Siemens VersiCharge EVSE

[MikeD]

Elephanthead: Tempting as it is to use the Versicharge (dialed down to 1/2 maximum 30a current) on a 20a circuit, the instructions (and so probably the UL listing requirements) do not allow it. From the "Installation and Operations Manual" (Document Number: 813540 [no version/date]):

A -- VersiCharge electric vehicle charging stations can draw up to 30 A at 240 VAC, 60 Hz (7.2kW of power). The complete electrical structure of the building must be adequately sized to handle the entire building energy load, under peak conditions, as well as the charging station load under operation.
B -- Verify that the 30 A draw from the VersiCharge will not exceed the loading for the Main Breaker of the structure.
C -- A 2-pole, 40 A dedicated branch breaker is required for both cord-and-plug installation and hard wired installations.
D -- Circuit must be sized for the max amperage requirement. Do not de-rate breakers or conductors based on amperage adjustment.
E -- The Siemens VersiCharge has the option of reducing the output amperage, to allow installers to define the power output of the device. This is designed to help installers and users manage installation costs and the amount of retrofitting required to install the VersiCharge.
F -- Amperage adjustment dial is for use by a qualified technician only.
G -- Purpose of the amperage adjustment switch is to limit the max power that can be delivered by the charging station.
H -- To provide additional protection, Siemens recommends the use of GFCI circuit breakers. Though this is not required by code, this will provide an additional level of protection for users and their property.

So the circuit must able to handle 40a, which implies at least 8/2 AWG w/ ground, protected by a 40a circuit breaker.

So what is the value of the current limiting feature? One might be that although you have a Leaf with a 6.6kW on-board charger, at home you mainly charge at night and have a full 7 or 8 hours period of time (say, 11:00p to 7:00a) to recharge and for some reason to need to or choose to limit the current demand. As example, perhaps you currently only have 100a (or less) service, and household load calculations indicate it is sufficient for 1/2 (or 3/4) maximum current VersiCharge operation, but not 30a. Or perhaps you have 200a service, but have two (or more) Leafs and a VersiCharge for each -- and again need to or choose to limit the current demand.

 

[srl99]

MikeD: I was under the impression this was the "don't need no steenkin' UL approval" board, based on all the fawning over hacked factory L1 EVSEs.

What's the UL problem? Dialing down the max amps is still using the EVSE within it's specs.

 

[MikeD]

srl99: You ask a very good question -- what is the risk of using the VersiCharge "dialed down" to use a maximum of 15a, say, on a 20a circuit (typically NM 12/2 w/ground AWG cable with 20a circuit breaker)? They aren't spelled out anywhere that I can find, but I can think of two (for all I know there may be others).

One risk, I believe, is that the VersiCharge malfunctions either via software or hardware (or both) and erroneously signals the EV that its maximum current (30a) is available rather than the dialed down current (say 15a). (I have to believe that there must be fairly foolproof internal safeguards to prevent it from erroneously signaling the EV an even higher current than its rated maximum!) If the wire to the VersiCharger is thinner than 8 AWG, say 12 AWG, it likely will cause an overloaded circuit, i.e. the wire gets hotter than the insulation is rated for (typically 60C or 75C), and it is possible that the wire's insulation can be degraded/damaged before the circuit breaker trips. Remember the car's charger may not always be drawing the 30a maximum, it may be drawing, say, between 20 and 25 amps -- and it may take a while for the breaker to trip (especially an old one). The insulation can get hard and brittle and crack over time -- posing risks for fire and shock.

Another risk is that someone (even an electrician) may inadvertently (or even deliberately!) dial the current higher, up to 30a, without realizing the danger, i.e. Murphy's Law.

I would guess that the latter is the more likely of the two.

 

[Nubo]

D -- Circuit must be sized for the max amperage requirement. Do not de-rate breakers or conductors based on amperage adjustment.

