Comment by struggle2 | Hacker News Reader

Comment by struggle2 | Hacker News Reader

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In Germany (and I think in the EU) you have a max. weight for cars of about 3.5T (~7716 pounds). You can drive cars that weight more than that but then your speed is limited to (I think 80-100km/h), you have to pay (more) toll and more importantly you have to get a special drivers license in most cases (cost + time).

Camper vans usually get very close to that limit. Even if the van has only 2 sleeping spots. Weight is definitely an issue there and most camper vans sold these days come with a solar installation on the roof.

With 100W of solar you can expect some additional autonomy as a camper. 200W is considered more than average solar for small camper vans in the EU.

A typical 200W solar panel weights in at around 10-13 kg + maybe 1-3 kg for the additional bracket.

11-16kg is something you would think about.

Thats also the reason why flexible panels are already used for some camper vans. They also have the advantage than you can put them on un-even surfaces.

The VW Grand California for example can be ordered with a flexible panel at the front side:

https://de.wikipedia.org/wiki/VW_California#/media/Datei:VW_...

16 kg on 3500 kg is nothing and you definitely need 200W and not 40W

The limit is 3500 kg, if you’re at 3300 kg stock then you only have 200kg to play with when retrofitting.

Also it’s 200W/m2 but camper roofs are a lot more than 1 square meter so you just cover a larger percentage of the roof with solar.

I'd rather have 5x the power and find a few kilos somewhere else to save.

If efficiencies were within a few percents.. sure.. but when we're talking about a factor of 5+, it doesn't seem to be worth it.

If by 5x the power you mean 1kw then your up into the 70kg/150lb range for the panels and brackets which isn’t that easy to shave.

3500kg for the whole vehicle including interior + 100L of water + 100L of Diesel + 50 L of gray water + 2 Passengers + 1 shower + 1 bed + 1 kitchen + 2x11 l gas etc.

As I mentioned: A typical camper van is borderline at 3300 kg already so you have 200 kg for cloths, food, water to drink, bedding, etc. It even matters whether or not you gained 10kg during winter or lost 10kg.

16kg equates to about 2 lithium ion 100WH batteries 1-2 bikes for bike tours 1 grill + extra gas for a barbecue

etc.

So you can decide between those or a conventional solar panel or you just pick panels that weight less then you can have both.

The limit is for maximum authorized mass (which is basically "what manufacturer says" it can carry max) not current mass.

I doubt anyone will ticket you over being 10 kilos extra...

On top of that you could probably pick any other part to make lighter and come out cheaper than buying fancy solar panels

No you are incorrect. There are 2 maximum masses: the one from the manufacturer and then the legal mass limit. Legal mass limit = MIN(3.5t, max mass according to manufacturer) or more precisely MIN(max_mass_you_are_certified_for, may_mass_according_to_manufacturer).

It is not about + or - 10 kg. But things definitely add up. 10kg here - 10kg there.

Solar panels is something that is under the control of whoever buys the vehicle. You have almost no influence of the vast majority of what makes up the van.

You also risk insurance issues when your car is over weight.

Believe me - weight is definitely an issue.

Who is weighing your van, and when? Genuine question, as this practically doesn’t happen in the US for anything with fewer than 18 wheels.

It happens all over the EU. Police will randomly select semis and camper vans and ask them to follow them to a weighting station. For example in Germany they are spread out along the Autobahn - same in France and NL.

The weight is usually determined by 4 scales (1 for each wheel).

Then they look at your papers which also includes information about max load at the front + back.

If you are over weight you have to get rid of the additional weight and if you can't they will seize the car. You get fined. It does happen.

It happened to me twice in Germany, once in Norway and once in France.

I'm pretty sure that in EU the limit is for the actual current weight, that you can get a huge ticket for an overweight vehicle and that the police use mobile and fixed vehicle scales to enforce that (I specifically remember Austria doing that a lot)

I read an article about it in Czech a while ago, so I don't have a link at hand, but you should be able to find it easily.

Those flexible panels you mentioned are around 17% efficient and 50-100W/kg. Cells bonded to a fiberglass structure you're making anyway go around 200W/kg

5% efficient cells only make sense if applying them is about the same cost as paint and in applications like highway barriers or walls.

The cost is longevity. Flexible panels don't last anywhere near as long as conventional rigid panels. But they're handy, for sure, if you want a simpler installation.

For a country like Germany. You will need way more panels to cover at least for semi-cloudy days. I don't think clouds will have much respect about your autonomy.

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