Inverters and the Hype
This is something I posted on my blog sometime last year.
When you live in Nigeria, one thing that you are aware of is the electricity company. If you stay in town long enough, you will begin to ask questions about how they work and why their presence is always felt because the purpose for having them is actually why you are bothered that is, there is no LIGHT.
I am no writing about NEPA or PHCN. I don’t have the energy nor the LIGHT for that type of endeavor. I believe some brave heart Nigerian will take up that challenge. I am focused on a now popular alternative to NEPA/PHCN i.e the INVERTER.
Inverters are not new. Their operation and availability in the global market has been known to those in the power industry and science lab.
In the last few years, they have become ubiquitous with every person that can shell out the minimum cost acquiring them and talking about them.
In simple terms, inverters are direct current(DC) to alternating current(AC) converters. The DC is supplied by the batteries which stores the energy and the inverter converts that energy to AC. In compact systems, the inverter also acts as a battery charger or AC-DC converter so that when there is an external power source either from a power generator or AC mains supply or the output of a solar panel, the batteries can be charged.
While this is a contributor to why they are popular, it is the sales pitch that actually drives the huge interest in them. part of the sales pitch is as follows, they are silent, have auto-switch over, no fumes, no maintenance, e.t.c.
Basically these are the exact opposites of what generators are and when you look at the reality that almost every household has a generator, then the picture becomes clearer on why everybody is talking about inverters.
Now I wont talk about the various brands of inverters or various brans of batteries rather I will talk about the experience I had with my setup and use that opportunity to put something out here for posterity.
The typical system is made up of the inverter and the battery bank. of course you have breakers and interconnect cables and the likes (I advise you to use a qualified tech when attempting to install your system. He or she will know all the things you need to make it work). The typical battery voltage is 12V and this is installed as required either in series or parallel depending on your setup. This is not the battery type used in starting your car, those are usually high discharge current at small interval type of batteries rather, what you need is the Deep Cycle batteries. These batteries dont deliver very high currents like the car batteries rather, they can discharge what they can over a period of time without being ruined.
My setup is a 24V battery system which means 2 12V batteries in series. I had a nice time using it to the point that when I go to bed at night, and forget I am still in Naija because I sleep well and this is another selling point. Anyway after sometime I observed that the discharge time was dropping. It eventually came to a head when I was out of a fully charged system within 3 hours that was when I woke up from the honeymoon. After much test and tinkering, I found out that one of the batteries has lost some of its internal cells. Most batteries are built from a collection of 2v cells in series to form the big 12V batteries as we know them, a reminder of this is when you top up the battery electrolyte(water) and you have to open each cell to add the distilled water. Back to my story, the bad battery was not giving its portion of the load so the good battery was doing all the work and as it got weaker, I lost discharge time on my system.
Solution to the problem is that I had to change the 2 batteries to bring my system back to where is should be as well as incorporate a battery equalizer that makes sure that no battery is overcharged or over discharged.
I am not sure why my battery failed. But it was an expensive failure considering that fact that batteries are the major investments in the inverter setup. So for all the hype, that batteries last for at least 5 years, which is true in some cases, it is also very true that they can fail within a year and in some cases much less.
If you are shopping for a system, be interested in the quality of your batteries as well as the inverters and also be clear on the type of load you can put on the system irrespective of the size of your setup.
By all means enjoy your inverter it is a good thing.
Illumination and power consumption
April 22, 2012 by Jide Ajayi • Issues • Tags: electricity, life, light •
The one thing that is good about incandescent light bulbs is that they emit heat other than the light they are made to give.
While that is a good thing in climes that experience low temperatures as a part of the yearly weather circle, it is not really
something that those that have a routine temperature value of 30 degree C and above will relish in anyway particularly when the
wattage of the bulb begins to climb up to 100 watts and above. I have a theory though that it keeps the level of moisture down
if the area is prone to high humidity levels so that is another good thing.
The other thing that is a disadvantage to the use of incandescent light bulbs is the issue of power consumption. How? you may ask
then let me explain. The first assumption is that power supply in the area of use is constant i.e. at 110V or 240V which is required
to ensure that the bulb is functioning properly. The next thing to look at is the power rating. a 40W bulb is smaller that a 60W bulb
but bigger than a 20W bulb. which constant voltage and varying wattage, and using a basic power formula of
Current I x Voltage V = Power W
It means a 20W bulb will consume 0.08A or 0.18A, a 40W type will consume 0.17A or 0.36A
When this is multiplied by 60 min The value of current drawn and therefore the value of power drawn increases for the quantity of bulbs
lit and how long they are on for and what the wattage is. This adds up when the cost of electricity is not just from the public grid but
self generated through the use of inverters and power generators.
I already hear the cry about how power generator consumes a fixed amount of petrol and that should not matter. I respectfully beg to disagree
and present my reasons for doing so.
1, Generators are rated. This means they have capacity and limit in terms of the load they can support.
2, The high the load on the generator the more the consumption of fuel experienced as the generator will speed to to maintain its rated
capacity output and so consume more fuel per hour than for a lighter load on the same system.
So if you have a generator rated 2000W and you have ten 100W bulbs put on, the combined power consumption of those bulbs is 1000W which is
half of the capacity of the system, with a few more equipment powered, it is easy to attain the capacity of generator with half of the load
being consumed by lighting.
The same principle applies to the inverter but it is more pronounced here because the battery capacity in this case is finite and as current
drawn or power consumed increases, the runtime of the system reduces sharply, this the original equipment manufacturers OEM are quick to point
out.
So if you have a 1000W inverter system with the same set of light bulbs, your total reserve power will be depleted in about an hour which
definitely is not funny when the cost of setting up the system is put into the equation.
So the way out of spending some much power and money on illumination is to do a simple thing, that is change out the light bulb to types that
help minimize cost and give the same utility. Use energy-saving bulbs or compact fluorescents lamps CFL.
Energy-saving bulbs or CFLs are bulbs designed to give illumination similar to the equivalent rating in incandescent bulb with way less power consumption
so an energy saver bulb that gives the equivalent of 100W illumination may consume about 15W of power. so using our example, that will cost
150 watts to provide the same illumination but less stress on the system which means the inverter may now last for about 7-9 hours and the generator
can no run longer putting more money in your pocket.
The down side though is that it does not provide as much heat as the incandescent bulb and a lot of people cite that as a reason for not wanting to use
it. As I already acknowledged in the opening, it depends on where you are and what the unique challenges are.
But in some time, there may be no more incandescent bulbs to buy as the manufacturers may start focusing on improving on the existing energy-saver
types as reported here and here as well as this