China Is About to Bury Elon Musk in Batteries

Interesting report from Bloomberg:  as demand for Li-Ion batteries increases, we should expect to see affordable Li-Ion become much more widespread and available for other uses – such as portable power in camper vans, etc. While this is on the 5–10 year horizon, it’s interesting to keep tabs on.

We’ve already seen a similar effect with GPS chips, cameras, and other components in the so-called ‘smartphone bounty’.

Lithium-ion batteries have long been used in smartphones, laptops, and other personal electronics, but demand is forecast to explode in the next five years as electric vehicles proliferate and power companies install giant storage systems to smooth the ebb and flow of wind and solar.

Telsa produced nearly 84,000 vehicles in 2016 and has said it plans to make 500,000 in 2018.

While Tesla may be building the biggest and splashiest factory, the Chinese government has launched a sweeping effort to increase the country’s dominant market share.

Roughly 55 percent of global lithium-ion battery production is already based in China, compared with 10 percent in the U.S. By 2021, China’s share is forecast to grow to 65 percent, according to Bloomberg New Energy Finance.

“This is about industrial policy. The Chinese government sees lithium-ion batteries as a hugely important industry in the 2020s and beyond,” Bloomberg New Energy Finance analyst Colin McKerracher said.

In all, global battery-making capacity is forecast to more than double by 2021 to 273 gigawatt-hours, up from about 103 gigawatt-hours today. That’s a huge opportunity, and China doesn’t want to miss it.

Source: China Is About to Bury Elon Musk in Batteries – Bloomberg

Disconnecting the starter battery from the chassis on a RHD Sprinter

There are some good videos that show you how the standard electrics work on a Sprinter. Here’s one that opens up the distribution box on the house/starter battery.

However, many videos and blog posts assume you have a left hand drive model. Even the manual – written in UK English – assumes you have a LHD model.

I wanted to figure out how to disconnect the battery so I could safely connect a split charger. Here’s how I found the ground point from the negative terminal of the battery on our 2012 NCV model.


Remove the trim around the footwell on the passenger side. Helpfully, it’s marked with a battery icon


Remove the toolbox cover in the passenger footwell by turning a slot headed screwdriver in the plastic fastener


Unscrew the four screws holding the lower console casing in place. You’ll need to lift up the heavy floor mats to reach this. Slide the casing horizontally towards the seats.


There’s the earth point for the black cable from the negative post of the battery, on the centre console column. The battery is under the black panel in the footwell.


A closer look at the earth point


Inside the battery compartment. This is an aftermarket battery. You can just see the distribution box from the positive terminal (red cables) down on the right hand side

Sizing batteries and solar panels

One of the first steps in planning the electrical system is figuring out what size battery and solar panels we need.

That depends on a few key factors, which will vary for everyone. In our case, they are:

  • Price: we are price-sensitive!
  • Level of luxury / number of appliances: we don’t want a TV, microwave, Air-condioning, hot water, etc. So our electricity needs are quite modest
  • Dependence on electricity: at the moment, we’d like to mix our fuel usage, so gas will be a big part of the mix: mostly for cooking and heating
  • How close to civilisation: we want to go wild, not stay in campsites with hookup power. That means we want to go a long time on just the battery and solar power.

Continue reading “Sizing batteries and solar panels”

Is it a good deal?

I’m spending a lot of time on the Autotrader website, looking at near-identical pictures of Mercedes Sprinters. When I’m doing this, I’m trying to answer one of two related questions:

  • Is this van good value for the condition it’s in?
  • How does it compare in value with other vans I’ve seen that look similar?

But there are so many of them. They’re all white, they’re all in much the same condition. After a while they all blur into one another.

I love to nerd out with systems and technology, and I’m always interested in defining methods for solving problems, rather than ad hoc approaches. And this problem is a great candidate for such an approach. That ‘blurriness’ is a factor of the quantity of data, and its homogeneity. However, those factors also favour a data analysis approach – albeit a pretty casual one.

