.
That said, I have never found a reason to mess with the guts of a microwave oven.
So, will 0bama give me a couple of really large caps for free?
Don’t hold your breath.
I was 5 when dad taught me about capacitors. He had an axial lead electrolitic charged up on his bench near his DeVry books.
He picked it up by one lead.
Looked at it.
Set it down.
Picked it up by the other lead, looked it over and set it down.
Then he went back to the DeVry books.
So I reached over and picked it up.. with both hands.
It was a learning experience.
He did, during that teachable moment impress on me how capacitors worked, and how to be safe around them. I already knew about the brown shorts part.
/johnny
If I want to keep the freezer frozen... after the 1st day, I hook up the genset, and run it until the compressor in the freezer shuts down. Then I shut down the gentset. Doesn't take long. Just listening to the load on the genset will tell you when that happens.
I don't need idle standby in a situation where gas is in short supply.
/johnny
I am just venturing into ham radio.
Took the practice exams and passed with little study.
I don’t have the desire to broadcast, and even less to give my contact info to a three-letter federal agency.
I tune and tune, but mostly just hear guys talking about their gear and antenna.
I rarely get reception from overseas, have not mastered dx yet.
I have built some large audio tube amplifiers, and did consider using a microwave oven xfmr. Never did it, just used off the shelf stuff. A 480/120 industrial control transformer is impressive and cheap when wired step-up.
Good talking.
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