Category: Hardware
Product Number: LT3652
Hi, I need some help regarding the LT3652 circuit that I designed...
The charger is supplied by the isolated 100v -> 24V DC/DC, 1.6 A. The 4s1p LiFePo4 battery is connected between the KL30F and KL31, where constantly 45 ma - 250 mA of current is being drawn at all times, depending on the loads connected.
I chose the maximum current to be 1A, the Charge voltage (float voltage) to be 14.1V (3.525V per cell). The charger starts the recharge when the voltage is 13.71 V (0.04 V of target, so let`s admiss it is the correct value) and stops charging at around 14.05 V (0.05 V of target value, also can be considered as correct). But the problem is the charge current. The maximum charge current when starting the voltage is around 300 mA and it starts decreasing immediately. It sometimes decreases below the 100 mA (0.1 max current). Is it a normal behaviour? I wanted to use the time termination which is set to 4h and 20 min. Maybe You have some other recommendations? Will the current get bigger as the voltage of the battery will be lower? I discharged the battery to 12V, but the charging current did not get higher than 250 mA.
How does the charging algorithm work exactly? What am I doing wrong and what can I do to increase the charging current to correct value?