[JRP3]

The 144V Curtis is no secret, there is still some question as to what the max current will be, I think it's limited to 500 amps, instead of the 550 or 650 of the 120V 1238-7501 and 7601.

[dragonsgate]

Dragonsgate said "Even though Bryan at HPEV told me some of what was coming I am not sure if he wanted me to start blabbing about it."
JRP3 said "The 144V Curtis is no secret, there is still some question as to what the max current will be, I think it's limited to 500 amps, instead of the 550 or 650 of the 120V 1238-7501 and 7601." Dragons gate says "Boy! that is a load off my mind."

[ev-converter]

Originally Posted by ricklearned

I was at an EV show in LA a couple of weeks ago and heard a similar thing from the people at Curtiss. They told me that HPEV had a couple of 144v controller prototypes for evaluation. They did not tell me to keep it to myself. On this Friday I am going to Ontario to pick up my AC35 package that I ordered from Thunderstruck. While there I will ask how the evaluation is going. I'm a noobie so I am sure I won't pick up on the technical stuff like our more experienced posters.

500amp @ 144/160vdc 12v contactor makes AC-50 really sing

[JRP3]

1238-7601 at 650 amps x 120V = 78KW
The new controller at 500 amps x 160V? = 80KW, not that impressive even if it can actually run at 160V.

[Supergrover]

Originally Posted by JRP3

1238-7601 at 650 amps x 120V = 78KW
The new controller at 500 amps x 160V? = 80KW, not that impressive even if it can actually run at 160V.

Well, 80kW isn't great, but it isn't that terrible either. To put those figures into perspective, the Nissan LEAF is also 80kW with a single fixed gear ratio. I would think an 80kW motor mated to a manual transmission should yield pretty respectable performance as long as the vehicle isn't too heavy. The LEAF isn't particularly light and it still has some punch off the line.

I just wish there were some more competition and choices in the AC realm.

[JRP3]

I'm not saying the 80KW isn't good, I'm saying that claiming the new Curtis controller, (which might only add 2KW or so), makes a big difference with the AC50 is dubious at best.

[Hippie Djohn]

Originally Posted by JRP3

1238-7601 at 650 amps x 120V = 78KW
The new controller at 500 amps x 160V? = 80KW, not that impressive even if it can actually run at 160V.

That's not how you calculate power for 3-phase AC motors.

use this:
P=√3*V_RMS*A_RMS*cosφ
V_RMS = (Batt_voltage/√2)

But yes the ratio is the same.

Originally Posted by JRP3

I'm not saying the 80KW isn't good, I'm saying that claiming the new Curtis controller, (which might only add 2KW or so), makes a big difference with the AC50 is dubious at best.

Voltage will sag less with 500A if we assume the cells are the same.
So higher voltage @ load = more power.

[JRP3]

Good point about the voltage sag, which will be more or less of an issue depending on the cells used.

[Coulomb]

Originally Posted by Hippie Djohn

That's not how you calculate power for 3-phase AC motors.

use this:
P=√3*V_RMS*A_RMS*cosφ
V_RMS = (Batt_voltage/√2)

True. But cosφ is typically around 0.82, which is very close to √2 / √3, so the √3 / √2 * cosφ comes to close to unity anyway. So the very convenient Batt_Voltage * A_RMS is a great approximation. There are also the losses of the controller, if you want to get really pedantic; at around 130 VDC, the ~2.0 - 2.5 V drop across each IGBT (and there are two in series) becomes moderately significant. Less so at 160 V, of course, but not by much. [ Edit: as pointed out below, this is actually an argument to use phase voltage and current, not the approximation. ]

[Hippie Djohn]

Originally Posted by Coulomb

True. But cosφ is typically around 0.82, which is very close to √2 / √3, so the √3 / √2 * cosφ comes to close to unity anyway. So the very convenient Batt_Voltage * A_RMS is a great approximation. There are also the losses of the controller, if you want to get really pedantic; at around 130 VDC, the ~2.0 - 2.5 V drop across each IGBT (and there are two in series) becomes moderately significant. Less so at 160 V, of course, but not by much.

True... but if we are calculating single hp's for the new Curtis it will make a differens ;-)
If the power is calculated direcly from the phase current and voltage, it includes the controller loss.