Flicking through the MSVA guide a few months ago planted an idea which has taken some time to develop... I spotted this class in Woodsmith's thread, but I think he opted for the IVA (may have been long enough ago to be the SVA) which has more challenging regulations.
Limits apply to L7E heavy quads on unladen weight, payload and power.
- Weight limits don't include fuel, which for EVs means traction battery weight is excluded. If you use OEM modules and build a metal framed box to hold them with detachable connections on the outside of the box, and that box bolts onto the chassis, can you legitimately present the vehicle for weighing with the entire battery box removed?
- The L7E weight limit is 400kg, but if your L7E is "for goods" the weight limit is 550kg. I couldn't find a definition in the document of "for goods".
- If the body had a coupe-style silhouette (e.g. Porsche 924, VW Scirocco, VW Corrado) or a shooting brake silhouette (e.g Reliant Scimitar GTE SE5, Volvo 1800ES) but with no aft side windows, would that be "goodsy" enough?
- Is there some guideline about the ratio of passenger space to cargo volume?
- I assume submitting a quad for MSVA test as "for goods" would result in the V5C being issued with an N1 class rather than M1. Is this likely to increase the cost of insurance disproportionately? For dual carriageways, my Ford Transit Connect is restricted to 60mph rather than 70mph since it is not deemed a "car-derived van", whilst I believe the Citroen Berlingo van can legally do 70mph (even though the Berlingo range are more like a van and a van-derived car, rather than a car and a car-derived van). Which speed limit would apply to this quad?
- For the power limit, the MSVA manual states "the maximum net engine power not exceeding 15kW" for heavy quads, but for light quads "fitted with an electric motor with a maximum continuous power not exceeding 4kW".
- Given the inconsistent wording, it's not clear to me whether "net power" means peak or some time-boxed continuous rating, and by "net" do they mean that power wasted as heat doesn't count?
- I would naturally expect to over-specify components like the controller/inverter and cabling to avoid future failures. We all know industrial motors are rated conservatively, but using a "15kW" 3-phase ACIM with a controller capable of much more (for surprisingly long periods of time) raise suspicions?
- The IVA update which introduced a requirement for ECE-R100.1 certification created a lot of debate and chatter, but none of the articles I read mentioned MSVA at all. Is it safe to assume this certification won't be necessary? Of course, rules on shielding, colouring and labelling of HV components would still be observed.
My current idea:
- Spaceframe chassis, like the Exocet.
- Fibreglass body panels.
- Using Mazda MX5/Miata wishbones but not the subframes, to avoid the additional weight and physical constraints.
- Possibly using bellcranks with coilovers mounted flat under the body, so the body won't have to work around strut tops.
- Motor driving a Mazda 7" diff at 3.6:1, either coupled directly or with a very short propshaft. Using the MX5's wheels as a ballpark, 205/45R16 means a circumference of 1.86m, so about 1000 wheel rpm at 70mph (assuming reasonable aerodynamics, cruising should take about 14kW), and 1000 motor rpm should take it past 20mph.