After simplifying my design it’s time to further decide on details for my electric Volvo Amazon wagon. To do this it is convenient to be able to have the actual physical parts next to the 3D drawings. Therefore I stopped by at New Electric to pick up the maintenance switch, fuse holders, chargers and several contactors.
The chargers do fit nicely in at the sides.
Fuse holder research
I wondered whether the Hager L501PV fuse holders for the high voltage, low current fusing were suitable of direct current applications. On the side and in the technical documenation is mentioned: “Nominal voltage (alternating current):
690/1000 V”.
Via WhatsApp I contacted Hager and even got a reply at 23:00 PM.
The next morning I received a confirmation that the holder is indeed suitable for 1000VDC.
Silent vacuum pomp
I also picked up a Hella UP-28 vacuum pump from an electric Smart Car and als often used in Volvo diesels. I thought it was quite noisy. The 80 dB below was perhaps measured too close and without a load but still a lot of noise.
I searched for alternatives and found the Ford A426C and the Mes Dea 70/6E2. I knew Martijn (who converted Volvo 240 to full electric) also uses some Mes Dea components I asked which pump he used. He confirmed to use exactly that one and was satisfied with it.
Hella UP-28 versus Mes Dea 70/6E2
Therefore I bought one at Heijnsdijk Electric Cars and did a test.
My first test of the Hella was without a load but this is not the way it’s implemented. This second test was with load. For the Mes Dea it was a little more difficult since it has a build in pressure sensor and shut of quite quickly. I had to allow some air in to make sure it continued pumping.
dB versus dB(A)
I measures in dB(A), so with a correction for the sensitivity of our ears. In absolute dB’s the pumps are equally loud but the tone of the Hella is higher and we are more sensitive to that freqency.
There is a difference of 2,5 to 3 dB between the pumps. This seems little but the scale is logarithmic and the experience of noise is subjective. I found online that subjective doubling of noice is about 3 dB up and a factor 3 on experienced intensity.
Therefore I’m happy with exploring other options and have chosen to use the Mes Dea.
Contactor box & busbars
Designing a contactor box from scratcg is of course nice, but using a standard metal box is cheaper and quicker. I started sketching with some standard available sizes from Rittal and they seem to fit.
I can exactly use a box of 40 x 20 x 12 cm.
And I’ll have plenty of room for all the components.
I’m not sure which busbar / powerbar I’ll be using but tend to prefer the Blue Sea 2104 (in grey) even though the BEP 777-BB4S-500 (in blue) is a little cheaper. Another open question is the custom busbar connecting the shunt and contactors in the battery box.
I’ll probably just use a flat strip of 20×3 or 25×2 and bend it myself.
