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Where can I buy a replacement relay?
@Mark Fickett - I don't know if you'll see this, I hope you do. I was able to resolve it by cleaning the connectiosn with sandpaper using the guide I linked. I did save this on my Amazon Wish List for the future. Tempted to just buy one to hold onto it.
OpenEVSE Support
@Greg B. You would need the 12v coil model. The one on your Amazon List is 6V.
Are you able to directly link me to one? Any vendor is fine, it will really help me locate the right one instead of going off visuals.
OpenEVSE Support
The Packard C240C is a great option, in it not quite drop in but close. The contactor is more robust, available and less expensive. The Struthers Dunn is almost impossible to find on the open market.
The down sides of conversion are you have to remove the ring terminals and replace with furreles (we have kits) and the contactor requires 208-240v so Level 1 120v charging is not possible.
QUESTION are the relay regular relays or they have a diode like it says here,
Relay control
The transistor and resistor on PB0 and PD7 are straightforward open-collector switching circuits. The reverse bias diodes across the relay coil protect the transistors from coil collapse voltages when the transistors are turned off.
https://openev.freshdesk.com/support/solutions/articles/6000052070-theory-of-operation
OpenEVSE Support
@RIFF the diode is on the control board on the DC relays, There is an onboard MOV for the AC contactors. THe DC relay is a "regular" relay with a 12v coil and AC contactor with 208-240v coil.
thank you for the reply
If using a 6V Struther-Dunn relay it's possible to limit the activation current for the relay with a series resistor but the driver would need to supply 2x the current since 1/2 of it is wasted across the resistor.
Does the driver on the control have the power to do this? (333mA)
OpenEVSE Support
@Jeff Nelson The relay driver on OpenEVSE is 12v and already does support closing the relay at full power then dropping down to lower power to hold.
The command lives in the open_evse controller firmware (not the ESP32 WiFi module) — firmware/open_evse/rapi_proc.cpp / rapi_proc.h, and it's gated behind V5+ hardware.
$Z0 <closems> <holdpwm>
closems(0–255) — milliseconds the relay coil pin is driven fully HIGH to guarantee pull-in before switching to PWM. Default100.holdpwm(0–255, where 0 = 0% and 255 = 100%) — the PWM duty cycle used to hold the relay closed after pull-in. This is the value you lower to cut hold power. Default255(full power, no reduction) — so out of the box it does nothing until you set it lower.
Example: $Z0 100 128 — 100ms full-power pull-in, then hold at ~50% duty cycle.
BTW if you add a series resister and double the resistance your current will drop in half not double. The increases resistance will allow less current through at a fixed voltage.
5 volts at 200 ohms =
Current (I) = 0.025 ampere (A)
Power (P) = 0.125 watt (W)
5 volts at 400 ohms =
Current (I) = 0.0125 ampere (A)
Power (P) = 0.0625 watt (W)
Greg B.
I received the Stuck Relay RED error. Advanced Series - 48A/40A. I followed the steps in this guide to clean the relay and it's working again, but I'd like to buy a replacement relay to have on hand. The only relay in the OpenEVSE Store does not look at all like mine. I've had a ticket open for awhile asking for this additional information, but I have not received an answer. My relay looks like the one I included a pic of below. Where can I purchase a replacement relay?
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