Interesting reaction to a purely academic question. I don't need to measure current on my applications so I was curious why others wanted to read current. Although RTFQ has nothing to do with my question, I think gervais was pretty much on target.

Referencing my issue 14 of AMP'D called, Storing Lithium for Longevity, you can see that with Lithium Polymer batteries, the voltage alone can be used as a "gas gauge".

This comprehensive list from MaoChris is an excellent answer. Thanks!

There are several benefits for current reading during flight:
- Calculation of used capacity from the LiPo.
- Fine-tuning of LiPo/motor/propeller combinations.
- Set up of an maximum allowed current controlled by the FC.
- Figure out the current change of the MR with different payloads.

Originally Posted by Greg Covey

Interesting reaction to a purely academic question. I don't need to measure current on my applications so I was curious why others wanted to read current. Although RTFQ has nothing to do with my question, I think gervais was pretty much on target.

Referencing my issue 14 of AMP'D called, Storing Lithium for Longevity, you can see that with Lithium Polymer batteries, the voltage alone can be used as a "gas gauge.

To some degree your statement is right Greg. However, the voltage of a LiPo pack is depend on many factors, like IR, current consumption, size of the cables in the MR and how many connectors are installed before the actual voltage measurement. So to define the remaining capacity in the cells just by the voltage is a bit difficult and differ from pack to pack as well as if you use the same pack in a different bird.

So I do believe, the current measurement version (converted to consumption / mAh) is more accurate.

REM: This is my personal opinion, so please don't shoot me out of the sky.

I got quite some of these questions via PM's and I thought I better post the answers here.

To post here all the quality control during the production would be a very long story, so all I can say is, that it is carried out and recorded.

The final QC before the boards are shipped, is a setup with an FC (Pixhawk) and connected to MissionPlanner to check the calibration values for current and voltage measurement.
This final test result will be passed to the customer together with the order confirmation and shipment tracking number by e-mail.

REM: Which power module supplier out there actually use the PM to power up a real FC before shipment ?

So I hope everybody understands, that if I say "safety first"... then I mean it.

Originally Posted by MaoChris

To post here all the quality control during the production would be a very long story, so all I can say is, that it is carried out and recorded.

Really ? I donīt remember one "flash protocol" for a PM (and I bought several) .

Others would sell this as calibrated or think thats too much...

OK, here it comes... a really, really, and I mean really, stupid question:

Why are there two red wires and not black/red going in and black/red coming out???

thanks,

G

You donīt need the fat GND wire for current measurement. Stays untouched. Shuntboards with + and - wires soldered pretty close to each other, bear certain risks.

Originally Posted by gervais

You donīt need the fat GND wire for current measurement. Stays untouched. Shuntboards with + and - wires soldered pretty close to each other, bear certain risks.

Copy that... Thanks.

G

Originally Posted by neavissa

OK, here it comes... a really, really, and I mean really, stupid question:

Why are there two red wires and not black/red going in and black/red coming out???

thanks,

G

An "Hall Sensor" does not care about polarity, only about the current flow trough a single wire in the right direction. So the sensor can be installed into the "positive" or "negative" main wire, only important is that the current flows according the "arrows" on the sensor board.

At the moment there are "red" wires preinstalled at the board...

BTW, there are no stupid questions... there are only stupid answers sometimes.

Good news, for anybody who wants to get one of the 200A sensor board with UBEC.
The web shop is up and running, just visit: www.mauch-electronic.com

REM: The web page itself needs some facelift and updating... please forgive me about that.

Originally Posted by MaoChris

An "Hall Sensor" does not care about polarity, only about the current flow trough a single wire in the right direction. So the sensor can be installed into the "positive" or "negative" main wire, only important is that the current flows according the "arrows" on the sensor board.

At the moment there are "red" wires preinstalled at the board...

BTW, there are no stupid questions... there are only stupid answers sometimes.

Copy that. Thanks...

Ok, I ordered one to check out and have on hand for my next build...

This would be awesome if it was integrated into a square power distribution board with 45mm mounting holes.


Well, it's awesome already, but the less separate components, the cleaner the build.

I think I may pick one up too. Very nice work. Looks completely professional and functional.

I've also got some of these units on my way for testing

Originally Posted by RotoRon

This would be awesome if it was integrated into a square power distribution board with 45mm mounting holes.
Well, it's awesome already, but the less separate components, the cleaner the build.

The less separate the components, the higher the risk of failure and impacts.

And:

Originally Posted by MaoChris

Why sensor board and UBEC are separated ?
- A switching power supply can be a very “noisy” part in the power supply chain and it is very difficult to shield the coils (1.5MHz) from the current measurement board. So it was decided to keep the two away from each other.

Another thing is, that users tend to place those 45mm boards right underneath (or close to) the FC, which sure is looking good but not a good idea concerning RF and EMI impacts.

For me its the best solution to place the tiny sensorboard very very close to the battery plug and to hide the extra BEC separately.