They don't care--the car routinely feeds DC back into the pack and charges the cells during regen, current easily flows in and out of the cells all the time. The BMS boards merely monitor and report cell voltage, they aren't used to measure current.
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They don't care--the car routinely feeds DC back into the pack and charges the cells during regen, current easily flows in and out of the cells all the time. The BMS boards merely monitor and report cell voltage, they aren't used to measure current.
roblab
Active Member
Exactly. The big question is: Why? And there is no reasonable answer. But it keeps coming up over and over and over and....
SW2Fiddler
We Are Cognitive Dissidents
I just smile at the thought that people shopping Tesla cars, bring their imagination along with them. This is not the worst thing that could happen, not by a long shot...
Two answers: "because it's there" and "because it's needed". To my knowledge, nobody has done it so far and it's a motivation enough.
But it's also very much helpful if you want to do roadtrips outside of the SC network with reasonable average speeds. Seattle to Alaska is an extreme example - it's unlikely to be traversable by EV vehicles in the near future.
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No. Just no.
I've actually studied mechanical engineering and getting all the stresses correctly in this case will be nightmare. And you will need to attach a "pusher" trailer rigidly in several points, so simple turns will become... complicated. And in the end, you're quite likely to end with an uncontrollable car flying off a bridge rather than with an immovable car with a broken HVDC system.
green1
Active Member
Not to go too far off topic, but last I heard it was very difficult to find an inverter capable of working with the particular voltage of the MS pack, if that's not the case, I'm quite interested in hearing what inverter was used?
green1
Active Member
Assuming you're talking about the inverter, any chance you could link to it or provide a make/model? I'm not having much luck searching today...
If you need a 400V -> 220V inverter, search for "400V grid tie inverter" on Google. They are used in solar systems, so there are plenty of suppliers.
For example: Tesla Motors Club - Enthusiasts & Owners Forum
Audie's referring to driving a Tesla between the 'lower 48' and Alaska without use of a generator -- just judicious use of available chargers and electrical outlets. Here's the GuyHall thread for reference:
T5 - Tesla Tijuana To Tundra Tour - California to Alaska
I found another Tesla owner interested in this project. He has an early S40 and wouldn't mind getting a range extender.
We tried connecting a charge controller to the HVDC to see what happens (the controller is smart enough to only provide power when the battery is connected). Everything just worked! We were able to drive around 100 meters in total at low speed using a long NEMA 14-50 extension cord. Next step: using a more powerful charge controller (this one was limited to 4kW).
We tried connecting a charge controller to the HVDC to see what happens (the controller is smart enough to only provide power when the battery is connected). Everything just worked! We were able to drive around 100 meters in total at low speed using a long NEMA 14-50 extension cord. Next step: using a more powerful charge controller (this one was limited to 4kW).
Cyberax, you sound crazy enough that I have another idea to bounce off you. Off-topic, but along the lines of "because it's there".
How about towing a 5kw accordian-folding solar array and a micro-wind turbine to visit all 49 states on renewable energy only? I had originally thought of it to be towed by an RV so that one can take their time road-tripping, but then I found your topic and wondered if a model S w/ eco-hitch wouldn't be a faster solution? Especially since you can sleep in the S with the seats down.
The itinerary would essentially be drive from 4am-6am, park in open field and unfold panels and secure wind turbine, plug in car and go hiking. Come back near sunset and fold-up panels and go to bed. Wake up at 4am, pack up wind turbine and drive until 5% charge. Repeat.
Crazy enough?
How about towing a 5kw accordian-folding solar array and a micro-wind turbine to visit all 49 states on renewable energy only? I had originally thought of it to be towed by an RV so that one can take their time road-tripping, but then I found your topic and wondered if a model S w/ eco-hitch wouldn't be a faster solution? Especially since you can sleep in the S with the seats down.
The itinerary would essentially be drive from 4am-6am, park in open field and unfold panels and secure wind turbine, plug in car and go hiking. Come back near sunset and fold-up panels and go to bed. Wake up at 4am, pack up wind turbine and drive until 5% charge. Repeat.
Crazy enough?
You can't get around the fact that the amount of recoverable solar energy is about 400 Watts per square meter with the best possible solar panels in the best possible conditions. So you'll need to haul around 40m^2 of panels to get a reasonable charge rate.
