Monday 6 January 2014

Voltage sensing fixed & Chargers Final Assembly nears completion

Found the problem with my voltage sensing circuit, I have accidentally used a 0.1uf ceramic capacitor for C32 instead of the correct 1uf, swapped it out for the correct 1uf value and tried calibration again, 10 volts better on the first sensing during calibration, and once you punch in the correct value it then senses voltage bang on correct, Sweet!
Wired up some fans I had ripped off a bunch of old CPU coolers I had laying around and bolted them to the outside of the case to suck air through the Ali box I have the charger fitted into now, wired the into the 12V circuit and fitted an AC mains cable for now whilst I continue testing.
I got a belt (Electric Shock) off the case the first time I fitted it into the case and discovered that the heat sink appears to have some voltage on it, proved this by removing the metal machine screws holding the heat sink to the case and the problem disappeared, not sure if this is right but I noticed a post from Arber on the EV forum (diyelectriccar) who has the same non PFC charger and he is also getting around 30v AC on his case, I posted a reply stating I had the same problem and promised him I would check mine to see what the voltage was i.e. AC/DC and how much, but I have not had the chance to test this as yet. However I know it is AC as I know what AC electrocution feels like having put my hands in the wrong place to many times before (use to be an apprentice TV engineer/Tea boy in the days of CRT TV’s) but it would be good to get a reading anyhow.
Continued testing the charger over the next few days and melted a few more AC power plugs :-$, I think it is time to move onto getting my J1772 Lead wired in and working as this would solve all the overheating AC plug issues and allow greater currents to be drawn and therefore faster charging.
I am not really interested in fast charging at home but on the go it would be a very handy feature, I noticed today that my most local EV meet is in Portsmouth around 60 miles from me, my car has 40 mile range so I could stop in to the Little chef at Fontwell and charge whilst getting a spot of lunch get to the meet have a short spin and get back to the little chef for the next charge to bring me home again, it’s that or take the Diesel or maybe I should organise a more local meet.
Damn it is getting exiting I can’t believe I am nearly able to travel in this little electric beauty, talk about Electric Dreams!
Heck maybe I will fit an additional battery box in the front there is plenty of room for it and I could use the extra weight for grip  whilst racing ,but I think I would be better off waiting till I replace my battery completely and by them 3-5 years from now (probably 3) I will hopefully be getting a much better energy density for my cash, this year 170kwh batts are available if expensive and I hear of 200kwh also being available this year, bring it on!

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