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Truma • Solar & Battery Charging

Truma SDC 10/20 Solar Dual Battery Charger

Official technical documentation and workshop diagnostics for Solar Charge Controller.

View official manual on manufacturer's site ↗

Technical Specifications

Battery TypesGel, AGM (Absorbed Glass Mat) or liquid electrolyte, 12V (24V) lead-acid, 50-100Ah (SDC 10) or 50-200Ah (SDC 20)
Not Suitable For6V batteries, non-chargeable batteries, nickel-cadmium batteries
Battery Type SettingSet for battery 1 only (battery 2 assumed same type): 1 = Gel (pre-setting), 2 = AGM, 3 = Liquid (liquid electrolyte).
Charging Current DistributionSettable split between battery 1/battery 2, from 0 (0%/100%) to 9 (90%/10%) in 10% steps; pre-setting is 5 (50%/50%). Once battery 1 is fully charged, all charging current is fed to battery 2 regardless of the set value.
Pwm Charging Frequency0 = 25Hz (pre-setting), 1 = 50Hz, 2 = 100Hz - adjustable to reduce possible interference.
Battery 2 ScalingOn 24V systems, double the 12V values shown to work out the 24V equivalents.

Reference

B2 H1 H2 H3 H4 H5 H6 T X1 X2 X3 X4 X5
Front panel legend from the source handbook. Note: the source document's own troubleshooting table (below) refers to "LED H2" as showing battery 1's status, which conflicts with this legend's own labelling (H1 = battery 1, H2 = battery 2) - an inconsistency in the source material itself, not a transcription choice. Use this diagram to identify the physical LED positions on your unit rather than relying on the H1/H2 label alone.
  1. H1 Function display LED - battery 1
  2. H2 Function display LED - battery 2
  3. H3 Battery type LED - AGM, gel, liquid
  4. H4 Charging current distribution LED
  5. H5 PWM charging frequency LED
  6. H6 Numeric display - shows the values of H3, H4, H5
  7. T Query/change operating mode button
  8. B2 Internal temperature sensor
  9. X1 Connection for external temperature sensor B1
  10. X2 Connection for battery 1
  11. X3 Connection for solar module
  12. X4 Connection for battery 2
  13. X5 Connection (RJ-45) for optional remote display

Master Troubleshooting & Diagnostics Matrix

Error Code / IndicatorSymptom / MeaningPossible CauseStep-by-Step DIY FixSuggested Actions
N/A
LED H2 flashes (the source document's own troubleshooting table labels this as the battery 1 status LED - see the reference diagram on this page, whose own panel legend labels H1, not H2, as battery 1's LED; this is an inconsistency in the source material, not a transcription choice)
Poor or incorrect connection between the device, the battery, and the solar module.
Check the connections between the device, battery and solar module are on the correct terminals, and test the battery, the solar module and the fuse.
DIY Safe
N/A
LED H2 flashes in longer intervals (the manual's own table calls this battery 1's LED, though its panel legend gives battery 1 as H1)
—
This is normal - the battery is fully charged, no action needed.
DIY Safe
N/A
LED H2 shines steadily (the manual's own table calls this battery 1's LED, though its panel legend gives battery 1 as H1)
—
This is normal - the battery is being charged, no action needed.
DIY Safe
N/A
LED H2 flashes in short intervals (the manual's own table calls this battery 1's LED, though its panel legend gives battery 1 as H1)
The battery isn't charging.
If necessary, replace the faulty battery.
DIY Safe
N/A
LED H2 does not shine at all (the manual's own table calls this battery 1's LED, though its panel legend gives battery 1 as H1)
Battery not connected, or over-voltage.
Check the battery connection and check for overvoltage. Contact Truma Service if this doesn't resolve it.
DIY Check / Tech Fallback