Supplemental Battery Pack

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The thought occurred to me why don’t they design EV’s so they could tow a small trailer that has a supplemental battery pack? That way the car could have a smaller 150-200 mile range for day-to-day driving and then the few times a year you go on a long trip, you rent a battery trailer so you have 500 mile range and can recharge car and trailer battery at the same time. What would be the drawbacks? Safety?
 

Burt

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I think that the powers that be would site safety in this case..
I suppose so. Seems like there’d be away to address this concern. Maybe take it further and downsize the car to be a grocery getter and make the battery trailer a pickup truck bed with motors so it’s easier to tow.

And when the trailer isn’t being used for transportation, it could balance the power grid.

As far as speed limitations, I don’t know whether there is a natural limit for small trailers that can’t be overcome.
 
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I'm sure it would be less safe, considering many can't even drive safe without a trailer and have no ability to back up with a trailer.

Sees kind of silly to me, rent a trailer when you can just rent an ICE vehicle. Recharing both the car and trailer needs twice as many recharge stations when they are the problem already, quantity/locaton and their speed of course.

Once there are no more ICE vehicles, there will necessarily be more and faster charge stations to suit this need of society so today it seems like you are just looking to cause problems rather than leveraging existing tech.

"And when the trailer isn’t being used for transportation, it could balance the power grid."

This is a terrible idea, another problem is a shortage of batteries (cells, manufacturing, materials) in the first place, so wasting them on trailers is the wrong thing to do. We won't be able to supply even 25% of society with batteries for EVs within the next two decades, without wasting them on trailers. Slowing the EV adoption rate due to that, makes things worse for the long trips because then less perceived need and budget towards more recharging stations.
 
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I just think that the battery location specifications are party because of a crash rating standard for safety with a protection value for the battery. Meaning, in a crash the battery will be protected from impact and failure which can result in fire or explosion.

Maybe they could put the battery into a impact resistance setup like our nuclear transportation setups!

So, maybe if they can skirt around the battery protection requirements, maybe perhaps because its a trailer and not an auto, yes it would be an awesome aux battery source.

I don't think it will work.. Maybe the energy you expend towing the extra weight of the trailer would nullify the energy requirements for towing the extra weight of the battery.
 
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The thought occurred to me why don’t they design EV’s so they could tow a small trailer that has a supplemental battery pack? That way the car could have a smaller 150-200 mile range for day-to-day driving and then the few times a year you go on a long trip, you rent a battery trailer so you have 500 mile range and can recharge car and trailer battery at the same time. What would be the drawbacks? Safety?

That is a step backward not forward. At least IMO.
 

JHZR2

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You don’t want to know how expensive that would be….

I think at that point make the trailer a little genset that connects to the charging connector.

Essentially, the bmw i3 was the right idea. Make an ev with a truly tiny, efficient apu. Run it when it makes sense.

Ruined by stupid US EPA and IRS regulations.
 
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You don’t want to know how expensive that would be….

I think at that point make the trailer a little genset that connects to the charging connector.

Essentially, the bmw i3 was the right idea. Make an ev with a truly tiny, efficient apu. Run it when it makes sense.

Ruined by stupid US EPA and IRS regulations.
Agreed.

The i3 and Volt, with a little refining, could have been so perfect.

A plug-in hybrid, basically a BEV with onboard generator, is the way to go IMO. It would allow me to do 90% of driving EV only and eliminate range anxiety on longer trips.
 

Burt

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Agreed.

The i3 and Volt, with a little refining, could have been so perfect.

A plug-in hybrid, basically a BEV with onboard generator, is the way to go IMO. It would allow me to do 90% of driving EV only and eliminate range anxiety on longer trips.
I don’t know. Driving around with the weight of a built in generator (and all associated maintenance) for 10% of your driving in a car the is used less than 5% of the time seems like a waste. Better to borrow it.

I think you’re overlooking the benefit of downsizing the battery, weight and cost of the car for everyday use and the higher utilization of the combined assets bring down costs.
 
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I don’t know. Driving around with the weight of a built in generator (and all associated maintenance) for 10% of your driving in a car the is used less than 5% of the time seems like a waste. Better to borrow it.
"Better to borrow it."

That's inconvenience. I don't want to be inconvenienced when my helicopter needs a part and I'm meeting a mechanic the next state over at 3am. Mostly I commute. Sometimes I don't.

I want a car that serves me, not vice-versa.
 
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The real solution will be when the batteries are standardized and as easy to change as the battery on your cordless drill. You just pull into a change station and they swap batteries in the same time as it would take to fill a tank. All batteries would be rentals kind of like propane tanks. You use the charge and they refill it from a green source (solar, wind, hydrogen). You pay a flat rate swap fee. This way the government can tax the battery swap to get their road taxes, gas station owners have a replacement for selling gas, big corporations still control the flow of energy and consumers get to pay for it. Everybody is happy and all is right in the world. Plus you create a ton of new jobs as battery techs at stations.
 
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The average driving per day is like 35 miles.
Charging from home works great. Chargers work pretty well too when necessary.

Right now, if you regularly need to drive over 300 miles per day, you don't need a trailer battery, you need a different car.

Battery swap would never be used because the vast majority of owners charge at home and rarely charge on the road. This is what I call ICE group think. EVs are different; it seems many want to turn them into ICE.

As more locations open up, like condos, apartments, shopping centers and especially places of work, it will be easier and easier.
Heck, the Kaiser hospitals around here have smallish charging stations located in various places around the facility.
Arounf here, prospective work candidates are asking for charging at work. I have talked to people who charge at work and "never charge at home".

A car's idle time is its charge time.
 
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Basically none of the math works. You can't tow a generator because the amount of power you'd need would have to make it a pretty big generator, not some small few hundred dollar one. Same with the battery pack, probably at least 10k for a pack you could tow.

