Without really watching the video (although I did later fast-forward through it), if 50 miles requires 15 kWh of energy stored in the battery
https://youtu.be/fGZ1zbqAGA0?t=280
He claims he gets "around 80ah" per battery. It's a bank of 12 lead acid batteries, 144 nominal.
He claims "150-300 watt-hours per mile."
Duncan first pointed this out to me, but, a fantastic rule of thumb is that anyone who uses lead acid batteries, lies about them. So just expect to be lied to whenever anyone talks about their lead acid batteries. It's become a bit of a game for me, read or hear about a build using lead-acids, wait for the lies, wait for the lies, find the lies... oh there they are, right on schedule. People even get a particularly identifiable "
lead acid liar" look in their eyes when it's their time to lie about lead-acids. It's like they're in court trying to give testimony they know is misleading but maybe technically correct in some circumstances, and are trepidatious about the possibility of getting called on it.
Yeah, this Volkswagon with a rectangle on it
outperforms electric Miatas on Wh/mile. Sure bro. 150. Y'know, downhill. This one time.
Let's check some math.
12x 12v = 144v nominal.
"around" 80ah batteries (any 'around' qualifier means he's hedging a lie, that's probably rounded up, and it's probably measuring what he puts into them at 60% efficiency, but whatever we have to start somewhere, let's take that)
80ah * 144v =
11,520 watt-hours absolute max. MAX. Brand new, 20-hour discharge.
His peukert losses when discharging in under an hour are probably 40%.
11,520 * 60% =
6912 watt-hours. BRAND NEW.
He gets 50 mile range he claims.
6912 watt-hours / 50 miles =
138.24 watt-hours per mile.
Sure.
He claims he uses "
150, 250, 300 amps... uhh.. per battery... and that gives me my 50 mile range. A lot of people like to talk watt-hours so that gives me 150-300 watt-hours per mile."
Well,
150wh * 50 miles = 7,500Wh, which is not enough even for his likely best case with new batteries.
300Wh * 50 miles = 15,000 Wh .... which is higher than his batteries are even spec'd for at 20hour discharge, brand new, by 30%.
His actual current draw is more revealing.
150 amps * 144 = 21,600 watts.
300 amps * 144v =
43,200 watts. Boom. The actual power requirements of driving.
6910 watt-hours available / 43,200 watts of what it actually takes to move the vehicle at speed = 0.16 hours of battery capacity. 9.5 minutes.
Suppose he's going 50mph at that draw (with a 100lb motor?). 0.16 hours * 50mph = 8 miles.
His actual range, on brand new batteries, is 8 miles. 10 if he's going 60mph.
Ya think this guy's family is just tired of Dad's non-stop bullshit? They're humping down the road at a crawl, panicing every time a vehicle comes up behind them, shuffling forward 20 miles a day, if they're on a hill they can see farther than they can drive in a day, and then every time another camper talks to them Dad's out there bragging "50 miles".
I mean, if you're going to just phrase stuff in the most lenient way possible, why not go all the way? Why not calculate your range at jogging speed and tell people that? It's some kind of half-truth people feel comfortable with quasi-misleading people. They know when they say 'range' what everyone thinks, so they fudge it enough to not be laughed at but no further.
that suggests a 2000 watt (peak) solar array, and full sun exposure. That's 20 square metres (or square yards) or so of panels, or at least far more than what fits on a VW van. So, what were his power and energy numbers?
He said 8 amps in full sun, 150v.
8 amps * 150v = 1200 watts.
That's 12 square meters. So, 4m x 3m, or, 6m x 2m? 6m = 19' x 6'?
The van is 14' long and 5'6" wide.
But whatever, call it 4.5 hours of peak-sun per day average. 1200 watts * 4.5 =
5400 watt-hours per day.
Let's check that against his plug-in math.
He says he can plug it into any 120v, but usually he tries for 220v, 30amp plug, which charges it up in about 2.5 hours.
220 *30 = 6,600 watts * 2.5 hours =
16,500 watt-hours.
Roughly accurate for his battery pack size to account for charging losses.
Which also means that he needs 16,500 / 5,400 =
3 days to charge it up, presuming he's not using it for cooking (which he does), refrigeration (never turns it off), and all the other DC systems.
Here's another gem:
"The message here is, slow down. The message is, if you go 40, 50 miles an hour like this, your range goes up so dramatically. You have everything you need with you so you have no reason to go fast, or get to."
I mean, I get his point, but the purpose of a vehicle is to MOVE, otherwise you just have a crappy building. The whole, stop and appreciate the journey this starts to take a backseat to the panic'd charging-planning routine.
His van can literally only travel, at low speeds, best case, with new batteries, fully charged, to full and complete deep discharge, 15 miles in a day of solar charging. You can see farther than that.
At some point I kinda start thinking, if that's all you can do, then why bother with EV? The little generators that most people with a tent trailer bring can supply enough power to move his van along. He's looking at like, $4/day in gas and it's only running it an hour.