Just got back from Costco. I noticed that they seem to be carrying more survival type stuff (at least at the Arundle Mills (Maryland) location). They have the new Dorcy Spyder lights; a 15+2 pack of glow sticks for like 12 bucks; roadside emergency kit; and what looked to be a fairly well stocked first aid kit. I'm going to go back with some more money next time and look at them more carefully, and maybe even buy some stuff, or at least get some specs to get your opinion on.

-Chris

Our local Costco (Fredericksburg VA) has had Xantrex 1000W inverters for sale for about $65. Xantrex bought Trace, which was the top of the line company in inverters.

Grab a 120 amp-hour deep cycle marine battery from Wally-World and some #2 or #4 battery cables, and you're all set for some alternate energy.

I fired mine up tonight when bad thunderstorms rolled through. I hooked up the kids' PS2 and 13-inch color TV, and my laptop so I could continue surfing uninterrupted and without fear of frying my computer.

Hi
One small point. I have heard you computer is just as likley to get fried in a thunderstorm through your phone line. At least that is what I've been told from a salesman at a local electrical store.
Your best bet is probably not to go on line at all.
Joblot

Hi
Further to my last post, my surge protector even has a special plug for my phone line...point proved?
joblot

>>>>Your best bet is probably not to go on line at all.

What? Heresy! <img src="images/graemlins/shocked.gif" alt="" />

>>>>Further to my last post, my surge protector even has a special plug for my phone line...point proved?

Uhhh…not really. I’ve never seen a surge protector that *didn’t* have a phone line port. Unfortunately, in the US, almost every one of those cheaper protectors is just a souped-up extension cord. Your mileage may vary in Scotland.

Lightning can do nasty things to anything that’s plugged into the wall, or even individual parts of an appliance that is plugged in.

I do have a great surge protector – it’s a Newpoint (http://www.newpoint.com) that actually grounds all three wires and not just one. IIRC, in the US, most of the cheaper ones only ground one wire, but there are three going into your computer. The protector needs to have grounding to ALL THREE wires. These units are more expensive but well worth the money to ensure that your computer and house don’t burn down.

And BTW, I have a cable modem, so there are no phone lines involved. Point proved? <img src="images/graemlins/wink.gif" alt="" />

hi there
I concede to the higher authority, when it comes to surge protectors.
However, rather than test the equipment, I will still be unpluging during a storm, if only for peace of mind. I too have a broadband connection.
joblot

Thanks for the heads up on the Dorcy Spyder lights at Costco, I have been waiting several months for the Frederick store to have them in stock. I guess I will check tonight to see if they have received their supply. Pete

Mamabear2,

How long are you able to run the PS2, tv, and computer off the battery? I was thinking of setting up a system like that coupled with a battery tender to make sure it's always ready. I figured it'd be a good addition to the generator. A battery system could power stuff upstairs a lot easier than the generator can.

I'm thinking I'd want to run a 25 watt tv, a 20 watt fluorecent light, and a fan (don't remember watts). It'd be great if I could get three or so hours out of battery with this load.

-Blast

>>>>>>> I'm thinking I'd want to run a 25 watt tv, a 20 watt fluorecent light, and a fan (don't remember watts). It'd be great if I could get three or so hours out of battery with this load.
***************************************************************************
Good questions…first, some disclaimers. Hopefully all my math is correct and coherently organized. If not, feel free to point it out. I’m no electrical expert or math whiz by any stretch of the imagination. To me it's still PFM how the light comes on when you throw a switch. <img src="images/graemlins/grin.gif" alt="" />

The short answer is approximately 4 hours and 15 minutes.

Here's how to figure it out for any configuration:

Assume you’re using a 12-volt, 115-amp-hour, deep-cycle marine trolling battery (about $65 from Wally World) to supply DC power to the inverter, which converts it to AC power for your TV, fan, PS2, and light.

