# Wiring diagram check



## Dunstan (Jan 31, 2013)

Hi there,


Would someone with an ounce of knowledge be kind enough to check my wiring diagram and tell me if they see anything wrong, please?

Click on the image for a full-size version:


I realize I still have to add in a few things, but for now I just want to make sure I'm on the right track.

Questions:

• Is the whole "key switch" business referring to the ignition where I put the car key in to start it up?
• I'm not really sure what I do with the ignition connection on the MiniBMS board yet. Where should that connect to in the diagram?

FWIW, I've never worked on a car or held a soldering iron before, so you might need to use small words and be patient with your feedback.

Thanks for your help.

-- Dunstan


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## Caps18 (Jun 8, 2008)

Key switch would be what you use to start your car and turn it on. Don't most Key Switch relays have two wires coming off of them? The relays I've used in the past do, but my experience is very limited.

The ignition connection on the BMS would probably go to the 'H' in Key Switch if I had to guess. It would turn the BMS on when the car is started and turn it off then it isn't on. Having said that, are you sure that the Key Switch goes on the + terminal? I don't know, but the circuit wouldn't be complete if both B+ and IGN are +.

And ask around about how critical a BMS is with a LiFePO4 battery pack... I need to do some more research on that and as to what real world testing without one has shown. I think if you start them off evenly, they do pretty well.

Where are the gauges, power brake pump, other components, and 12V to the car systems? How is the 12V battery going to get charged? Where is the battery disconnect?


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## Dunstan (Jan 31, 2013)

Caps18 said:


> Key switch would be what you use to start your car and turn it on. Don't most Key Switch relays have two wires coming off of them? The relays I've used in the past do, but my experience is very limited.


I don't know, I've never seen one before.




Caps18 said:


> Having said that, are you sure that the Key Switch goes on the + terminal? I don't know, but the circuit wouldn't be complete if both B+ and IGN are +.


I copied that bit of logic from this diagram. But maybe I got it wrong?




Caps18 said:


> Where are the gauges, power brake pump, other components, and 12V to the car systems? How is the 12V battery going to get charged? Where is the battery disconnect?


Well I'll only have the one spyglass gauge (not shown here yet), no power brakes, and I've not included the headlights and things in here for now – I'll do another diagram for that when the time comes. As for charging the 12v battery, I'll eventually get a DC-DC converter, but for now I'm going to just run off the 12v battery and charge it at home. And the battery disconnect... I don't know where that would go in the diagram. Do you have a suggestion?

Thanks.


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