This would be great for flying with li-ion packs. I vaguely remember there was a feature request for this but I cannot find it anymore.

Quick question though, are the time limits set in deciseconds? I don't think that time unit is used anywhere else in INAV so maybe it's better to change it so either seconds or milliseconds. Also, a max burst time of 60 seconds could be useful depending on how you set the constant and burst currents/powers.

This would be great for flying with li-ion packs. I vaguely remember there was a feature request for this but I cannot find it anymore.

I vaguely remember a similar request but I can't find it either

Quick question though, are the time limits set in deciseconds? I don't think that time unit is used anywhere else in INAV so maybe it's better to change it so either seconds or milliseconds. Also, a max burst time of 60 seconds could be useful depending on how you set the constant and burst currents/powers.

Yes deciseconds. TBH I would much prefer having the settings be seconds but I also like the tenth of a second granularity. The best would be to switch to float but that would double the storage size for the timing settings from 8 bytes to 16 bytes, I am not sure it is worth it.

Hmm yeah, perhaps this should be made more intuitive on the configurator side at some point (but not only for this feature, iNavFlight/inav-configurator#1201).

Can you increase the max value for limit_burst_current_time and limit_burst_power_time to 600? I have a 18650 pack that specifies a burst current for up to 60 seconds.

Hmm yeah, perhaps this should be made more intuitive on the configurator side at some point (but not only for this feature, iNavFlight/inav-configurator#1201).

I wanted to add these settings to the GUI but I wanted to use the generic settings interface and there is an issue with that in the configuration tab. I'm not sure what is going on.

Can you increase the max value for limit_burst_current_time and limit_burst_power_time to 600? I have a 18650 pack that specifies a burst current for up to 60 seconds.

Let's make it even 300s

Hi @shellixyz ,

I aim at using a li ion battery on my 5"quad to do some longer time flight (smooth flight not freestyle), but I would like to keep quad motor configuration as it is to be able to switch from long flight to freestyle (shorter flight) mode. If I understand this PR, it is the solution to limit power. I would like to test it on my lipo first to see if it will be still flyable with limits for li ion. Do you know which kind of parameters I have to set in the Cli to tune this?

Arnotlse

@ArnoTlse

I will add documentation for this soon. There are 4 parameters you can set to change the behavior:

limit_cont_current which is the continuous allowed current (eg 45 = 4.5A)
limit_burst_current which is the burst allowed current (eg 100 = 10.0A)
The burst current is allowed for limit_burst_current_time (eg 100 = 10s)
limit_burst_current_falldown_time specifies the time for the current to ramp down to the continuous limit when the burst reserve is soon to be depleted

You can find all the settings and their description in the documentation. Settings for power limitation begins with limit_

Hi @shellixyz,

Ok, thanks a lot.
I will test it.

Arno

Hi @shellixyz,

Another question, does it works also with battery profile? I mean, can I limit the current using the parameter you mention depending on the battery profile used?

For example, if I want to limit current with specific values to use li ion battery safely (30A max) when selecting battery profile n°2 and go back to default value for battery profile n°1, is it manageable? Or are the variables for current limitation unique and apply to all battery profile?

Arno

Not in 3.0 but that will be possible in 3.1

OK, great. Thanks for the information.

Arno

Hi @shellixyz,

I have made a flight yesterday with such limit configured :

• Limit_cont_current = 200
• Limit_burst_current = 250
• limit_burst_current_time = 100
• limit_burst_current_falldown_time = 100

I have made some vertical acceleration test (gently accelerating) to see if the limitations will be floored by those settings. I have experimented at moment, a very short déstabilisation of the quad following quickly by a complete shutoff of the quad in flight when pushing throttle. When I get it back, I have to disconnect and reconnect the lipos to make it work again. Disam/arm not working. Unfortunately, the log is corrupted. It has stopped recording before this event. So it is just what I have observed.

Do you know if it is a normal or expected behavior? Do I have also to configure limit_power stuff related to limit_current?

Arno