[Tom Blandford]

I have 4.1kWp of solar and a new VW ID4 (no V2G unfortunately, and no battery in the house yet). I want to install a charger but I’m not sure whether to get Zappi or Ohme. I can plug the car in 3 days per week and overnight. I only need to charge the car once per week. Zappi charges from PV first and probably works well with Octopus Go to top up the remainder at night. Seems the best option. But I’m keen on trying Octopus Agile + Outgoing and I like the Ohme charger much better. I want to install it on a wooden post too. I’m worried it will see a high import tariff and turn off, even when I am exporting. Does it check the outgoing rate and/or know if I am exporting or importing? Might this functionality be added soon? Seems an obvious add. Any advice on charger/tariff?

 

[Harry6]

Hi, I say go for the Zappi. They are definitely set up for solar and with the Hub you will have smart control.

 

[gbt]

You can use the eSense input of the Zappi to control boosting on demand (along with timed boosting). People have hooked up smart switches with IFTTT integration (which has supported triggers for Octopus Agile) to trigger boosting when import rate is lower than some limit.

You can do this by running an extra cable to the Zappi and just plugging in the smart socket in your house, but it’s a bit silly as then you have two power supplies to the unit that needs isolated for maintenance (and should be labelled as such). You can fit a wireless smart socket inside the unit and run it off the same supply as the charger itself, but it’s a little non-standard.

Here’s a thread on the internal version: Using Zappi E-Sense feature to Boost Charge...

 

[Jeremy Harris]

My vote would be for the Zappi, not only because it does what you probably need to do well, but also because it's not a re-badged bit of imported Chinese kit and because it has a good built in safety provisions, that have been proven to work well, so is much simpler in terms of what's needed for the install to be safe and compliant with the regs.

 

[Tom Blandford]

Thanks all. Very helpful. Zappi it is! Octopus Go is probably best for starters. I’ll think about mods and OA+OO once I’m up and running. Since I am laying a cable underground, I might add a dummy 13A cable in case I need extra wires later!

 

[Harry6]

Or you could put in a 32a commando socket?

 

[Spiny]

I use a Zappi, it works
If you are running a cable yourself then bury a conduit if you can and in the future you can pull what you like through it

 

[DSLRed]

Sounds like you have made the decision but to throw in an alternative view, I would go for the Ohme. In fact, I did.

My reasoning was that if i were to go for the Ohme, i would not be consuming my excess from the solar so it just goes to the grid instead and i get the SEG payment for it. Then instead, I charge at night on Octopus Go, which is only very slightly more cost than the price I got for the export. If the difference between your SEG payment and your Octopus Go overnight rate is say 2p, you would need to get through a lot of charging saving 2p per kwh to equate to the cost difference between the Zappi and the Ohme.

Quick cig packet calculation - if the difference in price between import and export is 2p, and the difference in installation cost between Zappi and Ohme is say £400, you would need to get through 20k kwh before the difference in cost is paid back by the Zappi.

Obviously, those import and export prices may widen over time, but I think sometimes, you can over complicate it.

 

[Jeremy Harris]

Or you could put in a 32a commando socket?

Doesn't meet the requirement for having any smart functionality, though, does it? A 32 A commando socket must be installed with both DC tolerant earth leakage protection and open PEN fault protection, both things that are built in to the Zappi, making the Zappi a simpler installation. The parts required to install an interlocked 32 A commando, that is safe and compliant with the regs/law comes to around £300 to £360, plus labour, to which the price of a safe and reliable portable 32 A charge point needs to be added, one that has the required smart functionality (and, FWIW, I personally wouldn't include a re-badged bit of essentially unknown Chinese kit into that category).

 

[Oli]

You’ve got enough PV to make the Zappi worthwhile. I’d steer away from Octopus Agile though, as Go is MUCH cheeper so far this year.

 

[Xtopher]

You’ve got enough PV to make the Zappi worthwhile. I’d steer away from Octopus Agile though, as Go is MUCH cheeper so far this year.

Some good info here about Agile prices at the moment - Wholesale energy prices and Agile Octopus - for now I would stick to GO. Agile was cheaper until earlier this year I'd say with anecdotal evidence of being on Agile for a good few months last year before the prices went mad. If you have an iPhone and Octopus customer, then the 'Octopus Compare' app is a good app to help see which products are best.

 

[Harry6]

Doesn't meet the requirement for having any smart functionality, though, does it? A 32 A commando socket must be installed with both DC tolerant earth leakage protection and open PEN fault protection, both things that are built in to the Zappi, making the Zappi a simpler installation. The parts required to install an interlocked 32 A commando, that is safe and compliant with the regs/law comes to around £300 to £360, plus labour, to which the price of a safe and reliable portable 32 A charge point needs to be added, one that has the required smart functionality (and, FWIW, I personally wouldn't include a re-badged bit of essentially unknown Chinese kit into that category).

I have been trying to find what the two unit were that you thought might protect the supply was it a Matte? I did see something that CEF had for sale

 

[Jeremy Harris]

I have been trying to find what the two unit were that you thought might protect the supply was it a Matte? I did see something that CEF had for sale

No, not the matt-e, as it doesn't really reliably detect an open PEN fault, and can trip out for other reasons, like a supply voltage glitch. All told, it's not a great solution IMHO. The best stand alone connection box (i.e. to provide the required protection for an outlet that doesn't have anything built in) is probably the Viridian unit, with the optional 6mA DC earth leakage sensor. This connection box is easy to wire to the supply cable feeding the charging outlet and provides a resettable Type A RCBO (given over current protection and resettable residual current protection), DC sensitive earth leakage protection and also has an open PEN fault protection device that actually senses when there is a fault current flowing from a PEN fault, so a great deal better than just measuring mains voltage and guessing whether there may be a fault (which is essentially what the matt-e does). There are other units around with voltage sensing relays, which is essentially what the matt-e is, but they all suffer from the same problem in that this method cannot reliably detect a PEN fault.

The Viridian box uses a very similar open PEN fault protection system to the Zappi, and is probably only very, very slightly less effective than the protection offered by either fitting an earth electrode or by using the Indra charge point, with it's local earth sensing option.

The Viridian connection box is sold by Ecoharmony (I have no connection with them at all, other than as a customer): EVSE Connection Centre with PEN Loss detection - IP65

 

[Tom Blandford]

Interesting point about the difference in installation cost versus the difference between the night tariff and the feed-in day tariff. Could be playing with only a few quid here! By chance I have a spare earth rod in exactly the right place, so that helps push towards Ohme being cheaper too.

I have a feeling that Ohme will soon add a feature which allows net consumption to be an input. Combined with tariff data for Octopus Outgoing, that would be powerful. But would the current chargers be upgradable?

Not an easy choice. Probably not worth worrying about. Shame there isn’t a do-it-all solution at this time.