Victron Energie Atlas Combi 12V/800W Battery Charger/Inverter Teardown

I do a teardown and test of a Victron Energie Atlas Combi 12-800. It is a combined battery charger and 230VAC inverter. The battery charger of the Atlas Combi is suitable for a 230 VAC, (50 Hz) mains voltage. The charger works automatically, so batteries may remain permanently connected to the charger, even during winter storage. The Atlas Combi is suitable for starter batteries and semi-traction batteries of the lead/acid type in open or sealed designs. The inverter converts the 12 VDC into 230 VAC, 50 Hz. I have also done teardowns on UPS systems at up to 60 kVA storage capacity!

Atlas Combi Power Electronics

The inverter for 12VDC generation uses RFP70N06 MOSFETs, which are rated for 70A at 60 VDC. A output transformer for sine wave filtering is located in the back of the cabinet. The battery charger uses a TIC263 TRIAC, which are rated for 400-800 VDC with a current peak of 175 A.

Atlas Combi Control Electronics

The control sections uses a SG3526 as the pulse width modulation control circuit.

Atlas Combi Changeover

When a mains voltage is connected to the Atlas Combi, the inverter is automatically switched to mains after about 10 seconds. This changeover is indicated by the yellow “load on mains” LED (the “load on inverter” LED goes out) and the inverter is immediately switched off. More information about this changeover is given in section 5.4.The inverter section With the Atlas Combi switched on (i.e. switch set to “on”) the inverter’s own no-load power consumption per model is: A full-load efficiency of approximately 91% is achieved through the use of FET transistors (see illustration 1). The Atlas Combi has a “stand by” facility, as standard. It is activated by setting the switch to the “auto” position. This switches the inverter to a lower stand-by voltage at times when the external equipment does not require power. This limits power consumption to 2 Watt and the inverter operates
when a load is detected. Substantially reduced power consumption is achieved when there are intermittent loads. The sensitivity of the AES (Automatic Economy Switch) can be adjusted

Atlas Combi Battery Charging

The automatic part of the charger starts up about 5 seconds after the charger switch has been set to the “on” position and 230 VAC is present. 12 V battery voltage, the charging current reaches a maximum at a battery voltage of 12 V. The standard settings for boost charging voltage and float charging voltage are 14.25 V and 13.5 V respectively.

Victron datasheet specifications

Inverter Input

  • Nominal input voltage: 12 VDC.
  • Input voltage range: 10 -17.25 VDC.
  • Switch-on voltage: 11 VDC.
  • Switch-off voltage: 10 VDC.
  • Voltage ripple: maximum 5% RMS.
  • Nominal input current: 80 amp.
  • Maximum input current: 150 amp.
  • No-load in “auto” mode: 2 Watt.
  • No-load in “on” mode: 7.5 Watt.
  • Input fuses 4 x 30 Amp (car fuse).

Inverter Output

  • Output voltage: 230 VAC + 5%.
  • Frequency: 50 Hz; + 1 Hz.
  • Waveform of output voltage: Trapezoidal.
  • Power factor: 0.9 capacitive to 0.4 inductive.
  • Maximum Power at 20°C: 800 Watt, power factor 1.
  • Maximum Power at 30°C: 700 Watt, power factor 1.
  • Switch-on behavior: The inverter can start under any load conditions. The nominal output voltage is reached in 50 msec.

Automatic Economy Switch (AES)

  • Switch-on: 9.5 Watt.
  • Adjustable sensitivity: 2 – 48 Watt.
  • Switch-off: 4.5 Watt.
  • Test voltage on “auto”: 65 Vrms 50 Hz.
  • Efficiency: 91% (maximum).
  • Dynamic stability: Maximum surges of 10% when switching on and off at 50% nominal load. Recovery time is 1/2 period.

Overload protection

The delivered power is limited electronically to: 185% (12 Volt battery) of the continuous power at the nominal input voltage.
Short-circuit protection: The output is short-circuit proof. The short-circuit current is 2.75 Arms. Ambient temperature protection: Sensors measure the temperature of critical components. The sensors switch off the inverter if the temperature on the FETs rises above 75°C and/or the transformer temperature rises above 140°C. The inverter restarts automatically after the components have cooled down.

High/low input voltage protection

The inverter switches off automatically at values above 17.25 VDC and below 10 VDC.

Battery charger Input

  • Nominal input voltage: 230 VAC.
  • Frequency: 47 – 63 Hz.
  • Input voltage range: 10%.
  • Input voltage fuse 230/240 V: 1 x 10 amp slow; 5 x 20 mm.
  • Power factor: 0.7 inductive.

Battery charger Output

  • Nominal charging voltage: 12 VDC.
  • Boost charging voltage: 14.25 VDC.
  • Float charging voltage: 13.5 VDC.
  • Charging characteristic: according to DIN 41772.
  • Voltage stability: 1 %.
  • Output current: 30 amp.
  • Trickle charge fuse 15 Amp (car fuse).


  • Maximum switching capacity: 2300 Watt.
  • Changeover time: 0.1 sec.
  • Changeover delay: ca. 10 seconds.
  • Protective device: ceramic fuse, 10 amp slow; 5 x 20 mm.


EMC: Electro-magnetic compatibility according: Council Directive 89/336, EEC Emission EN 55014 (1993), EN 60555-2 (1986) and Immunity EN 50082-1 (1991).
Mechanical data: Noise level: 40 dB(A).
Cabinet: Aluminium, resistant to seawater. Protection: IP21. Color: Blue (RAL 5012), epoxy. Dimensions (H x W x D): 350 x 250 x 213 mm. Weight: 16,5 kg.
Connecting points: Output/input 12 VAC: M8 screws. 230 VAC terminals (2.5 mm2).
Cooling: Natural cooling. Relative humidity: 95% (maximum).

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