Portable emergency battery pack would be great to have in trunk for emergency.
Portable emergency battery pack for the trunkbe f
- Thread starter JCP in DCL
- Start date
Candleflame
Active Member
you'd need a huge battery. Not just because of the transfer losses but also because... well... the battery has to be huge.
I might add here, the only method which has so far been proven to be highly effective for Teslas to get emergency range is to pay someone with a Diesel to tow you around for a few minutes.
Even diesel/gasoline generators just don't really make enough power for it to be worth it.
I might add here, the only method which has so far been proven to be highly effective for Teslas to get emergency range is to pay someone with a Diesel to tow you around for a few minutes.
Even diesel/gasoline generators just don't really make enough power for it to be worth it.
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Why, Carrying around such a thing would reduce your effective range for every trip, and I cant think of how this would help you, other than the silly hypothetical situations like "what if you were driving across the desert and ran out of electricity" that people that dont have EVs tend to spout out.
DirtyT3sla
Member
It just doesn't make sense. If there were room/money for more batteries somewhere, they'd just be built into the car already.
So a cell makes 3.7volts and you need enough of them in series to get to the 350volts or so the car uses, then you need enough in parallel to supply the necessary amperage, then you need hardware to tap it into, then you need to think ahead to store it at 50%. You have filled a crumple zone with something that needs lots of protection.............
It works have to be expensive too. If stretching range minimize HVAC use and slow down, draft mildly not tailgate.
It works have to be expensive too. If stretching range minimize HVAC use and slow down, draft mildly not tailgate.
As others have indicated there's a little problem here with physics and electricity.
And maybe to put it another way, if it was easy and cheap enough to do, then why would Tesla not have just added that to begin with?
Just to give a little comparison, the DC-AC converters that you buy at stored handle about 300 watts. A 120V charger for the Tesla that adds a few miles per hour requires 1200 watts. A car battery has only about 600 Wh total storage and you would need a really big DC-AC inverter to charge the car.
So, a 12V car battery and a larger DC-AC inverter would give you, maybe 2 miles, (Although there weight would probably reduce range by that much)
Big Earl
bnkwupt
I disagree. You already have an enormous battery ... plan appropriately and have AAA as a backup.
afty
Member
Let's look at some of the giant battery packs available now. Assume a Model 3 uses 240 Wh/mi.
Anker Powerhouse - 400 Wh, $500, 9 lbs, +1.7 mi range
Goal Zero Yeti 3000 - 3024 Wh, $3000, 68 lbs, +13 mi range
Tesla Powerwall - 13,500 Wh, $6700, 276 lbs, +56 mi range
So this is a thing you could do, but you would really want to spend several thousand dollars and drive around with all that extra weight in the trunk just to get a few extra miles in case of emergency?
Anker Powerhouse - 400 Wh, $500, 9 lbs, +1.7 mi range
Goal Zero Yeti 3000 - 3024 Wh, $3000, 68 lbs, +13 mi range
Tesla Powerwall - 13,500 Wh, $6700, 276 lbs, +56 mi range
So this is a thing you could do, but you would really want to spend several thousand dollars and drive around with all that extra weight in the trunk just to get a few extra miles in case of emergency?
Better to put a small gas generator in the truck with some gas cans... Kind of defeats the point of an electric car...
So another thing. Really the GZ is the only practical option. But then it wouldn’t be as simple as plug in the battery and go. You would have to charge of the 110 inverter and even if the yeti inverter would handle the load you would need to sit plugged in for 7-14 hours to get the ~13 mile range.
As for the generator. I have a 15k 240v generator with a 14-60 receptor. It weighs ~450 lbs (without fuel) and takes me and both kids (11 and 13) to move. I did a trial and got 7% (~20 miles) of range in an hour.
But the inefficiency of the 120volt charge would consume some of the 13mile capacity of the Yeti probably a big chunk.
I see this idiotic question come up from time to time. Usually it's asked in this form.
"What if you find yourself out of energy somewhere?"
Well, since teleportation technology doesn't exist, it's impossible to just "find yourself" somewhere in your car. You were driving it to get to that point, so how were you driving during the last hour+ leading up to that moment? Pay a little bit of attention to your buffer as you drive and just...don't let that happen.
