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Charging the Roadster
- Thread starter malcolm
- Start date
The ClipperCreek unit has a hidden latch underneath with a hole to secure it with a SMALL padlock if desired. Hole diameter for the lock is approx 1/4 inch, and also very hard to reach (good for "theft" deterrent, bad for owner access). Not sure how well a padlock will actually fit in there, right next to the storage position for the charge-plug.
Edit: of course the "securing" is more of a "safety" lock, not an "energy theft" deterrent. But there might also be a way to lock the charge-plug in place with some minor additional hardware.
Edit: of course the "securing" is more of a "safety" lock, not an "energy theft" deterrent. But there might also be a way to lock the charge-plug in place with some minor additional hardware.
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JRP3
Hyperactive Member
I wonder if over time Tesla's will end up with scuff marks where the cord drapes on the fender? Maybe they should have gone with a lower charge port location, like on the back bumper? I see an afermarket for "cord coozies" or something :biggrin:
graham
Active Member
An excellent question. I get the feeling that it is less of a worry with the heavier gauge cable of the HPC as it does not bend as easily. But if you use the mobile charger a lot -- especially the MC120 -- this will become a worry.
It also makes me give even more thought to billarnett's brilliant "cable from above" set up in his garage.
If this really worries someone, he could get himself a peace of rubber tube (cca 5 inch long, an inch thick) and mount it on the cable just behind the plug. It should hold that cable a little bit farther off the car, just enough not to touch the fender.
Tesla battery meter lies to you....
As you know the Tesla does not fully charge or drain the battery in standard mode, it only charges the battery to 90%. I was confused because the battery "gas gauge" shows a full charge after a night of charging. If I switch to range mode with a full charge, the battery meter now shows 90% like I would expect. So the battery meter lies to me in standard (and I assume storage mode?). This is the right thing to do UI wise and shows that Tesla has put a lot of time into the user experience of the roadster.
As you know the Tesla does not fully charge or drain the battery in standard mode, it only charges the battery to 90%. I was confused because the battery "gas gauge" shows a full charge after a night of charging. If I switch to range mode with a full charge, the battery meter now shows 90% like I would expect. So the battery meter lies to me in standard (and I assume storage mode?). This is the right thing to do UI wise and shows that Tesla has put a lot of time into the user experience of the roadster.
Cottonwood
Roadster#433, Model S#S37
I have decided that I want maximum charging flexibility. In addition to the 110V-12A (MC120) mobile charger that comes with the car, I have ordered both the 220V-70A (HPC) garage charger and the 220V-30A (MC240) mobile charger. Here are some of my thoughts on taking the mobile chargers with me.
Lets get an idea of charging rates. People give the charge times (empty to full) for each charger; according to Tesla, they are 3.5 hours for the HPC, 10 hours for the MC240, and 34 hours for the MC120. These do not quite make sense if you check the numbers based on power, then it should be 24A at 220V for the MC240 to get 10 hours, or 30A at 8 hours. For the MC120, 39 hours is more like it at 12A. See my spread sheet below. It does make sense that slower charging rates are more efficient because there is less I*R drop in the batteries. Also, the capacity of the battery pack is often listed as about 50 kW-hr.
I will need to figure out how to insert Picasaweb pictures, but here is a link to the spreadsheet: Picasa Web Albums - Butch - Tesla
I like simple rules that I can keep in my head. If we assume that a full charge is 50kW-hr, and the range is 220 miles, then the energy per mile used is 227 W-hr/mi. At 220V and 110V, the HPC charges at 67.8 mph from 70A, the MC240 charges at 23.2 mph at 24A, and the MC120 charges at 5.8 mph at 12A. So a very simple rule to remember is that the charging rate in MPH is approximately the Amperage at 220V and half the Amperage at 110V; easy to remember.
All of this says on a trip, you want as much power (V*Amps) as you can get. On the other hand, 110V-15A plugs are the most common thing we can find. If I stop for a 2 hour lunch and plug in the MC120 and an easy to find receptacle, then I can extend my range by 12 miles, not great, but it might get me home at the end of the day.
Now lets look at cords and adapters.
The MC120 is easy. It has the standard "Edison" 5-15 plug and all I probably want to carry is a good 100' 12/3 contractor grade extension cord. That weighs about 12 pounds, and cost about $50. I could save a couple of pounds and bulk as well at about $10 using a 14 gauge cord, but lose a couple of Volts (2%) in charge rate.
The MC240 gives us the interesting mobile charge rate; after all this is the one that will top up the battery in 8-10 hours from complete discharge. On the other hand, it is the one that is more of a challenge in finding a receptacle. The plug is a NEMA 14-50 that is pretty standard for high power RV hookups and new installs of house ranges, but there are other source of 220V that I may want to suck power from.
