Charging while driving?

[Perovskite]

Ok, I know this sounds a little crazy but does anyone know if it is possible to use the charge port to charge the Bolt while you are driving the car???

My purpose for the question is that I would like to have the option to use my Bolt on a long distance trip and drive to areas that do not have charging stations.

Assume that I have a compact 10kW genset mounted on a trailer hitch on the rear of the car and I have wired the 240V output of the genset into a charger of appropriate size which is then wired into the charge port of the Bolt.

Assume that I don't care about voiding my warranty and that I assume all of the associated safety risks that would come with this idea.

Assume that if this is possible that I will be driving in such a way to be using less energy than the charger is supplying to charge the battery.

Assume that I have thought of all the expenses that this might incur and that I am ok with incurring this expenses.

I'm looking for people that have direct knowledge of the charging system and any interlocks that may be present that would allow or prevent one from charging while driving.

Thanks!

Paul

 

[leodoggie]

The charging control circuitry will not allow this, in fact the dash will flash " unplug charging port".

 

[Perovskite]

That's what I suspected and was afraid of.

So what would happen if I applied power to the charge port using an approved charger while the car was driving down the road?

Does the car itself have electrical control systems that would disconnect the charge port from the batteries?

Is there communication or feedback between the car and the charger? Or is the charger directly connected to the battery bank and the charger decides on the charge curve based on the characteristics it is sensing from the battery?

Just because the car reminds you to "unplug charging port" does that prevent you from moving the car?

A quick experiment would be to sit in the car while it is charging and see if you can put the car in drive and move forward a little bit.

Thanks for any clues to understanding some of the inner workings of the charging design in this car!

 

[leodoggie]

The car will not move unless you unplug the charger.

 

[michael]

There are two main ways to do what you have in mind. However they make more sense for older 80-mile class cars...the Bolt's inherent range make this whole thing far less necessary.

As stated above, interlocks prevent using the main charge port. However, you could (but shouldn't) have a separate DC charger (Brusa or similar) that directly charges the battery while driving. This requires getting involved with the high voltage system. It can and has been done, but it's difficult, expensive, and potentially dangerous. I mention it because it can be done.

A much easier way (but also probably not needed) is the use of a "pusher trailer". This is a trailer which you attach to the car with a standard hitch. It has a small engine (maybe 30 HP) and when needed pushes the car along the road, supplementing the main drive system. You can think of it like being on an infinitely long downhill.

These have been done several times in the past

http://ecomodder.com/forum/showthread.php/powered-trailer-idea-ev-pusher-trailer-make-conventional-2975.html

I personally know a guy who regularly drives a RAV-4 EV between Utah and Southern California this way. He has a homebuilt trailer with an old VW engine, uses it for the long transit and then unhitches and parks the trailer while at either end.

But with the Bolt, really the need has pretty much gone away.

 

[DucRider]

There are two main ways to do what you have in mind. However they make more sense for older 80-mile class cars...the Bolt's inherent range make this whole thing far less necessary.

As stated above, interlocks prevent using the main charge port. However, you could (but shouldn't) have a separate DC charger (Brusa or similar) that directly charges the battery while driving. This requires getting involved with the high voltage system. It can and has been done, but it's difficult, expensive, and potentially dangerous. I mention it because it can be done.

A much easier way (but also probably not needed) is the use of a "pusher trailer". This is a trailer which you attach to the car with a standard hitch. It has a small engine (maybe 30 HP) and when needed pushes the car along the road, supplementing the main drive system. You can think of it like being on an infinitely long downhill.

These have been done several times in the past

http://ecomodder.com/forum/showthread.php/powered-trailer-idea-ev-pusher-trailer-make-conventional-2975.html

I personally know a guy who regularly drives a RAV-4 EV between Utah and Southern California this way. He has a homebuilt trailer with an old VW engine, uses it for the long transit and then unhitches and parks the trailer while at either end.

But with the Bolt, really the need has pretty much gone away.

Or you could consider an i3 REx :idea:
You could very well find that the range on the BMW would be about the same as a Bolt with a trailer.

 

[Perovskite]

Thank you for all of the thoughtful replies. I agree that the extended range of the Bolt makes this wacky scheme less of a possible issue but something I wouldn't mind tinkering with nonetheless. With my last car I had the dashboard off making modifications within 30 minutes of driving the car off the lot at the dealership. So I'm not afraid to tinker.

I would like to have more background education about how the EV batteries are engineered and how the charge cycles is regulated. I work with high power, high voltage inverters everyday at work so the voltages and currents in an EV are modest and easily worked on safely in my opinion. The work application has nothing to do with cars though and doesn't involve the charging of batteries. So a slightly different beast with different loads that the inverter will experience.

