Anyone here using solenoid valves? How do you deal with voltage spikes?
Recently came across a discussion in another forum about a DIY ballast system using a small gear pump wired with a N.C. solenoid valve coupled to a floating piston ballast tank (syringe).
The valve prevents water from entering or leaving the tank when the pump is stopped. only when the pump is running whether fill or empty will the valve activate.
i consulted Google Gemini A.I. for info how to wire up solenoid with the pump.
Wiring a standard DC solenoid valve directly to a brushed Motor ESC is a clever way to control it, but it creates a specific technical problem.
When you turn off the solenoid valve to hold your depth, the magnetic field inside its coil instantly collapses. This sudden collapse generates a massive high-voltage spike (often over 100V to 200V) traveling backwards through your wires that can burn out the transistor, MOSFET, or relay channel controlling the valve. or
cause severe electromagnetic interference (EMI), causing your submarine's RC receiver or microcontroller to randomly glitch, reset, or lose signal mid-dive.
It suggested using a voltage spike protector like a flyback diode.
But as flyback diodes are strictly polarized. You cannot connect it across the solenoid terminals. When you hit reverse on your RC transmitter, the ESC will flip the voltage polarity. The diode will instantly become a direct short-circuit. This will likely burn out your esc or blow its internal overcurrent protection.
Since a regular diode won't work with a reversing ESC output, you have two options to safely suppress the high-voltage spikes:
Option A: Use a TVS Diode (Recommended)
Replace the standard 1N4007 diode with a Bi-directional TVS (Transient Voltage Suppression) Diode rated for your voltage (e.g., a 1.5KE15CA or SA12CA for a 12V system).
Option B: Use a RC Snubber Circuit
Wire a small resistor and ceramic capacitor in series, and place that combination across the solenoid terminals.
Recently came across a discussion in another forum about a DIY ballast system using a small gear pump wired with a N.C. solenoid valve coupled to a floating piston ballast tank (syringe).
The valve prevents water from entering or leaving the tank when the pump is stopped. only when the pump is running whether fill or empty will the valve activate.
i consulted Google Gemini A.I. for info how to wire up solenoid with the pump.
Wiring a standard DC solenoid valve directly to a brushed Motor ESC is a clever way to control it, but it creates a specific technical problem.
When you turn off the solenoid valve to hold your depth, the magnetic field inside its coil instantly collapses. This sudden collapse generates a massive high-voltage spike (often over 100V to 200V) traveling backwards through your wires that can burn out the transistor, MOSFET, or relay channel controlling the valve. or
cause severe electromagnetic interference (EMI), causing your submarine's RC receiver or microcontroller to randomly glitch, reset, or lose signal mid-dive.
It suggested using a voltage spike protector like a flyback diode.
But as flyback diodes are strictly polarized. You cannot connect it across the solenoid terminals. When you hit reverse on your RC transmitter, the ESC will flip the voltage polarity. The diode will instantly become a direct short-circuit. This will likely burn out your esc or blow its internal overcurrent protection.
Since a regular diode won't work with a reversing ESC output, you have two options to safely suppress the high-voltage spikes:
Option A: Use a TVS Diode (Recommended)
Replace the standard 1N4007 diode with a Bi-directional TVS (Transient Voltage Suppression) Diode rated for your voltage (e.g., a 1.5KE15CA or SA12CA for a 12V system).
- Why it works: Bi-directional TVS diodes are completely non-polarized. They block current in both directions up to their rated voltage limit (around 13–15V) and will safely absorb the high-voltage spike from the solenoid when it turns off, regardless of which way the ESC was driving it.
Option B: Use a RC Snubber Circuit
Wire a small resistor and ceramic capacitor in series, and place that combination across the solenoid terminals.
- The setup: A 10 to 47 Ω resistor (1/2 watt) connected in series with a 0.1 μF ceramic capacitor (rated for at least 50V).
- Why it works: Like the TVS diode, capacitors and resistors are non-polarized. The capacitor absorbs the high-frequency voltage spike, protecting the ESC's MOSFETs without creating a short circuit when the ESC reverses.
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