Ventilation required state

[Benjamin Staubli]

Hi all,

i don't quite get the thing with the "ventilation required" state (state D).

When is the ventilation needed? What is ventilated? How does it affect the charging process?

Does it depend on the car model whether it ventilation is required?

I understand that if ventilation is required, the car puts a 270Ohm resitor in place instead of the 1.3KOhm. is this right?

Thank you all for your help!

[Lee Howard]

On 08/19/2013 02:06 PM, Benjamin Staubli wrote:
> i don't quite get the thing with the "ventilation required" state
> (state D).

Some batteries can release hydrogen (and perhaps other gases) while
charging. If the EV is being charged indoors, then these gases need to
be vented in order to prevent a dangerous environment. The EV which
contains such batteries is tasked with knowing when such ventilation is
required and signalling this indication to the EVSE. The EVSE is
required to turn the ventilation on in order to continue charging.

> When is the ventilation needed?

Whenever the EV says that it is.

> What is ventilated?

Gases.

> How does it affect the charging process?

Charging can only continue in such a condition as long as venting is on.

> Does it depend on the car model whether it ventilation is required?

Certainly. Some batteries do not need venting.

> I understand that if ventilation is required, the car puts a 270Ohm
> resitor in place instead of the 1.3KOhm. is this right?

I'd have to refer to the spec although I'm sure that others here can
answer that immediately.

Thanks,

Lee.

[chris1howell .]

The Ventilation required state would be for a vehicle with Lead Acid batteries. The charging process of Lead Acid batteries produces hydrogen. When an EV requests ventilation the EVSE should either turn on ventilation and allow charging or go into an Error state and deny charging. OpenEVSE by default goes into an Error state if ventilation is requested by the EV.

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[Nicholas Sayer]

Lead-acid batteries, when charged, can generate hydrogen gas as a byproduct. With enough batteries, the amount of gas could wind up being explosive if kept in a confined area. EVs that have such batteries can signal to the EVSE that they must be charged outdoors or in a ventilated area with state D.

[Benjamin Staubli]

Thank you all for the fast answer!

How many cars do require ventilation? It can't be that many, since OpenEVSE doesn't support it, right?

Thanks again for the support!

[Nicholas Sayer]

I don't believe there are any production cars presently that require it. When I went to REFuel 2013, there was a Porsche 912 that had been converted to a BEV. I believe it had all lead-acid batteries. They must have weighed a ton. I don't know if that guy had added J1772 or not, but if he had, it would have been appropriate for him to signal state D instead of C.

On Monday, August 19, 2013 2:06:35 PM UTC-7, Benjamin Staubli wrote:

[Rush - EV@TucsonEV.com]

The ventilation command goes to the EVSE unit, which in turn 'should' have a relay that energizes a fan of some sort to ventilate the garage or parking space that the EV is in. 

It is for cooling the the room and hopefully the car's charging system.

Rush

www.TucsonEV.com

On Monday, August 19, 2013 2:06:35 PM UTC-7, Benjamin Staubli wrote:

[Lee Howard]

It's for ventilating the room - not cooling per-se.

Some batteries emit a gas when they charge and that gas must be ventilated.

Fortunately, most cars don't have such batteries, and thus, State D
doesn't get used ever with them.

If the intention is to provide cooling for the ambient temperature, then
J1772 sure does not make that very clear.

Thanks,

Lee.

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[Nick Sayer]

On Sep 23, 2014, at 11:18 AM, Lee Howard <fax...@howardsilvan.com> wrote:

> It's for ventilating the room - not cooling per-se.
>
> Some batteries emit a gas when they charge and that gas must be ventilated.

This is absolutely correct. Cars charging unsealed lead-acid batteries from J1772 must use state D to indicate to the EVSE that it’s unsafe to proceed unless the car is outdoors or the interior space is ventilated. That’s why it’s an optional error state in OpenEVSE. If you know your EVSE plug is only able to be used outside, then it’s safe to ignore state D, but not otherwise.

Oddly, most commercial EVSEs error unconditionally on state D, even if they’re installed outdoors. That can only serve to encourage owners of retrofit cars using lead-acid traction batteries to “fib” to the EVSE, with potentially hazardous results.

Fortunately, my perception is that just about everybody is using LiPoly nowadays, which makes the whole thing moot.

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[Learnmode]

Hello All,

I am new to EV technologies.

Is there any snap shot or guide how to install ventilation to EVSE ( Indoor and outdoor)

Regards,

Deepak S