1938241-00-A Smart Current Limits Meter - Wall Connector

[DBeckwith]

I have a need for a DCC-9 type product and am hoping this will do the job.

Our local Tesla parts manager said it costs $320.00 and several thousand are at the Lathrop warehouse. This is 1/3 the price of a DCC and potentially more effective. However I'm unable to order one.

Does anyone have information on this item or how to order it?

 

[JohnB007]

What does this do?

 

[RTPEV]

What does this do?

Lacking any concrete information, I searched the Tesla parts catalog, and it would appear that this is a part of the wall connector.

So my recommendation would be to buy a wall connector and scavenge it for the part you need.

 

[DBeckwith]

What does this do?

The name implies a simple way to maximize charging without upgrading infrastructure. Search for dccelectric for a similar product.

 

[JohnB007]

So for those who already has a wall charger working, this is not relevant, correct?

 

[RTPEV]

The name implies a simple way to maximize charging without upgrading infrastructure. Search for dccelectric for a similar product.

So wait, are you going by the name only? You don't have a spec of some sort to determine what it really does? (I tried to get more information from the Tesla catalog, but either I don't know how to use it, or it doesn't work).

Are you looking for some kind of device that will limit current draw on a given circuit? The whole service panel (shutting down non-critical circuits if necessary?)

 

[DBeckwith]

So for those who already has a wall charger working, this is not relevant, correct?

Yes, unless your wall charger is limited by a maxed out infrastructure. For example, most 100 amp service panels probably aren't able to handle the full 60 amp circuit needed for the wall charger 48 amp maximum charge. This may achieve it at a fraction of the cost.

 

[RTPEV]

Yes, unless your wall charger is limited by a maxed out infrastructure. For example, most 100 amp service panels probably aren't able to handle the full 60 amp circuit needed for the wall charger 48 amp maximum charge. This may achieve it at a fraction of the cost.

The wall charger can be set to a lower output power if needed. Granted, I think what you may be looking for is something that will dynamically allow the wall connector to supply 48 amps when there is excess power available, but drop to a lower amperage when the panel is supplying power to other circuits, right?

 

[DBeckwith]

So wait, are you going by the name only? You don't have a spec of some sort to determine what it really does? (I tried to get more information from the Tesla catalog, but either I don't know how to use it, or it doesn't work).

Are you looking for some kind of device that will limit current draw on a given circuit? The whole service panel (shutting down non-critical circuits if necessary?)

Yes to both.

I want to install a wall charger but have limited infrastructure. There are DCC (Demand Charge Controllers) or EVEMS (EV Energy Management System) solutions available that avoid costly infrastructure upgrades. Though much cheaper than a service upgrade, they still cost more than the charger and have other limitations.

I got to thinking that a better solution could be designed to communicate with the Tesla Wall Charger. So I searched and found this.

Outside of my own needs, I've pondered the challenges of building out level 2 charging. After thinking about it more, a Tesla DCC would greatly simplify condo, apartment and destination charger options. Such a product would fit Tesla's sustainability mission.

 

[DBeckwith]

I think what you may be looking for is something that will dynamically allow the wall connector to supply 48 amps when there is excess power available, but drop to a lower amperage when the panel is supplying power to other circuits, right?

Yes, exactly.

 

[JohnB007]

Yes, unless your wall charger is limited by a maxed out infrastructure. For example, most 100 amp service panels probably aren't able to handle the full 60 amp circuit needed for the wall charger 48 amp maximum charge. This may achieve it at a fraction of the cost.

Got it.

I do have a 60A breaker, and charge rate set at 48A, so I guess this doesn't apply to me...

 

[RTPEV]

Yes, exactly.

I do have to ask: do you actually need 48A? For most people that is overkill. Personally I have a 30A EVSE and that is sufficient to charge my car from ~25% to 80% in 5-6 hours (i.e. overnight). In fact, my EVSE (homebuilt J1772 hydra) can charge our 2 EVs at once, and while this is a rare event, we did both charge the same night the other night, and when this happens we each only get 15A. And even then our cars both charged between 9:30pm and 7:30am the next morning.

Granted, some people actually do need 48A because they need quick TAT on charging, but for most people, 48A is overkill.