There are many considerations to weigh up when looking for a van for a campervan conversion. But we’ve fixed many of the variables:

  • Model: Mercedes Sprinter
  • Long wheelbase
  • High top
  • NCV (post-2006) variant
  • From a dealer, not a private seller
  • Under 100,000 miles on the clock

There are lots of Sprinters on the market with these specs, so it’s easy to compare them across the other factors that we’re considering:

  • Price
  • Mileage
  • Age
  • Condition

Condition seems to be mostly a factor of age and mileage, so that gives us three variables to compare. So I made a spreadsheet to record some basic information about each van:

  • URL or identifying label
  • Registration plate, location, or other comments
  • Mileage
  • Year
  • Price (inc. VAT if applicable)

(Interestingly, VAT-free vans don’t seem to be much better value. It looks like the sellers are recovering the 20% ‘discount’.)


I wanted to give each van a score to indicate how ‘good’ it is – a factor of how new, and how few miles are on the clock. In order to compare these very different values I needed to normalise them to a standard range. Fortunately, there’s a formula for that:

zi = (
   xi − min(x)
   ) ÷ (

Bear in mind when doing this calculation that higher numbers are better for year of manufacture, but lower numbers are better for mileage. So ‘max’ and ‘min’ could be more usefully substituted for ‘best’ and ‘worst’

That gives each van a score of 0 – 1 for year, and 0 – 1 for mileage. Combining (adding) these gives an overall score for each van.

But those factors aren’t equally important, so I also included a variable weighting modifier. For example, if we think that mileage is twice as important as age, we can multiply the mileage score by 2 before adding the two values together. Then I multiplied the result by 100 to make the numbers easier to read.

The final ‘how good is this van’ quality score is calculated like this:

Quality = 100 * (
   (Mileage Weighting * Normalised Mileage Score)
   (Year Weighting * Normalised Year Score)

Using a weighting of 1 for the age and 2 for the mileage, this gives every van a score of 0 – 300.

Plotting a trend

Putting this quality score on a scatter chart mapped against asking price gives a picture of how all the vans vary in value for money.

Adding a trend line allows us to see which vans are good value for money across the price range. Everything below the line is comparatively cheap, and can be easily contrasted with other vans that are of the same ‘quality’ or the same price.

It’s also easy to set a price limit (draw a horizontal line across the chart at the maximum price we willing to pay) and identify all the good value vans below this limit.


The more data we can collect the better. It helps to reduce the impact of outliers on the overall picture – outlier data can skew the average and make the trend line misleading. For example, private sellers are often much cheaper, but not necessarily where we want to buy from. Adding lots of cheap vans from private sellers pulls the trend line down, making the other vans seem much worse value (which may be accurate if you’re happy to buy from a private seller). Conversely vans from Mercedes dealerships come at a premium, and push the trend line up.

On the flipside, the chart makes it very easy to see outliers, and then prompt further research to explain them.

Perfection is the enemy of good

I’ve found this to be a useful tool to help make sense of all this data. But I’m conscious that fiddling around with spreadsheets and scatter charts could just be my way of stalling; of avoiding making a decision – a commitment.

To some extent this approach is about managing uncertainty and the discomfort that comes with it. We want to buy a good van, at a good price, and it’s uncomfortable negotiating that purchase process when we’re not experts in the field. But you can’t remove all risk, you can’t avoid uncertainty in life (that’s called ‘being dead’). At some point we have to let go.

Wood selection for framing and cladding: do the math

I’m evaluating different materials for cladding the walls of the van, and for building frames and panels for furniture (bed, kitchen units, etc.)

Commercial outfitters here in the UK use materials I find unappealing, whereas DIY convertors often stick to what they can find in the out-of-town DIY store. I’d like to weigh up – literally – the pros and cons of a few approaches that are in scope for me.

Absolute weights

Weight is a key factor, not least because of the payload limit of the van. But also efficiency, handling and sizing. I consulted a few sources to find out the weight of different wood types. The excellent Collins Complete Woodworker’s Manual gives ‘average dried weight’ for a range of hard and soft woods. (This is just a selection of woods that are available to me, and might be appropriate.)

Soft woods

  • Sitka and Norway spruce — 450 kg/m3
  • Pines (White, Ponderosa, Yellow) — 420 – 480 kg/m3

To verify, I weighed some 44mm square batons I bought from Wickes (the same product is also available at B&Q). It’s usually labelled as ‘whitewood’ or  spruce. It worked out at 423 kg/m3.

