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EV

cfherrman

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I have never studied any of the electric vehicles of any kind so consider me ignorant on the subject. With that being said, can anyone explain to me why an EV battery can't be charged while the EV is in motion? In my simple thinking mind, you should be able to generate current for a battery charge while the EV is in motion.

I'm assuming your taking about using the wheels moving to charge the battery, this is regenerative braking and it will stop the vehicle, so to keep going you would have to put power to the motor
 

Spud_Monkey

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If one lives on a photovoltaic system in the extremes of what most are use to and are able to do so then these EV's along with others are possible. Not much is different between a photovoltaic system and a EV, both use a battery, need battery chargers which require charge controller and instead of going to a inverter with the power it goes to a electric motor.
I live off the grid as most know and it gets down to forty below zero here, if the battery on these couldn't take the extremes then I would be screwed as it's same battery tech that some of my stuff runs on.
Don't think you can get parts and these are hard to work on, here this guy alone is doing it along with other rebuilds with the cars Tesla makes. Only matter of time and few guinea pigs later before same can be done with Tesla semis.
https://www.youtube.com/c/RichRebuilds
 

Delmer

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I have never studied any of the electric vehicles of any kind so consider me ignorant on the subject. With that being said, can anyone explain to me why an EV battery can't be charged while the EV is in motion? In my simple thinking mind, you should be able to generate current for a battery charge while the EV is in motion.
that's what the current hybrid cars do, they use a smaller engine, and a battery/charger/motor, so the battery powers the car for some miles until the engine turns on, then the engine and battery work together for higher power, then the engine charges the battery at cruising speed and braking. The physics gains nothing at steady state cruising from a hybrid setup, and loses from the weight and complexity, but the real world gains from the smaller engine (but really mostly from the other mods like tires, tuning etc.)

I'm definitely one that has changed opinion in the last three years as TS says. I'd buy an electric vehicle in a heartbeat, heck, I'd buy two. But I buy used vehicles, and it will be a long ways until they get to my price range, but I think they will someday, and they've reached the point where they will suit me fine. I don't care about more than even 20 miles of range, I have another vehicle for that, or 75% battery efficiency, still cheaper than other fuels. There are plenty of disposable vehicles sold new everyday, and many of them should be electric. What the govt subsidies should be is another question.

Whether Tesla sells one, or a thousand semis, they'll find homes like Crane Operator said, it won't and doesn't have to be OTR or logging. Would make more sense to make a toter for the distribution center first, but that's not where the headlines come from.
 

digger doug

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I have never studied any of the electric vehicles of any kind so consider me ignorant on the subject. With that being said, can anyone explain to me why an EV battery can't be charged while the EV is in motion? In my simple thinking mind, you should be able to generate current for a battery charge while the EV is in motion.
You could plaster the roof of the cab & trailer with solar panels, that would help extend the range a wee bit.
It all boils down to simple math. How much per hour does the truck draw in running ? How many sq. ft. of panels can you apply to the truck, and how much wattage per hour will they put out to charge the batteries ?
 

cfherrman

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Battery heat/cold and cycle issues are a very little issue due to battery technology and battery controllers.

Tesla cars already have cooling systems for the batteries, they may undersize on the semis which will cause problems but then they will fix it, it's not like something like that never happened on a car/truck.
 

cfherrman

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You could plaster the roof of the cab & trailer with solar panels, that would help extend the range a wee bit.
It all boils down to simple math. How much per hour does the truck draw in running ? How many sq. ft. of panels can you apply to the truck, and how much wattage per hour will they put out to charge the batteries ?

You also need to add in cost of solar panels to life of them, the cost per kw on solar doesn't compare to the grid so Tesla will never do that.
 

John C.

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Installing solar panels on trailers would make a lot more sense than just putting them on the truck. It's just another wire to hook up to the truck when they are coupled. Put an isolator switch between the panels and the coupler to truck to prevent arc when connected and away you go.
 

DMiller

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Not quite so easy as have to match Voltage with Incoming power, Tesla Batteries for Cars are 200+V, the trucks has not been discussed but to get appropriate Ah capability to HP would have to be Higher. The Bus batteries on the Metro units are not divulged either but use a 7200V charging system at 300+amp draw Per Bus. The Surge In-Rush current is why they had to have their own substation for the chargers as initiates at over 1000a. Those do also have Regenerative Braking but only adds minimally to overall life support for the batteries, intended to last four hours on charge, have extended to 5.5 so far. Batteries pack on the Metro Buses weighs in at 4600 lbs.

