DIY Electric Car Forums banner

Check out my Schematics

3217 Views 8 Replies 4 Participants Last post by  omonoid
I used the schematics from Gav's helpful website as a base, and changed a few things to match my build.

One problem with mine could be that my pot box (pb-5) doesn't have a micro controller, so i cant run the KSI relay through it. Instead i just plan on wiring it straight to ignition does that work?

Also i have a fan that normally runs off an outlet to use for trunk battery ventilation. I planned on wiring that directly to the charger so when the charger is plugged in the fan turns on. I may use a standard surge protector to link the fan, 12v battery charger and charger. Is that ok??

Thanks :)
See less See more
1 - 9 of 9 Posts
looks like a complete circuit to me. I can't comment on the particular question you raised about the ignition. My thinking on the surge protector would be that it is dependent on how many amps you're putting through your charger. You've got [email protected]?A, presumably somewhere in the 2-10 range, for the aux bat. If you're drawing [email protected] or so for the main pack, your breaker may not handle it being all on one circuit, and your power strip may not be able to handle that either. Worse case scenario though, you flip the breaker and have to figure something else out.
yeah i dont think you can buy surge protectors rated differently so im just wondering if a standard one works or not
I just had a thought that might be useful to you. In college we didn't have enough power outlets in the room, so instead of getting a power strip, we got a 3-way extension cord. This is a heavy duty (like 40 amp I think) extension cord used for shops and things as such. Mine was only about 3 foot long but on the end it has 3 grounded 120v plugs. Something like that might do just fine, and then you only have to worry about the breaker and making sure the cord isn't getting hot.

Edit: this isn't quite what I have but the idea is the same. Mine is the industrial orange and a little bit sturdier looking
Dear Omonoid,

I am not completely sure (I am from the AC domain, so DC is not my field really), but I think the charger is not connected properly.

The way you have drawn the picture, the charging current is going to go through the controller, and needing the main contactor to be closed during charging.

I would think (and with my AC controller I know that I need to do this), that the charging circuit is in parallel with the drive circuit.

Please feel free to correct me, as I make this remark from the theoretical point of view, being far away from doing this installation myself.


See less See more
- the charger is shown in series with the battery, but should be parallel to it, directly connected to it.

- word "precharge" doesn't seem to point to anything, no resistor is shown across the contactor's main terminals.

- don't know what is the bottom small wire on the controller, going to the shunt. Maybe its some controller model I am not familiar with, you didn't mention what controller this is.

Hope this helps
Oh your saying the charger should be on a different circuit? That makes sense.

I am afraid we (Dimitri and I) mean something else:
The charger and the drive circuit are both in parallel w.r.t. the battery.

With other words:
The charger is connected (via fuses) to the - and + poles of the battery
The controller is connected (via contactor + precharge etc.) to the - and + poles of the battery

If you use a shunt to measure currents and do tracking of charging state, then one one connection of both the charger and the controller is connected to this shunt instead of a battery pole, and the other side of the shunt connected to this pole. This way you can measure both charging and de-charging currents and energy flows.

Is this clearer now?


See less See more
yeah. Ill re-draw it a bit and post up a revised version.

oh and that black wire on the controller is the ground i didn't really know what to attach it to

I wrote precharge cause i was going to put a resistor between the contactor's terminals, and didnt know how to write it.

I have no experience making schematics so sorry for its roughness
1 - 9 of 9 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.