pic voltage monitor avg over bats in parallel Connection

Thread Starter

longpole001

Joined Sep 16, 2014
62
Hi guys ,

Was thinking of having a voltage divider network from each battery and join the divider output together for an average ,not tried it this way would it work ok for an average over 2 bats


cheers

sheldon Capture.JPG
 

dendad

Joined Feb 20, 2016
3,914
You can replace resistors B and D with one 75K.
But it really would be better to monitor each battery independently.
Are the batteries connected together or where do they go? If they re just connected together in parallel, only one voltage divider is needed.
Can you show the connections?
 

Thread Starter

longpole001

Joined Sep 16, 2014
62
the bats have a charging cct and reverse polarity cct , fuses on each ,
a low drop diode on positive on each with 2 cathodes joined , to feed a DC DC converter to get a higher voltage , the bats are basicly in parallel

i was not happy just to connect battery monitor to the common cathode point as the voltage drop although each would change with current load / temp

reason for using the same resistor in the divider value is that the smd package has 4 of the same value in them , and as the voltage ref = 2.048v , and with no volt drop the voltage = 4.2v , so that works well for divider at the same values for r1, r2 for each bat
 
Last edited:

dendad

Joined Feb 20, 2016
3,914
If you have a spare ADC input, monitor each battery separately. That is much better. Otherwise, you cannot detect a failed battery.
 

Thread Starter

longpole001

Joined Sep 16, 2014
62
yes good point
out pins on the pic , but that point of failed bat may be worth the effort of extra pin made free some how , code take care of the avg over the bats
 
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