One thing to consider is that there is headroom in the Alltrax controller.
I am currently runing my 48V controller on 46 cells which works out to 55.2
volts nominal rather then 48v. The upper limit of the controller is
actually 60v and 46 cells will settle down to below 60v after it's been off
charge for a while or if I apply a small load to it for a few minutes. I
would imagine on the 72v controller you could sneak an extra 10 cells in
raising your nominal voltage from 72 to around 84, although it's hard to
know until you give it a try. One thing to be careful of if you try this is
that you need to be sure the controller is disconnected during charging so
that you don't accidently overvolt something and burn it up. While on
charge my 48v controller would see 75+ volts if I did not disconnect it.
This is not hard to do, I just have my main contactor setup to drop the
controller out of the circuit, so as long as I remember to turn the key off
while I am charging everything is fine.
damon
From: Mark Hastings <[EMAIL PROTECTED]>
Reply-To: ElectricMotorcycles <[email protected]>
To: ElectricMotorcycles <[email protected]>
Subject: Re: [ElectricMotorcycles] 48 or 96volts with a tropica motor? AC4?
Date: Mon, 28 Nov 2005 06:07:49 -0800 (PST)
Damon,
Thanks for your example and the simple test. I ran my rear wheel out and I
get 2900 rpms. Examining my commute this means I'll probably spend roughly
2 miles at 2500 rpms then 6 at 2200 and finaly 3 miles at 1500 getting home
at night. The commute is really flat except for a brief spot in the middle
where there is some tiny hills. Note: I can't change my ratio I am pretty
sure it is set in stone by the shaft drive.
I'm going to check again with that I can fit. The problem is that once i
get above 72 I see a big price jump in components. The alltrax goes up to
72 and there are alot of choices 48 and below. There is a 72-96 volt
Navitas(?) which I never heard of. Of course there is the Zilla which would
be more expensive then my EV truck or the curtis which is half the price. I
never had luck with a curtis but that whine would mean I wouldnt' need to
add any sound so people would here me starting off from a stop sign/light
or in a parking lot. eww.
Is there another option for a controller? I am just wondering if my motor
is going to at most see 2900 rpms which a 48 volt controller could easily
exceed would having a higher voltage be of any benefit? It is possibly that
it would give me more top end accelleration? maybe I can fit two strings of
72 if I use saddlebag ;-) just kidding..
damon henry <[EMAIL PROTECTED]> wrote:
With a 14 to 41 gear ratio and using the same Tropica motor my motorcycle
does 60mph at an estimated 3000 rpms. I did the math way back when I first
built the bike by rolling it 100ft and counting the revolutions of the
motor
shaft. Taking the 100 ft number and muliplying it by 53 will tell you your
RPMs at 60mph. This works since there is a little less then 5300 feet in a
mile and at 60mph you cover the distance in one minute.
You will have no problem running your motor at 96v as these motors can be
run up to about 120v. The name plate rating is 72v. When you run the motor
at a higher voltage it is good to advance the brush timing to keep the
motor
from arcing. Running at a higher voltage is easier on a motor (to a point)
as it allows the motor to spin faster and cool more efficiently. The
controller could care less.
If I were you I would definitely do 96v.
damon
>From: Mark Hastings
>Reply-To: ElectricMotorcycles
>To: [email protected]
>Subject: [ElectricMotorcycles] 48 or 96volts with a tropica motor? AC4?
>Date: Fri, 25 Nov 2005 08:04:45 -0800 (PST)
>
>I was test fitting BB600's the other day and I think I have found that I
>can get about 96 volts on the motorcycle without much problem. While it
>probably would be easier to run one string at 96 volts I am concerned
that
>even at my top cruising speed I'll only be sending <48 volts or maybe <36
>to my tropica version (AC4?) of the 6.7" ADC motor.
>If I remember correctly a few weeks back I found a note that it turns
>faster then the A89 6.7" motors by a good 30-50%
>Based on that I think it is more a limitation of the RPM to voltage curve
>then my gear ratio and in reality I can't change either. (yeah yeah it's
a
>shaft drive)
>1) Do you think always having the controller step down so much is going
to
>create heat problems and waste energy? Or ruin the controller? If so I
>could run two strings of cells and halv the voltage
>2) Does anyone have any experience with this motor on a motorcycle and
know
>the voltage to rpms or voltage to speed and could give me their gear
ratio?
>