A device that uses 1 amp per hour will in theory deplete your battery in 115 hours. An inverter/battery powering a 5-amp device would last in theory 23 hours (115 ÷ 5 = 23); 25 amps would be 4.6 hours. Notice all the in theory disclaimers? Using an inverter causes a power loss of some amount. Most experts quote a 10-20% reduction in the run time. Just be aware that you aren’t going to get that 115 hours of battery use if you’re running an inverter.

If you have all DC appliances and can run them directly off your marine battery, then that power loss won’t be quite so bad. But if you’re like me, you don’t happen to have a 12V DC fan lying around (I should, they’re pretty cheap - under $10)

So, you wanna hook up your PS2, a 25W (watt) TV, a 20W light, and a fan. As long as you have a good-sized inverter, you could throw caution to the wind, plug everything in, and see if it all works or if your inverter just vaporized itself….not recommended unless you have a 2000 watt inverter (or higher)!

So get a piece of paper & a pen, and check out the specs label on each electrical device you want to run. Write it down 'cause you'll forget it. Some will have the watts listed…others will have only the amps. It doesn’t matter ‘cause we have the (easy) math to figure it out.

Convert everything into one unit, preferably watts.

My little floor fan only lists .9 Amps, but I want to know the wattage it uses.

The basic formula is Volts x Amps = Watts.

So 120V x .9A = 108W for the fan using AC power (we’ll figure in the DC part in a sec).

108W (fan) + 79W (PS2) + 25W (TV) + 20W (light) = 232W total.

At the very least you’ll need a 500W inverter (about $45 or so). Double the needed watts for the start surge, and you’ll know how big an inverter to use – at a minimum.

(BTW, it’s more efficient to run a 500W inverter for a 232W draw than a 1000W inverter, but I wouldn’t sweat bullets over it.)

Now, to figure out how long your 115 amp-hour marine battery will power your goodies before needing a recharge:

remember V x A = W?? We’ve got volts (12 -- remember, it’s a 12 Volt DC battery), we’ve got watts (232), so just jiggle the formula around to solve for amps: W ÷ V = A.

232 watts ÷ 12 volts = 19.3333 amps. Be conservative and round up to 20.

The battery is in theory a 115 amp-hour battery, so:

115 amp-hours ÷ 20 amps = 5.75 hours of battery life.

BUT, don’t forget the inefficiency penalty for using an inverter. I’d knock off about 1.5 hours, just to be safe. So you can figure about 4 hours and 15 minutes (4.25 hours) of battery time.

After I got hooked on battery power, I walked around the house & garage and made a list of all the devices I might possibly want to use. The first thing to go was my hair dryer --1500 watts, a real hog!! <img src="images/graemlins/crazy.gif" alt="" /> <sigh> What price beauty……

If you need more battery time and your inverter can handle it, get another marine battery and hook them up in parallel. Then instead of only having 115 amp-hours, you’d have 230 amp-hours (in theory, again, don’t forget the slight energy loss) to use up.

Just to beat a dead horse even more, I’m a big fan of inverters & batteries. Do you already have a generator? I decided against getting one because it’s a gas hog (4-5 gallons/day IIRC) and extremely noisy. The noise aspect bothers me the most. First-hand accounts (I think on ETS as well as other sites) of long-term power outages quoted many survivors as saying they had to sit up day & night with a shotgun to ward off burglars. People drove around neighborhoods in Homestead, FL, after Hurricane Andrew looking for gennys to steal. Pretty ugly. However, if someone gave me a Honda genny, I sure wouldn’t turn it down <img src="images/graemlins/grin.gif" alt="" />

Battery power is quiet, clean, cheap, and reliable. My next goal is to get some solar panels for trickle-charging the batteries.

Sorry this is so long – hope it starts to answer your questions.

(PS) On reading this before posting, I see that you weren't asking about using a PS2 or Nintendo in the equation, but I'm too lazy to rework all the math. <img src="images/graemlins/smile.gif" alt="" />

Mamabear2,

I think I'm in love. <img src="images/graemlins/grin.gif" alt="" />
That was exactly the sort of answer I needed because it taught me how to calculate this rather than just telling me the answer. I really appreciate that.