"What if you find yourself out of energy somewhere?"
Well, since teleportation technology doesn't exist, it's impossible to just "find yourself" somewhere in your car. You were driving it to get to that point, so how were you driving during the last hour+ leading up to that moment? Pay a little bit of attention to your buffer as you drive and just...don't let that happen.
There are a lot of places that do not have nearby superchargers... Look at Oklahoma, there are only 5 places in the state... You cannot even go east on I40 since there is a 350 mile gap between superchargers... (OKC to Littlerock).
I have to be very careful. I have a home and work charger that gets me by, but bad weather causes major range anxiety. I have had to pull into an RV park and charge a couple of hours in the past (caused by a big detour/road closure).
Things like pouring rain in cold weather can kill your range.
I know. I live in one of those places and have dealt with this for over 5 years. When my car got delivered, for the first year and a half, there still weren't any Superchargers within range I could drive to.
Yes, well aware.
Don't say you can't. You can, but it's less convenient. I had a 14 hour drive home from Salt Lake City that should normally take about 5 hours because I was using slow 40A AC charging the whole way back when there weren't any Superchargers there.
I have also done drives where I had to be very careful of my range. I drove from Sisters, OR all the way to Baker City, OR without stopping, with the cruise control set on 45 mph and no heat. to make it. It took about 5 freaking hours!
I am very well aware of that and have encountered those types of things, like snow storms.
And yet, I will repeat my comment:
"Pay a little bit of attention to your buffer as you drive and just...don't let that happen."
There is so much information about the energy usage in the car's displays. Charge up enough to have a comfortable buffer for conditions to start, and then drive so as to preserve a comfortable margin, and adjust your driving style as needed as you are driving to make sure it doesn't drop too fast. And if you need to, pull off early to a fallback plan B for charging before it becomes a desperate problem with no options. You can prevent running out.
My closest supercharger is ~2100 miles away and requires a passport to get there... also all the RV sites are closed for the 6-8 months of winter.
Kilotango74
Active Member
I'm picturing a Mars rover with solar panels strapped to the top ala Mark Watney.
Legen---dary
Member
A betavoltaic battery in the boot would certainly be a nicety; something in the 500W range. The car could then trickle-charge itself for a few decades. What is the opposite term for "vampire drain?" Vampire gain? (Roof-mounted solar panels may also cause vampire gain).
Other than that, it would be great if Tesla cars could charge each other if needed. The Tesla pick-up, with a 200kWh battery, could find a stranded Tesla vehicle in the boonies, and charge it at at least level 2 rates.
Once the Tesla semi is common, a mobile charging station would be feasible. If run on autopilot a battery-tanker fleet could shuttle power from remote non-grid-connected energy farms to highway pullouts. This way the supercharger network could be filled in or adapt on the fly to demand. Battery tankers could even recharge at regular superchargers, or better, at megachargers, before being redeployed.
billionaiire
Member
Don't they already have ideas to strap a solar panel on the roof of the car and connect it to the car battery as a backup charger as it drives? Vampire gain may be software controlled to be switched off when the battery is full and if driving, it goes to helping the car move?
davewill
Active Member
Yeah, this comes up regularly, and it's as impractical as hauling around a spare traction battery. The amount of PV you can possibly put on the roof a car is so small and the engineering needed so significant, that it's a complete non-starter.
Legen---dary
Member
The skin of the car being solar is not entirely a non-starter. Compared to optimized stationary applications, or the amount of power one obtains from even a level-1 charger, it is rather minimal, but that's not the point.
An array covering the model 3 would yield about 2-3 kWh a day in optional conditions. It's a tiny amount, but not insignificant, especially when factored against the longevity of such a car.
Decades ago the university of Queensland built a solar car that would add 12k km a year just parked in the sun. A recent German startup has also taken this route and is doing very well.
So, although solar on a car may at first seem impractical, it isn't in all cases, and the engineering involved is far from complex.
If integrated from the factory the cost would also be utterly negligible.
I can see integrated solar both on the skin of the car and windows as being normal in the future; that along with entire building envelopes.
If the look, the cost, the longevity and complexity have all been solved, then it would be illogical to not include solar.
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