This is a repost of Andrews previous post as he too is having similar problems. It almost looks like I have a bad reference voltage on the board. Is there a way to verify that I have a working reference voltage?
Any help would be appreciated.
-Ed
"
Hi,
I recently hooked up a new 3DR power module and APM 2.5. When connected to the APM, I confirm that the relevant power monitor settings are:
- measure: Voltage & Current
- type: 3DR power monitor
- ver: APM 2.5+ 3DR power mon
This automatically sets the voltage divider to 10, and the amps per volt to 18.0018. However:
- When powered by my standard full 2200mAH 3S battery, APM reports 11.1 instead of 12.6
- When powered by USB, APM reports .5v.
-When full throttle is applied only 3A are read.
I confirm in full param list that A12,A13,10,18.0018 are all set. Using up to date (latest) version of MP, Arduplane. Tried firmware reload, eeprom format, CLI factory settings reset.
Anyone see my issue?
(I seem to be able to use "manual" settings by setting power monitor type to "Other", and entering in measured V or voltage divider, and a value for amps per volt - but I don't know an accurate amps per volt, and I'd rather find out what is wrong that prevents the standard/supported automatic method from working with this up to date equipment and software)."
Replies
Hi Ed, you need to adjust the volt divider under full parameter list. On 3.1 Rc this parameter is BATT_VOLT_MULT, and I have mine set to 10.3 vs the recommended 10.1. Also my amps per volt (BATT_AMP_PERVOLT) is set to 16.
I ended up plugging in an external current/voltage monitor into mine and adjusting these parameters until the values lined up with what my external monitor was reading.
I notice that when there is no load, with the new settings the voltage reads high, but once I fly, the values are correct.