Battery management and sport mode

beach_Dr · Oct 12, 2018

So some background: 1.35km out over ocean, get a Return to Home Now message at 34% battery, so turn around and return to home (flying manually, not auto RTH), crosswind on shore seems actually bit of ahead wind to come home. Only making 20kph with obstacle avoidance off, watching battery percentage drop steadily.

Previous post I've read say switch to sport mode, much more efficient, which I would normally do to return home from ocean, but I don't normally push it that long (but the whale calf was cute)

And recently I've read a couple posts about how sport mode caused sudden power drop and falling from sky, when engaged at low battery percentage, due to sudden increase in voltage draw. So watching battery tick quickly under 20%, wasn't keen to risk a sudden drop in the ocean. Again...

I eventually altered course and flew north 50m up the beach, with more crosswind, less head wind, so managed 34kph, and controller started its angry warning scream and mavic went into auto land at 9%, which happened to be 3m from my feet, after flying her down the beach again.

So what's the opinion? Engage sport mode initially at 34% on RTH? Engage sport mode after noticing the slow progress, even at battery <20%? Forget sport mode at low battery? Or just quit flying over the ocean?

tcope · Oct 12, 2018

The _correct_ option is to be at the landing position or very close at 30% battery. If you are not, any option is then risky, period and up to the person flying. It simply becomes a crap shoot.

Robert Mitchell · Oct 12, 2018

Just my opinion, (others can chime in), sport mode is not more efficient. It allows you to return home faster, and against higher wind speeds, when necessary, but at a higher power cost.

In other words, if you can get home using normal mode, do so. Only use sport mode if you can’t make progress against the prevailing wind conditions.

If you don’t have enough power to make it home, sport mode won’t help.

Canuk · Oct 12, 2018

If you want to fly out far watching critters you can raise the battery warning up to a higher level . It should give you more time to come home

Meta4 · Oct 12, 2018

beach_Dr said:
So what's the opinion? Engage sport mode initially at 34% on RTH? Engage sport mode after noticing the slow progress, even at battery <20%? Forget sport mode at low battery? Or just quit flying over the ocean?

Just like driving your car hard and fast, Sport Mode on the Mavic is not fuel efficient at all and burns battery fast.
If you want to do ocean flying just allow a comfortable safety margin because a mistake or something unexpected out there can ruin your day.
And keep an eye on the wind, particularly what it will mean for your return flight.
Flying out against a strong headwind is no worry because it means an easy flight home.
The other way round can end up very unpleasant.

beach_Dr · Oct 12, 2018

Canuk said:
If you want to fly out far watching critters you can raise the battery warning up to a higher level . It should give you more time to come home

This was not the standard battery level warning(which is set at 30%) but the 'you only have enough battery to return home, do now so' warning. The little moving mark on the top battery bar that adjusts according to your distance from home point. Can you adjust that too?

Takes so long to find the critters, in 18min of flight time before landing at 9%, only got 5min of video, rest is spent flying out, flying back and trying to match a distant splash with where you think the bird is... I should rather just not break my golden rule of 'don't fly more than 1km offshore!'

Fortunately for my sanity (unfortunately for video), whale season is practically over now, and surfers tend to stay closer to the beach.

Mossiback · Oct 12, 2018

As others have stated, use Sport mode as a last resort against a head wind. Sport mode is not the most efficient power use setting. OA off is, which you are already doing. It would be better to change altitude in hopes of finding less wind.