Charging the Roadster

[doug]

Cool, but looks like you're missing data from about 9:30 to 11:30pm.

 

[ra-san]

This may be off topic, but then again, I think the topic of *how* to measure energy use in a good way is very topical to charging the roadster.

I've installed the TED 5000 meter on my 14-50 outlet in my garage. Last night was my first night of charging. Here's the graph of the power draw (in blue) and voltage (in red). I was pulling 40A.

I've been waiting for a product like the 5000 to come out. Looks like it may not qualify as revenue grade accuracy or be accepted for performance based incentive reporting, but it otherwise looks like it has everything I was looking for in a monitoring package.

I didn't think it was out yet though! How'd you get your hands on it, and would you recommend it for monitoring the energy use of roadster charging?

I'd looked at a range of other meters from simple refurb utility meters to other logging units, but price and accuracy vary a lot and I hadn't found anything that was easy to read at a glance without a PC, logged data and had decent software for use with a pc, and didn't cost a bundle (if not directly, then indirectly due to panel and electrician costs). I'd pretty much given up on finding that combo, and decided to either go with a simple (but revenue grade) modular digital display non-logging meter for a couple hundred dollars, or see if the monitoring solutions for a solar install could add on another leg to monitor.

Unfortunately there's no Kill-A-Watt type 240V, 100A $20 plug in meter (or link it if there is!)

Actually, speaking of charging the roadster and the Kill-A-Watt 120V meter, fyi it works well for measuring 12 Amp charging, but will incessantly beep, warning you of over-current use if you try to use it to measure 15A (with the MC120 and manual setting of the VDC current limit) or 16A (with the RFMC) charging, which is unfortunate. It's a great feature to have, but I wish it were rated for 20A, and the alarm was defeatable so I could use it in a 20 Amp rated circuit. Not sure of any other product in it's price range that does that though.

 

[Palpatine]

I've installed the TED 5000 meter on my 14-50 outlet in my garage. Last night was my first night of charging. Here's the graph of the power draw (in blue) and voltage (in red). I was pulling 40A.

I assume you were using a signature edition RFMC? :wink:

 

[Tdave]

I didn't think it was out yet though! How'd you get your hands on it, and would you recommend it for monitoring the energy use of roadster charging?

I emailed them and they said they had limited supply available currently. Website still says coming soon because they can't deliver in volume.

It seems accurate enough. Very flexible. Allows downloading of raw second, minute, hour, etc data. Dashboard shows a variety of instantaneous data. Allows you to enter your electricity rates (including seasonal and time-of-day rate changes) and shows you dollars being used.

The one thing I couldn't find is a non-resettable grand total. Best it can do is show you monthly totals going back 2 years, daily totals going back a month I think, and similar hourly historical totals, plus the charts that can be by second, minute, or hour.

The UI is through your browser to the unit which is on your home network. And they have the remote display that shows summary screens without having to go to your computer.

I assume you were using a signature edition RFMC? :wink:

Yes. Yes I am.

 

[Nichen]

Full charge in 45 minutes

HI guys this is my first post ever I did hear Elon Musk mention putting Quickchargers for trial purpose late this year or early 2010, charging cars in 45 minutes. Was it meant for the Tesla Roadster or the Tesla Model S? It seems funny if it's for the Model S, because of its release in 2011.

Does anyone know anything about this?

Thanks / Nick

 

[tomsax]

HI guys this is my first post ever I did hear Elon Musk mention putting Quickchargers for trial purpose late this year or early 2010, charging cars in 45 minutes. Was it meant for the Tesla Roadster or the Tesla Model S? It seems funny if it's for the Model S, because of its release in 2011.

Does anyone know anything about this?

Thanks / Nick

My understanding is that the Roadster is not wired for the high-power DC connection that is required for a quick charge.

BTW, the quick charge is usually described as an 80% charge in 45 minutes, not a full charge. Stuffing high current into nearly fully charged cells is bad for longevity; even charging with an HPC or MC240 ramps down the current as it nears the full charge.

 

[dpeilow]

Question: Why is a high-power DC connection necessary for fast charge?

 

[BBHighway]

Question: Why is a high-power DC connection necessary for fast charge?

Probably because AC power has to be rectified first before it can be used. The car has a built in rectifier for 120VAC and 240VAC, but the rectifier would become unmanagably large and give off an unmanagably large amount of heat at the power levels required for a 45 minute charge.

At that point, it makes more sense to move the rectifier outside the car. If you did that at 120VAC or 240VAC, then the car would need a special connection and wouldn't be able to charge at an ordinary standard outlet. A 400V charge is already a non-standard outlet, so there's no downside to external rectification.

 

[dpeilow]

We've been talking about similar issues in the Charging the Roadster - EU Style thread. 400V is a standard outlet in Europe.

There are some small high-power diode based rectifier blocks on the market that can handle 150A. Could this be used? It seems to give off 350W at 150A output - not a massive amount of heat when compared to the losses in the batteries, but obviously quite a small area to extract the heat from. Obviously this device's output would need filters, too.

