Maximum power of charging

[Alessandro]

What is the max power I can charge the battery from my home charger (220 V, 3 kW) ? I say that because I have a ~ 6 kW solar pv that can give me an extra 2-3 kW on a regular basis, so could I charge the battery from those 10 kW, at max ?

 

[MikeS]

'I can charge the battery from my home charger (220 V, 3 kW)’ - If you mean you have an EVSE (electric vehicle supply equipment), like for example the BMW i wall box pure, rated at 3kw, then this is what will constrain your max charge rate. In simple terms 3kw divided by 220v = 13.6 amps

 

[Alessandro]

Thanks for you answer.
Actually, I haven' t any electric car, yet, but I'm trying to find infos how I could maximize my solar PV potential and the devices eventually needed - the optimal should be to have a device capable to set different power levels, depending on the solar PV production in that range of time (edit : for example, with a home 220 V, 3 kW connection I have available at max 4 kW electric continuos for 3 hours plus the instantaneuos solar PV power, if any)

 

[Alessandro]

By the way, how many net kWh does it take to fully charge your i3? Does it change anything from a pure BEV and the Rex version ?

 

[MikeS]

It is possible to set the i3 to charge at a specific time so you could choose to have it charge during the time the PV normally produces an output. There are systems available that monitor PV outputs and switch on devices accordingly but I have not yet seen anything that specifically uses the PV output.

 

[MikeS]

For a full charge I guess 18.8 kw. I understand the battery is rated at 22kw but it only ever uses 18.8kw.

 

[Alessandro]

Thanx again, as far I understand 18,8 kWh is the part of the 22 kWh battery actually used in the i3, but there is also some charging loss, I guess (something like 80-90% at least, so those 18,8 kWh becomes 21 to 23,5 kWh depending of the kind of charging). That also means, if I understand it correctly, that with the help of my solar PV (mostly of the year) potentially I could fully recharge from zero a BMW i3 in a 3 to 4 hours. If it's so, not bad...

 

[BrianStanier]

The maximum that the i3 can charge at using the standard Mennekes type-2 'fast' connector is 7.4kW. You can only use that if you have an EVSE such as the BMW wallbox with that rating. I don't understand what you mean by 'having a 220V 3KW home charger. If that is an EVSE rathed at 3kW then you can only charge at 3kW because you must have an EVSE between the i3 and the power supply.

 

[Alessandro]

Thanks again.
For instance, actually my main concern would be to set the charging process so that I can use the home elect power only (with no solar) or if possible the sum of solar power (when available) plus home power, say 6 or 8 kW, I hope it's clearer now

 

[BrianStanier]

If your solar array feeds into your mains supply as is the usual arrangement, and you can monitor the solar power and you have an EVSE
which can change the maximum current they supply then it should be possible with some extra circuitry. As far as I know the BMW wall box does not allow this.

 

[Alessandro]

The maximum that the i3 can charge at using the standard Mennekes type-2 'fast' connector is 7.4kW. You can only use that if you have an EVSE such as the BMW wallbox with that rating. I don't understand what you mean by 'having a 220V 3KW home charger. If that is an EVSE rathed at 3kW then you can only charge at 3kW because you must have an EVSE between the i3 and the power supply.

Ah, ok. So, if I started to charge at 7.4 kW then I can't swithch a bit later to, say, 3 or 4 kW (due to loss of solar power) ?
Assuming I had that power, instead, does it mean that with this 7.4 kW connecton it takes only 3 hours to charge the battery, including losses ? By the way how much does it cost ?

 

[ultraturtle]

This reply assumes that you are in the USA. It would help all of us to help you if you would kindly update your location on the Profile in the User Control Panel (click upper right icon). Sorry if I guessed wrong....

... By the way how much does it cost ?

There's a thread on that. See http://www.mybmwi3.com/forum/viewtopic.php?f=10&t=692

My take is

...you can easily install a 30A EVSE yourself for less than $700 (EVSE $570 from Bosch or $590 from Clipper Creek, breaker $15, old work box $2, 8ga wire $0.83/ft), or make and install your own for less than half that (https://code.google.com/p/open-evse/). If Congress renews the credit (unlikely), you can recover 30% of the installed cost on your 2014 tax return (http://www.irs.gov/pub/irs-pdf/f8911.pdf), bringing the net cost to less than $490.