Can I combine having an extension cord when I need it at 220V with adapter plugs for other services. The solution was inspired by looking at Inspired by Charger Adapters This solution uses a 3 wire extension cord and 3 prong plugs. I would rather keep all 4 connections of the 14-50 connectors, L-L-N-G. Searching, I could not find any 14-50 extension cords and because they would be rated for 50 amps, I probably would not want carry them anyway. A cord that does look promising is a 30 amp cord used in many generator applications: Reliance 30 Amp, 50 ft, 4 wire cord, Reliance Controls PC3050 - 30-Amp (4-Prong 50-Foot) Generator Power Cord This cord uses the NEMA L14-30, twistlock, connectors which are less likely to pull loose.
Here are the adapters that I will now need to make. If I use the L14-30 as the intermediate connector, then I can put as many of the above extension cords as I want in the middle to reach remote receptacles.
Adapters:
The last connection is an interesting Rube Goldberg arrangement, but doubles the charge rate when you can't find a good 220V receptacle. The Quick 220 system suggested earlier in this thread, Demonstration – Power 220 - 240 Volt Equipment from 110 – 120 Volt Outlets., lets you find two 110V plugs that use opposite phases (hots) of a 220V system and put them back together for a 220V-15A circuit. This could be used with the MC240 to get 220V-12A charging or 12 mph! The receptacle on the Quick 220 is a 6-15 that only has 3 conductors L-L-G. If the other 3-wire connections work we can make a L14-30R to 6-15 adapter and away we go. On the other hand, I may be tempted to modify the Quick 220 and take out the 6-15 receptacles and put in a L14-30R and then I can just plug in one of my 220V extension cords. BTW, the 110V extension cord will work for the second leg of the Quick 220, also.
Thoughts?
Butch in Boulder
Connector Reference: NEMA connector - Wikipedia, the free encyclopedia
Lets get an idea of charging rates. People give the charge times (empty to full) for each charger; according to Tesla, they are 3.5 hours for the HPC, 10 hours for the MC240, and 34 hours for the MC120. These do not quite make sense if you check the numbers based on power, then it should be 24A at 220V for the MC240 to get 10 hours, or 30A at 8 hours. For the MC120, 39 hours is more like it at 12A. See my spread sheet below. It does make sense that slower charging rates are more efficient because there is less I*R drop in the batteries. Also, the capacity of the battery pack is often listed as about 50 kW-hr.
I will need to figure out how to insert Picasaweb pictures, but here is a link to the spreadsheet: Picasa Web Albums - Butch - Tesla
I like simple rules that I can keep in my head. If we assume that a full charge is 50kW-hr, and the range is 220 miles, then the energy per mile used is 227 W-hr/mi. At 220V and 110V, the HPC charges at 67.8 mph from 70A, the MC240 charges at 23.2 mph at 24A, and the MC120 charges at 5.8 mph at 12A. So a very simple rule to remember is that the charging rate in MPH is approximately the Amperage at 220V and half the Amperage at 110V; easy to remember.
All of this says on a trip, you want as much power (V*Amps) as you can get. On the other hand, 110V-15A plugs are the most common thing we can find. If I stop for a 2 hour lunch and plug in the MC120 and an easy to find receptacle, then I can extend my range by 12 miles, not great, but it might get me home at the end of the day.
Now lets look at cords and adapters.
The MC120 is easy. It has the standard "Edison" 5-15 plug and all I probably want to carry is a good 100' 12/3 contractor grade extension cord. That weighs about 12 pounds, and cost about $50. I could save a couple of pounds and bulk as well at about $10 using a 14 gauge cord, but lose a couple of Volts (2%) in charge rate.
The MC240 gives us the interesting mobile charge rate; after all this is the one that will top up the battery in 8-10 hours from complete discharge. On the other hand, it is the one that is more of a challenge in finding a receptacle. The plug is a NEMA 14-50 that is pretty standard for high power RV hookups and new installs of house ranges, but there are other source of 220V that I may want to suck power from.
Can I combine having an extension cord when I need it at 220V with adapter plugs for other services. The solution was inspired by looking at Inspired by Charger Adapters This solution uses a 3 wire extension cord and 3 prong plugs. I would rather keep all 4 connections of the 14-50 connectors, L-L-N-G. Searching, I could not find any 14-50 extension cords and because they would be rated for 50 amps, I probably would not want carry them anyway. A cord that does look promising is a 30 amp cord used in many generator applications: Reliance 30 Amp, 50 ft, 4 wire cord, Reliance Controls PC3050 - 30-Amp (4-Prong 50-Foot) Generator Power Cord This cord uses the NEMA L14-30, twistlock, connectors which are less likely to pull loose.
