Hi Charles. Thanks for the reply.
Sorry forgot to mention that the DC supply is 9.5V
Output voltage during (possible) auto-sleep mode: 7.92V
The battery voltage is 7.4V. Haven't got any higher voltage batteries to test it with.
During the auto-sleep, I connect and reconnect the battery, the output voltage continues to measure 7.92V, the chip doesn't wake up, and STAT1/Red doesn't come on.
As soon as I connect/reconnect the DC supply, the chip operates as normal. Using the same battery, STAT1/Red comes on, indicating charging. Output voltage measures 8.2V.
If i take the battery out (while the chip is 'awake') the output voltage measures 8.43V.
At the moment pin 8 EN is connected straight to Vcc as per the datasheet example. However if I pull EN low, and enter sleep mode on purpose, the output voltage measures also around 7.92V. Since these two voltages are the same, this makes me think that the chip is in fact entering sleep mode automatically after a set time, although there is no mention of this in the datasheet.
I've done lots of charge and discharge tests. The lowest BQ24005 output voltage i've measured is about 8.3V, when a completely empty battery is connected.
Finally, according to the datasheet, when normal sleep mode is triggered by pulling EN low, both indication LEDs off STAT1 and STAT2 switch off, and i confirmed this in hardware. However, in 'auto-sleep', STAT2/Green stays on.
This is a problem as the user could insert an empty battery, see the green light on, and believe that the battery is fully charged.
Could this be an undocumented feature?