Prevent EV charger draining home battery

So I have an issue, my zappi was installed yesterday and for the most part it will work how i want it to. Home battery will charge from pv first and then any excess will go into the EV. During my Go period the battery will not discharge and the car will charge. HOWEVER there will be times I will need to boost the EV outside of my Go window and ideally do not want this to drain the home battery. My installer says there is no way to do this.

Anyway I can set the zappi to boost charge from grid only? Or do I have to accept that outside the hours of 2130 - 0230 if i boost charge the car it will drain the battery?

GE can we get a PAUSE DISCHARGE option added? On a mobile app would be great!

THALL you on Android?
Custom App
Gives you a pause button and some charge and discharge sliders.

The MyEnergi api is well documented now so you can also go down that route similar to what I do with My Ohme and Ondra chargers to automate should you wish (If you search on here I’ve some examples)

hoggy That'll do 😀 Cheers for that. I wish there was a hardware bypass though, just have it use solar and grid. But this will do the job. Cheers

I've got a zappi and the method I use is...not being able to get an EV! 😆

judgepd I know that method! Though my order has been brought forward from the first week of September to the last week of July. Hopefully it will come sooner!

I was thinking more about this zappi setup and i am going to ask for the priority of the system to be changed to PV, home, zappi, GE battery. As the zappi needs 1.4kw minimum and will only work when the car is plugged in I think this makes more sense!

UPDATE : checking through the zappi 2 wiki page I found https://myenergi.com/wiki/zappi-v2/13650-2/ section Supply Grid Battery. It can be done!

THALL depends on.your setup.

AC inverter coupled GE battery yes.

Hybrid GE inverter and battery no.

Also the Zappi will have all of your PV generation up to 7kw prior to charging the GE battery unless it's below 1.4kw (ignoring background load).

I've found it's not an issue until you drift into the space where the battery is having 2.5kw but you don't have enough PV generation to get the Zappi to run as you really need 4kw of PV at that point.

You could use the battery charge slider to tweak on the GE side but you end up with the same issue if it's not continually tweaked as generation changes.

I'd love to see an option to charge the car if there is PV available and divert the excess into the battery instead but that requires integration from the GE side or some clever stuff with HA or other APIs.

It's worth noting if you have a Myenergi hub it's not fussy where the CT clamp feeds are, my grid CT feeds the Zappi whereas my Eddi is connected to the inverter (and DC coupled battery) output.

yandards I do have the AC3 inverter so my thinking is setting the advanced options on the zappi 2 to Avoid Both will work just how I want. If the car is already charged or not plugged in the zappi will not hog the PV leaving the GE system to charge. If this works how I think it does then I should be able to leave everything setup without messing with sliders, apps etc. So moving forward the only setting I need to change is turning on and off Timed Charge in the GE ecosystem as we move from winter to summer and back.

So priority model for me will be
PV
House
Zappi (will only start drawing PV once 1.4kw available)
GE Battery (will take PV up to 1.4kw, then after the zappi is finished)

Plug n play, no tampering with other setting. Hopefully.

Don't forget if you've got an overnight charge set on the zappi then the avoid drain and avoid charge settings won't help. You need to set a timed charge on the battery for the same time (even if you set a percentage of 5% or 10% so it doesn't actually charge) to stop the battery discharging.

I'm hoping my daytime plan will be nice and simple, I always want the battery to charge first and fill and if there is still excess solar after that then charge the car.

THALL should be fine with the AC coupled setup as your PV inverter feed and battery feed are different.

As you just have the battery you can set the avoid drain option for the battery inverter CT clamp feed.

Depending how your wiring side is setup and how far away the Zappi is it might be worth having a Harvi for the CT clamp feeds from your PV inverter and battery inverter.

I'll be interested to see how it pans out as I don't know if you have the option within the Myenergi app side to prioritize the Zappi over the battery charging - mostly as mine is a hybrid so it doesn't work at all!!

judgepd The overnight boost charge will still drain the battery? I didn't realise that. I thought the avoid options would effectively bypass the battery.

yandards Got a harvi, the zappi is 15m cable run away from the clamps etc. This sparky was the only one who listed a harvi, the others just listed extra ct clamps. Though this installer is worrying me as didn't appear to know about the Drain options on the zappi! He was also due first thing this morning and its now 11 and still not here. Fills me with confidence!

I believe avoid drain/avoid charge only work when charging in eco+ mode.

My installer didn't know about that option either and also told me I could power my house using the EV plugged in to the zappi...I wish!

judgepd My installer didn't know about that option either and also told me I could power my house using the EV plugged in to the zappi..

Wow. 😅

THALL The myenergi installer reference stuff gets pretty murky when you are installing multiple bits of kit.

I was all set to go and buy another CT clamp so I could at least see my combined inverter and PV output on a much higher refresh frequency rate. Then digging into the documentation it transpires that if you have a hub you can plug any CT clamp into anywhere pretty much any unit.

I've just gone and grabbed the Zappi instructions, page 24 and 25 of rev 1.6.3 Mar 21 cover the battery side of life.

You'll need to set the CT type to AC battery on GE inverter output live to consumer unit, 1 CT on the supplier metering unit live and the final CT on the live output from the PV inverter to consumer unit.

That should see a PV icon and battery icon in addition to the Zappi, grid and house icons on the myenergi app.

If you've got a combined PV and battery icon it's been set wrongly to 'gen and battery'.

You then have an avoid drain, avoid charge or avoid both options on the Zappi for the battery stuff, avoid drain prevents the zappi draining the battery when using surplus power from PV or wind, avoid charge prioritises the Zappi over battery charging - this will take all available PV up to 7kw. Avoid both should do both of the above.