Here are the adapters that I will now need to make. If I use the L14-30 as the intermediate connector, then I can put as many of the above extension cords as I want in the middle to reach remote receptacles.
Adapters:
- NEMA 14-50R to receive the Tesla Charger to L14-30 to plug into extension cords or other adapters
- L14-30R to 14-50 for the other end of the extension cords to plug into RV and new Range Receptacles
- L14-30R to 14-30 for the other end of the extension cords to plug into new Dryer Receptacles
- L14-30R to 3-wire, 10-30 and 10-50 plugs for old Dryer and Range Receptacles; with Neutral and Ground tied together (L-L-NG) will the GFI trigger? This is a question we need to figure out when someone gets an MC240.
The last connection is an interesting Rube Goldberg arrangement, but doubles the charge rate when you can't find a good 220V receptacle. The Quick 220 system suggested earlier in this thread, Demonstration – Power 220 - 240 Volt Equipment from 110 – 120 Volt Outlets., lets you find two 110V plugs that use opposite phases (hots) of a 220V system and put them back together for a 220V-15A circuit. This could be used with the MC240 to get 220V-12A charging or 12 mph! The receptacle on the Quick 220 is a 6-15 that only has 3 conductors L-L-G. If the other 3-wire connections work we can make a L14-30R to 6-15 adapter and away we go. On the other hand, I may be tempted to modify the Quick 220 and take out the 6-15 receptacles and put in a L14-30R and then I can just plug in one of my 220V extension cords. BTW, the 110V extension cord will work for the second leg of the Quick 220, also.
Thoughts?
Butch in Boulder
Connector Reference: NEMA connector - Wikipedia, the free encyclopedia
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You have certainly "done your homework".
I think you could be a trailblazer for others to follow.
I bet some of the engineers within Tesla have done much of what you propose, but their "prototype solutions" aren't something they are willing to share with customers directly. (Codes, documentation, support and all that).
I recall seeing a picture (back from 2006) of EP2 being recharged at Pebble Beach off of two 120V extension cords. I think they have had that contraption cobbled together before, but so much has changed since then who knows.
By the way, more food for thought in your research:
Re: I Need Electrical Help!
Battery Charger Schematic - Interview with Lee Hart
(A little knowledge can be dangerous... Be very careful what you do here!)
By the way, more food for thought in your research:
Re: I Need Electrical Help!
Battery Charger Schematic - Interview with Lee Hart
(A little knowledge can be dangerous... Be very careful what you do here!)
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This reminds me of all the headaches I've had taking my electrical appliances from USA to NZ. One of my DVD players went up in smoke after using an "adapter". They sell adapters here that just convert the plug end, not the voltage!
I asked around about voltage converters but they were apparently huge beasts that cost a fortune and could only power 50 Watt or less devices (???)
I just don't get how they make some things (cell phones, etc) that are inherently dual voltage in such a small device, but to do it manually requires an electrical engineering degree??
I really want to get the most out of any EV I own, so kudos to your efforts.
I'm still so confused though, :frown: they should have EVs 101 class at uni
I asked around about voltage converters but they were apparently huge beasts that cost a fortune and could only power 50 Watt or less devices (???)
I just don't get how they make some things (cell phones, etc) that are inherently dual voltage in such a small device, but to do it manually requires an electrical engineering degree??
I really want to get the most out of any EV I own, so kudos to your efforts.
I'm still so confused though, :frown: they should have EVs 101 class at uni
Small switching power supplies tend to be "universal voltage" able to take 240@50hz or 120@60hz without difficulty. Old fashioned transformer based adapters just divide the voltage, so if you hook a US transformer directly to 240V you get too much (double) voltage to the device.
Typically the wall adapter says on it what input voltages it accepts.
Typically the wall adapter says on it what input voltages it accepts.
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That's a lot of thinkin'. I will add my humble suggestions.
Keep with black cables to disguise dirt longer between cleanings.
Mount all "box" adapters in Pelican or Storm cases.
Advantages:
They are stronger than most plastic electronic project boxes.
They won't show scratches like painted project boxes.
They are waterproof (at least to begin with).
They will not damage or scratch your car/trunk area as much as any-sized metal box.
Many many size choices.
They have handles.
Keep with black cables to disguise dirt longer between cleanings.
Mount all "box" adapters in Pelican or Storm cases.
Advantages:
They are stronger than most plastic electronic project boxes.
They won't show scratches like painted project boxes.
They are waterproof (at least to begin with).
They will not damage or scratch your car/trunk area as much as any-sized metal box.
Many many size choices.
They have handles.