Looked up generic EV Bus Battery, Each Cell is rated at 24v, HOWEVER, the Safety Responder sheets state can be anywhere from 390-690v present on machine.
KSeries_First_Responder.indd (nfpa.org)

20180901E_BUS_bateries_data_sheet_EN (bmz-group.com)
 
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Delmer

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Solar panel installation retrofits rarely make sense on residential roofs if you consider the installation and hassle of re roofing. They won't make sense for a long time on anything moving, unless it's a slow boat, or an autonomous small ag tractor.

I would think regenerative braking is great for a city bus, or garbage truck, or a mailman. Not so useful on a semi, even for urban delivery. As far as heat and cold, they can develop cooling systems just like early gas engines cooling systems evolved. I haven't seen that they've solved the cold issues if the battery has to sit outside not charging and starts the day at -20.
 

Old Doug

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I have a buddy that has a golf cart with panels on its roof. If in was rich i would buy one of these trucks then hire out to a generator factory.
 

cfherrman

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Electric hp compared to diesel HP is way different, similar to steam HP to diesel.

200-300 HP on electric would probably have the same performance as a 400-500 diesel hp except on the top end of speeds (60-70 mph) then electrics would really need to have a matching HP especially on hills. Remember how hybrids really use the gas motor at highway speeds because there's more power and efficiency there then electric, but around town the electric is way more efficient.
 

digger doug

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Electric hp compared to diesel HP is way different, similar to steam HP to diesel.

200-300 HP on electric would probably have the same performance as a 400-500 diesel hp except on the top end of speeds (60-70 mph) then electrics would really need to have a matching HP especially on hills. Remember how hybrids really use the gas motor at highway speeds because there's more power and efficiency there then electric, but around town the electric is way more efficient.
What does speed have to doo with an electric drive ?
 

Delmer

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electric HP is no different than gas or diesel HP, the difference is a typical electric motor will have a service factor of 1 or 1.2, meaning it can AVERAGE 1.2 times the rated HP, so it can peak at double the rated HP typically. While a gas or diesel will have an absolute peak HP and it will be only available at one speed and falling off at varying speeds. Not such a big deal with lots of gears. I don't know if Teslas HP are under rated, I doubt it.
 

Truck Shop

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Are we not painting ourselves into a exceeding additional Blind Hole Corner??

Why yes we are. It won't be long and everyone can watch everyone get Skinny.
The Only thing that has a way of changing people is when {Their belly button
starts scraping on their spine}.

Hunger has a way of changing mind set.
 

cfherrman

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What does speed have to doo with an electric drive ?

A electric drive at 0 rpm has it's most torque, the faster it goes the less power it has. When a ev truck is at highway speeds it will be at it's lower power rating, hence my saying of electric hp is different than diesel hp.

You guys should watch a 80 HP stream engine do a sled pull, it will beat diesel engines with 2-3x more power. 80 HP at 60 rpm is quite a different monster than diesel, the same goes for electric.

If you put a 500 HP Tesla truck at 60 mph then have it take a hill and compare it to a 500 HP diesel with weights bring the same, the diesel will kill it, now put both trucks at the middle of the hill at 0 mph, the Tesla will kill the diesel
 

Mobiltech

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I have never studied any of the electric vehicles of any kind so consider me ignorant on the subject. With that being said, can anyone explain to me why an EV battery can't be charged while the EV is in motion? In my simple thinking mind, you should be able to generate current for a battery charge while the EV is in motion.

You can’t recover energy from the spinning wheels without slowing the wheel down which would defeat the purpose of driving. You can however recover the energy of a wheel moving the suspension up and down on bumps in the road. I have seen a shock absorber that generate current when it absorbs the movement of the suspension.

https://www.seminarsonly.com/mech & auto/electricity-generating-shock-absorber.php
 

Truck Shop

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Years ago when the Milwaukee Line was still operating {can't remember the term for overhead electric
system used} catenary. the one thing a engineer did not like to have happen-stopping on a grade. When ever
that did happen on the Boilston Grade up from the Columbia River a track crew was sure to be called
out. The engines even with sand added would cut a long divot in the rails from spinning drive wheels.
Sometimes up to 6 full length rails. The power from a standing start on a grade was hard to regulate
at the rheostat for a start without damage to rails. The drive wheels usually had to be changed in short
order.

Told this by a old Milwaukee engineer and a guy that worked that section as part of a track crew.

Steam and electric is torque from zero.
 
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