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6S Batterysensor for FrSky TwoWay

PostPosted: Sat Jul 31, 2010 10:10 am
by takilara
At some point, I will probably use a microcontroller to receive GPS data, and individual cell voltages from my 6S battery.

However, as a starting point, I am planning to use a simple voltage divider to connect to the "outer" pins of the balance connector.

6S Voltage Divider_crop.png
Preliminary schematics
6S Voltage Divider_crop.png (2.13 KiB) Viewed 2493 times


This should have approximately 3mA current draw, so should not affect flight time too much..

One issue though, i have no "polarity protection", if i connect the balancer plug the wrong way, I will probably blow something Is it possible to put a diode or something in series to prevent incorrect orientation? Will this have an effect on the resistor numbers?

Re: 6S Batterysensor for FrSky TwoWay

PostPosted: Sat Jul 31, 2010 11:08 pm
by RCModelReviews
A diode won't make much difference (just 0.6V-0.7V) which is just 3% of the nominal voltage from a 6S lipo.

Re: 6S Batterysensor for FrSky TwoWay

PostPosted: Sat Jul 31, 2010 11:31 pm
by takilara
I didn't have any suitable diodes around, so i'll skip them for now,
soldered up, and measure 3.25 at output with fully charged batt, now i only have to set up the alarms and test it...
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Re: 6S Batterysensor for FrSky TwoWay

PostPosted: Sun Aug 01, 2010 12:25 am
by RCModelReviews
Given the low-current involved, any diode (from a 1N4148 to a IN4007 would have done), they all have about the same forward drop and a few mA won't cause any heating. Good job though -- looks great.

Re: 6S Batterysensor for FrSky TwoWay

PostPosted: Sun Aug 01, 2010 7:40 am
by takilara
I only had very large power diodes here (larger than that stripboard), and was too anxious to connect it up to look for any other