Frequently asked questions

about Combis

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**What battery capacity do I need**

**to fit a Mass Combi 12/2000 or**

**24/2000?**

A simple rule of thumb states that a

12-volt system needs a minimum battery

capacity of around 20 % of the inverter

capacity, while the corresponding figure

for 24-volt inverters is 10 %. The battery

capacity required for a 12-volt Mass

Combi 2000 is therefore at least 400 Ah,

while a 24-volt Mass Combi 2000 needs at

least 200 Ah.

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**How much power does a Combi**

**use?**

The efficiency of Mastervolt equipment is

very high due to the application of high

frequency (HF) technology. If the Mass

Combi needs to power a Senseo coffee

machine (1450 watt) for instance, power

consumption will be 1450 watt divided

by the onboard voltage of 12 volt = 120

amps. Making a cup of coffee takes less

than a minute, so consumption in Ah can

be considered fairly small at 120 x 1 min

= 2 Ah. The power used by the inverter

itself is negligible.

**TECHNICAL BACKGROUND**

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**Does the Combi need a lot of**

**ventilation?**

The Combi (if installed in a cabinet) needs

very little ventilation – two approx. 80 cm²

(9 x 9 cm) ventilation openings are the

minimum required. Combis that are used

in high ambient temperatures, or are

expected to be operating at full capacity

for a long period, require openings that

are at least four times as large.

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**How thick should the battery**

**cables be?**

To calculate the right cable size,

determine the highest possible current

which will flow through the cable. For the

Combi this is the inverter current. When

running at full capacity, a 2000 W inverter

for instance draws around 200 amps

from the batteries (100 amps for a 24-volt

system). The rule is simple: For every

3 amps you need 1 mm² in cable

thickness. The advice for a Combi

12/2000 would be 70 mm² cable

thickness and 35 mm² for a 24-volt

version.

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**Is the Mass Combi noisy?**

HF technology has rendered large low

frequency transformers obsolete, so you

no longer have the irritating humming

sound generated by equipment with

a large transformer. Ultra quiet and

temperature-regulated ventilators take

care of the cooling, ensuring that noise

levels are kept low. The only remaining

sound is the soft hum of the cooling air.

A Mass Combi can therefore be installed

virtually anywhere.

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