That said the bit I highlighted in bold is interesting as it implies it only stops that in the event of PV being used to charge the car not overnight charging which is a bit weird.

I've got my GE battery on a charge overnight in-line with the Go hours, the car only gets charged overnight between those times so I don't see any battery drain from the house to the car.

My understanding of ECO+ mode is that its gives an allowable percentage of the charge to be grid supported, problem with that is that the GE side will then meet that demand to prevent grid draw. There is some merit in having a touch of battery support during PV charging due to cloud cover - a lot of cars will fail a charge and lock the charger out after a number of disconnect and reconnects.

I am going to try the 'Avoid both' option but I think I already did and there was issues. I'll play around with this later.

My battery went 100% today from the solar so I just plugged in my granny and shoved the excess into the car from the solar and minimal from the battery.

THALL Hi I'm confused by your Harvi comment. I have a Harvi, it has 3 sets of terminals to connect the CT clamps. Once you connect in the Harvi the Zappi picks it up wirelessly via the Hub. You just have to tell the Zappi what each one does.

My Harvi has 2 ct clamps connected (one to grid, one to battery) and is 25 metres from my Zappi.

mjkelly5a What was my comment again?

Turns out as i have dual PV I will need a second harvi and another CT clamp later. For now the setup will just monitor 1 pv, the grid and the battery

THALL A Pause battery button is being added in the app and portal. thanks for the feedback.

Danlambert (GivEnergy) Would there be any chance of making a locked posts listing ETA for all the work and changes being made behind the scenes? Even a list of things to help the end user plan for changes and new features.

mjkelly5a @THALL so I set the Zappi to 'Avoid Both' whilst the sun was out. Lo & behold it worked. 2.4kwh from the array went into house 1st 0.3kw & the remaining into the car. The sun clouded a bit, dropped to 1.2kw and 0.3kw went to power the house and the remainder to the battery cos it was under 1.4kw. However the MGL was set to 60% so I'm not sure what was happening there. In theory 840 kw (60% of 1.4) should have powered the car.

The really annoying thing was that for 30 second or so on each switchover most of it went to the grid.

But the the reply really really really annoying thing was the long haired general arrived home put the kettle & tumble dryer on so the experiment came to an abrupt end! 😆

mjkelly5a Following a length chat with myenergi to check all of my settings I have gone with a MGL of 100% so need a full 1400w surplus before charging from solar rather than topping up from the grid at all. I have also increased the wait period from the default 30 seconds to 60 seconds. myenergi reason was some EV's will only allow a limited number of stop starts for charging so a longer period before starting is beneficial. Obviously I can not test any of this yet...... But my current model is this

PV
Home
EV
GE Battery

So the GE battery will grab anything between 0 and 1400w, once it gets to 1400w the zappi will grab it if the EV is connected and charge the car instead. ECO+ mode set as default with a scheduled boost charge for my Go Faster times, the GE battery set to charge from grid during those times and I will just move the charge slider down to 4% (minimum) during spring summer etc. Win win. Hopefully!

I am still considering looking at Agile again, though having the EV and doing 16k miles per year might make that a bad idea. Still considering a second harvi and extra CT clamp to monitor my second pv but that is purely a luxury monitoring only so might save £70 and not bother.

My zappi settings
Charge settings
Eco+ settings = set min green level to 100%
Plug-in charge to YES
Default mode = ECO+
Settings
Lock Function
Charge = NO

Advanced menu
Supply Grid
Device = Device limit to MAX
Network = Export margin to 0w
Battery to avoid both
Esense input = Disabled

The statement 'some EV's will only allow a limited number of stop starts for charging so a longer period before starting is beneficial' is an interesting one. If you are getting an ID3 then when they 1st came out they wouldn't charge on a Zappi for exactly that reason. MyEnergi had a real mare with VW on it when VW failed to follow global charging standards. that statement was one of the issues and it applied to a lot of smart chargers.

They asked me would I allow a local VW ID3 1st edition owner to come to my house and try to charge. he did and the issues he was facing were the car and not Zappi related. He gave the car back and I got a nice bottle of Malbec as a thank you.

VW had to amend & change a lot of SW stuff after some of this came out.

I moved mine (eNiro) down to 30 seconds and it's been ok for 18 months now.

This statement 'So the GE battery will grab anything between 0 and 1400w, once it gets to 1400w' once the GE battery is 100% does it all go into the car?

mjkelly5a Well fingers crossed the stop start issues are better now, mine should come with the version 3 software as standard. Its not being built until the start of June!

If the GE battery is full any generation between 0 and 1399w will export to the grid. If generation goes over 1410 (i think its 1410w on my zappi screen) it will charge the car. So should be minimal export to the grid, and only importing from the grid during my cheap rate.

EDIT: going through my setup in my head has convinced me not to bother with Agile. I wont be able to stop it draining the GE battery. Unless the tariff automation syncs perfectly so the GE battery sets to charge only when the Zappi does? So it will be less faff if I just stay on Go.

THALL Not sure if you are on the MyEnergi forum but this is a decent post https://myenergi.info/viewtopic.php?p=48216#p48216

mjkelly5a I am on there but don't currently post.

Surely with the increasing popularity of hybrid inverters there needs to be either:

1) An output that can emulate what a CT would show for battery charge/discharge from the hybrid inverter
2) a standard API agreed so that things like car chargers can query the rates and avoid problems like this.

Hybrid inverters are probably not going away any time soon and the zappi settings seem a bit of a bodge to make it sort of work.

The pause discharging is useful, albeit not quite the same as a standard. Can the pause be time scheduled too?