 

[JohnB007]

I do have to ask: do you actually need 48A? For most people that is overkill. Personally I have a 30A EVSE and that is sufficient to charge my car from ~25% to 80% in 5-6 hours (i.e. overnight). In fact, my EVSE (homebuilt J1772 hydra) can charge our 2 EVs at once, and while this is a rare event, we did both charge the same night the other night, and when this happens we each only get 15A. And even then our cars both charged between 9:30pm and 7:30am the next morning.

Granted, some people actually do need 48A because they need quick TAT on charging, but for most people, 48A is overkill.

It is an overkill. My car gets back to where I need (even had to do 5% -> 100% overnight) and still had plenty of time left to do battery warm up, etc in the morning. I do charge between 7pm to 7am though.

I only installed 48A because the cost difference was zero, according to my electrician.

I am thinking of reducing it for normal usage and only increase it when I need it... Hmm, TeslaFi does have "Set Charging Amps"... That might be the solution.

 

[RTPEV]

It is an overkill. My car gets back to where I need (even had to do 5% -> 100% overnight) and still had plenty of time left to do battery warm up, etc in the morning. I do charge between 7pm to 7am though.

I only installed 48A because the cost difference was zero, according to my electrician.

I am thinking of reducing it for normal usage and only increase it when I need it... Hmm, TeslaFi does have "Set Charging Amps"... That might be the solution.

If you have the capacity, then it doesn't hurt anything to charge at the higher amperage. In fact, it will be more efficient. The one exception might be if you are on a time-of-use plan and have demand charges, are charging on-peak, and want to minimize those demand charges due to other active loads in your house. But if you are charging off-peak, this shouldn't be a concern.

I think @DBeckwith 's concern was that they didn't have enough capacity in their panel/service to support that power level.

 

[JohnB007]

If you have the capacity, then it doesn't hurt anything to charge at the higher amperage. In fact, it will be more efficient. The one exception might be if you are on a time-of-use plan and have demand charges, are charging on-peak, and want to minimize those demand charges due to other active loads in your house. But if you are charging off-peak, this shouldn't be a concern.

I think @DBeckwith 's concern was that they didn't have enough capacity in their panel/service to support that power level.

Yup understood.

I _think_ I read somewhere that lower charge rate increases the battery life, but again, I could be wrong as I'm not an expert in this field.

It will become very useful for me again, when Ontario introduce "ultra low rate" which spans from 11pm to 7am. Having 48A is nice if your cheapest charging window is only 8 hours.

 

[RTPEV]

Yup understood.

I _think_ I read somewhere that lower charge rate increases the battery life, but again, I could be wrong as I'm not an expert in this field.

This may be true at high Supercharger speeds, but even there the BMS will protect the battery. At L2 speeds it's actually better to charge faster ss the ancillary equipment (cooling system, converters, etc) will be active for less time.

 

[DBeckwith]

Does anyone have a suggestion where we can find out more about this product? I've tried the local Tesla service center parts manager, contacted Tesla energy support and have an email pending from Tesla online sales.

I have a project deadline coming up.

 

[RTPEV]

It doesn't appear to be a product, but rather a part.

 

[Rocky_H]

I _think_ I read somewhere that lower charge rate increases the battery life, but again, I could be wrong as I'm not an expert in this field.

There's some truth, but it's not infinitely true at all levels. If there were two people walking and one were walking at half a mile an hour and the other at a quarter a mile an hour, would you say that one is "fast" and one is "slow"? No, definitely not. They are both slow, even though one's speed is technically twice as much as the other.

That's how this is with home charging speeds on the batteries. ALL home charging is very extremely slow from the battery's perspective. Quibbling around between 7 or 11 kW just isn't doing anything about the charging speed for the battery that can take over 200 kW. The truth of what you have heard is about reducing the speed some from the very powerful very high end--not when it's already slow at the low end.

 

[DBeckwith]

I wonder if this part allows the wall charger to connect directly to the meter like the Tesla Backup Switch does.

Tesla Backup Switch | Tesla Support

Tesla Backup Switch is a new component in the Tesla Powerwall system that facilitates access to backup power. Learn more about Backup Switch.

www.tesla.com