Using 69.4v charger for LiFePo battery

Batteries, Chargers, and Battery Management Systems.
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Shortcircuit   100 µW

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Joined: May 17 2021 10:39am
Location: Visakhapatnam, INDIA

Using 69.4v charger for LiFePo battery

Post by Shortcircuit » May 27 2021 12:41pm

Is it ok to charge a 48v LFP battery (6Ah cells 15s BMS) with 69.4v or 71.4v charger . I know I should be using 54v charger for 48v battery. But in case of emergency can I use a 69.4v or 71.4v chargers if available ? What happens if I use a higher voltage charger (For emergency purpose ) ??

john61ct   100 GW

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Joined: Dec 18 2018 2:06pm

Re: Using 69.4v charger for LiFePo battery

Post by john61ct » May 27 2021 2:51pm

You can always use a charge source that CAN get up to a higher voltage than you want to terminate at.

But if you ALLOW it to go much higher, you can

1. at best reduce the cell longevity

2. break other devices on that circuit

3. destroy the battery quickly

4. start a major FIRE kill people and destroy the nearby buildings

So, either sit there in an alert state watching the voltage climb at the pack posts with an accurate DMM the whole charge cycle, no drinking drugging dozing off allowed

or (much better) get an adjustable HVC circuit in there (at the pack posts) that cuts off the source at its inputs when your desired setpoint is reached.

Thus the source does not even need to be an intelligent charger with automated stop-charge

but can be a dumb cheap Mean Well PSU or DCDC converter.

Shortcircuit   100 µW

100 µW
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Joined: May 17 2021 10:39am
Location: Visakhapatnam, INDIA

Re: Using 69.4v charger for LiFePo battery

Post by Shortcircuit » May 27 2021 8:10pm

Ok thanks

fatty   10 kW

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Re: Using 69.4v charger for LiFePo battery

Post by fatty » May 28 2021 5:14am

No, that is fundamentally unsafe.

radio05   10 mW

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Re: Using 69.4v charger for LiFePo battery

Post by radio05 » Jun 18 2021 11:06am

The highest voltage of iron-lithium battery is 3.65v, and the highest voltage of 15-string battery is 54.75v. Higher than the rated voltage will directly damage the battery pack and even cause safety accidents. It is not recommended to charge beyond the rated voltage and rated current, and the battery should be equipped with a protection board for balanced charging . Lithium iron batteries are relatively safe, not absolutely safe.

radio05   10 mW

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Re: Using 69.4v charger for LiFePo battery

Post by radio05 » Jun 18 2021 11:09am

Finding the right power source for charging is the only way to ensure safety and battery life

999zip999   100 GW

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Location: Dana Point So. Cal

Re: Using 69.4v charger for LiFePo battery

Post by 999zip999 » Jun 18 2021 12:18pm

No don't do it.

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