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Mecer UPS / Inverter / Solar Batteries [Deep cycle]

Buy Mecer UPS / Inverter / Solar Batteries [Deep cycle] - online in South Africa

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UPS, Solar and Inverter battery (Deep cycle batteries)

Your UPS system is one of the most crucial components in your critical power infrastructure, and for your UPS, the batteries are really the “heart” of that system. Even though your UPS needs that heart, batteries are often neglected.  Regardless of the batteries you choose, all batteries decrease in their ability to store and ....more..
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UPS, Solar and Inverter battery (Deep cycle batteries)


Your UPS system is one of the most crucial components in your critical power infrastructure, and for your UPS, the batteries are really the “heart” of that system.

Even though your UPS needs that heart, batteries are often neglected. 

Regardless of the batteries you choose, all batteries decrease in their ability to store and deliver power over time.

Eventually you will still have to replace UPS batteries on a schedule to get the best usage out of your UPS.

Deep-cycle batteries

Deep-cycle batteries are designed to be regularly deeply discharged during normal operation.

Deep-cycle batteries are effectively capable of discharging up to 80% of its capacity.

The best lifespan vs cost method is to keep the battery at an 50% depth of discharge.

How long will a deep cycle battery last?

Deep cycles are rated in Volt-Amps (VA). A volt amp is how many amps the battery can supply at a certain voltage before it is flat.

100Ah is quite popular and it will supply 12V at 1 Amp for 8.3 hours (12V x 1A x 8.3 hours = 100Ah)

By using an inverter, you can power 220V devices. The battery will supply a certain amount of current at 12Volts dc to the inverter, which coverts this to 220V ac.

Battery energy charge when displayed as kWh and Ah

Some batteries are rated in kWh (Kilowatt hours) while others are rated in Ah (Amp-hours). These two can easily be converted to each other.

How to convert Ah to kWh

Multiply the Ah and the Voltage of the battery which will give you the answer in watts, divide by 1000 further to get the answer in Kilo-watt hour.

Popular battery energy charge (Ah to kWh / kWh to Ah)

7Ah 12Volts =  84Wh
9Ah 12Volts = 108Wh
100Ah 12Volts = 1.2kWh
200Ah 12Volts = 2.4kWh

48Vdc 12Kwh = 250Ah
48Vdc 3.5Kwh = 72.9Ah

VA and Watts
The power in Watts is the real power drawn by the equipment.  Volt-Amps are called the "apparent power" and are the product of the voltage applied to the equipment times the current drawn by the equipment. Volts-Amps is always higher than Watts. The difference between the two is called the "power factor (p.f.)".

A power factor (p.f.) in the 0.6 to 0.8 range is typical.

Real power in watts = Apparent power in VA x Power factor

Other losses to take into consideration

Using an inverter is very inefficient compared to grid power, there are are number of losses between the battery and final device:
  • Peukert constant is the efficiency of the battery. A  Peukert constant close to one indicates a well performing efficient battery with minimum losses and higher than one means less efficient battery.
  • Inverter efficiency is the ratio of the usable AC output power to the sum of the DC input power and any AC input power. Typical grid-tied inverter efficiencies exceed 95% under most operating conditions. Efficiency changes as a function of AC output power, DC voltage, and inverter temperature.

Calculating accurate times for different devices without actually running the device is not difficult, it is impossible!

So what we have done below, is made some typical assumptions, and simplified the whole calculation.

We are using a power factor of 0.8.

Remember that inverters and batteries have losses - we have excluded this from the calculation to simplify this as much as possible.


Typical power for 55" LED TV = 150Watts
  • We are using a power factor of 0.8 (typical pf averaged)
  • The supplied power needed = (Watts / pf) = (150Watts/0.8) = 187.5VA
  • To get the Amps supplied by a 12Volt battery, we need to divide the VA by 12V
  • (VA divide by 12V) = 214.28VA / 12 V = 15.625Amps
  • To get the hours, simply divide the battery's Ah by the Amps
  • (Battery Ah / Amps) = 100Ah / 15.625Amps =  6.4hours

Using the same formula with the same assumptions, we get the following times:
  • 18 Watts florescent light  = 53 hours
    (22.5VA, 1.875A @ 12V, 53hours on 100Ah)
  • 42" inch TV 79Watts = 12.15 hours
    (98.75VA, 8.2A @ 12V, 12.15 hours on 100Ah)

*If you need higher accuracy, take the efficiencies into consideration, and get an accurate power factor.

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