Does anyone have any recommendations for one of those things that diverts excess solar power into the hot water tank?

I’ve got 4kW on the roof, and it seems like I could dump the excess into the hot water tank, rather than burning gas from Russia.

I have one of these. https://www.marlec.co.uk/product/solar-iboost/

Works fine.

both me , my old man and my cousin run wireless solec ~200 quid easy install. – Cheaper if you go for a wired one – although we all use them on oil filled rads/portable air con units to heat/cool the house as required

I have one of these. https://www.marlec.co.uk/product/solar-iboost/

Works fine.

We have one of those. Works fine.

Just fitted a Solar iBoost. I put a smart thermometer on the tank so can see that it’s doing its job.

Another solar iboost user. Last week was very good, averageing 13Kwh per day into the hot water.
Between now and spetember / october, the oil boiler will probably be used for HW top up may 2 days a month, when we have a couple of heavy cloud days in a row.

Solar iBoost has been around a while so should be pretty good.

I have one that I can’t remember the name of which is OK.
I’ve also got an Immersun at the beach place (which is entirely electric) and that’s excellent with lots of options, such as remote boost*

Once the water is hot it sends spare generation to a dedicated heater which helps to keep the house warmer than it would be otherwise.

I’d get another if I could but they’re pretty expensive now 🙄

* I monitor the hot water temperature using a Raspberry Pi and if the it isn’t hot enough at 4pm then it switches on a wireless socket that applies a small voltage to a port on the Immersun which activates the boost function.
So theoretically, even on a cloudy day there will always be enough hot water for everyone in the evening.

Thanks. Sounds like iBoost+ gets the STW vote of approval.

I have a solic 200 £160 https://www.ebay.co.uk/itm/255175334227

You don’t need fancy displays or buttons or wireless, fit and forget.

I fitted it myself at the consumer unit as the immersion has its own circuit here.

You should get a qualified electrician though.

I had an Imersun but like the company it went pop a few years ago. Wish I had pulled my finger out and replaced it as it gave us free hot water and we didn’t use any gas between may and October! (Other than cooking)

I have the Solic. Works great, easy to install. The iboost is more expensive, but does give you a fancy screen. I monitor the hot water temperature from a basic lcd control panel fed by the 2 sensors in the HWT. During March I’ve not had the hot water on at all (from gas) as the immersion has been heating the water really effectively. I do have showers in the middle of the day to make the most of it though!

I had an Imersun but like the company it went pop a few years ago.

The original company went pop, but I think that somebody else bought everything and are still running.
I also think that you can get them repaired. I bought mine as a faulty unit that had been repaired about 9 years ago and it’s been perfect.