Battery question - 48v LGecolfp

[Liam52]

My battery came today, 48v LGecolfp brand, highly rated at Amazon. It was fully charged after only about 15 minutes.
I got it mounted in my frame with new 5mm rivnuts. After plugging it in, I got curious about the voltage at the XT60 plug lead. Strangely, I got a 48.5v reading with the battery off, and a 53.5v when on. Why do I get any reading at all when off? Something wrong? Or some weird electronics magic?

 

[Smaug]

The 48.5 V reading you got may have just been showing the residual charge left on the output capacitor. If you tried to load it, it would drop right to zero.

a "48 V" battery is really thirteen 3.6 V cells in series. Nominal is actually 46.8. They get "48 V" from using 3.7 V as nominal, which is incorrect, but that's marketing for you.

When fully charged, lithium cells are at 4.2 V per cell, so a fully charged pack would read 54.6 V or thereabouts. (I wouldn't worry about your pack being 1 V low)

 

[munirider]

Yes, what Smaug said, it's just residual, as soon as you put a load on it will go to zero. Even the motor can hold a residual charge, while soldering xt90s connectors on I let the motor leads come in contact and got a good spark.

The fact that it came to full charge in fifteen minutes is not great, it means your battery was charged and stored at full charge which isn't good for Lithium ion batteries. Might be why it isn't coming up to the full 54.6V.

 

[Liam52]

Thanks for the info guys.