Comparing solar immersion heater diverters (water heating).

[Gareth J]

Don't know enough about how they all work to comment on why, but I did have "conflict" issues between a solic and an iboost. In theory the 200W export threshold of the iboost (older version) should give priority to the zero export solic. And it did, most if the time but occasionally got the wrong way round. However, putting more distance between the CTs seems to have stabilised them.

Another thing ice remembered; you can extend the wire of an iboost (and maybe others?) by about 20-30m. Much longer than this and nothing happens. Add on a similar range for the wireless part and you've a very useful ~50m+ range. Although chews through the batteries a bit and not as reliable as one where wireless unit is right next to the iboost.

[Oldgreybeard]

But surely, "before", in terms of any spacial position on the same cable, makes zero practical difference, because distance is always proportional to time on any cable (due to the cable velocity factor) for any step function and that cable time difference is so minute as to make zero practical difference, because it's completely swamped by massively larger response time delays in the devices.

I still maintain that the (very real) race condition that determines which device takes priority has nothing at all to do with where along a cable run a measurement happens, and is solely down to how fast each device responds to the change.

[Gareth J]

But surely, "before", in terms of any spacial position on the same cable, makes zero practical difference, because distance is always proportional to time on any cable (due to the cable velocity factor) for any step function and that cable time difference is so minute as to make zero practical difference, because it's completely swamped by massively larger response time delays in the devices.

I still maintain that the (very real) race condition that determines which device takes priority has nothing at all to do with where along a cable run a measurement happens, and is solely down to how fast each device responds to the change.

I agree that the position up/downstream can't make a difference. But apparently, they can be too close to one another.

[Oldgreybeard]

I agree that the position up/downstream can't make a difference. But apparently, they can be too close to one another.

They can, as the magnetic field leakage from one can mutually interfere with another ones that is very close to it, I believe. IIRC, there's a recommendation I read somewhere that says they need to be at least something like 20mm apart, to reduce the risk of this.

[sharpener]

But surely, "before", in terms of any spacial position on the same cable, makes zero practical difference, because distance is always proportional to time on any cable (due to the cable velocity factor) for any step function and that cable time difference is so minute as to make zero practical difference, because it's completely swamped by massively larger response time delays in the devices.

I still maintain that the (very real) race condition that determines which device takes priority has nothing at all to do with where along a cable run a measurement happens, and is solely down to how fast each device responds to the change.

But they are not on the same cable. It's a question of whether the topology is

A) (my arrangement - battery priority): Grid - Diverter CT - [AC-In -Victron ESS- AC-Out] - tee off to PV inverter - CU - Diverter - Immersion circuit

or B) (hot water priority): Grid - [AC-In -Victron ESS- AC-Out] - Diverter CT - tee off to PV inverter - CU - Diverter - Immersion circuit

These configurations are deterministic, that is they do not rely on propagation delays/race timings to work correctly, they depend only on which current flow the diverter views as being "surplus".

[Woodyeyes]

I self installed an Eddi just over a year ago together with a Harvi and hub. After a couple of hours getting my head round where to place the CTs and which settings to use I got it working and talking to the app. Since then its worked without any problems at all. I had an Zappi fitted in June and I got that to integrate with the eddi and app too. In the 12 months to 31st Oct I generated 2384 kwhs, and my export total was only 77kwhs.
I paid £566 for the Eddi, hub, and harvi.
I have a 3kwp pv system.
In the first 12 months of use I diverted a total of 661.3kwhs into my immersion tanks (I have two of them). At 33p a unit that's a saving of £218, so in another 18 months it will have paid for itself. I'm well happy with that.
The units look solid, and well made. The myenergi forum seems busy with lots of helpful types on there. I'm confident if I neede tech support I'd be able to get it from there.
I'd recommend them.

[nowty]

@Woodyeyes, (and others if its not in your sig) how big (in litres) are your two water tanks ?

And what EV have you got or what is the battery size ?

PM me if you like.

[Woodyeyes]

145L each tank.
I ordered a mg ZS LR EV on 6th Dec 2021 as a lease deal with Vanarama. I’m still waiting! Latest estimated delivery date they gave me is April 2023.
Last month I popped into my local mg dealer and ordered a mg 4 instead. They quoted 8-16 weeks. I’m buying the mg4.
We’ll see which one turns up first and cancel the one that doesn’t.
The mg4 has a 64kw battery.

[nowty]

145L each tank.
I ordered a mg ZS LR EV on 6th Dec 2021 as a lease deal with Vanarama. I’m still waiting! Latest estimated delivery date they gave me is April 2023.
Last month I popped into my local mg dealer and ordered a mg 4 instead. They quoted 8-16 weeks. I’m buying the mg4.
We’ll see which one turns up first and cancel the one that doesn’t.
The mg4 has a 64kw battery.

If its ordered its going on the secret list.
https://camelot-forum.co.uk/phpBB3/view ... 120#p22664

[John_S]

I have a Solar Immersion to divert PV export to my 170ltr Megaflo.
Performed faultlessly since a DIY install in 2013.

I am currently boosting it during the Octopus Go 4 hr window as solar is not sufficient in winter and I reckon electricity at 7.5p is better than gas at @ 10p per kWh.