# AC Schematic/Wiring Diagram



## JRP3 (Mar 7, 2008)

The Curtis manual here might help you out, there is a schematic in it for their AC system: http://www.thunderstruck-ev.com/AC_drive_performance.htm


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## Grant_NZ (May 28, 2008)

JRP3 said:


> The Curtis manual here might help you out, there is a schematic in it for their AC system: http://www.thunderstruck-ev.com/AC_drive_performance.htm


Thanks JRP3

The diagrams in the manual are a bit out of my league  I was hoping for something like this, a bit more simple for the simple folk


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## Gavin1977 (Sep 2, 2008)

Well i havent built an electric car yet. But i would say that the wiring would be virtually identical. Only difference would be that you would have an AC Motor and controller, and you would have three wires going between your motor and controller, rather than two. Oh and if you wanted to measure motor amps/voltage you would need AC meters rather than DC.


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## Grant_NZ (May 28, 2008)

ok so this is what I came up with so far, a modified version of the above but using Lithium, yet to add balances and a BMS

Please feel free to advise if electrocution is a potential using this


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## Gavin1977 (Sep 2, 2008)

You're making it too complicated.

You dont need an inverter. An AC Motor controller _IS_ the inverter. Actually an extememly sophisticated one at that. It will take your DC battery voltage and convert it into a variable voltage and frequency AC signal depending on speed, load, throttleposition etc.

To power your 12v accesories, you still use a DC - DC converter and hook it up to your battery pack.


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## Grant_NZ (May 28, 2008)

ok thanks Gavin... I’m a noob at this 

I’ve removed the inverter and ran a positive wire to the controller, would this also need a negative from the main battery pack or can it be earthed to the chassis?

Also in regards to the DC/DC converter, from other diagrams I’ve seen a stand alone 12V battery powering the accessories and therefore, where would a DC/DC converter be needed?


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## JRP3 (Mar 7, 2008)

You need to charge the 12 volt battery somehow, so either a DC/DC converter to use pack voltage to keep it charged or you need to charge it separately when you get home.
I'm not sure why you have a wire going from the motor to the circuit breaker, the only wires going to the motor will be the 3 large ones from the controller,
then a smaller bundle with encoder wires. You really should try to understand the Curtis schematic, there's a lot of extra stuff there you don't need but the basics are there as well. Other than the controller to motor wiring, everything else should really be the same as a DC setup.


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## Grant_NZ (May 28, 2008)

Is it possible to wire in the 12V accessory battery to the main charger? 

I've been reading the Curtis schematic and its starting to make sense, I see what you mean by the extra stuff; break pot and emergency reverse??


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## JRP3 (Mar 7, 2008)

The only way to wire a 12 volt battery to a charger is if the charger is 12 volts, or if you use something like a Minn Kota 440/460 which charges a pack as individual batteries. They only go to 48 volts though, 4 batteries. Or you wire the 12 volt battery through a DC/DC converter and then it stays charged by the pack.


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## Grant_NZ (May 28, 2008)

I've changed the wiring diagram so there's now a DC/DC converter to charge the 12V accessory battery as well as a fuse block. I also ran a negative from the controller to the DC/DC converter, is this correct or should it be earthed to the chassis? 

I also noticed that the Curtis controller has a motor temperature sensor, can this be wired to a warning light in the dash?

When the batteries get to the desired DOD, is it too geeky have a voice over from Scotty asking for more power? 


Grant


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## JRP3 (Mar 7, 2008)

I'm actually not sure of the DC/DC wiring. I think it should be positive and negative from the pack to the DC, then the DC to the 12 volt battery. I know the pack battery should not be grounded but the 12 volt probably would be through the 12 volt vehicle wiring.
The Curtis is connected to their 840 display which shows temperature and other parameters.
Here's a diagram with a DC/DC in it, in a DC system.


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## Grant_NZ (May 28, 2008)

Nice diagram, a lot easier to understand

So according to Gavin, all that's required is to replace the Warp 9 with an AC motor and wire the controller to the motor. Do any of the other parts need to be removed or wired differently?

Thanks


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## tj4fa (May 25, 2008)

A few notes for now:

It was mentioned earlier that the high voltage system _should not_ be grounded to the chassis. DO NOT ground the high voltage system to the chassis. Electrocution and destruction of components is likely.

In your diagram, you have the positive and negative connections to your battery pack right next to each other. For electrical safety purposes, have your negative lead coming from one side of your pack and your positive lead coming from the farthest positive battery terminal in your pack.

Your main fuse shows it connected to a positive _and_ negative terminal on your battery pack. Doing that will result in a dead short. It will blow up on you when you touch the terminals to your battery pack to the fuse ends. Big arc and flying molten metal shrapnel likely.

Put the main power fuse in line (series) with one of your battery cables. The same applies with your circuit breaker that acts as your emergency disconnect. Install the terminals to only one battery cable (possibly the other cable than what your main fuse is connected to). 

I'm not sure how you are wiring your 12V system, but I would recommend leaving the factory 12V fuse block like it is and add a seperate fuse block in your motor bay for supporting only your new 12V devices (contactor(s), vac pump, controller heat sink fan(s) ect. 

You can either find a wire in your motor bay that is hot when the ignition is turned on or run a new wire from the vehicle's existing fuse block (spade terminal maybe) that becomes hot when ignition is turned on. Either way, make sure the wire gauge is big enough for your new devices with a fuse size rated to protect the circuit. 

I would also recommend installing a new/reconfiguring your existing inertia switch in series in this ignition line so as to drop out power to your main contactor in the case of a collision/rollover. 

That's all I can do for now...I'll be back.


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## JRP3 (Mar 7, 2008)

Grant_NZ said:


> Nice diagram, a lot easier to understand
> 
> So according to Gavin, all that's required is to replace the Warp 9 with an AC motor and wire the controller to the motor. Do any of the other parts need to be removed or wired differently?
> 
> Thanks


One thing to be considered, in any system, is if the precharge resistor and diode are handled by the controller. Most DC systems need them to be added, but I know the Curtis AC controller handles precharge and diode internally.


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