Contactor Control
How to Tune udcsw on ZombieVerter VCU
Precharge completion voltage. Main contactor closes when bus reaches this.
๐ What Does It Do?
Precharge completion voltage. Main contactor closes when bus reaches this.
๐ฏ Recommended Values
Default value: 330
Valid range: 0 to 1000
Inverter-Specific Recommendations
350
350
350
350
350
288
Tuning Strategy
Start with the default value and adjust in small increments. Monitor vehicle behavior after each change before making further adjustments.
๐ก Tuning Tips
Set to about 85-90% of pack voltage. For 400V pack: ~330-350V.
๐ฌ **BENCH TESTING:** On a low-voltage bench supply (12-30V), set udcsw=0 to bypass precharge entirely. Then take it off 0 and set correctly for your real pack voltage.
1. Is udcsw โค pack voltage ร 0.9?
2. Precharge resistor right value? (50-200ฮฉ)
3. 12V power to contactor coils?
4. 'T15Stat' spot value = ON?
5. 'udc' rising during precharge?
6. Voltage sag after close = resistor too low wattage
โ ๏ธ Common Mistakes
๐จ CONTACTORS NOT CLOSING?
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๐ Related Parameters
Other parameters in the Contactor Control category that work together with udcsw: