Tuesday, September 26, 2017

Generators vs batteries (part I)

Part I: The generator
(disclaimer: here are just some useful general tips regarding the use of generators, always make sure to read the manual which comes with your device thoroughly. Only the manufacturer of your device can give exact instructions!)

In previous blog posts the scenarios for a power outage have been described and based on recent deaths which occurred in the aftermath of hurricane Irma in Florida it's perhaps time to look at advantages, disadvantages and also (life threatening) dangers of generator use.

Concerning the danger of carbon monoxide (henceforth called 'CO') poisoning it's perhaps best to warn people about it by using the suicide (or murder if you will) methods used in various Hollywood (and other) movies. A car in the garage, the motor running and a hose from the tale pipe leading into the car, often while the windows are taped to seal the car's interior. That dramatic scenario is perhaps as misleading as those modern age fake explosions used by skilled special effects specialist in order to make those action packed movie scenes even more dramatic. They use gasoline in addition to 'fireworks' in order to produce those great fireballs, when a car explodes or a grenade hits the ground next to a bunch of grunts.

Those cars in the movie scenes don't need 'sealing' since the carbon monoxide produced by every combustion motor (especially running on diesel !) is so poisonous because it attaches to the red blood cells in your blood stream much more easily than the oxygen you breathe. So even if the concentration of CO in the air you breathe is quite low it easily attaches to every blood cell which runs through your lungs and blocks it ! So it's sufficient to breath a low concentration of that gas over a longer period until most of your red blood cells are "blocked" and therefore incapable of transporting that life sustaining Oxygen.
This CO gas is odorless, so can't smell it just as you can't smell Oxygen, so you wouldn't even know about the concentration in the air. At this point we come to the second perhaps misleading 'Hollywood knowledge' concerning exhaust fumes. In the movie or with ancient old combustion engines you have perhaps a highly visible 'smoke' coming out of the exhaust. Modern engines however could be running so efficient, could be constructed in order to fulfill other environmental norms that the 'smoke' is much more or even completely invisible.

So when you have read the introduction you would perhaps understand why on every generator there is a caution sticker indicating that likely chance of suffocating/dying when you use that generator indoors, or even outside but in proximity of windows, doors, ventilation intakes.

So by now it's clear that you should never, ever use a generator inside your home or workplace, but that said the next problem emerges:
How to connect your electrical cables safely to the generator even during wet weather ? Another question has also to be asked then: Is my generator designed to get operated during rain showers at all ? Is it safe electrically as well as it won't corrode (rust) during being exposed to the elements ?
It would be best to have a 'checklist' at hand when going to purchase a new or a used generator and if the packaging of that machine doesn't give answers to ask the salesman or read the operating manual before you buy it.

Even when everything is OK and you have the best generator money can buy there are a few rules to know when intending to use it. Preferably test it once before you have to use your generator when you experience a power failure. By using it prior to a real emergency you will know already what to do and you don't have to do it the first time when it's perhaps completely dark. It's also good to know in principle how a generator works in order to prevent some problems with the el. consumers (like lamps, radios, TVs, home appliances, etc) you intend to use. Did you know for instance that it takes a few moments once you started the motor until the generated electricity has stabilized ? Let the engine run for a few moments until it reaches its nominal RPMs and if your generator has a voltage indicator: until the nominal AC voltage level has been reached.

1st let your generator run until power voltage and frequency have reached  nominal levels (e.g. 110 V , 60Hz(USA) or 230V and 50Hz (Europe)) and then plug in the AC cables !

You also have to think about how long a tank full of gas or diesel would last until the lights go out again. Make sure that you have enough fuel at hand for a refill. Use only canisters which are approved for fuel storage. When refilling think about the operating manual again and what it says about refilling while the engine is still hot. Often manufacturers recommend to let the engine cool down before you start refilling in order to prevent spontaneous combustion outside the engine. If you don't have enough storage capacity at the place where the generator is producing electricity you also have to think about transport to the nearest gas station, canisters and also money for purchasing new fuel. During 'normal times' usually no problem at all, but what happens if there's a wide spread power outage which also affects the gas station in your neighborhood ? 
No gas, because the pumps at the gas station won't work without power !
When you don't have cash in your wallet ? Also bad luck, because the ATM also needs power as well as the card reader at the gas station which could accept your credit card provided there's electricity and a working online connection to your card provider. 