That's certainly doable, but it will resemble "The Martian" book quite a bit. Expect to spend a lot of time cursing the weather - cloud cover degrades the solar panels efficiency immensely.
Oh, and you can forget the wind turbine. It won't even recoup the energy cost required to haul it.
Short of extensive hacking on the CAN bus and bypassing the drive inverter interlocks, you will not be using Tesla's on-board charger. The car will happily accept DC voltage however, as long as it's isolated from the chassis and doesn't exceed the max charge rate that the BMS stipulates. (normally shown as the "dashed lines" when it gets lower than max regen)
I did this exact thing with a Capstone Microturbine generator on my 2011 Nissan LEAF. On a Tesla, it's not needed as long as you are driving where there are superchargers, but in 2011 there was only one CHAdeMO for fast-charging a LEAF and it was offline most of the time. I made the trailer that can charge the LEAF while driving and also can fast charge cars while stationary with a CHAdeMO interface.
I did this exact thing with a Capstone Microturbine generator on my 2011 Nissan LEAF. On a Tesla, it's not needed as long as you are driving where there are superchargers, but in 2011 there was only one CHAdeMO for fast-charging a LEAF and it was offline most of the time. I made the trailer that can charge the LEAF while driving and also can fast charge cars while stationary with a CHAdeMO interface.
Yes, we're planning to limit charge to about 80% just to be on the safe side. And in the end 16kW is not that much.
We're going to try this controller next: Electric Motor Werks, Inc. - SmartCharge-12000 - a 12kW Universal Voltage EV Charger - Fully Assembled Tested
I'm glad I'm not the only crazy person here
What was the total weight of the trailer? I'm aiming to keep it under 250kg if I can.Sorry to be the bearer of bad news, but your plan will fail and you are wasting your money on that charger. First off it's not galvanically isolated, so it's going to immediately trip the Tesla BMS isolation failure and it will then power the car down. (safety) Secondly, 12kW is not enough power for highway driving. I'd say you need 20kW minimum, and my trailer is 30kW which is enough for comfortable use.Yes, we're planning to limit charge to about 80% just to be on the safe side. And in the end 16kW is not that much.
We're going to try this controller next: Electric Motor Werks, Inc. - SmartCharge-12000 - a 12kW Universal Voltage EV Charger - Fully Assembled Tested
I'm glad I'm not the only crazy person here
My trailer comes in at around 150kg fully fueled. The microturbine engine has one moving part and no lubricants, and it's so clean it doesn't need a catalyst on the exhaust to meet California emissions standards.
Kalud
Active Member
Wow, nice project. Did you describe it more somewhere else ? On a Leaf forum perhaps ?
Yeah, it made the news a bit back in 2011:
How one inventor wants to boost EVs with a towable turbine
2012 Nissan Leaf Gets Unofficial Jet-Powered Range Extender, Quick Charger
Here's my post on the Nissan Leaf forum: The “range–extended†EV (BEVx) considered - Page 9 - My Nissan Leaf Forum
The journalists never get the facts straight. It was a proof-of-concept engineering test, never meant to be a product, but it worked well. It's a modified Capstone C30 turbine with recuperator. It can put out from 250 to 700 volts DC at up to 30kW and it's 27% efficient at it's peak.
How one inventor wants to boost EVs with a towable turbine
2012 Nissan Leaf Gets Unofficial Jet-Powered Range Extender, Quick Charger
Here's my post on the Nissan Leaf forum: The “range–extended†EV (BEVx) considered - Page 9 - My Nissan Leaf Forum
The journalists never get the facts straight. It was a proof-of-concept engineering test, never meant to be a product, but it worked well. It's a modified Capstone C30 turbine with recuperator. It can put out from 250 to 700 volts DC at up to 30kW and it's 27% efficient at it's peak.
I was told that it is galvanically decoupled and can be used in CHAdeMO stations, with full insulation and ground leakage test modes. And I wouldn't trust anything that leaks HVDC to the ground.
12kW would be enough to range-extend Tesla to about 400 miles and that is usually enough to get to a DCFC charger even in remote regions.
I wouldn't mind getting more power, but it will require way more work. I looked at microturbines but I can't find a commercially available small enough turbine/generator combo (where did you get it?). And getting past 16kW for piston-powered generators usually bumps you into a high-power towable industrial packages that are way too heavy for a generator-trailer.
Would you mind sharing the details of your trailer? What did you use for the high-voltage system?
