DIY Electric Car Forums banner

how does an ev start

2915 Views 10 Replies 7 Participants Last post by  toddshotrods
This is an old ford ranger that was converted by professionals in 1996.
The truck has an automatic transmission. I have come to learn that an ev with automatic transmission needs to have the motor idle, to make the transmission work. When I turn ignition on, all the accessories work. If i crank the motor starts spinning. when I stop cranking, the motor stops. I feel like I need to learn how I am supposed to start it. Just recently I tried cranking, while the shift is in park, and pressing the gas pedal. The motor starts spinning faster. I have not tried putting the shift to drive and crank, I was afraid. I am hoping there is someone out there that could help me understand. Just like an ice car, this one has a starter relay, bolted on side of the engine compartment, passenger side. One of the wires goes to the controller. I checked for voltage to that wire and it only get 12volts when I crank. I don't understand why the motor spins only if I crank, what am I missing?

you can see the truck here[email protected]/
1 - 11 of 11 Posts
I think this was mentioned in your other thread.

Your motor is supposed to have a low speed setting to keep the auto pressured up. That would mean the motor would be running when ever the key is on.
However, if you wire it to the 'running' or ignition position of the switch then it will start up the moment you turn the key. You might not want that as it could be in drive and start to move off on its own.

Maybe the 'crank' starter position is supposed to latch a relay that then stays on when you release the key. Perhaps that part isn't working.

Need to see photos of the wiring layout to work out what has been done.

Is there anyone local to you who can help you trace the wiring and see what is going on?
If I understand the gist of your question, an EV does not normally have use of a "crank" position in the ignition. It is usually "ON" or "OFF". The "ON" setting usually runs 12v to the main contactor closing it. "OFF" opens the main contactor. However, people can design their car any way they see fit, so what "generally" happens in an EV may not fit your particular case. If it were me, I'd be tempted to contact the "professionals" who built the car and ask them a few questions....
yes, my question is: why do I have a cranking option?
When I crank, a contactor in the controller engages and makes the motor go, when I stop it disengages.
The starter relay has a wire that goes to the controller, the wire only has 12 volts when I crank. I am pretty sure that is the wire that makes the contactor engage. What needs to happen for that contactor to stay engaged after cranking?

here is a photo of the relay, the red wire goes to the controller and the orange goes to the charger, not sure why.

I tried to contact the company, Pro Electric Vehicles in Penn Valley, they are not in business and I can't find anything about them, only that Craig Mc Cann was the president, but it is a very common name.

I don't know anybody that knows enough about my conversion around here, I live near San Jose. If you do, please let me know. Thanks guys.


See less See more
For a temporary fix, so that you can work through the rest of the vehicle, use a switch.

Get a switch and connect one end of it to a 12V supply that is controlled by the ignition or accessories position of the key. Connect the other end to the wire that was on the cranking position of the key.

Then when you turn the key on you can flick the switch and make the motor 'idle'. You can then test everything else.

In the mean time you can either decide to keep the switch and fit it somewhere convenient or you can use the crank position on the key to work a latching relay.

I would go with the latching relay myself as it will auto off when you turn off the key.
here is a photo of the relay, the red wire goes to the controller and the orange goes to the charger, not sure why.
O.K. So am I missing something here?

The 2 large guage cables are both on the same post and no connection to the other post. Looks like this contactor is useless.

See less See more
That is that IC starter soleniod. It is not used, but the small red w/blue strip wire is your start wire for the soleniod. Does the red w/blue strip wire have power to it when you turn it to crank? Does it got to the main wiring harness, or has it been splined into? I believe he is right about putting a toggle switch on to trouble shoot, but you have to make sure which wire is hot when the switch is turned to crank. thius way you can find out if there are any other problems.
Ok, Major is right, i am not sure why they did that. Maybe they did it as a safety switch to make sure there is 12 volt supply, i don't really understand this things. I am wondering if there is a problem with an other relay, that it should stick on after i crank. If i keep the ignition in crank and i accelerate, the motor goes faster but the dash display shows an error code, it is related to voltage being to high, coming from the potentiometer. So, i don't think that adding the external switch will work.

I posted a little video here, hoping it will help you understand, thank you for all you are doing to help
Sorry Michaels33, i forgot to answer you. I am not sure about the toggle switch, maybe the system was disigned to be started with crank, so, maybe there is a relay that should stay on, after crank, but it is not working, if i by-pass the ignition switch, the controller reads too much voltage coming from the pot box, when i accelerate, not sure why.

If i crank, the red/blue wire gets 12 volts, if i don't, it has 0 volts.
It looks like they were just using the IC starter solenoid as a terminal block to connect the two heavy gauge wires. Not real sure about why the starter wire from the key is running to it, but it does sound from the description that a relay is supposed to latch or lock on when you turn the key to the start position. Have you experimented with holding it there for different lengths of time to see if it eventually does latch? I would guess that someone has been messing with the wires trying to get it working and changed some things. It would be natural, if one was doing that, to put the starter wire back on the solenoid as it would seem to belong there. There could also be some missing parts, or substitutions that are confusing things. I would just develop a new plan and revise the current wiring to suit.
1 - 11 of 11 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.