Forum Discussion
- Have not even tried the math, but a question.
If the trailer had a large battery pack at maybe 48 volts, 500 amp/hrs, and about 1800 watts of solar, how much assist could they provide to the tow vehicle?
Guessing it could be done via a 3000 watt inverter powering the ev the same way and speed as a 30 amp outlet.
Would it provide enough to be worthwhile? Huntindog wrote:
valhalla360 wrote:
Huntindog wrote:
There is a big problem with your math.
55 amps at 400 volts is not 55 amps at 12 volts. trailers would need to operate at 400 volts in order for it to be only 55 amps.
I'm really struggling not to say...duh!!!.
Of course, the power feed from the trailer to the EV needs to operate at the same voltage to the main EV battery pack. That's why I specified it as matching.
If you want to run the house loads in the trailer, you would use an inverter that would convert the 400v DC to 120v AC (see the F150 system for an example).
There might also be a step down transformer to provide a bit of 12v power. Most EVs still maintain a small 12v battery for non-propulsion electrical needs.
Have you ever taken a look at how RVs are wired?
The thought of 400 volts in an RV,,,,,, is scary. :E
The 400 volts in an EV is just in the drive units. It would be (and is) the same for a trailer with an electric drive unit. Electric cars have normal 12 volt systems for all the standard automotive systems.valhalla360 wrote:
Huntindog wrote:
There is a big problem with your math.
55 amps at 400 volts is not 55 amps at 12 volts. trailers would need to operate at 400 volts in order for it to be only 55 amps.
I'm really struggling not to say...duh!!!.
Of course, the power feed from the trailer to the EV needs to operate at the same voltage to the main EV battery pack. That's why I specified it as matching.
If you want to run the house loads in the trailer, you would use an inverter that would convert the 400v DC to 120v AC (see the F150 system for an example).
There might also be a step down transformer to provide a bit of 12v power. Most EVs still maintain a small 12v battery for non-propulsion electrical needs.
Have you ever taken a look at how RVs are wired?
The thought of 400 volts in an RV,,,,,, is scary.
On edit: I do not see where you specified "matching":Etime2roll wrote:
Let me know when the RV park starts charging for running a second A/C. (or even three)
They are getting more electric than many of us. Is that wrong? Who decides? Am I paying for that?
Generally, that's exactly what RV parks do.
With rare exceptions, dual air/con RVs are 50amp and 50amp sites typically come with a small surcharge over 30amp sites. The extra power consumption is one of the key reasons for the surcharge.
While you can connect a 50amp RV to a 30amp outlet, you generally will be limited to running 1 air/con unit.Huntindog wrote:
There is a big problem with your math.
55 amps at 400 volts is not 55 amps at 12 volts. trailers would need to operate at 400 volts in order for it to be only 55 amps.
I'm really struggling not to say...duh!!!.
Of course, the power feed from the trailer to the EV needs to operate at the same voltage to the main EV battery pack. That's why I specified it as matching.
If you want to run the house loads in the trailer, you would use an inverter that would convert the 400v DC to 120v AC (see the F150 system for an example).
There might also be a step down transformer to provide a bit of 12v power. Most EVs still maintain a small 12v battery for non-propulsion electrical needs.valhalla360 wrote:
wanderingaimlessly wrote:
Funny, nobody addressed what I thought was really odd about the article on this prototype. Supposedly this thing will "help" the tow vehicle to gain range.
Either the trailer would have to have a large battery and a means of providing power TO the tow vehicle, which currently the EV's are not set up to accept.
Or, it would have it's own drive motors to assist in propulsion.
If it provides propulsion via its own wheels, that will get interesting for how quickly it senses what is needed, and actually how the tow vehicle could end up reacting to the "push" from the trailer. And a flat tire on the trailer would do??????
Also, how heavy will this battery pack have to be? What starts out as a small light trailer will get heavy in a hurry.
Considering the current crop of EVs are heavily over powered and since they have tons of low end torque, I think it would make far more sense to work out some sort of charging bypass system rather than a whole secondary drivetrain that has to be coordinated with the tow vehicle drivetrain.
This would keep the towing mechanics essentially the same as any standard tow vehicle other than an electrical cable from the trailer to the tow vehicle to deliver that power.
Assuming the EV is operating at somewhere around 400v (I believe that is what Tesla uses), dumping 30hp from the trailer battery to the car would be around 55amps. It would need some safety considerations but well within technological capability.
For reference, I ran some numbers and my F250 with V10 needs a bit under 70hp running empty and around 100hp towing a 7000lb trailer. So if the trailer can provide the extra 30hp, you would in theory have the full range of the tow vehicle. Maybe bump it up to 35hp to account for the extra weight of the battery in the trailer but still within reason.
This would require some sort of collaboration with the manufacturer but I'm betting it's just a simple interlock where if you are charging, the car's computer won't put the vehicle in gear, so it should be a relatively simple thing to bypass it.
There is a big problem with your math.
55 amps at 400 volts is not 55 amps at 12 volts. trailers would need to operate at 400 volts in order for it to be only 55 amps.- ^^^Not talking about random RVers or Joe Public. Actual science pros with real edumacation and all that. The true informed.
shelbyfv wrote:
consider that virtually nobody with an informed opinion
I would consider that virtually many "informed" OPINIONS are based on information which is basically BS. These boards are a great example.time2roll wrote:
Let me know when the RV park starts charging for running a second A/C. (or even three)
They are getting more electric than many of us. Is that wrong? Who decides? Am I paying for that?
You most certainly are paying for that in the cost of your site unless the park has individually metered sites, where they charge you for your actual use at checkout. The park is not taking added costs for electricity from their bottom line, they're taking it from yours.time2roll wrote:
Thank you, seems obvious doesn't it? This thread has devolved into the usual EV bashing. Judging from past posting history that was probably the intent. EV phobics should consider that virtually nobody with an informed opinion thinks we can continue using ICEs as we do now. Right now EVs are the only other game in town. It doesn't really matter if we imagine higher costs or if we may be inconvenienced initially.Gdetrailer wrote:
Let me know when the RV park starts charging for running a second A/C. (or even three)
Never called anyone out as "thief" but, getting something for "free" is not exactly "free" to someone else.
Absolutely no one gives me gas, electric, phone, my home, my vehicles, my RV or anything for free. No one fills my tank for free, no one gives me food to eat for free.
They are getting more electric than many of us. Is that wrong? Who decides? Am I paying for that?
