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#### EVDL List

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Discussion Starter · ·
Unfortunately, the freeway onramp leads to a very steep climb for maybe 1/2
mile. You hit the freeway going about 50 mph, and have to accelerate to 65
mph on that climb. In 3rd gear, my EV just doesn't have the torque to do
it. In fact, it loses speed. I've got an ADC 8-inch motor, which has a
redline of 8,000 rpm. According to my calculations, the motor would be
doing 7,600 rpm at 60 mph in 2nd gear. Would it be save to accelerate up to
60 in 2nd gear for that short stretch? That way, at least, I wouldn't be
typing up traffic.

Thanks.

Bill

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#### EVDL List

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Discussion Starter · ·
Hi Bill,

> I've got an ADC 8-inch motor, which has a
> redline of 8,000 rpm. According to my calculations, the motor would be
> doing 7,600 rpm at 60 mph in 2nd gear. Would it be save to accelerate up
> to
> 60 in 2nd gear for that short stretch?

Your motor will have *very* little power at that rpm.

at what rpm does your controller come out of motor side current limit?
is there a range in which you are in battery current limit?

either of those events determines your max power (torque at the wheel).
possible acceleration.

if you try to spin the motor past the point where your controller comes out
of current limit and goes full on, torque falls off exponentially.
for most DC motor, controller, battery setups, this occurs between 2000 and
3000rpm.

Matt

----- Original Message -----
From: "Bill Dennis" <[email protected]>
To: "'Electric Vehicle Discussion List'" <[email protected]>
Sent: Monday, November 22, 2010 5:45 AM
Subject: [EVDL] The Torque is the Torque, of course, or course

> Unfortunately, the freeway onramp leads to a very steep climb for maybe
> 1/2
> mile. You hit the freeway going about 50 mph, and have to accelerate to
> 65
> mph on that climb. In 3rd gear, my EV just doesn't have the torque to do
> it. In fact, it loses speed. I've got an ADC 8-inch motor, which has a
> redline of 8,000 rpm. According to my calculations, the motor would be
> doing 7,600 rpm at 60 mph in 2nd gear. Would it be save to accelerate up
> to
> 60 in 2nd gear for that short stretch? That way, at least, I wouldn't be
> typing up traffic.
>
> Thanks.
>
> Bill
>
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#### EVDL List

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Discussion Starter · ·
On 21 Nov 2010 at 14:45, Bill Dennis wrote:

> In 3rd gear, my EV just doesn't have the torque to do it.
> In fact, it loses speed.

I know it sounds odd, but try 4th, not 2nd. Especially with a DC series
motor, torque is much higher at low RPM. When you need more acceleration,
you actually have to >upshift<.

Just watch out for motor heating and battery stress from the high currents
that result.

David Roden - Akron, Ohio, USA

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