# Precharge Circuit



## edsammy (Jun 15, 2009)

I wanted to share my precharge circuit that I created. It uses a 555 timer chip to close one relay that connects the precharge resistor to the controller and then another relay to close the contactor. Check out the details here: circuitsandshirts.tk
Hope you enjoy.


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## omonoid (Aug 30, 2009)

so you turn the key, the controller precharges for a set time, then the car turns on?

nice.


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## Jimdear2 (Oct 12, 2008)

edsammy,

Thanks, I'm completly non electronic. I've been looking for something simple like that.

This is the kind of thing that should put into the WIKI.

Jim


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## ElectriCar (Jun 15, 2008)

Cool and thanks for your efforts in posting it. But help me out, I'm confused at the part of the drawing on the bottom around the 5V regulator, the A1, A2 and the 300 ohm resistor in there. After studying it briefly it appears you have an SSR in there. I just don't understand it the way you drew it. I've never seen an SSR drawn on a schematic that way.


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## edsammy (Jun 15, 2009)

The schematic symbol for a solid state relay just seemed too confusing to me so i drew it as a square with 4 connections. The bottom connections are to power the relay itself (right is ground, left is 5 volts from the regulator) and the top connections are connected when the relay is powered with the 5 volts. A1 is connected to the first post of the main contactor which is also connected to the main pack (144 volts). A2 is connected to the second post of the contactor but only when the SSR is powered.

Sorry if this is confusing


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## ElectriCar (Jun 15, 2008)

OK I can see that. What I always did was draw the square you did but label the 4 connection points as they are labeled on the relay. If I had a scanner I'd do it for you but I'm "in between" scanners now.


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