Charging Ebike Battery through the Discharge Wires

johndcoffman

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My ebike battery came with a charging port (accepts 2.5mm barrel connector) and a discharge plug (XT60 connector). Can I charge the battery through the discharge connector (XT60)?
 

Anton

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Separate charge and discharge wires on your ebike battery means an internal BMS (Battery Management System). If you charge through the discharge wires, the BMS wont switch off the charger. It also might not charge at all if there is a low voltage FET cutoff.

If it does charge through the discharge wires, it may not properly balance the cells and one cell will always get overcharged. You would need to charge with a timer which switches off before any cell hits the HVC (High Voltage Cutoff).

I would charge through the charge port, it's there for a reason!
 

johndcoffman

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Thank you. One of my batteries accepts a male XLR pin. I plan to solder an adapter, but I am not sure which pin is positive and which pin is negative. All the YouTube videos seem to refer to audio connections, and I gather it doesn't matter for microphone cables. I am pretty sure it does matter when charging my battery. Does anyone know how to solder these XLR pins for charging a battery?
 

SirWilliam

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I am still in the learning mode on Lithium batteries, BMS`s Chargers etc. Is it the BMS that switches the charger off. My Charger cuts off when my 13 S battery reaches 53.9 Volts. Is this normal??
 

Anton

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I am still in the learning mode on Lithium batteries, BMS`s Chargers etc. Is it the BMS that switches the charger off. My Charger cuts off when my 13 S battery reaches 53.9 Volts. Is this normal??
The BMS balances the cell groups to make sure they all end up at the correct voltage. Almost all BMS's limit the amount of current that can go into the battery pack, and most of them will limit how much current can go out of the battery.

The chargers job is to charge to the 54.6V that the pack needs to end up at. The BMS will allow the cell groups to charge up to a full charge (in this case 4.2V). When a cell group reaches max voltage, the BMS stops the charge and begins balancing the individual cell groups.

So for your 13S battery pack, the BMS will take a reading for each of the cell groups. Most cell groups will be at 4.20V, but one cell group might only be at 4.15V. The BMS will then drain the other cell groups down to 4.15V. The BMS then allows the charger to send another full charge to the cells.

If you are still ending up with 53.9V after a full charge, it means that one or more of your cell groups is not taking and holding the full charge.
 
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SirWilliam

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Thanks for your reply Admin.
However after a few readings during re-charging I began to wonder my Vrezend -YZPOWER-42 charger was giving me sufficient volts
What I find is that it kicks out at 53.9 Volts and all my 13 banks are at 4.15/4.17 Volts
Is this a defective charger??
Regards
Bill Clark
 
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