E -- The Siemens VersiCharge has the option of reducing the output amperage, to allow installers to define the power output of the device. This is designed to help installers and users manage installation costs and the amount of retrofitting required to install the VersiCharge.

G -- Purpose of the amperage adjustment switch is to limit the max power that can be delivered by the charging station.

These seem self-contradictory, or at least confusing. How do you "manage installation costs and the amount of retrofitting" when adjusting the max amperage, if not via selection of lower-amperage circuits?

 

[srl99]

If the breaker is properly sized for the wire, you will trip the breaker on overload. I don't know what the NEC says about the subject, however.

 

[Elephanthead]

I guess the only UL approved use of the current limiter is if you know that at times you are using say 80 amps of a 100 amp service before installation, you would run a 40 amp circuit to the versicharger and limit it to 50% so you wouldn't trip the main when everything turns on at the same time. This allows you to save installation costs by not having to upgrade the main service, and not under install the unit or its circuit, or violate code.

I don't know how the unit limits current but the setting is mechanical by means of a screw.

 

[TurboFroggy]

Dialing down a EVSE is nothing new. Say you had previous 40A EVSE's installed with an old connector like an Avcon or Paddle charger. The wires might only be 6 AWG and good for only 40 amps due to distance etc. If you buy a bunch of 70A EVSEs all in a bulk deal or to standardize on parts, it can be dialed down to match the available service.

The Tesla High Power Wall Connector (HPWC) can be adjusted from 32 amps all the way up to 80 amps (40 amp breaker up to 100 amp breaker) with internal dip switches. https://www.teslamotors.com/sites/default/files/blog_attachments/ms_hpwc_installation_guide.pdf

 

[srl99]

Let's not forget the vehicle is supposed to obey the pilot and only draw up to the advertised current. A popular L1 EVSE mod, puts out a 16A pilot on both 120 and 240, and relies on the vehicle to limit 12A on 120V (bad bet).

 

[TurboFroggy]

Let's not forget the vehicle is supposed to obey the pilot and only draw up to the advertised current. A popular L1 EVSE mod, puts out a 16A pilot on both 120 and 240, and relies on the vehicle to limit 12A on 120V (bad bet).

The "dial down" within the EVSE does indeed adjust the pilot to report a lower amount of current available to the vehicles onboard charger. All EVSEs have a current measuring device integrated into the unit. If the car draws more than what the EVSE is set to the EVSE will open the contactor with an error light on the unit.

 

[smkettner]

Could you install more if on a shared circuit? Say 200a circuit, 40a requirement would normally be 5 max. If you dialed them all back to 20 amp required could you put 10 on that circuit? Any single fail to limit power and it would not overload the main. Otherwise the language is rotton.

 

[TurboFroggy]

If you had say 200 amp service, as long as you didn't go over 80% of that, 160 amps then that would be fine.

You could have 4 40 amp units each on a 50 amp breaker, that would be fine.

8 of them dialed down to 20 amps on 30 amp breakers would also work.

You could have a mix as well, say 2 units set for 40 amps on 50 amp breakers than 4 at 20 amps on 30 amp breakers all feeding to a 200 amp service.

Anything with a 3.3KW onboard charger, which only draws 16 amps anyway, would be fine on the 20 amp dialed down EVSEs.

2013 Leafs with the 6.6KW chargers could plug into the 40 amp EVSEs etc.

If you could ensure staggered charging times, say via charge timers in the cars, you could have 10 units set for 40 amps each on 50 amp breakers as long as no more than 4 would be charging at once. Think about the breakers in your panel at home. If you add up all the amp ratings on all those breakers they are way more than the 200 amp main service breaker, same thing applies here.

 

[srl99]

Any source for the 70A version of this? Seems like just the ticket for the few vehicles which can take 40A (RAV4EV, Model S w single charger).

I'm looking for a source for parts - I'd like to swap my black faceplate for a grey one.