 

[Alessandro]

No, actually I'm in Europe (Italy) right now (and I' m not a BMW i3 owner, not yet at least). Thanx so much anyway, very useful infos

By the way, an other problem I could face to is to have a "mobile" charger in two or more different houses (both with solar PV plants), say, for example, at home and a friend of mine' s house, what about it ?

 

[Alessandro]

An other point where I' m a bit confused is which kind of charging is the most efficient, for example I heard that 6 kW is more efficient than 3 kW and so on, is that true ?

 

[CompuMagic]

I am investigating chargers for my ordered i3 (USA). It has been stated that 7.4 kW is the max the car can handle form a home charger, but in all of the chargers I have looked into they are all rated at 7.2. Does anyone know of a charger that can charge at the full 7.4?

 

[ultraturtle]

No, actually I'm in Europe (Italy) right now (and I' m not a BMW i3 owner, not yet at least). Thanx so much anyway, very useful infos

By the way, an other problem I could face to is to have a "mobile" charger in two or more different houses (both with solar PV plants), say, for example, at home and a friend of mine' s house, what about it ?

Most EV owners keep it simple and use a wall mounted aftermarket EVSE at home, and keep the plug-in unit that comes with the i3 in the car for other charging opportunities.

 

[ultraturtle]

An other point where I' m a bit confused is which kind of charging is the most efficient, for example I heard that 6 kW is more efficient than 3 kW and so on, is that true ?

For other EVs, overhead losses at different charging power levels are similar, making higher powered charging slightly more efficient. I assume the i3 will operate similarly.

 

[ultraturtle]

I am investigating chargers for my ordered i3 (USA). It has been stated that 7.4 kW is the max the car can handle form a home charger, but in all of the chargers I have looked into they are all rated at 7.2. Does anyone know of a charger that can charge at the full 7.4?

Look for a 32 amp EVSE. A lot of them are 30 amp, including the one I installed. It'll take 3% (roughly 5 minutes) longer to get a full 18.8 kWh charge, but I saved $300.

Here's a 32 amp Leviton unit: http://www.homedepot.com/p/Leviton-...-ft-Cord-031-EVB32-M8L/204366717?N=5yc1vZc3gj

 

[AviatorMan]

Thanks again.
For instance, actually my main concern would be to set the charging process so that I can use the home elect power only (with no solar) or if possible the sum of solar power (when available) plus home power, say 6 or 8 kW, I hope it's clearer now

Alessandro,
I think you are asking two questions, and one of them is if you can use the solar power, added to the mains power, to charge faster. But most houses have much more power, for example my total mains power available is 48KW, so in theory I could charge an i3 in 20 minutes. But I think we are limited to the charging equipment, not the amount of power available, so I do not think the solar equipment will provide faster charging.

 

[CompuMagic]

I am investigating chargers for my ordered i3 (USA). It has been stated that 7.4 kW is the max the car can handle form a home charger, but in all of the chargers I have looked into they are all rated at 7.2. Does anyone know of a charger that can charge at the full 7.4?

Look for a 32 amp EVSE. A lot of them are 30 amp, including the one I installed. It'll take 3% (roughly 5 minutes) longer to get a full 18.8 kWh charge, but I saved $300.

Here's a 32 amp Leviton unit: http://www.homedepot.com/p/Leviton-...-ft-Cord-031-EVB32-M8L/204366717?N=5yc1vZc3gj

Thanks for that info... but look at this: http://www.leviton.com/OA_HTML/SectionDisplay.jsp?section=50194
It says 7.7Kw :

– the Evr-Green 320 Level 2 Home Charging Station. The new device provides up to 32 amps at 240 volts AC (7.7 kW output) – reducing the charge time of any SAE J1772™ compatible electric vehicle by seven percent when compared to leading competitors


And check their latest: http://www.leviton.com/OA_HTML/SectionDisplay.jsp?section=58375&minisite=10251

up to 40 AMPS and 9.6 KW... would either of these work with the i3?

Looks like it costs about 1200.00 on their site... it also says: The Industry Exclusive 40A Charging Station will optimize the charge time for vehicles with onboard chargers larger than 6.6kW.

Amazon has the surface mount for 949 but I read you should also get the kit in order to use the plate for mounting:
http://www.amazon.com/gp/product/B007Q12X6U/ref=oh_details_o01_s00_i02?ie=UTF8&psc=1

And the charger itself: http://www.amazon.com/gp/product/B00DG1479A/ref=oh_details_o01_s00_i03?ie=UTF8&psc=1