New Comms Hub 🐙 - No gas 1/2 hourly readings

Heedtheadvice

Here are the diagrams I mentioned at last. Apologies for the delay.

The diagram is based upon the Zappi manual instructions and is a bit more pictorial than the block diagrams

The first is the normal connections through the CTs as advised by Myenergi. (It should be noted that the Zappi has provision for extra CTs but that is not available on all EV Chargers so the simple common case is depicted)

That connection and CT positioning Scheme suffers from the potentially unwanted case of the Storage Battery discharging in to the EV as the BESS CT clamp measure the total property grid current which includes the EV charging current

This second diagram is a simple modification to route the EV charging neutral not directly back to the consumer unit but via the BESS CT clamp. 

The modified Neutral routing removes the needs for any Henley blocks. 

The downside is that the Neutral is a permanently installed routing.

There are thus three very effective installation method to avoid unwanted BESS discharge:

1 The original diagram as posted by SuzeQStan with Henley blocks  and the better simpler more conventional  routing posted by QrizB with just one Henley block. Advantage being the ability to Change the BESS CT clamp position and thus use the Battery to help or solely charge the EV (if there is sufficient BESS capacity). Downside could be the need to physically move the clamp to change functionality which is not for everybody or possible not practical.

2 The Reroute of the Neutral: simple again avoiding any Henley blocks but not possible to change functionality without a rewire or extra switching

3 The Zappi extra CT method ( not shown ) where a CT clamp measures BESS current and can take that into account to prevent BESS discharge. Advantage here is that the functionality is under software control through a Zappi option setting and thus does not involve changes near the electrical circuits which may be inconvenient. Not everyone has a Zappi and often simpler chargers.

All three methods should work well but I would prefer number 3 ( a Zappi charger) so as to easily change functionality by a button press or two; and then the versatility of QrizB's method.

squirrelpie

Heedtheadvice said:

There are thus three very effective installation method to avoid unwanted BESS discharge:

[snip]

All three methods should work well but I would prefer number 3 ( a Zappi charger) so as to easily change functionality by a button press or two; and then the versatility of QrizB's method.

The other difference is that only the third method shows all the various components being routed through the CU and thus (perhaps) protected by an RCD. I'm aware that some EV chargers have internal RCDs now, but is that true for all of them?

QrizB

squirrelpie said:

Heedtheadvice said:

There are thus three very effective installation method to avoid unwanted BESS discharge:

[snip]

All three methods should work well but I would prefer number 3 ( a Zappi charger) so as to easily change functionality by a button press or two; and then the versatility of QrizB's method.

The other difference is that only the third method shows all the various components being routed through the CU and thus (perhaps) protected by an RCD. I'm aware that some EV chargers have internal RCDs now, but is that true for all of them?

With my diagram there's a mini CU between the Henley blocks and the EV charger. I left it out for simplicity, much as I left out the various isolators and generation meter on the solar PV leg of things.