Household electricity in Kerala is
provided by the state government run Kerala State Electricity Board (KSEB).
Electricity was already in place when we moved in as the builder had already
acquired connections for all villas in our community. From a peripheral point
of view things were functional but at the central level there remained several
issues concerning the power supply:
Our choice was a 2000 VA Hykon Pure
Sine-Wave UPS Mode Inverter matched with two 12V Exide batteries rated at 100AH
each. The inverter had a 1-year warranty while the batteries had 4. The water
in the battery needs to be compensated with ‘battery water’ (not distilled
water) which can be obtained from petrol stations every 2-months or so. So far
that has been the only maintenance we have done in our 18-months of ownership.
The total cost came to Rs 33K – battery pricing had increased by around 15%
right before our purchase and unfortunately that didn’t help matters. The 2000
KVA inverter with UPS mode was around Rs 9K. Performance-wise, it has worked
flawlessly and we are yet to be faced with a blackout due to inverter drain. On
hindsight, slightly lower capacity would have served us too. Also, as we
predominantly use laptops around the house the UPS-mode was never used – that
is again something we could have opted out. Overall, we consider this setup
good for household use.
09/2012 Update: The inverter broke - apparently, a transformer outage caused it and the service guy said the main board is toast. Since it had only a one-year warranty, fixing it would cost upwards of Rs 4000 and a one-year service plan would be an additional Rs 2500. Went with buying a new smaller inverter (900 VA Hykon Pure Sine-Wave UPS Mode Inverter) for Rs 8000 and Hykon took the old one back as scrap for Rs 2500. The battery connection was changed to "serial" instead of "parallel" so as to be able to connect to a 12V inverter as opposed to a 24V inverter previously - the backup capacity will be slightly reduced under this setup. We have come to realize that for our house the 2 KV one was too much capacity. Also, the switch lets us migrate to a single battery eventually once the two Exide ones we have breaks. Hykon's new inverters come with a 2-year warranty compared to 1-year warranty previously - this also made it an easier decision to take this route as opposed to fixing the previous one. Overall, our experience the past 30 months have been relatively flawless. One of the batteries needed to be serviced once and that experience was OK - they gave a standby battery while they took the Exide one for servicing but it took them almost two months to get it back...
Electricity was already in place when we moved in as the builder had already
acquired connections for all villas in our community. From a peripheral point
of view things were functional but at the central level there remained several
issues concerning the power supply:
a)
The main fuse boxes were already rusted out – builders
tout using standard equipment from brand-name manufacturers and hence it was a
surprise when Havell branded equipment rusted out so quickly. Apparently,
manufacturers are known to provide the builders with seconds at a huge discount
which probably explains the rust.
b)
The panel fuses had ratings between 6A and 30A which
would have sufficed to plug-in all standard equipment in the house. The problem
though was that these fuses were randomly connected to the various plug-points
which started tripping as soon as we started plugging in appliances. This
situation could have been easily addressed prior to handover, had the builder
tested it out.
c)
Several power-plug points and inverter connection
circuitry were requested as upgrades and we noticed they were only partially included
at handover. We could get the power-plug points to work after they were
associated with the right fuses, but the builders had totally neglected to
include the wiring for an inverter connection.
The items in the above list can all
be easily addressed by a good electrician. 
The main fuses were fixed at around
Rs 100/- or so a piece and inverter wiring from the panel fuses to power-points
setup previously for the purpose was Rs 800/-. Kerala encounters frequent power
failures and so many choose alternate arrangements to receive continuous power.
Newer residential projects now offer backup generators which is an excellent
option as no additional equipment needs to be installed inside one’s premises.
Generators are popular for household use as well, but we availed of an inverter
as our folks had a Honda generator that was really noisy and required a certain
level of on-going maintenance. Seems that the generators of today are much
better, but we are not sure by how much.
The main fuses were fixed at around
Rs 100/- or so a piece and inverter wiring from the panel fuses to power-points
setup previously for the purpose was Rs 800/-. Kerala encounters frequent power
failures and so many choose alternate arrangements to receive continuous power.
Newer residential projects now offer backup generators which is an excellent
option as no additional equipment needs to be installed inside one’s premises.
Generators are popular for household use as well, but we availed of an inverter
as our folks had a Honda generator that was really noisy and required a certain
level of on-going maintenance. Seems that the generators of today are much
better, but we are not sure by how much.
The market is rife with misleading
information on inverters. On inquiry, we received several offers from
small-scale operators who can build one either using “company” products
(expensive) or using no-brand products (economical). While many of them would
make it sound as though those are the only parameters involved for an inverter,
the reality is more involved.
