Charging 48v LiFePO4 battery with 52v Li-ion charger?

Awoo

New Member
Hello friends, I'm about to build a 48v 16s5p LiFePO4 battery but I don't have a charger specifically designed for this chemistry. Would it be safe to use this charger designed for 14s Li-ion cells?: https://lunacycle.com/luna-charger-52v-advanced-300w-ebike-charger/

It can charge Li-ion batteries to 90% of 58.8v which is the setting I intend to use it at, but if the charge voltage of the charger is a constant 58.8v and the charge voltage of the 48v battery is 58.4v, will there be a problem? Can I charge to 100% and just rely on the BMS to cut off charging at 58.4v? Will my 48v Daly smart BMS even accept the voltage, or are there some settings I could change? It seems like a 0.4v difference wouldn't be that bad but I want to be certain that I'm not harming the cells/BMS.

I couldn't get a clear answer about the charging voltage of the charger so I'm not even sure if it's a constant 58.8v until I connect the battery to it. Without a load it outputs 58.4v, which seems perfect. Do Li-ion chargers usually work this way?

Thanks for the help :)
 

snoobler

Solar Honey Badger
Moderator
Welcome to the forum.

At 58.8V, most Li-ion is at true 100% (4.2V/cell).

58.8V for LFP is at 3.675V.

If you already have that charger, and you have a BMS installed with suitable high voltage protection, it's fine. I would personally use it in that situation.

58.4 vs. 58.8 might be calibration error between your meter, the charger or both.
 

Burke

Solar Enthusiast
If you haven't bought a charger yet, why not get a charger that is set up for LiFePO4 right from the beginning then you don't have any charging gymnastics to deal with?
 

snoobler

Solar Honey Badger
Moderator
80% should be ~56V and 90% should be ~57.4V, only the 100% setting should be 58.8V.

In the context of LFP, the above recommendations are not absolute. SoC at a given voltage depends on C rate. 5A on a big battery will get it very full at lower voltages. One can obtain 95% SoC @ 54.4V at low current.
 

BlueFox

New Member
In the context of LFP, the above recommendations are not absolute. SoC at a given voltage depends on C rate. 5A on a big battery will get it very full at lower voltages. One can obtain 95% SoC @ 54.4V at low current.
Sorry I should have made it more clear in the reply, I meant in regards to what the charger should be outputting for a li-ion battery pack since that's what it was made for.
 

snoobler

Solar Honey Badger
Moderator
Sorry I should have made it more clear in the reply, I meant in regards to what the charger should be outputting for a li-ion battery pack since that's what it was made for.

I wasn't sure, so I added the context. :)

We are in agreement.
 
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