Iomagico

Hi,
I got an home wallbox 32A single phase 240V (7.2 kW) and used it without problems on my previous EV.
The EQS specs indicate same max speed for AC single phase charging but, as matter of fact, I can only charge at 16A (3.6kW).
Looks like the onboard charger works with 3 phase (11 kW) or 1 phase (3.6 kW) only, despite the specifications.
Any experience with one phase wallbox?

Diesel Benz

Where is your home? US, Europe, somewhere else? The reference to 240 V confuses me.

Iomagico

I am in Italy and we use 240V grid voltage.
EQS specifications says that onboard charger can delivery 11kW (16A) over 3 phases (400V) or 7.2kW (32A) over 1 phase (240V).
I am trying to charge @32A 1 phase 240V (7.2kW) but my EQS 580 only accepts 3.6kW (16A).
Almost any car with 16A 3 phases onboard charger (tesla, bmw, etc…) merges 2 phases to reach 32A 240V and Mercedes EQS Specifications says same.
Take a look on ev database for my car

https://ev-database.org/car/1484/Mer...C#charge-table

Diesel Benz

Your reference has an obvious mistake. The standard EQS Euro charger supports 11 kW from a 3 phase source. That is 16 A per phase. 3.7 kW from a single phase source, 7.4 kW from two phases, 11 kW from three.

The optional 32 kW charger would be capable for 7.4 kW from a single phase charger but a 32 amp single phase wall socket is quite rare in Europe. 32 amp and even higher 3 phase wall sockets appear everywhere.

Iomagico

My other EV is a BMW i3s with same 3 phases on board charger capable of 16A. But at same time it can merge 2 phases to achieve 32A on a single phase (7.2kW @ 240V). Same for every european Tesla, etc…

Diesel Benz

I see, haven't heard of such behaviour before this, thanks for sharing. Sounds a bit dangerous too. If you were charging from a 3-phase plug and one fuse gave up (say another consumer in the house), the car would try 32 A from a 16 A feed. The wallbox is not able to tell the per phase max amperage and the car would not know it should stay at 16 A. Another fuse would give up.

By the way, where do you try to use this 32 A single phase wall socket? At my place in practise all family houses have 25 A main fuses, no way to install a 32 A wall plug. Even 16 A schuko sockets is not recommended for long term use, like charging a car. The factory emergency charger that came with the W213 plug-in hybrid was physically max 16 A but was coded for max 10 A. Why would you want to use a 32 A single phase charger instead of an 11 kW wallbox?

Iomagico

My home installation is a 3 phases 22A each for a total of 5kW for each phase (15 kW on 3 phases). This power is provided by 3 inverters connected to a lithium batteries storage feeded by the photovoltaic panels. This is an off grid system.
I already have an 11kW 3 phases wallbox which I use for the BMW i3s.
My previous EV was a Jaguar iPace which had a one phase onboard charger 32A (7.2kW) so I bought a special wallbox which merge 2 phases in one to achieve a total of 32A.

https://evtun.com/chargers/accelev-2...r-6kw-8kw.html

I never had a single problem with it and even if the logical solution can be to swap those wallbox for my 2 cars, this is just impossible because of the garage wiring installation.

Diesel Benz

Please tell us more about your lithium battery storage. How many kWh and how much have you paid for the system (with or without panels)?

Iomagico

Sure.
I have a grand total of 8.3 kW peak power PV installed on my roof (29 panels) and around 50KWh lithium storage.
I’m a lithium storage designer and own a specific company and used a very special chemistry for my storage.
Commercial prices for PV are around 1.2 k€/kW (installed) and storage it depends on many factors but an estimate can be around 1.2/1.5 k€/KWh

Diesel Benz

Any option to add an interface for DC-charging the car? A bit better efficiency but most of all a lot faster charging.

Iomagico

That’s is still my secret dream…..
Only real obstacle is to increase the actual storage voltage (around 50V), to 400V.
Doing that efficiency should increase around 10% (considering a 3% inside the inverter to convert to AC and 7% for the onboard charger).
IMHO for domestic installations, it makes no big sense.

Diesel Benz

Why not an up-switcher from the current 50 V source? Not very different from a 400 V three phase AC supply? The DC source should anyway work under control from the car, the source should set the charging current as ordered by the car.

Agreed that DC charging is not very important for domestic use but you seem to be almost there already and this would solve your 32 amp AC charging problem too. It would not have to do anything like 100 or 200 kW and still help to quick charge for an unexpected long trip.

Iomagico

Storage is placed at around 25 meters from the EVs and to achieve a quick charge I have to think on 20kW DC.
This is 400A @ 50V and this is not a joke for cabling.
Even if I put the step up voltage very close to the storage have to think on cabling a long distance with very high DC voltage.
Not that simple, believe me.

Diesel Benz

The very high DC voltage is not much different from your 400 V 3-phase AC to your house, peaks much higher than 400 V.

A pity if your battery pack is that far from the garage. Having the step-up converter at the battery would reduce the amperage but the DC charger controlled distance from the car would become unacceptable.

I'm still puzzled why you insist on single phase AC charging while also being so concerned about about wire amps. Interesting user case anyway!

Iomagico

I am insisting on my single phase wallbox just because I already got it and it is already installed and working…..
To be honest I never thought EQS would accept just 16A on a single phase so have to find a workaround. Will probably buy a portable 32A 3 phases wallbox which can be useful even during a trip or when I need to pull out more than 3.6kW from my house (typically when my storage is already full and sun is shining)