Solar PV controller switch
 

Hi there,

Am planning to get a PV controller switch to feed my twin immersion tanks. My electrician is recommending solarimmersion. How feasible is it? Any ideas?

Welcome to Ecorenovator. :)

Can you provide a bit more information about your setup?

Hi,

I have one of these installed in my home https://www.earthwiseproducts.co.uk/product/solic-2000/ Works really well diverting all of our excess solar power (within 20w) to the immersion heater. It is a cheaper alternative to some other systems that have a few more features. I have found it to be very reliable.

Prior to this I used a mk2pvrouter from the openenergymonitor project that I built using a emontx and a SSR. See https://learn.openenergymonitor.org/...sion/mk2/index

I changed to the solic-2000 purely to satisfy my electrician. We have a 1.5kw PV system and also have a small wetback (booster). Our cylinder is a bit small at only 180l with 2 of us we very infrequently need to "boost" the cylinder with imported power. If I was to do a new install I would go for a 300l cylinder and maybe 2-3kw of PV.

These diverters seem essential to make the economics of PV work in New Zealand. Our power companys pay us about $0.07kw/h for export power and sell us power at about $0.30kw/h so it makes sense to use all of your generated power onsite. With the cost of battery storage I believe these are the best system to store the excess energy given most peoples water heating is about 1/3 of total power consumed.

if you want to use PV solar to heat water, why not a heat pump water heater? 1500W worth of heat on only 500W worth of solar.

See my post over in the heat pump geothermal thread. Problem with using a heat pump is speed control to ensure all of your excess generated power is being used without importing from the grid. Not an easy thing with current available heat pumps. The technology is there used in mini splits to modulate output to temperature but there seems to be no simple way to modulate to avalible power.

you may not be able to ensure that ALL of your excess generation is consumed. you'd end up using 0.5kW worth of solar for the HPWH, and selling 1kW back to the grid. not sure what's available in your region, but here we have standalone 500w 80gal HPWHs.

Ok, so in the other thread, your question was aimed towards space heating using a floor slab. If you're looking for a good vessel to dump your excess pv power into that's readily available premade, as well as useful and efficient, you should know what to go buy. It has wheels and uses lots of energy to provide transportation.

Too True thanks Jeff. Ultimately I want to heat my home with excess solar and using a heat pump would seem to be the most efficient way of doing this. My plan at this stage is to tinker with water heating using a small fixed speed compressor from a dehumidifier just to better understand the "building blocks" and work my way up to whole home heating. Im pretty certain theres a steep learning curve with this stuff. This site looks like a wealth of information and im sure ill be doing a lot of reading.

Ok so check out Jake's (memphis91) thread. He pulled a good one off, then switched it up to get even better results.

https://ecorenovator.org/forum/geoth...er-heater.html

Also, start reading the homemade heat pump manifesto. AC hacker's quest started out with good intentions and grew as he documented his efforts. His thread attracted many ambitious people and hit critical mass. The explosion of information has educated and motivated a huge crowd. It's a massive thread, but absolutely worth reading.