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Old 05-31-2012, 06:11 PM   #1
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Default 3-wire lipo connector?

Hey guys- I just bought a 2s 180mAh lipo battery for my Losi BL micro Rally car. I have no issues changing the connector, but what to do with the third (blue) wire?

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Old 05-31-2012, 07:06 PM   #2
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Which battery did you buy?

Just guessing here, but since it's a 2S battery, if it only has 3 wires coming to 1 plug, then it probably is designed to use the same plug for balance charging that it uses for powering the vehicle. (Not sure if you're aware, but most of the bigger packs use something similar for balancing the cells inside, PLUS the two larger main power wires for powering the vehicle and quick charging, so 5 wires total...)

My suggestion, rather than changing the plug, make an adapter between the 3 wire plug and the type that your car takes. That way, you can properly balance charge the battery AND use it in your car without any really hack wiring tricks.

We are talking about a micro car here, so you don't really have to worry about current draw.
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Old 05-31-2012, 07:07 PM   #3
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Quote:
Originally Posted by BlueGlowBoy View Post
Which battery did you buy?

Just guessing here, but since it's a 2S battery, if it only has 3 wires coming to 1 plug, then it probably is designed to use the same plug for balance charging that it uses for powering the vehicle. (Not sure if you're aware, but most of the bigger packs use something similar for balancing the cells inside, PLUS the two larger main power wires for powering the vehicle and quick charging, so 5 wires total...)

My suggestion, rather than changing the plug, make an adapter between the 3 wire plug and the type that your car takes. That way, you can properly balance charge the battery AND use it in your car without any really hack wiring tricks.

We are talking about a micro car here, so you don't really have to worry about current draw.
+1 to that

and tampering with wires on lipo's is pretty risky
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Old 05-31-2012, 07:52 PM   #4
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Thanks for the feedback. The car actually came with an adapter, but it doesn't quite match up the connector on the battery. Looks like the red and middle blue wires merge into one, while the black wire stays on its own.

Looks pretty simple to me.

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Old 06-01-2012, 09:30 AM   #5
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I don't think they actually merge...otherwise you would be creating a short circuit across one of the batteries.

Likely, on the battery you show, The blue lead is connected to the positive of one battery and the negative of the other.

If you test the pins with a volt meter, red to blue should read ~3.7V, Blue to black should read ~3.7V and red to black should read ~7.4V. Whichever pair reads 7.4V are the ones you would want to use for your 2 pin adapter.
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Old 06-01-2012, 12:52 PM   #6
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Quote:
Originally Posted by BlueGlowBoy View Post
I don't think they actually merge...otherwise you would be creating a short circuit across one of the batteries.

Likely, on the battery you show, The blue lead is connected to the positive of one battery and the negative of the other.

If you test the pins with a volt meter, red to blue should read ~3.7V, Blue to black should read ~3.7V and red to black should read ~7.4V. Whichever pair reads 7.4V are the ones you would want to use for your 2 pin adapter.
Thank you, exactly what I needed.
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