I've already gone through the house calculating wattages for stuff, so I know hom many watts I'll be drawing, but I couldn't figure out how the amp-hours rating on the battery played into this.

As for the generator, I've worked out a deal with several neighbors where we'll shift it from house to house to power the fridge/freezers/etc. One is a cop, one is an avid hunter, and the third is ex-military. And me, well, I'm the chemist everyone calls "Blast" . My 4th of July parties are legendary. Between the four of us the generator is well guarded. We live in an area prone to hurricanes with power outages ranging from hours to days. I actually plan on using the generator mainly to recharge the deep cycle battery(s) so that I'll have useful power inside the house at night. I'll have a small tv and a fan all night long, but it looks like the margarita machine will sit idle. <img src="images/graemlins/frown.gif" alt="" />

-Blast

p.s. Freaky timing! A co-worker just showed me a gas-powered blender in today's Wall Street Journal! God bless America!

Blast (love the moniker!),

A chemist, huh?? My quantitative analysis professors tried for 2 quarters to teach me how to figure molar quantities (or is it volumes?). I promised never to try & titrate anything if they'd just give me a 'C' and let me get the he## out of the Chem Building!

My baby sister, though, got a Ph.D. in organic chemistry from UC Berkeley. Go figure. She got all my chemistry genes. <img src="images/graemlins/mad.gif" alt="" />

It sounds as though you're in good company with your neighbors. All of you can contribute & no one will be leeching off the others with the genny use.

In your first post about your 25W TV-- I thought that was kind of high until I doublechecked my little 'Tornado Room' 5" B&W TV. It pulls 18W! I was surprised at that -- thought it would have been way less. It will also run off TEN 'C' cell batts, so I guess I shouldn't have been surprised.

Look into the LCD TV's for a low power unit with decent picture quality - problem is they cost $$$$$$

Hey, Mamabear, good explanation! I didn't check your math, but your method is good.

Technically, W= VxA is only accurate for DC and it takes a bit more math to figure wattage for AC supplies, but for the purpose of figuring this sort of thing out, how you demostrated it is practical and good enough.

My inverter knowledge is sadly out of date (other than owning some), but for other reasons I've been asking some questions lately. The modern inverters are pretty much all true sine wave now (or close enough to not matter) and efficiences are supposedly 90% or better. (hmmm - I am confident of the sine wave, but need to see real figures to believe the efficiency claim - maybe. Dunno.)

All the inverters we have are well-protected against overcurrent. All will deliver 2x rating (or 3x in one case) for a brief period to account for starting loads. If any of them are overloaded, they simply shut down, no fuss. The surge capability can be misleading if one doesn't do the math like you did. Example: I can fire up a Bosch reciprocating saw with one of the 600 watt inverters and it runs great, just like on line power - the surge capacity is more than ample to fire it up. And the NO LOAD current draw once running is well within the rating, taking only about 3 amps (maybe 360 watts, more or less). Try to cut something with it, and poof! no juice after a couple of seconds. That's because the working power requirement is much higher than that inverter can deliver for very long - it takes about 900w to actually USE that saw.

Battery capacity is a whole 'nother topic, but your advice was pretty good. Like you said, do the math!

Regards,

Tom

Tom the last thing i read on inverter efficiencies was about as clear as fog. The efficiencies are measured against a load that is the most efficient for the inverter in question. As in if you have a 500w inverter that works the best with a 400w resistive load, that is the efficiency stated. Going to a motor load that is 400w such as your saw would have a different efficiency rating.

Blast, being a chemist this is something you probably already know all of this, but here is a couple of links to battery theory and operation. Basically what kind of battery to chose and how to take care of it so you can get the most out of your inverter.

http://www.uuhome.de/william.darden/dcfaq.htm

http://www.wind-sun.com/Batteries/Battery_FAQ.htm

RayW,

Thanks for the links, they did teach me stuff I didn't know. The part about deep cycle batteries not reaching their full potential until being cycled ~10 times was new to me. I assumed like most things each time they're run they come back weaker.