Hard woods

  • European beech — 720 kg/m3
  • American white ash — 670 kg/m3
  • American white oak — 770 kg/m3


My local timber merchant also stocks lovely BB Grade Birch Plywood, and they gave me the specs for a couple of thicknesses:

  • 12 mm 8×4 sheet — 25.25kg (707 kg/m3)
  • 9 mm 8×4 sheet — 19.50kg (728 kg/m3)
  • 6 mm — extrapolated: 749 kg/m3
  • 18 mm — extrapolated: 665 kg/m3

These are the woods and panel materials that are available to me (discounting the crap I don’t want to touch).

Wall cladding

Many DIYers seem to go for either cheap plywood faced with car felt, or wooden cladding boards, made from spruce or maybe pine.

I like a wooden finish, but those cladding boards are either thin or heavy. Here’s a typical review of some 8mm spruce cladding (just labelled ‘softwood’) from a DIY store:

At least 20% of these poor quality timbers where so warped, bent or sub standard that they could not be used for the project. They are only finish sanded on one side witch means that you cant switch boards around to hide knots and holes where knots where.

Large chunks where often taken out of the tounges or groves making them incredibly hard to fit together. Every single piece is labled with an incredibly sticky label that is impossible to peel off on the face side of the board making for a enfuriating few hours of peeling and scrubbing.

This chimes with my experience too. You could go for thicker boards, but then you’re looking at some serious weight. To clad an 8′ x 4′ area with 14 mm softwood cladding would weigh about 18.8 kg. The same area in 6 mm birch ply (which has a lovely finish) would weigh about 13.4 kg.

There are other factors of course, (how well does the cladding conform to the curves of the van, does it need to bear weight or hold a screw), but the weight and aesthetics certainly point to the thin 6 mm ply as a good option.

Furniture framing

I’ve made lots of furniture out of stud timbers and that 44mm section whitewood. It’s fine, and in certain orientations and thicknesses, adequately strong.

But I’m interested in using something that cuts more cleanly, is stronger and has some flex for the construction of cabinet and bed frames. Ash looks promising here. I need to do some practical experiments – and more research, but the weight difference doesn’t look too bad, especially when you consider you could get away with smaller cross-sections of wood for many applications in the van.

Great design and build tour 

There are many good van build videos on YouTube. But this is an exceptional one. It’s comprehensive (close to one hour long), and Lee, the van designer and builder, has clearly thought deeply about so many aspects of the design.

It’s a great watch; he seems like a lovely guy, and his design philosophy, which is one half spontaneous (build it, use it, iterate, don’t worry about perfection), one half attention to detail (material choice, usage, interaction design, maintenance) is such a good primer for anyone thinking about deisgn approaches.

What to look for when buying a Sprinter

Some useful advice on common failings of the Mercedes Sprinter:

One of the Sprinter’s most common faults is problems with the diesel engine’s high pressure injection system. It’s called the ‘black death’ though it’s not as bad as is sounds if it’s caught early enough. The seals around the injectors go, causing a chuffing from under the bonnet.

Put the heater and fan on in the cab and if there’s a faint smell of what should be coming out of the tailpipe then they’ll need looking at. A black build up around the injectors also highlights the issue. Depending on how bad it is, you could be looking at anywhere from £150 to £500 fix.

Check the propshaft on any prospective purchase, they tend to fail at about 100,000 miles though they’re not too expensive provided you don’t source it from a dealer where they’ll charge around £800. For all other parts we’d suggest genuine only, particularly brakes.

The oil filter within the engine of 2007 Sprinters can become blocked and this causes the engine oil to be expelled through the dipstick hole (even though the dipstick is in place) leaving the engine to seize.

As with any vehicle though they’re not perfect, one of the most visible problems being their tendency to rust. Bear puts this down to abuse, and the amount of operators running them without ply linings inside, though lots also attribute the Sprinter’s pockmarks to thin, water-based paints. Best advice regarding the bodywork is if it’s scratched or dinged, get some touch-up on it quickly, Mercedes-Benz’s warranty very particular in its cover regarding surface rust.