Cottonwood
Roadster#433, Model S#S37
The more I think about this, the more that I don't think that there will be a problem. In all systems, the neutral is tied to ground somewhere. In modern installations, the ground is connected to neutral at the supply transformer and usually at the service entrance/supply panel of the house. See Ground and neutral - Wikipedia, the free encyclopedia. Because the GFCI (ground fault circuit interrupter) in the MC240 designed to detect current from one of the line sides to ground, and there is always a G-N connection somewhere on the supply side, it should not matter if that connection is close (the old dryer receptacle adapter) or far (the supply transformer). The real problem is if there is a GFCI on the service side. For 3-wire receptacles like used for an old dryer, a GFCI won't be there or the receptacle won't work for most dryers.
As far as I can tell, the only problem will be with the Quick 220 Power Tap on GFCI circuits. In fact, they even say this won't work at step 1 on Demonstration – Power 220 - 240 Volt Equipment from 110 – 120 Volt Outlets. If this is a problem, it should be fixed by rewiring the output of the Quick 220 Power Tap to use a 4-wire L-L-N-G receptacle like the 14L-30R I have suggested as the standard intermediate connector for my mobile adapter kit.
This experiment of connecting neutral to ground when only a 3-wire receptacle (L-L-NG) is available is one that we will have to try. With luck, I will have an MC240 and a Tesla to try in 2-3 months. I also have incentive, because I have a mountain vacation home about 100 miles from my home that has an old 3-wire dryer plug (10-30) for me to use. If anyone has (or will soon have) an MC240 and a Roadster, please contact me at <[email protected]> and I will be glad to work with you for an early (and safe) test.
I think the further away you get from the Neutral<->Ground tie the more chance there is of some induced differential being present, so the GFCI could get trigger happy even if it is tied together some distance away.
But my knowledge in this area if fleeting, so I could be wrong.
But my knowledge in this area if fleeting, so I could be wrong.
Cottonwood
Roadster#433, Model S#S37
A GFCI only looks at current differences between Line and Neutral for 110V apps, and between the two lines for 220V apps. For this reason, voltage differences between Neutral and Ground should not matter. If it did, then ground faults on other circuits would induce false alarms on good circuits.
From GFCI Basics:
Thanks, Cottonwood.
So I am thinking about it like this.
If lightning struck your power lines and a surge came down the line you want to make sure the extra current bleeds through the breaker box ground and not through the charge cable. For instance if you were holding onto the end of the cable and just about to plug it into your roadster just as lightning hit the lines and some of the current found it easier to get through you (to the ground through your feet) than it does to go back to the breaker box grounding rod then you would want the GFCI to notice and disconnect the charge cable.
Now another situation is you set the end of the charge cable on a grounded item, like on top of a metal freezer in your garage. If some other device in the house has some issue, like a bad connection on one of the leads, and it is trying to run some current to ground and the impedance to the breaker box is higher than the impedance through the charge cable then you could get some leakage going through the charge cable, but not necessarily enough to trigger the GFCI. In other words, I think that wiring issues elsewhere in your house could sometimes cause some current to try to leak through the charge cable so the GFCI has to be just sensitive enough to catch bad leaks, but not so sensitive to trigger of small surges like when fluorescent light ballast is starting up, etc.
Also, I wonder how the charge cable is grounded through the roadster when plugged in? At some point you start to wonder about the resistance of the tires which separate the chassis of the vehicle from physical ground. Tires with good winter performance tend to have more silica which makes them less conductive. Tires with more carbon and less silica are more conductive.
So I am thinking about it like this.
If lightning struck your power lines and a surge came down the line you want to make sure the extra current bleeds through the breaker box ground and not through the charge cable. For instance if you were holding onto the end of the cable and just about to plug it into your roadster just as lightning hit the lines and some of the current found it easier to get through you (to the ground through your feet) than it does to go back to the breaker box grounding rod then you would want the GFCI to notice and disconnect the charge cable.
Now another situation is you set the end of the charge cable on a grounded item, like on top of a metal freezer in your garage. If some other device in the house has some issue, like a bad connection on one of the leads, and it is trying to run some current to ground and the impedance to the breaker box is higher than the impedance through the charge cable then you could get some leakage going through the charge cable, but not necessarily enough to trigger the GFCI. In other words, I think that wiring issues elsewhere in your house could sometimes cause some current to try to leak through the charge cable so the GFCI has to be just sensitive enough to catch bad leaks, but not so sensitive to trigger of small surges like when fluorescent light ballast is starting up, etc.
Also, I wonder how the charge cable is grounded through the roadster when plugged in? At some point you start to wonder about the resistance of the tires which separate the chassis of the vehicle from physical ground. Tires with good winter performance tend to have more silica which makes them less conductive. Tires with more carbon and less silica are more conductive.
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