Precharging necessary?

[Stephen Chapman]

Application: 36V lawn tractor conversion with Curtis 1206 controller and 6.7" series wound GE motor.
http://www.evalbum.com/2502

I'm wiring this up now, is a precharge resistor necessary for this low voltage app?

Stephen Chapman

[mark at evie-systems]

A pre-charge resistor will not hurt you, and your contactor will thank you, even for this low-voltage.

If your contactor is "open air", go out to your unit at night with all the lights off and flip the contactor on, you'll see a neat little blue flash.

Stephen Chapman wrote:

Application: 36V lawn tractor conversion with Curtis 1206 controller and 6.7" series wound GE motor.
http://www.evalbum.com/2502

I'm wiring this up now, is a precharge resistor necessary for this low voltage app?

Stephen Chapman

[damon henry]

The precharge resistor is primarily used to protect the bank of capacitors inside your controller from huge in rush currents.  Your controller will last longer with a precharge resistor.  Since a lawn tractor is not something you will be driving everyday and turning on and off a lot, it may not make that big of a difference, but I would add it.  For a number of years, the precharge circuit on my motorcycle was a simple pushbutton momentary switch and a resistor wired across my main switch.  Before I turned the key on, I simply held this button down for a few seconds.  In my case I was using an Alltrax controller which had an LED that indicated when the controller was charged, so once that lit up I would let go of the button and turn the key.

 

damon
 

> Date: Mon, 9 Nov 2009 12:49:43 -0800
> From: [hidden email]
> To: [hidden email]
> Subject: [EVDL] Precharging necessary?
>
>
> Application: 36V lawn tractor conversion with Curtis 1206 controller and 6.7"
> series wound GE motor.
> http://www.evalbum.com/2502
>
> I'm wiring this up now, is a precharge resistor necessary for this low
> voltage app?
>
> Stephen Chapman
> --
> View this message in context: http://n4.nabble.com/Precharging-necessary-tp585108p585108.html
> Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.
>
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>

     
_________________________________________________________________
Windows 7: Unclutter your desktop.
http://go.microsoft.com/?linkid=9690331&ocid=PID24727::T:WLMTAGL:ON:WL:en-US:WWL_WIN_evergreen:112009
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.sjsu.edu/mailman/private/ev/attachments/20091109/792c5d1f/attachment.html 
_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev

[Lee Hart]

Stephen Chapman wrote:
> Application: 36V lawn tractor conversion with Curtis 1206 controller and 6.7"
> series wound GE motor.
> http://www.evalbum.com/2502
>
> I'm wiring this up now, is a precharge resistor necessary for this low
> voltage app?

I would use one. It's job is to extend the life of the main contactor
and the controller's capacitors, which applies for any pack voltage.

--
Lee A. Hart | Ring the bells that still can ring
814 8th Ave N | Forget the perfect offering
Sartell MN 56377 | There is a crack in everything
leeahart earthlink.net | That's how the light gets in -- Leonard Cohen

_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev

[Stephen Chapman]

Hi Lee,
I know there have been MANY discussions regarding different components for limiting the current into the controller during precharge, is there anything wrong with using a small DC motor?  I like the idea of a stone simple audible indication and small motors are really cheap....

Stephen Chapman

Lee Hart wrote:

Stephen Chapman wrote:
> Application: 36V lawn tractor conversion with Curtis 1206 controller and 6.7"
> series wound GE motor.
> http://www.evalbum.com/2502
>
> I'm wiring this up now, is a precharge resistor necessary for this low
> voltage app?

I would use one. It's job is to extend the life of the main contactor
and the controller's capacitors, which applies for any pack voltage.

--
Lee A. Hart | Ring the bells that still can ring
814 8th Ave N | Forget the perfect offering
Sartell MN 56377 | There is a crack in everything
leeahart earthlink.net | That's how the light gets in -- Leonard Cohen

_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev

[Elithion]

> is a precharge resistor necessary for this low voltage app?

I can't see why not.
Here is some info on selecting a precharge resistor for EVs.
http://liionbms.com/php/precharge.php#Resistor
D'de

_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev

[Lee Hart]

Stephen Chapman wrote:
> Hi Lee,
> I know there have been MANY discussions regarding different components for
> limiting the current into the controller during precharge, is there anything
> wrong with using a small DC motor?  I like the idea of a stone simple
> audible indication and small motors are really cheap....

Now *that's* an interesting idea! :-) It's not hard to find high voltage
DC motors (like an electric drill or vacuum cleaner with a "universal"
motor in it). They would run fine on DC. When you first switched it
across the contactor, the motor will quickly spin up to full speed, then
slow down as the controller precharges. When the motor stops, you're
precharged.

--
Lee A. Hart | Ring the bells that still can ring
814 8th Ave N | Forget the perfect offering
Sartell MN 56377 | There is a crack in everything
leeahart earthlink.net | That's how the light gets in -- Leonard Cohen

_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev

[Evan Tuer]

On Tue, Nov 10, 2009 at 6:03 AM, Lee Hart <[hidden email]> wrote:

> Stephen Chapman wrote:
>> Hi Lee,
>> I know there have been MANY discussions regarding different components for
>> limiting the current into the controller during precharge, is there anything
>> wrong with using a small DC motor?  I like the idea of a stone simple
>> audible indication and small motors are really cheap....
>
> Now *that's* an interesting idea! :-) It's not hard to find high voltage
> DC motors (like an electric drill or vacuum cleaner with a "universal"
> motor in it). They would run fine on DC. When you first switched it
> across the contactor, the motor will quickly spin up to full speed, then
> slow down as the controller precharges. When the motor stops, you're
> precharged.

You could leave the fan attached to provide a bit of load.

But there's not an awful lot wrong with just using a power resistor
and suitable transistor or relay to switch it...

_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev

[Stephen Chapman]

Exactly!   Since I am only using 36V, I was thinking of using a small PM motor, maybe with a resistor in series depending on the rated voltage of the motor.  I have some speed 700 motors laying around rated at 18V or speed 400 motors rated at 12V.  I could use a resistor or maybe even multiple motors in series...

This solution provides audible feedback and is free for me.  For higher voltages, a small motor could be used in a parallel/series solution with a power resistor to accomplish the same result.
Stephen Chapman

Lee Hart wrote:

Stephen Chapman wrote:
> Hi Lee,
> I know there have been MANY discussions regarding different components for
> limiting the current into the controller during precharge, is there anything
> wrong with using a small DC motor?  I like the idea of a stone simple
> audible indication and small motors are really cheap....

Now *that's* an interesting idea! :-) It's not hard to find high voltage
DC motors (like an electric drill or vacuum cleaner with a "universal"
motor in it). They would run fine on DC. When you first switched it
across the contactor, the motor will quickly spin up to full speed, then
slow down as the controller precharges. When the motor stops, you're
precharged.

--
Lee A. Hart | Ring the bells that still can ring
814 8th Ave N | Forget the perfect offering
Sartell MN 56377 | There is a crack in everything
leeahart earthlink.net | That's how the light gets in -- Leonard Cohen

_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev