Haven’t found the exact device needed, so built my own.
Replaces timer.
This uses a simple two wire connection to any battery from about 24v to 100v.
Two set points:
Charger on-led on
Charger off-led off
Example:
set to 80v and 72v
When battery reaches 80v ac power is cut to charger
If battery self discharges to 72v charger will again be “plugged in”
I’m sure these are, or soon will be, available commercially, but for now I only find 12vdc or 220vac powered voltage relays. This is self powered by main battery voltage.
Good idea for someone to run with. Not sure if I want to make a bunch of them. Parts are dirt cheap.
You can have this one and I have parts for one more.
Have one available. $100
Money back if you return it.
If Mike gets them in production price may be different.
Ps.
I owe Mike money, so he’s on the free stuff list.
I was considering making something like this from a Raspberry Pi ZW($15) and a SonOff AC smart outlet($15) but I just need to figure out a good way to measure the battery voltage. Maybe some SPI based ADC board and some high precision resistors would do it.
There is more to the cost though like a 5V USB power supply to power the rPiZW, an outlet splitter so the rPi ZW is always powered and the other outlet powers the Sonoff switch.
The rPi ZW would be in AP mode so while the switch connects to WiFi, it would be the Wifi presented by the rPi ZW. Lots more can go wrong in this setup as there’s a boat load of software running the rPiZW( Linux ), Mosquito MQTT messaging system and Tasmota firmware on the Sonoff switch.