For the Bolt I'm hoping I can sneak some power directly into the battery bank, possibly bypassing the current sensors so the computer doesn't know that there is external power being fed into the battery. Essentially making the generator appear to be part of the battery's charge.

The challenge that I see at the moment would be tightly regulating the DC input to match the charge state of the battery pack. This would likely require an appropriately sized buck/boost converter stage.

Wow, michael, I just looked up the Brusa chargers and that is exactly what they have built but with lots of extra controls complete with CANbus controlled charging. They look pricey. $1-$2k would be my guess. I can build a simple 10kW converter for under $500. I'm thinking that I might be able to get away with a single regulated output voltage. Match the output voltage of a certain discharge state of the battery pack. Then the computer would see that the battery just stays at a 50% charge level for as long as the generator is running.

Is it possible to access any diagnostic modes on the Bolt to get sensor outputs from the various voltage, current, and temperature sensor's? Ideally something I can port into a computer for analysis.

Does the Bolt have a OBDII or similar scanner port? I have a bluetooth adapter that I can plug in and wirelessly read engine, transmission, and safety subsystem data.


I remember reading about the push trailers years ago. I think control might be a bit of an issue. But an interesting thought nonetheless!

The I3 Rex is an interesting compromise and a good suggestion. I want an all electric car 98% of the time and then 2% of the time I want some extended range that allows me to go 400-600 miles and not worry about where or if I can charge.

 

[devbolt]

While I get the urge to tinker, I have to say it probably will be hugely inefficient to do what you want to do. And probably pollute a lot more than just simply renting an ICE vehicle for the occasional long trip. Or you could buy a Volt where most of the engineering has been done for you.

That said, there is someone who took a propane powered gas turbine generator on a small trailer and wired it in to his Leaf so he could tow it behind him:

http://www.greencarreports.com/news/1070677_2012-nissan-leaf-gets-unofficial-jet-powered-range-extender-quick-charger

 

[Michael1]

A much easier way (but also probably not needed) is the use of a "pusher trailer". This is a trailer which you attach to the car with a standard hitch. It has a small engine (maybe 30 HP) and when needed pushes the car along the road, supplementing the main drive system. You can think of it like being on an infinitely long downhill.

These have been done several times in the past

http://ecomodder.com/forum/showthread.php/powered-trailer-idea-ev-pusher-trailer-make-conventional-2975.html

I personally know a guy who regularly drives a RAV-4 EV between Utah and Southern California this way. He has a homebuilt trailer with an old VW engine, uses it for the long transit and then unhitches and parks the trailer while at either end.

But with the Bolt, really the need has pretty much gone away.

How does he control the amount of push?

 

[Perovskite]

devbolt, I don't completely agree on the efficiency aspect but you make a very good point about the emissions issue with using a standard ICE genset. It is rare that the genset will have ANY pollution control. Even the propane powered ICE gensets which are supposed to be more environmentally friendly produce significant NOx unless they have a catalytic converter... I have looked closely at the Volt, test drove one and concluded that I really didn't want to be lugging an ICE around plus fuel and the added maintenance just so I could take a couple of long distance trips a year.

Would anybody in the pure EV community be interested in a clean ICE unit, available for short term rental, that would provide a temporary range extension on their EV? Seems to me that could fill the gap that some poeple see as the barrier to going to a pure EV as opposed to a hybrid. Many people only need 50-100-200 miles of range for 98% of their driving. That extra 2% could be filled by a relatively inexpensive plugin module that slides into a trailer hitch on the back and plugs into the car to maintain a charge level. Kind of like the "hold" driving mode in the Volt where the Volt's ICE runs to keep your battery power for the stop and go city driving... For me personally, it would make the leap to a pure EV a no brainer since I would only need 1 car and I could rent a ICE "range extender" for those couple of long trips to the middle of nowhere I take every year.

Michael1, It looks like the ecomodder, Ingineer, from the MyNissanLeaf forums used a turbine generator to power the Brusa chargers that charge his Nissan Leaf. The turbine generator doesn't produce propulsive thrust like an airplane engine but instead turns a turbine connected to a generator to create electric power. He has added some paralleled Brusa chargers so he can supercharge his Leaf. Basically, what he built and what devbolt pointed out is what I was thinking of for the Bolt. I was thinking of using a more conventional and significantly less expensive ICE generator though.

 

[devbolt]

The whole point of driving an EV is to be more environmentally friendly by reducing your emissions to zero, or near zero. Throwing an ICE genset into the mix will significantly increase your emissions to begin with as there is little in the way of emissions control on them as you note. All of the ICE gensets I found online that could provide enough juice to recharge the battery in the Bolt would end up adding maybe 20 miles of range for every gallon of gas burned.