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I have the following problem: I have a 12.8V LiFePO4 Battery that powers the circuit and a lead acid charger with Intelligent MCU Control of 12V and 1.5 A to charge the battery. When the battery is charging, the load is taking current partly from the battery and partly from the charger, putting the battery in a state of constantly discharging and charging. If I understand correctly this is not good for the battery as it lowers the capacity in the long term.

When I connect the load directly to the charger it provides enough current.

The goal is to prevent the load from taking current from the battery while the battery is charging. I created this circuit as a possible solution and would like to know if it could work, or is there a better way, maybe an existing component, a BMS, or other solution?

I also found this BMS (VE.BUS BMS 8-70 V) but dont know if it serves the purpose, or/and is an overkill.

Any help is very much appreciated.

Charging and not charging circuits

Victron Energy VE.BUS BMS 8-70 V

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  • \$\begingroup\$ "the load from taking current from the battery while the battery is charging" is not physically possible. Either the battery is charging or it's not - current can't be flowing in both directions at the same time. If (charger current) - (load current) is positive then the battery is charging; if it's negative then the battery is discharging. You need to ensure that your charger can supply more current than your load needs to ensure that there's some left over to charge the battery. \$\endgroup\$
    – brhans
    Apr 27 at 12:39
  • \$\begingroup\$ You also need to ensure that your charger is ok with both supplying the load and charging the battery at the same time - that this doesn't confuse the charger's detection of when the battery is fully charged. \$\endgroup\$
    – brhans
    Apr 27 at 12:46

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