Following are some parameters to consider when
buying an inverter and batteries for household use:
Following are some parameters to consider when
buying an inverter and batteries for household use:
a)
Regular vs Sine-wave Inverter: Regular inverters (aka
modified sine wave inverters) produce an output closer to a square wave than to
a sine wave. The output is sufficient for most household equipments with the
exception of certain laser printers and specialized equipment. A downside with
such inverters is that motorized equipments such as fans will have a humming
sound when operating on inverter power. As pure sine-wave inverter produces a
near perfect sine-wave similar to regular household power such problems are
avoided. A sine-wave inverter can cost 15-20% more than a regular inverter.
b)
Regular vs UPS-mode Capable Inverter: During electrical
outage, the inverter supplies power from its output. Though the switchover is
almost instantaneous it is not continuous. Devices relying on continuous power
such as a home PC will not function well as the computer power will go down
during this switchover. With an inverter in UPS mode the problem is bypassed,
as power is supplied continuously from the inverter causing no switch-over when
supply disrupts. A more optimal solution is to use regular mode pure sine-wave inverter with a
compatible UPS for the home PC - UPS does not work well will the older square-wave inverters. The main reason for vendors to include a UPS mode is for the system to be sold as a computer accessory - computer equipment and accessories have significant tax benefits and so the net cost to the consumer is reduced. Laptops are spared of this problem as it
powered by its own battery. Modern modems and wireless routers recover quickly
from a power switchover and consequently the need for UPS mode in households has
lessened over the years.
c)
Battery and Inverter
Capacity Selection: Choosing the right battery capacity and a matching inverter
is critical when setting up an inverter power. If at all possible many vendors
choose to let slide the topic of battery AH rating and promote the battery with
the lowest rating at the lowest cost. Choosing to minimize cost on battery is
being penny wise and pound foolish for the resulting inverter will have very
limited backup capacity. Battery price
increases rapidly with AH rating rise – 125AH batteries are almost twice as
expensive as equivalent batteries rated at 75AH. Battery
capacity indicated in AH specifies how many Amps it can supply, assuming it
lasts an hour. A 75AH battery can supply 75 amps for an hour, 10 amps for 7.5 hours,
or any other combination adding up to 75AH. The two types of inverters are the
12 volt inverter fed from a regular 12V battery and the 24 volt inverter whose
input is from two such batteries. In general, inverters rated over 1200VA
require two 12V batteries. To arrive at what to select, the first step is to
start with the average expected load and how long the backup power should last.
For e.g., if the average load is estimated to be 200W and power backup is
desired for 10 hours, battery capacity should be 200AH for a 12 volt battery
(200W/10 = 20 amps; 20 amps x 10 hours = 200AH) or 100AH for a 24 volt battery
(200W/20=10 amps, 10 amps x 10 hours = 100AH). Another variable that needs
consideration while selecting battery capacity is the discharge rate. The
listed rating is for a 20-hour discharge and the capacity decreases to around
50% of the listed rating for a one-hour discharge. So, as the average load
increases, you need more battery capacity. In this e.g., since the discharge is
10 hours, the battery capacity decreases to 90%. So for 24 volt battery a
rating of roughly 110 AH is required as opposed to the 100 AH calculated above.
d) Warranty:
Inverters generally come with a 1-year standard warranty although few
manufacturers offer 2-year warranties. Once the warranty expires, a maintenance
contract can be opted for at roughly 25% of the cost of the inverter per year
which, in our opinion, is high. Battery warranties come in all guises with
no-name batteries sporting just “verbal” warranty from the local guys to 4-year
written warranties for Exide batteries with good reputation. Depending on brand
name, warranty, and AH rating cost varies.
e)
Solar Inverter: Solar home power systems drawing along
similar lines have started appearing in the market. Currently, such systems are
suitable only for selected areas of the house and require special wiring and
compatible devices.
Our choice was a 2000 VA Hykon Pure
Sine-Wave UPS Mode Inverter matched with two 12V Exide batteries rated at 100AH
each. The inverter had a 1-year warranty while the batteries had 4. The water
in the battery needs to be compensated with ‘battery water’ (not distilled
water) which can be obtained from petrol stations every 2-months or so. So far
that has been the only maintenance we have done in our 18-months of ownership.
The total cost came to Rs 33K – battery pricing had increased by around 15%
right before our purchase and unfortunately that didn’t help matters. The 2000
KVA inverter with UPS mode was around Rs 9K. Performance-wise, it has worked
flawlessly and we are yet to be faced with a blackout due to inverter drain. On
hindsight, slightly lower capacity would have served us too. Also, as we
predominantly use laptops around the house the UPS-mode was never used – that
is again something we could have opted out. Overall, we consider this setup
good for household use.09/2012 Update: The inverter broke - apparently, a transformer outage caused it and the service guy said the main board is toast. Since it had only a one-year warranty, fixing it would cost upwards of Rs 4000 and a one-year service plan would be an additional Rs 2500. Went with buying a new smaller inverter (900 VA Hykon Pure Sine-Wave UPS Mode Inverter) for Rs 8000 and Hykon took the old one back as scrap for Rs 2500. The battery connection was changed to "serial" instead of "parallel" so as to be able to connect to a 12V inverter as opposed to a 24V inverter previously - the backup capacity will be slightly reduced under this setup. We have come to realize that for our house the 2 KV one was too much capacity. Also, the switch lets us migrate to a single battery eventually once the two Exide ones we have breaks. Hykon's new inverters come with a 2-year warranty compared to 1-year warranty previously - this also made it an easier decision to take this route as opposed to fixing the previous one. Overall, our experience the past 30 months have been relatively flawless. One of the batteries needed to be serviced once and that experience was OK - they gave a standby battery while they took the Exide one for servicing but it took them almost two months to get it back...
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