Hi All,
Currently having issues reaching maximum charge rate with the BQ24650 connected to 12V 7A SLA Battery (and 12V 25A)
Has anybody experienced this problem or reached a ? We aim to be charging at 5A constant current until the VFB > VRECH.
The BQ24650EVM has been helpful, but hasn't solved the problem of max charge on the main product.
I've used the formulas for the device and also the bqstroller calculation tools_V1.5.xls to confirm my calcs.
It's configured to L1 = 2.2uH and 40uF . R6 = 0.006R
Previously had L1 = 10uH and 20uF R6 = 0.006R
See Figure 8 in SLUU444A based off
- Single Battery = 10.78VDC (Unconnected)
- Rises to 12.20VDC and rising (Steady Constant Current 0.467A) (5.6W) when connected to Battery Terminal.
- Output of the Switching is ~600Hz, clean square wave.
- STAT1 = Charging
- TS = 1.966VDC
- Solar Input = 21.8V ~333mA (7.2W)
- 8.3.3 Battery Current Regulation = ICHARGE = 6.667A
- 8.3.4 Battery Precharge = 0.667A
- 8.3.9 Converter Operation = 16.97kHz
- No RTC.
SLUSA75A - Figure 14. Operational Flowchart for bq24650, we appear to be in the (Regulate Fastcharge Current state)
Just unsure if that's the best we can achieve with the BQ24650?
As a separate test, we setup a circuit like slva437a.pdf (Figure 2 - Sch for Pulse Charging) to see if it increased the charging rate.
RP-T = 499k
RB = 100k
RP-B = 5MOhm
VBULK = 12.78VDC
VRECH = 12.27VDC
This also didn't change the charging rate
Thanks for your time if you have any constructive help.