As we know, the PEM itself handles 40kW at close to this voltage under regen. Whether it could handle that much power for more than a few seconds is a different matter, though. Bring on the liquid cooling.

 

[TEG]

Thanks, BB, that is what I was going to say...

Also, along with the size/weight/heat, there is also a cost factor on the components for those power levels. It starts to make sense to put them in the few(er) chargers than in the (many more) vehicles.

I don't think it is just a matter of rectifying the AC to DC... The pack wants specific voltages so you probably need a big inductor too, not just the rectifiers.

 

[dpeilow]

But if you supply the car with 400V DC at 150A or thereabouts, do you not have the same voltage step-down issues?

The cost for that rectifier block is ~$70. I'd pay for the option. :tongue:

 

[TEG]

I certainly don't know all the details... But I think the pack has a nominal voltage of 375V so something a little more (e.g.: 400V) may be appropriate as direct input to charge it. If you started with 480V then it might be too much.

So my point is that directly rectified line voltage is probably not the exact DC voltage you want for charging, so I envision that some sort of large transformer or inductor based circuit is needed to get the voltage correct.

I bet it is rather specific actually. For instance, if you are supposed to give the pack 390V, then 400V would be too much. Maybe some new PEM could accept a range of DC voltages for quick charging? I don't know. I just suspect that it would be better all around if the offboard quick charging equipment provided a very standardized DC voltage.

It might even be more complicated than that. It might want different voltages depending on what part of the charge cycle the vehicle is in at any given time.

 

[Young]

I certainly don't know all the details... But I think the pack has a nominal voltage of 375V so something a little more (e.g.: 400V) may be appropriate as direct input to charge it. If you started with 480V then it might be too much.

So my point is that directly rectified line voltage is probably not the exact DC voltage you want for charging, so I envision that some sort of large transformer or inductor based circuit is needed to get the voltage correct.

I bet it is rather specific actually. For instance, if you are supposed to give the pack 390V, then 400V would be too much. Maybe some new PEM could accept a range of DC voltages for quick charging? I don't know. I just suspect that it would be better all around if the offboard quick charging equipment provided a very standardized DC voltage.

It might even be more complicated than that. It might want different voltages depending on what part of the charge cycle the vehicle is in at any given time.

DC voltage conversion at high power level requires inductor, which can be very heavy. My guess is that the outboard charger should supply right voltage and current to the battery pack according to the request from BMS.

 

[richkae]

not a technical issue at all

120v and 240v outlets are an existing infrastructure. It makes sense to put the pieces into the car so you can plug into them with as simple an adapter as possible.
Theoretical outlets of any other voltage do not exist anywhere, since they will be completely new, it doesnt make sense to burden the car with anything necessary to charge from them.

Rich

 

[dpeilow]

120v and 240v outlets are an existing infrastructure. It makes sense to put the pieces into the car so you can plug into them with as simple an adapter as possible.
Theoretical outlets of any other voltage do not exist anywhere, since they will be completely new, it doesnt make sense to burden the car with anything necessary to charge from them.

Rich

That may be true in the US, but higher voltages are common elsewhere and so it makes sense to be able to plug in "with as simple an adapter as possible" at those locations. A car marketed globally should have a global charger/PEM design.

I bet it is rather specific actually. For instance, if you are supposed to give the pack 390V, then 400V would be too much. Maybe some new PEM could accept a range of DC voltages for quick charging? I don't know. I just suspect that it would be better all around if the offboard quick charging equipment provided a very standardized DC voltage.

I'm sure there are pros and cons, but the committee looking at the new IEC standard seems to have moved away from high power DC chargers to an AC standard that is easy to install at charging sites - with the trade off of a little more complexity on the car.

 

[Tdave]

Here's the chart for charging the Roadster from a full Standard charge to a full Range charge at 40 amps (NEMA 14-50 outlet, Eberhard connector). Note that it takes almost 2 hours to put in the those last 25 miles of range in a Range mode charge.

 

[doug]

New Tesla Universal Mobile Connector

Tesla Motors - charging
Tesla Motors - Charging Solutions

$1500, 40 Amps, supposed to be available in October

 

[ChargeIt!]

I am confused by the yellow star and the "(comes standard)" notation on the NEMA 14-50. Does that mean what the picture implies ... is not really what's being delivered for $1,500 ? (All those other useful adapters being extra cost items ?)

 

[doug]

I am confused by the yellow star and the "(comes standard)" notation on the NEMA 14-50. Does that mean what the picture implies ... is not really what's being delivered for $1,500 ? (All those other useful adapters being extra cost items ?)

That would be my guess.

 

[Palpatine]

I know what the real costs are to produce all of those adapters, even if all parts are purchased in high volume. It would kill all profit to provide 8 of them. Most people are only going to use two of them. 14-50 and 10-30. The others are rarely going to be found in a useful situation. But it is a great idea to make them available. Some people do know that they have access to certain receptacles and will want a specifc type. I get special requests quite often for adapters on the RFMC.

I really like the new Tesla design.