conrad taggart Posted October 5, 2021 Share Posted October 5, 2021 Anybody that uses FRSKY receivers may find the attached article of interest. http://www.50k-or-bust.com/Model Aircraft/Flight Battery Monitor 01.pdf Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted October 5, 2021 Share Posted October 5, 2021 Quite interesting. The SM modelbau Unisens sensor does it slightly different in that it only resets the mah counter if you put in a battery above a certain voltage, so say you have a 3s battery, you'd program the reset voltage to say something like 12.2v then only if you put a battery in that has a voltage above 12.2v will the mah counter reset. Quote Link to comment Share on other sites More sharing options...
Andy48 Posted October 5, 2021 Share Posted October 5, 2021 Sorry, but its reinventing the wheel, as the author indeed acknowledges! FrSky already have had a simple battery monitor the FBVS-01 available for many years. Instructions for connecting it to an analogue port on any of the Frsky receivers is here in section 10: https://openrcforums.com/forum/viewtopic.php?f=45&t=8724&sid=9dc6426169be09d97d2ebde9807da217 However, it is a rather crude device, and using the more common Frsky FLVSS is a far better way to go as it measures the voltage of each cell, not just the whole battery voltage. Thus you get considerably better security for your planes, as a failing battery will often have one cell much worse than the rest, and under load the battery voltage might look fine, but in reality one cell has a worrying voltage drop. The FLVSS is cheap enough, and considering it can be moved from model to model very simply it seems a no-brainer to me. 1 Quote Link to comment Share on other sites More sharing options...
MattyB Posted October 5, 2021 Share Posted October 5, 2021 1 hour ago, Andy48 said: Sorry, but its reinventing the wheel, as the author indeed acknowledges! FrSky already have had a simple battery monitor the FBVS-01 available for many years. Instructions for connecting it to an analogue port on any of the Frsky receivers is here in section 10: https://openrcforums.com/forum/viewtopic.php?f=45&t=8724&sid=9dc6426169be09d97d2ebde9807da217 However, it is a rather crude device, and using the more common Frsky FLVSS is a far better way to go as it measures the voltage of each cell, not just the whole battery voltage. Thus you get considerably better security for your planes, as a failing battery will often have one cell much worse than the rest, and under load the battery voltage might look fine, but in reality one cell has a worrying voltage drop. The FLVSS is cheap enough, and considering it can be moved from model to model very simply it seems a no-brainer to me. Completely agree, there is not much reason to go to that amount of trouble when you can buy an FLVSS instead that does a much better job for 14 squid and the screen free version for a tenner... Quote Link to comment Share on other sites More sharing options...
Andy Gates Posted October 5, 2021 Share Posted October 5, 2021 I use both of the FrSky voltage sensors which work well enough. I also use the bigger current sensor (Hall effect), with an alarm set to stop me cooking the ESC. Alarm goes off at 60A (the ESC rating) and another at 80A (burst rating). Does the job. Quote Link to comment Share on other sites More sharing options...
Andy48 Posted October 6, 2021 Share Posted October 6, 2021 14 hours ago, Andy Gates said: I use both of the FrSky voltage sensors which work well enough. I also use the bigger current sensor (Hall effect), with an alarm set to stop me cooking the ESC. Alarm goes off at 60A (the ESC rating) and another at 80A (burst rating). Does the job. I actually use both current and voltage sensing. Voltage sensing warns of either a used battery you are putting in again, or a battery near the end of its useful life. The current sensor provides the "fuel gauge" to see how much of the battery capacity I have used. Personally I always set my planes up so the max current is well within the motor and ESC rating, so that is never an issue. Flying any electric plane at max power gobbles up battery power disproportionately and reduces the battery life. Quote Link to comment Share on other sites More sharing options...
conrad taggart Posted October 7, 2021 Author Share Posted October 7, 2021 Except that you don't have to plug the balance lead of the lipo into the current reader every time you fly and take it out again at the end. This is fit and forget - you do what you normally do. I might be lucky but as I balance charge my batteries before I fly them I have never had one go significantly out of synch / balance during flight. If they are misbehaving I tend to pick it up when charging - either at the start or end of the charge ! Quote Link to comment Share on other sites More sharing options...
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