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Topic: Monitoring Battery Level - LiPo 3S 2200mAh 11.2V (Read 925 times) previous topic - next topic

ALIBE

Nov 26, 2013, 02:29 pm Last Edit: Nov 26, 2013, 02:32 pm by ALIBE Reason: 1
hello all
my current project (http://alibe.codeplex.com/) has an onboard LiPo 3S 2200mAh @ 11.2V.  As most of you know, if the voltage drops beyond a threshold (in this case 9v), one has to charge the LiPo as a NiCd (faking the charger really).  While this is a good workaround, i'd actually like to avoid doing this as I read that it reduces the battery life.

So, i was hoping i can build a battery monitor that keeps an eye out for when it falls below a certain Voltage level.  I have seen several breakout boards at sparkfun, adafruit, etc.

The purpose of this thread is to find out if and what ideas you might have tried for similar applications that have worked well.  I have seen a great circuit from MAXIM Voltage Monitor chips (MAX8211 and MAX8212 - attached the datasheet for reference).  While this seems very cool to implement, i would not like to re-invent the wheel if a breakout board that is arduino enabled is available.

Any and all feedback/guidance is greatly appreciated.

Thanks

MarkT

Two resistors form a voltage divider, take the centre-tap to an analog pin and you
can monitor with analogRead() - no extra board required.

Make sure the divider lower resistor has a resistance around 10k, and that the
analog pin will never see too high a voltage (perhaps divide by 2.5 will do here,
the battery should never be higher than 12.5V I guess.  Then 15k + 10k divider
would do.
[ I won't respond to messages, use the forum please ]

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