search

raomin / ESPAltherma

Monitor your Daikin Altherma / ROTEX heat pump with ESP32
MIT License
357 stars 121 forks source link

Custom board? #139

Closed glosair closed 2 years ago

glosair commented 2 years ago

Would anyone be interested in an opensource custom board If I design one?

Things so far.

Switching power supply. Serial voltage shifters. (5V to 3.3V).

raomin commented 2 years ago

Hello @glosair, thanks for the proposal. I don't think it's needed, or at least I don't personally feel the need for that. ESPAltherma was designed to be plug and play. ESP32 are 5v tolerant, Daikin ttl is 3v tolerant, and most of the time, you can steal power from the heatpump itself...

Now, if others are interested... I'll leave the issue open for a while.

andreapier commented 2 years ago

I'd be interested, but only if the board also includes relays (ideally 4: 1x heating, 1x cooling, 2x Smart Grid). Only 2 for smart grid would still be cool, though.

glosair commented 2 years ago

ESP32's aren't 5V tolerant, you might get away with it but.....

This board got extremely hot when connected as per the instructions. When I installed level shifters and connected I also found my version K board would not power the ESP32 pictured via it's LDO regulator.

image

IMG_20220913_144235

mauromorello commented 2 years ago

I used a LOLIN32 where there is a BMS onboard and can take from 3 to 7 volt in input; I put Vin from altherma in the battery connector;

From a forum found on web: An alternative is to power at 4.2V via the battery connector. The TP4054 can take up to 7V on its BAT pin, and the charger won't enable unless the voltage drops below 4.2V, so one could also supply, say, 5V via this connector. The D2 diode will protect USB.

image

glosair commented 2 years ago

I'd be interested, but only if the board also includes relays (ideally 4: 1x heating, 1x cooling, 2x Smart Grid). Only 2 for smart grid would still be cool, though.

No problems there, will have a look for suitable surface mount relays, will they need to be NO, NC or Both?

I used a LOLIN32 where there is a BMS onboard and can take from 3 to 7 volt in input; I put Vin from altherma in the battery connector;

From a forum found on web: An alternative is to power at 4.2V via the battery connector. The TP4054 can take up to 7V on its BAT pin, and the charger won't enable unless the voltage drops below 4.2V, so one could also supply, say, 5V via this connector. The D2 diode will protect USB.

I think it might be a problem with the LDO (analogue) regulator as the 5V on the serial interface will get clamped down to the 3.3V rail by the anti static protection and feed the chip with 3.3V + 0.6V (diode drop) ==> 3.9V and any serial coms will create a very unstable supply voltage. It looks like the boards that don't have a problem use a switching regulator as if running from battery you don't want to dump energy as heat from a regulator.

andreapier commented 2 years ago

No problems there, will have a look for suitable surface mount relays, will they need to be NO, NC or Both?

NO would work best. ESP Altherma supports both through a configuration switch, tough.

alexdelli commented 2 years ago

with relays included yes

raomin commented 2 years ago

Again, I don't want to oppose or anything. Building a board is a fun project, go for it! But, also, consider having a look at existing esp32 boards with relays. ESP32 are 5V (open) tolerant for IO pins, you should have no current dissipation (nor extra heat). A good addition to these (existing? future?) boards would be proper connection to X10A. but then the cable length can greatly vary from installation to installation...

I'll move this issue to the newly open discussion board