I'm trying to use up as much as possible of my 10kWp of grid connected solar PV without exporting any to the provider. I have a thermal store with 3 x 3kW heaters (230V) but of course, they should only consume whatever power is available, which means at least one of them being on PWM or something similar when Mr Sunshine isn't quite so bright.
There's at least half a dozen well tried devices on the UK market that will do this for 3kW max. but none for 3 x 3kW (t.b.h. there's maybe one, but I'm fed of asking their one and only technical man/owner to ring back).
So I found this controller in Europe, which looks like the cat's whiskers. https://solarcontrols.cz/wattrouter_mx.html
100A maximum measurement - tick, Windows management interface - tick, DIN rail mounting - tick, multiple temperature probe inputs - tick, timer schedules - tick, LAN, RS485 & USB connection - tick, 6 SSR outputs for proportional or PWM control - tick tick tick !!! .
Plus another two relay outputs that can control some 20A contactors for me if I want to block switch two of the three immersion heaters. It really is a nice bit of kit and the price is pretty good too.
However, how do I lash the outputs up to the heaters, what SSR specification, what heat dissipation is needed and so on?
This is going to be a step beyond my base skill level so I want to get it absolutely right. I'm not even sure if I should be using PWM or "proportional" control since the 80+ page manual doesn't give any guidance.
The SSR outputs appear to have various options, including 0-12V 200Hz to 10kHz and Sallen-Key filter, whatever that is????
I can post some screen shots of the specification and of the management software if this helps, otherwise they can be found here:
https://solarcontrols.cz/archives/eshop/WATTrouterMx_EN.pdf
https://solarcontrols.cz/live/wrmx/?lng=en
https://solarcontrols.cz/en/wattrouter_models.html
I'd be really grateful for some solid advice on how to control the heaters and possibly then expand the six outputs to other, power-hungry devices for when the water is fully warmed through.
Cheers,
Ian
There's at least half a dozen well tried devices on the UK market that will do this for 3kW max. but none for 3 x 3kW (t.b.h. there's maybe one, but I'm fed of asking their one and only technical man/owner to ring back).
So I found this controller in Europe, which looks like the cat's whiskers. https://solarcontrols.cz/wattrouter_mx.html
100A maximum measurement - tick, Windows management interface - tick, DIN rail mounting - tick, multiple temperature probe inputs - tick, timer schedules - tick, LAN, RS485 & USB connection - tick, 6 SSR outputs for proportional or PWM control - tick tick tick !!! .
Plus another two relay outputs that can control some 20A contactors for me if I want to block switch two of the three immersion heaters. It really is a nice bit of kit and the price is pretty good too.
However, how do I lash the outputs up to the heaters, what SSR specification, what heat dissipation is needed and so on?
This is going to be a step beyond my base skill level so I want to get it absolutely right. I'm not even sure if I should be using PWM or "proportional" control since the 80+ page manual doesn't give any guidance.
The SSR outputs appear to have various options, including 0-12V 200Hz to 10kHz and Sallen-Key filter, whatever that is????
I can post some screen shots of the specification and of the management software if this helps, otherwise they can be found here:
https://solarcontrols.cz/archives/eshop/WATTrouterMx_EN.pdf
https://solarcontrols.cz/live/wrmx/?lng=en
https://solarcontrols.cz/en/wattrouter_models.html
I'd be really grateful for some solid advice on how to control the heaters and possibly then expand the six outputs to other, power-hungry devices for when the water is fully warmed through.
Cheers,
Ian