FalconFour
Well-known member
So, this idea started bashing its way through my head last night... couldn't help but try to get it down in the forum and bounce some ideas around here.
A Leaf can regenerate charge using the motor controller at exactly the same rate it's also capable of plugging into a super-expensive CHAdeMO quick-charge unit. They both top out at 30kW. And, given the degeneration of my car's regeneration capability P), it seems to be just as tightly regulated for battery safety, if not more so. The only thing limiting this from being used for charging the car is that it's kinda clumsy and unsafe to drag one car behind another.
So, in the course of trying to piece together the puzzle of the regen "throttling", I thought of the idea of putting two Leafs together, facing the same direction, on a "linked dynamo" platform - just with a long set of free-spinning rollers from one car to the other. Both would be on, should start the sequence in neutral. One would enter Drive and begin turning the other car's wheels, the other would enter Eco mode Drive and slow the rollers down. The one in Drive would then slowly accelerate, and the one that's in Eco would start regen'ing to about half its capability - about 15kW - around 25 MPH. Since regen is speed-dependent (all at the throttle level, though - only limited by programming, so...), the "charger" car could probably go faster than that and get up to 20 or 25kW, within judgement of the rig's safety.
The end result would be a great test platform for regen and battery behavior, as well as an amazing low-cost solution to offer quick-charging in an area like Fresno without any quick-chargers to be found anywhere (and no business interest, it seems, in doing so). It would just take one fully charged car, and one of any other model EV with regen that needs charging. One charges the other, then goes back to charge its own battery at good-ole' L2. It'd put a ding on both odometers, of course, but given that 15kW is the motor power typically needed to go 60MPH and this system would be going more to the tune of half that... it'd probably only consume 1/2 the miles of capacity regained by charging. And there would be no air-resistance losses for regen - I'd estimate it somewhere in the 70-80% efficiency ball-park. A fully charged Leaf could probably charge another Leaf from VLBW to 80% just like a quick-charger. Alternatively, heck... a gas-guzzler could probably run at its peak efficiency while regenning an EV using this rig.
My big question is... how could (and, sure... "should") it be built? I can't imagine this kind of platform being useful in any other vehicle usage other than for an EV. I was envisioning a platform with two large metal pipes supported by a large number of ball bearings in a low-profile frame. The pipes could be removed from the frame for easier carrying and storage, though I don't know of any good way to unlink the two "bays" to make the pipes shorter. I'd probably need to link two shorter pipes together using a threaded connector, threaded in the direction of power flow, to get the right length pipe.
Much as I'd love to build it, I just have the mechanical knowledge and the concept, but no experience fabricating things. I know the base needs to be damn strong, the rollers and pipe perfectly smooth and level, and the cars would need to be restrained while running. And the rollers would need to be able to be locked (probably with a lock pin) to allow the cars to mount and dismount the rig. But I don't even know where to begin on the base... :?
A Leaf can regenerate charge using the motor controller at exactly the same rate it's also capable of plugging into a super-expensive CHAdeMO quick-charge unit. They both top out at 30kW. And, given the degeneration of my car's regeneration capability P), it seems to be just as tightly regulated for battery safety, if not more so. The only thing limiting this from being used for charging the car is that it's kinda clumsy and unsafe to drag one car behind another.
So, in the course of trying to piece together the puzzle of the regen "throttling", I thought of the idea of putting two Leafs together, facing the same direction, on a "linked dynamo" platform - just with a long set of free-spinning rollers from one car to the other. Both would be on, should start the sequence in neutral. One would enter Drive and begin turning the other car's wheels, the other would enter Eco mode Drive and slow the rollers down. The one in Drive would then slowly accelerate, and the one that's in Eco would start regen'ing to about half its capability - about 15kW - around 25 MPH. Since regen is speed-dependent (all at the throttle level, though - only limited by programming, so...), the "charger" car could probably go faster than that and get up to 20 or 25kW, within judgement of the rig's safety.
The end result would be a great test platform for regen and battery behavior, as well as an amazing low-cost solution to offer quick-charging in an area like Fresno without any quick-chargers to be found anywhere (and no business interest, it seems, in doing so). It would just take one fully charged car, and one of any other model EV with regen that needs charging. One charges the other, then goes back to charge its own battery at good-ole' L2. It'd put a ding on both odometers, of course, but given that 15kW is the motor power typically needed to go 60MPH and this system would be going more to the tune of half that... it'd probably only consume 1/2 the miles of capacity regained by charging. And there would be no air-resistance losses for regen - I'd estimate it somewhere in the 70-80% efficiency ball-park. A fully charged Leaf could probably charge another Leaf from VLBW to 80% just like a quick-charger. Alternatively, heck... a gas-guzzler could probably run at its peak efficiency while regenning an EV using this rig.
My big question is... how could (and, sure... "should") it be built? I can't imagine this kind of platform being useful in any other vehicle usage other than for an EV. I was envisioning a platform with two large metal pipes supported by a large number of ball bearings in a low-profile frame. The pipes could be removed from the frame for easier carrying and storage, though I don't know of any good way to unlink the two "bays" to make the pipes shorter. I'd probably need to link two shorter pipes together using a threaded connector, threaded in the direction of power flow, to get the right length pipe.
Much as I'd love to build it, I just have the mechanical knowledge and the concept, but no experience fabricating things. I know the base needs to be damn strong, the rollers and pipe perfectly smooth and level, and the cars would need to be restrained while running. And the rollers would need to be able to be locked (probably with a lock pin) to allow the cars to mount and dismount the rig. But I don't even know where to begin on the base... :?