 

[fooljoe]

Anyone have real-world experience with the pilot signal adjustment feature yet? This is the feature that most sets this apart from the rest of the EVSE field, contradictory warnings in the manual notwithstanding.

According to the manual, there's a dial with settings 0-4, which do the following:
4: full, 30 amp capability
3: 75% capability, or 22.5 amps
2: 50% capability, or 15 amps
1: 25% capability, or 7.5 amps
0: minimum, 6 amps capability

I love the adjustability, but the choice of settings is really weird. It would make a huge deal more sense to have the settings go 30/24/16/12 amps, to match 80% of common 40/30/20/15 amp-rated circuits, which I believe is what the only other adjustable EVSE out there, the SPX PowerXpress, does.

My question to anyone out there who has the unit is this: Is this dial actually an analog device, i.e. can you set it somewhere between settings 3 and 4 to get the more useful 24 amp setting, or between 1 and 2 for 12 amps? The (mostly) linear choice of settings leads me to believe this might be true, although I highly doubt it, and if so would add much more "versi" to the Versicharge.

By the way, it blows my mind that the SPX is the ONLY EVSE out on the market that will pair perfectly with a 30amp dryer outlet (which I'm sure is by far the most common type of 240v outlet that people might find available in their garages), and unfortunately it has some timer issues with the Leaf, and apparently doesn't work with the Rav4-EV (which is what I'm trying to work with here.)

 

[DarkStar]

The 80% rule:

32 amp max draw from a 40 amp circuit
24 amp max draw from a 30 amp circuit
16 amp max draw from a 20 amp circuit

So, if you are using a 30 amp dryer outlet, you need to set your EVSE to 24 amps or lower. For a 30 amp EVSE setting, you need to use a 40 amp circuit.

 

[fooljoe]

The 80% rule:

Hence my recommendation of 30/24/16/12 amp settings for 40/30/20/15 amp circuits. Of course the first could be 32 amps, but the cord/connectors commonly used are only rated for 30.

So, if you are using a 30 amp dryer outlet, you need to set your EVSE to 24 amps or lower

Hence my bemoaning the fact that you can't buy an EVSE that works well with the Leaf (and other EVs) and can be set to 24 amps. Sure, you could do less than 24 with the Versicharge or evseupgrade or an LCS-25, but given that a 30 amp outlet is by far the most common you'd think there might be a product that takes full advantage of it.

So has anyone played around with a Versicharge or what?

 

[smkettner]

The 80% rule:

32 amp max draw from a 40 amp circuit
24 amp max draw from a 30 amp circuit
16 amp max draw from a 20 amp circuit

So, if you are using a 30 amp dryer outlet, you need to set your EVSE to 24 amps or lower. For a 30 amp EVSE setting, you need to use a 40 amp circuit.

It would be interesting if the evse could go three hours at circuit max and then throttle back to 80% of circuit rating. By then the EV BMS might be tapering the current anyway.

 

[DarkStar]

The 80% rule:

32 amp max draw from a 40 amp circuit
24 amp max draw from a 30 amp circuit
16 amp max draw from a 20 amp circuit

So, if you are using a 30 amp dryer outlet, you need to set your EVSE to 24 amps or lower. For a 30 amp EVSE setting, you need to use a 40 amp circuit.

It would be interesting if the evse could go three hours at circuit max and then throttle back to 80% of circuit rating. By then the EV BMS might be tapering the current anyway.

Correct, the vehicle controls it's own charging rate.

 

[fooljoe]

It would be interesting if the evse could go three hours at circuit max and then throttle back to 80% of circuit rating. By then the EV BMS might be tapering the current anyway.

Interesting idea - so 3 hours is the cut-off for whether a load is "continuous"? There's no reason why an evse couldn't do that, it'd just have to have the capability on its logic board to program that in. That'd probably be an idea for open-evse to try out.

 

[Webguy]

I had an electrician install it and it works great. Now I don't just charge my Leaf, I inSiemenate it!