"Right now, we only have diesel for today and tomorrow. We're already working on refueling our tanks so we can extend our power generating capability, which is at 50% right now," Cruz Vivaldi said.
Lack of power and water has severely weakened the ability to treat patients at dozens of hospitals around the island.
       source: Hospitalized children at risk in Puerto Rico due to lack of fuel [CNN, Sep 26 2017]

If your generator isn't brand new, you also have to think about its 'mileage'(cars) or operating hours. The user manual should give you some recommendations about maintenance intervals and oil check/refill.
It's like a car: when you neglect it, it might break down rather sooner than later. (and darkness and a bleak life without electricity is back)
Also think about generator downtime during maintenance, and have it checked before disaster strikes and the generator is needed most. One more thing to think about when purchasing the 'right' generator is the difference between 'consumer models' which might last only for a few hours, but are not intended for 24/7h operation. Industrial quality generators(often running on Diesel) are much more expensive than consumer models with perhaps the same nominal capacity (measured in KW)

Industrial/military quality generators could also offer better 'power quality' which means perfect frequency(50 or 60Hz) stability and the 'shape' of AC power(sinus curve) which might matter with hyper sensitive electrical gear like computers or medical equipment. They also might be the preferred choice whenever you intend to use heavy machinery (power by strong electric motors), because when you start those powerful tools they "pull" a lot more amps from your generator than its nominal capacity.

If your generator has an automatic start feature by pressing a button or turning a key, it has a little starter motor like a car which needs sufficient battery voltage (often 12V or 24V) and capacity (measured in Ah) in order to work. If you have an old, empty battery your generator won't start and you can forget about backup AC power ! So this starter battery is also better checked/maintained in times when you don't have to use your generator. You should have a voltage meter if your generator doesn't have a build-in one. If your starter battery has too low voltage of course you should either have a charger or let it charge at your garage.

The fuel
Diesel
Most diesel engines are considerably heavier than their gasoline fired counterparts. The combustion process is much more "violent" and requires a sturdier construction of the engine. Diesel engines don't need a sparking plug, since they first compress air and the heat this pressurized air produces is sufficient to ignite the fuel which is injected into combustion chamber. So in general they are more reliable than gasoline engines which often have problems related to their high voltage system used for generating the 'lightning' in the combustion chamber. Often those cables detach themselves somewhere on the way from the high voltage coil to the sparking plug. There can also be multiple issues with moisture which makes the high voltage needed "disappear" to a degree where the sparking plug can't enough voltage to ignite the fuel.

Besides reliability issues, diesel engines in general also consume less fuel for same amount of horsepower (better use:KW). Most diesel engines can in principle burn other fuels like kerosene or certain plant oils like those produced from sun flowers. Caution: can run in principle means, that the construction of the engine would allow it, but often attached devices like fuel injection systems can't handle those plant oils, because they flow less good through tiny valves than regular diesel made from refined crude oil. Such fuels may also produce some side effects like residue after combustion, which influences the operation of the engine. (very often not beneficial). Alternative fuels could require some modifications to the engine which in most cases void the guarantee which came with the purchase! Alternative fuels are just mentioned here since many of the disasters mentioned here are taking place in areas where the diesel supply might get interrupted or where e.g. palm oil is easily available. There are many other sites on the Internet where expertise regarding alternative can be found, so people interested in this subject should do additional research first. The only thing EZR can assure reader is that a Volkswagen Diesel car I once owned did run on almost pure plant oils for about 120.000 kilometers (with some minor modifications/additions)

Diesel has also an advantage concerning a safety margin when handling the fuel. It doesn't ignite as easy as gasoline, thus refilling it is not as dangerous. Almost inert plant oils are even more safe, they ignite only when they get extremely hot (in the combustion chamber).

Diesel engines however are not that easy to start. They require more battery amps to get that starter motor going. They usually run at lower RPMs than their gasoline counterparts, but therefore in general they produce more noise/vibration than the other type of motor. So shielding them might be required, especially when intending to use telephones nearby or near a hospital or nursing home.

Diesel fuel 'stinks', sticks to your fingers ('oily') and should under no circumstance be spilled, since just a few drops could contaminate large amounts of soil and/or (drinking) water. Refueling should be done carefully in order not to affect the environment.

Examples of generator use during disasters
BACK UP POWER REQUIREMENTS FOR SERVICE STATIONS [cga.ct.gov, re Florida, Louisiana & California]
A superstorm Sandy legacy: Gas pumps that work when power is out [CSM, Oct 28 2013]

related articles/tweets

In Carolina, Puerto Rico people are lined up for nearly a mile to buy fuel pic.twitter.com/kRHkfp8WDO






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