I may be a chemist, but like most scientists 80% of what I know is very specialized. If you need to know the absorption characteritics of quaternary amines onto high-chrome steels I'm the guy you want. But if you are trapped on a tropical island with a sailor, a rich older couple, and two babes then maybe I'm not...huh...actually, count me in on that!
<img src="images/graemlins/grin.gif" alt="" />

-Blast

Unplugging from the wall anything you *don't* want fried during a lightning storm is a good idea.

Cheap surge protectors are basically a MOV (metal oxide varistor) between the "hot" leg of your power and ground that will hopefully shunt voltage spikes to ground. And there's a lot of "hope" in that "hopefully".

More expensive surge protectors will have three MOVs (one between each pair of inbound wires - hot-ground, hot-neutral, & neutral-ground) of beefier specifications, some RF choke coils to block radio frequency signals induced onto outside transmission lines acting as an antennae loading your inbound 60 Hertz AC with a bunch of hi-freq signals, plus a few other line-conditioning components.

Voltage spikes sufficient to fry electronics (especially digital, like computers) are an incredibly tiny fraction of the power contained in a lightning bolt hitting a power transmission line, coming into your house, and through your equipment on its way to electrical ground. Below is a sales blurb for a surge protector from Tripp Lite you can get for under $25. I'm not familiar with the 3570 joules-to-kilovolt conversion (or the number of kilovolts contained in a lightning blast) to figure if they are actually providing sufficient security for electrical equipment attached to the surge protector. If not, it'd be a quick quarter-mil to collect on their guarantee. <img src="images/graemlins/wink.gif" alt="" /> The TLP810SAT Surge Protector from Tripp Lite is a cost-effective way to protect a satellite TV entertainment center against surge damage. The TLP810SAT has 8 outlets and a 10-ft. cord with a space-saving right-angle plug. The unit provides 3,570 joules of surge energy absorption, enough to handle the strongest surges. ... Built-in RJ11 jacks prevent surges from damaging equipment connected to a phone line. Diagnostic LEDs and an audible alarm alert the user to potential power problems. This surge protector comes with $250,000 Ultimate Lifetime Insurance plus data recovery. No warranty cards required for coverage!

All that said, IMHO using a quality surge protector (which can be had cheap!) and even a UPS on your digital equipment is a good investment.

Unplugging is the best way to go. Buying better surge suppressors and ups's afford you a warranty for your equipment, but even these will not stop a lightning strike. My neighbor had a near strike from lightning and two ups's and the three computers that were plugged into them smoked. The ups company paid off and he bought new equipment, which he now unplugs when a storm is coming.

Back when i used to sell surge suppressors customers would ask, will this protect my equipment from lightning? What i used to tell them, a bolt of lightning will jump several miles to hit your house, do you think that there is anything in this little box that will stop it? That would usually get the point across that unplugging is the best way to go.

I picked up a 400 watt continuous/ 800 watt peak inverter for 25 bucks! at Culver City Costco, in Los Angeles. A lot cheaper and smaller than a generator for temporary power outages.

One problem with MOVs is that they will eventually fail. That is what they are designed to do - "absorb" the spike and dissipate it as heat, to the point of failure. And you will not know when they are going to fail.

MOVs backed up with a true “lightning arrestor” are the best option. If you can still find surge suppressors with gas-tube lightening arrestors and MOVs, you have a good combo. The gas tube will fire (like a florescent tube) sending the surge to the ground wire before the MOV can fail. The MOV will suppress the small spikes.

BlueFlame,

Check out www.omegaps.com and their ERICO / CRITEC line of surge suppression equipment, as well as their lightning equipment. Their TVSS units utilize the gas tube technology. Cruise through the *.PDF files for more detailed info.

Comanche7

disclaimer
I'm not an owner, business partner or even have a vested interest in this company. I've known the owner, and have purchased their equipment for almost ten years now, and never had cause to regret buying from them.

I'll check them out. Thanks for the link.

I did a search for a company I was familiar with in the 80's called TII. Turns out they are still in business, although most of their products are for telecom now. But here is a link to their current AC line/phone surge protector. Still has MOVs and gas tubes.