Also swapping battery packs can be tricky because the entire battery pack in a Tesla is in the 1200 pound range. So it's pretty heavy. Plus as you drive the car, the battery pack ages and you lose performance, maybe 1-2% a year and up to 20% or more if you're driving 100k so who wants to get suck with a weaker battery pack on an exchange?
 
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I could see a standardized swappable pack, maybe in the 40 pound range? And a spot in the frunk which could handle some number of them? 4, 5, 6? If it was a universal standard, you could buy/exchange them like propane cylinders, or they could stay in place and provide supplemental power. They wouldn’t even have to be full-current enabled…. They could moderate-charge the main battery, providing a constant supply while it provided the acceleration surge. One could set them up to only charge on-grid, not worrying about the cost of tying into regen. It’s basically like electrical gas cans. And very doable. In fact, in this arrangement they could be upgraded to newer tech in the future, just by adjusting interface parameters rather than gutting an entire vehicle. Would that add enough capacity to be valuable??

if I was taking a trip now into uncertain territory with an EV, at a minimum I’d carry my eu2000i with me. Fast? No. able to limp somewhere after 2 hours? Yes. And, I don’t own an EV - don’t yet fit my use case, but I’d love to have one. For now, however, it’d have to be a 3rd car for office commutes only. My 50 year old home… will be a nightmare to bring charging to the garage/driveway.

a fellow made a solar powered EV bicycle years ago and rode it coast to coast. The bike held him, the drive motor, and luggage packs. The trailer behind him held 4 full size panels, a few lead acid batteries, and the power management. It was a very long trailer. He made it across country just fine, albeit better on sunny days. PV would hold cruise, batteries wede needed for hills and cloudy stints. It was entirely too much weight to effectively pedal.
 
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Basically none of the math works. You can't tow a generator because the amount of power you'd need would have to make it a pretty big generator, not some small few hundred dollar one. Same with the battery pack, probably at least 10k for a pack you could tow.

Also swapping battery packs can be tricky because the entire battery pack in a Tesla is in the 1200 pound range. So it's pretty heavy. Plus as you drive the car, the battery pack ages and you lose performance, maybe 1-2% a year and up to 20% or more if you're driving 100k so who wants to get suck with a weaker battery pack on an exchange?
This is why EV's are not ready for prime time, but if you dont own the pack and exchange it every time it runs down its just like a propane tank, Who cares if its a bit rusty as soon as its empty you get another one and the propane company is responsible for pulling them out of service and refurbishing them. You wont be able to charge at home because then the government cant get their road taxes and they dont know if you used a green energy source to recharge which is after all the whole reason for going green.
It does not sound so great but when EV's become a serious contender they will regulate the sh** out of them, just wait.
 
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Some of the Zero motorcycles have a supplemental battery pack available, called a "Power Tank" that can be left in place permanently. I think it's about 3Kwh in real world terms. Which adds about or around 30% more capacity. That may depend on what bike you start with and how big the OEM battery is. Cost is just over $3K.

Interestingly, some folks have made their own by stacking up 18650's.

0101391_z-force-painted-power-tank-zero-ds-black-zm10-08208-13_320.jpg


maxresdefault.jpg
 
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I could see a standardized swappable pack, maybe in the 40 pound range? And a spot in the frunk which could handle some number of them? 4, 5, 6? If it was a universal standard, you could buy/exchange them like propane cylinders, or they could stay in place and provide supplemental power. They wouldn’t even have to be full-current enabled…. They could moderate-charge the main battery, providing a constant supply while it provided the acceleration surge. One could set them up to only charge on-grid, not worrying about the cost of tying into regen. It’s basically like electrical gas cans. And very doable. In fact, in this arrangement they could be upgraded to newer tech in the future, just by adjusting interface parameters rather than gutting an entire vehicle. Would that add enough capacity to be valuable??

if I was taking a trip now into uncertain territory with an EV, at a minimum I’d carry my eu2000i with me. Fast? No. able to limp somewhere after 2 hours? Yes. And, I don’t own an EV - don’t yet fit my use case, but I’d love to have one. For now, however, it’d have to be a 3rd car for office commutes only. My 50 year old home… will be a nightmare to bring charging to the garage/driveway.

a fellow made a solar powered EV bicycle years ago and rode it coast to coast. The bike held him, the drive motor, and luggage packs. The trailer behind him held 4 full size panels, a few lead acid batteries, and the power management. It was a very long trailer. He made it across country just fine, albeit better on sunny days. PV would hold cruise, batteries wede needed for hills and cloudy stints. It was entirely too much weight to effectively pedal.
Well you're way off on the weight and the range. The problem with stacking all the batteries in the trunk is the center of gravity. There's a reason that the battery packs are on the floor in the center of the car. If you want 6 battery packs weighing 40 pounds, that's 240 pounds in the trunk, throws off the driving dynamics although 240 isn't that much, if it was 1200, it'd be a lot. 240 pounds of lithium batteries won't get you very far is the problem. The model 3 battery pack is 1060 pounds and good for 310 miles but EPA claims 272 miles. At 1/4 of that in power, you're now at about 75 miles. So you'd be swapping battery packs every hour or two depending on how fast you're going.

Can you imagine the workout you'd get for swapping out 6 40 pound battery packs? That's not a simple single propane tank exchange. If you want to do the full battery pack on a Tesla, that would be 26.5 40 pound packs or more. Not too many people out there would want to move 40 pound packs a few feet 26.5 times. People on average are way too out of shape for that. Also keep in mind that Blue Rhino puts in 15 pounds on a propane tank so a full propane from them is about 32 pounds instead of 37 with a real full 20 pound tank.
 
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