Communications Cable requirements for the EV charger. What's needed?

I'm currently having solar and battery installed. the installation is almost complete and will be connected and commissioned in a couple of days. Part of the plan was to have a new EV charger that would take the excess solar and put into the car. Until recently, the go-to choice for this would have been the myenergi Zappi and I was about to commit to that but the GivEnergy announce the EV charger. I think once can assume that integration with the GE inverter and battery would be much slicker with the GE EV charger and reading the specs, that seem to be the case, so I've selected this for the EV charger replacement.

As folk will know, the charger will not be available for a little while and so my installer needs to prep the wires accordingly. Of course the power is already there it's just the comms cables.

The user guide on page 5 states...

A two core shielded communication cable must be wired between the charger and the EM115 meter, in order for the charger to charge the vehicle from excess solar.
Additionally, the charger can be wired directly to the GivEnergy inverter in to the meter communication port so that the charger can be controlled by the inverter (coming soon).

So does that mean two comms cables are needed? One from the charger to the EM115 meter and one from the inverter to the charger or is it just one from either? The manual states "additionally". Does either connection give the same function or does one offer more features over the other?

Can someone confirm please? As you might expect, I'd like the installer to have all the detail to put the cables in the right place now rather than re-route and drill later. I have reached my threshold on wires and holes in the house!

Thanks

Yorkie71 I think it's just saying that you need a single two core shielded cable either to the EM115 or the inverter.

In practice, most installers seem to use either a special EV charge cable with an ethernet cable within the sheath (quite expensive for long runs but very neat), or (as my installer did) a 6mm2 SWA cable with a UV-resistant Cat 5 ethernet cable tie-wrapped to it. Not as neat but it's clipped under the rendering bell, so out of sight anyway.

The Cat 5 has four pairs of cores, so could carry up to four Modbus/CT signals. Since the EM115 will also be connected back to the inverter over Modbus (even if over LORA), connecting the cat 5 cable to the EM115 would connect the inverter and EV charger although it's probably best to wait until the EV charger install to make the connections. Depending on where your inverter and EM115 are, the cat 5 from the EV charger point just needs to get to one or the other.

I would get confirmation from support@givenergy.co.uk in this instance.

There are so many items that need to be clarified in order to get the correct cables installed.

1/ The EV charger manual does not state where the EM115 meter should be placed. Presumably it should be monitoring the grid import/export, which is also a requirement for the inverter.
2/ The EV charger and EM115 have screw terminals for the comms cable, and a 'two core shielded communication
cable' is specified. The Gen2 inverters use an RJ45 socket for the meter comms connection, and an RJ45 plug does not suit being crimped on to that cable type. 1 twisted pair from within a CAT5/6 cable would suit better.
3/ The meter comms cable topology is not stated when the inverter is included. From my own knowledge of Modbus on RS-485 networks, a daisy-chain topology is required, so 2 devices each at end of line, plus 1 device in the middle with both in and out.
4/ It does not sound like the shared meter comms is supported yet, so you may be better wiring for 2 x EM115 for the grid import/export, with each one wired separately.

Thanks for the replies. I have emailed support with the question. Hopefully they will respond soon and if they do, I will post the answer here.

Simon_C

I would say that the EM115 for the inverter can be used for the charger as well, as all it is doing is reading the data to ascertain if there is excess solar being exported.
I very much doubt that GE would design something, that is to integrated into existing hardware, would need to have a dedicated EM115 and CT clamp. But let's see what response comes from GE.

@makse , I agree that it would be best if the inverter and the EV charger could share the same EM115 meter.

But it will be a shared Modbus network, so do both devices poll the same meter and risk data collisions on the network, or does 1 device poll the meter then publish the data to the 2nd device? Either way, they will need to play nicely together on the same network.

Simon_C
Since there can only be one master on an RS485/Modbus network, it must be assumed that they are designed to play nice if sharing of the bus is designed in.

Thanks for the information. It's all quite confusing really, well, it is to this newbie! I just need to make sure that as the EV charger won't be available for a while yet, that the installer gets the right comms cable in ready and doesn't have to faff with drilling and routing more cable later. Hopefully support will respond.

GE have confirmed that the EM115 for the inverter can be used for the EV Charger. Also connecting directly to the inverter will be support from the start.

makse did they mention when it would be available?

c_squared That wasn't a question in my email to them

If just had similar back from George on the support team. Very helpful, I hasten to add.

As far as I'm aware, wiring it through to the inverter itself is just an alternative. Some customers don't have an EM115 meter for instance.

I did request that the wording be changed in the EV install guide from "additional" to "alternative" as it suggest that the connection is needed in addition to what is standardly used.

makse I did.

We don't have a confirmed release date yet, however it should be before the end of the year.

Yorkie71 Midsummer need to start aligning then 🙂

makse Ah yes. I see what you mean.

Also GE agreed for me to swap out the cable for a longer one with no issues.

makse As in, longer than 5m you mean? If so, then yes, when they are eventually released, I could do with a 6 or 7m cable. Would be good to have that option.

Yorkie71 Yes. I have a pod-point with 7.5m and just reaches depending on parking situation. 5m would be no good.

Yorkie71 Also you would have to purchase the longer cable yourself and get it fitted to the charger by the installer.

I'm also waiting for this charger to be available. My fear is getting an installer to actually do the install - at the moment I'm finding (for a new battery install) - as well as many neighbours - installers are not even responding to request for quotes. Not only can you not get equipment but you can't get people to install. I'm happy with electrics and pc hardware/software. Do you think this EV Charger will be able to be installed by 'end users'? I can see myself in the position of having car in garage, ev Charger sitting there are waiting for months and not being able to get it installed. (Seems installers are only interested in the 'big' jobs - not the small. Fair enough I guess).

quarkrad I would contact local Sparkies as you don't need a specific EV charger installer.

The kit list and install instructions just need someone who can competently work of electrics.

Glad I have seen this as it gives a bit more info on the wired to the Inverter comments in the install manual.