I'm about to order a charge point as my solar panels should be fitted in the next week or so. I want to divert any excess solar to hot water so will probably buy an iboost or something similar. The extra cost of a Zappi over a Tesla wall connector is around £300. It'd take a hell of a lot of excess over and above what could manually be sent to the car to recoup that cost. More often than not it'd only be saving me the off peak Go tariff of 8p. It'd take many years to save the nearly 4000 units it'd need to cover the extra outlay.
In that scenario I’d recommend the Zappi and the Eddi combination. By far the best solution for what you need. Sure the Zappi looks very fisher price but it’s by far the best solution and it means your charger and water heater can talk to each other to make best use of the solar energy and any cheap overnight tariff you have.
For the record, I don’t own one, and have no interest in suggesting it other than it’s the best solution for what you actually need and ultimately will maximise your generation and stop you drawing grid power when you don’t need to.
It’s not all about cost (and 4000 units is not that much in the context of an electric car), convenience is a huge factor. You plug it in, it works.
There is no ‘quick it’s sunny, turn the charger on, oh no there is a cloud, turn it off’.
Why on earth would you think I would want to do that? I've two PWs (soon to be three), and don't care too much if I partly drain them as I'll have plenty of power left over. I have the option of setting how much solar to go into the cars and PWs; I like that.
I don’t mean to come across as defensive but it’s probably worth pointing out that a) you didn’t mention that at all and b) you are compensating with £18+k* worth of batteries with plans to add another £9k+* worth. Something like a Zappi costs £200 over a tesla charger (after pen fault device).
It’s not really how they are intended to be used either way and frankly, I don’t think most people want to have/need to constantly intervene with it when there is a product that will just sort it all out for them or shell out for tens of thousands of batteries to compensate for not having a smart charger.
*current prices