TECH ED’S CHOICE

Car (South Africa) - - TECH -

EV CHARG­ING STAN­DARDS

On read­ing CAR’S ar­ti­cle on the Jaguar I-pace (Au­gust 2018), I won­dered if an agree­ment has been reached among man­u­fac­tur­ers on stan­dard­i­s­a­tion of charg­ing sta­tions? It would be an­noy­ing, to put it mildly, if you got to, say, Coles­berg, and found a plug doesn’t fit. DOUG SCOTT Rhenos­ter­spruit The cur­rent an­swer is “no” but hope­fully the stan­dards will even­tu­ally merge into one.

Back­ground on bat­tery charg­ing

Re­mem­ber, bat­ter­ies are di­rect cur­rent (DC) while the elec­tri­cal grid em­ploys al­ter­nat­ing cur­rent (AC). There­fore, to charge an elec­tric ve­hi­cle us­ing a wall socket at home, the AC cur­rent needs to be con­verted to DC by an on­board charger be­fore the bat­tery can be charged. The max­i­mum power from the wall socket is lim­ited to 3,3 kw (a 15 A socket at 220 V), so the charger can be small enough to fit in the ve­hi­cle for nor­mal (slow) charg­ing.

For fast charg­ing (50 kw and higher), the charger can­not be housed in the car and is pro­pri­etary, i.e. a charg­ing sta­tion. When an EV plugs into a fast charger, the charger has al­ready con­verted the AC sup­ply to DC and sup­plies the EV bat­tery di­rectly with DC.

It’s clear the charg­ing meth­ods (slow and fast) need two sep­a­rate con­necters (and plugs).

Charg­ing stan­dards

For stan­dard (slow) charg­ing, many man­u­fac­tur­ers opted for the Type 1 con­nec­tor be­cause it of­fered safe home charg­ing with an on­board charger. Be­cause three-phase power sup­ply is quite com­mon in Ger­many, the Ger­man OEMS de­cided to take the Type 1 con­nec­tor and add two ex­tra pins to al­low three-phase home charg­ing that ups the charg­ing rate con­sid­er­ably. This con­nec­tor is now known as the Type 2 con­nec­tor and is the most com­mon con­nec­tor for stan­dard charg­ing.

When it comes to fast charg­ing, there are again more op­tions. Ja­panese man­u­fac­tur­ers agreed on the Charge on the Move (CHADEMO) stan­dard ini­tially fixed at 50 kw with a com­mu­ni­ca­tion pro­to­col over the CAN bus. Man­u­fac­tur­ers that signed up to this stan­dard in­clude Mit­subishi, Nis­san, Toy­ota and it was li­censed to Kia and PSA.

Ger­many was, how­ever, not pre­pared to pay the li­cens­ing fee for a tech­nol­ogy it did not agree with and adapted the Type 2 con­nec­tor with two ex­tra con­nec­tors for DC pos­i­tive and neg­a­tive and called this new con­nec­tor the Com­bined Charg­ing Sys­tem (CCS), as it al­lows nor­mal and fast charg­ing through the same con­nec­tor.

Tesla also uses the Type 2 con­nec­tor but han­dles fast charg­ing (up to 120 kw) dif­fer­ently when plugged into its own Su­per­charger charg­ing net­work.

One charger for all

At least com­pa­nies such as ABB are de­vel­op­ing charg­ing sta­tions with con­nec­tors for all the above, al­most like a fuel sta­tion with dif­fer­ent fu­els (93, 95 and diesel, for ex­am­ple). Let’s hope an agree­ment is soon reached be­tween man­u­fac­tur­ers to stan­dard­ise the charg­ing sys­tem.

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