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Re: [Need advice] Green LED keep blinking when charging

PostPosted: August 8th, 2015, 11:00 pm
by superpong
amb wrote:Look at your U1 chip. Is it a MCP73864? The behavior you describe seems to suggest that you have a MCP73862 instead. With MCP73862, the LED will blink green when the charge cycle is complete.


It is MCP73864. Should I replace with a new MCP73864?

Re: [Need advice] Green LED keep blinking when charging

PostPosted: August 8th, 2015, 11:25 pm
by amb
Not sure. The only cause of a flashing green light on the MCP73864 is if it's overheating (see the datasheet). Are the LiPo battery cells new and the recommended type? Measure the voltage across each of them at the end of charge cycle. What are they? Do the other sanity checks pass?

Re: [Need advice] Green LED keep blinking when charging

PostPosted: August 9th, 2015, 3:54 am
by superpong
amb wrote:Not sure. The only cause of a flashing green light on the MCP73864 is if it's overheating (see the datasheet). Are the LiPo battery cells new and the recommended type? Measure the voltage across each of them at the end of charge cycle. What are they? Do the other sanity checks pass?


OK I double checked.

- Temperature of my amp during playing and charging is normal in my opinion. Temperature of both batteries is very normal, not hot or warm.
- Lipo cells comply with suggestion in the mini3 thread. It's HM-4G6-Z-37 Walkera 3.7V 600mAh. I bought from --> http://www.ebay.com/itm/Two-2-HM-4G6-Z- ... 23551c79ae
- I let the amp keep playing music until batteries are depleted (no more sound outout). Then I connect the amp to the 9V adapter. the green led starts blink promptly. This is so strange.
- Here is measurement result.

(1) B+ B- = 7.35 and keep increasing during charging.
(2) OV B- = 7.34V
(2) OV B+ = 7.34V
(3) B+ COM = 3.68
(4) B- COM = -3.67
(5) LPW B- = 0 (almost 0V)

OL OG = 10.9 Mega Ohm
OR OG = 9 Mega ohm
OL IG = 1.8 Kohm
OR IG = 1.8Kohm
OG IG = Open circuit

One more thing I notice that output from my 9V adapter is about 11V (during charging). Would it be serious or may it harm my amp?
In general, I'm really happy with its musicality that this amp delivers except the fact that the charging behavior is so strange. However if it does not harm my amp, I may leave it as is.

Re: [Need advice] Green LED keep blinking when charging

PostPosted: August 9th, 2015, 3:59 am
by amb
The over-temperature I mentioned is not for the battery cells. It's for the MCP73864 itself. If your wall adapter is outputting 11V then that could explain it. You should get one that has regulated 9V DC output.

Re: [Need advice] Green LED keep blinking when charging

PostPosted: August 9th, 2015, 4:00 am
by superpong
amb wrote:The over-temperature I mentioned is not for the battery cells. It's for the MCP73864 itself. If your wall adapter is outputting 11V then that could explain it. You should get one that has regulated 9V DC output.


OK many thanks