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BQ24450 SLA charger

Other Parts Discussed in Thread: BQ24450

Hi!

I designed SLA battery charger with BQ24450, circuit is shown in the following figure 1.

battery voltage: 12V

battery capacity: 65Ah

pre-charge current Ipre=0.02A

maximum charge current Imax=5.0A

taper current Itaper=0.5A

Vth=10.8V

Vbi=13.68V

Vfloat=13.8V

Vboost=14.4V

Vrch=9.42V

figure 1) charge circuit

And charging current, battery voltage profiles are attached  following too.

figure 2) charge I/V profile

figure 3) 0 ~ 25000 sec expanded profile

 

1) Charger output voltage(battery voltage, Vbat) does not reach to Vboost, 14.4V, only 14.0V.

2) Charging does not terminated, the charger continues to supply a low current.

In this state, if places a load on the battery, charger is supplying all the load current. (see figure 2)

3) I understand the operation of the charger, as shown below figure 4.

Am I misunderstanding about this?

figure 4) recharge sequence

4) BQ24450 is correct to operate as shown in Figure 2?

I look forward to hearing any advice about this.

thank you

Best regards

Kwon