Mavic Pro Battery Mod

[chazz]

What are the packs like at the typical long range current draws? Say 1.2-1.3c.

I dont really know all i can say is looking at Airdata logs of my flights mine draw less then 10Amps. Isn't current draw something you see on your charts? Maybe i'm not understanding the question.

 

[lolo780]

I dont really know all i can say is looking at Airdata logs of my flights mine draw less then 10Amps. Isn't current draw something you see on your charts? Maybe i'm not understanding the question.

I mean the pack resistance at typical flight currents. We don't need high C rated batteries for a Mavic, but lowering resistance losses is always welcome. The question is whether the weight gain is worth it.

 

[chazz]

I mean the pack resistance at typical flight currents. We don't need high C rated batteries for a Mavic, but lowering resistance losses is always welcome. The question is whether the weight gain is worth it.

Not going by the tests i did with the P3. Weight loss wins unless the resistance gets so high it doesn't keep up with the Mav battery.

 

[chazz]

And your right i don't care about C rating as long as it can draw the 30amps if needed.

 

[chazz]

I like what i'm seeing with the protek batteries as long as the capacity is as advertised. The bigger MS lihvs are discontinued and this is a welcome replacement for the P3.

 

[lolo780]

Not going by the tests i did with the P3. Weight loss wins unless the resistance gets so high it doesn't keep up with the Mav battery.

If space wasn't at a premium on the Mavic I would have switched to 18650 cells like the real long range guys use.

 

[chazz]

If space wasn't at a premium on the Mavic I would have switched to 18650 cells like the real long range guys use.

They are?

I bought these Samsung 48G 21700 4800mAh Battery
and got a hover of over 40min but fighting the autoland that starts at around 3.5V and 20min into the flight kinda sucks... When I'm using a lihv auto land doesn't start until 3.4V. I'm hoping the 4s higher voltage helps with this. 4S = 16.8V to 10V during flight and the 3S = 12.6 to 7.5V... So if autoland starts at 10.5V i wouldn't have to deal with it as long with the 4S... But it is a heavy bastard.

 

[chazz]

If space wasn't at a premium on the Mavic I would have switched to 18650 cells like the real long range guys use.

Space? Space is only limited by how high you can fly

 

[lolo780]

They are?

I bought these Samsung 48G 21700 4800mAh Battery
and got a hover of over 40min but fighting the autoland that starts at around 3.5V and 20min into the flight kinda sucks... When I'm using a lihv auto land doesn't start until 3.4V. I'm hoping the 4s higher voltage helps with this. 4S = 16.8V to 10V during flight and the 3S = 12.6 to 7.5V... So if autoland starts at 10.5V i wouldn't have to deal with it as long with the 4S... But it is a heavy bastard.

I did an indoor hover test with a full weight, stock prop Mavic using Thunderpower 4500 and 3500 packs with stock labels and shrink plus the stock DJI battery. XT60 plugs with 12ga wires, basically a heavy pig. Auto land kicked in right at 40 min and I landed it at 40.5min. 414,000 watt seconds to the motors @ 170w constant draw.

 

[dirtybum]

I like what i'm seeing with the protek batteries as long as the capacity is as advertised. The bigger MS lihvs are discontinued and this is a welcome replacement for the P3.

Dilly,Dilly![emoji482]

 

[dirtybum]

Space? Space is only limited by how high you can fly View attachment 27203

Yeah I never understood why the Mavic guys started strapping things on the roof, like it was some old station wagon. They fit under the belly just fine and fly even better, you don't got to be a physics expert to understand that hanging under the belly is going to be better than something sticking up above the props.The design and low profile of the Mavic allows you to land on the big bricks underneath and barely cause a stumble, just sits upright
on the battery like it was landing gear.

 

[lolo780]

Space? Space is only limited by how high you can fly View attachment 27203

Too much drag for forward flight on that setup. I've analyzed all possible (sensible) battery configurations and cg positions for watt second per meter consumption with Csviewer. Up, down, sides, inline, side by side, even one straight forward off the nose.

 

[dirtybum]

Too much drag for forward flight on that setup. I've analyzed all possible (sensible) battery configurations and cg positions for watt second per meter consumption with Csviewer. Up, down, sides, inline, side by side, even one straight forward off the nose.

I say F the watt configurations, fly it and see what you get.[emoji41]
You know I've tried batteries strapped to every corner of the phantoms. Sometimes it looked pretty silly.

 

[lolo780]

I say F the watt configurations, fly it and see what you get.[emoji41]
You know I've tried batteries strapped to every corner of the phantoms. Sometimes it looked pretty silly.

I did fly them all, that's how I arrived at my current setup.

Top mount batteries are good for altitude runs. Insulation over top makes a tent to keep heat in that rises off the core and esc boards. Main battery plus external stay warm even in -54c air temps.
And the rounded top cuts through the air when going vertical. I averaged 20 watt seconds per vertical meter at 10m/s up for over 1000 seconds.

 

[Nofate]

I got a couple of those protek 4s 4200's. I checked the resistance with a meter i have that checks resistance and C rating and the Protek charger that i have that has a mohm reading . My Protek charger shows 59mohm total pack resistance and the other meter reads about 7.5 mOhms per cell and a C rating of 13 to 14C. The batteries aren't as advertised. They are still a good battery for what we need and they are very comparable to the MS lihv's but the 100C rating isn't true. The MS lihv's are rated at 10C and they measure between 11 and 14C...If I would have bought these needing the 100C for something other then the Mav i would have returned them. But i'm glad they came in I've been waiting awhile and i got the 3.6's and 8.5s coming maybe next week and hopefully i get some time to test. I did plug the 4s charged to 15.2V into the battery board to test and the bird fires up NP. I didn't fly it i just let it idle for a few minutes and it seems the cells run down evenly. So sooner then later ill charge it to 17V and hope it doesn't fry something I guess we'll see.

I am building a 5s 3600 pack for my racing quad (Chameleon) that has T60 motors and will hit it with 170 amps at full throttle if the packs will do it. That's not even 50c. I have full telemetry (current, volt, watts, gps) on it.

There is a mountain here in AZ I want to surf on the way down from its 2500 foot peak and see if I can bust 160 mph on the way down (quad does 95 on a 4s level flight now).

It eats Tattu 1500 95c packs for breakfast, going to be interesting to see how they hold up and the voltage suppression curve looks like. Will post here with my findings

 

[Nofate]

Yeah I never understood why the Mavic guys started strapping things on the roof, like it was some old station wagon. They fit under the belly just fine and fly even better, you don't got to be a physics expert to understand that hanging under the belly is going to be better than something sticking up above the props.The design and low profile of the Mavic allows you to land on the big bricks underneath and barely cause a stumble, just sits upright
on the battery like it was landing gear.

Hahaha, I dunno I mount mine on the top but now you make me want to put a wood panel skin and roof rack on it.....

 

[Nofate]

I like what i'm seeing with the protek batteries as long as the capacity is as advertised. The bigger MS lihvs are discontinued and this is a welcome replacement for the P3.

I think the capacity is dead on. I have been landing at 3.40 to 3.45 per cell and I pump 7200 to 7250mah back in to the 7430mah stock/protek parrallel pack. Discharge curve is extremely stable, with a nice predictable accelated drop off once it his 3.60. I imagine however that a pure protek pack would have a faster drop off like all high C packs do.

 

[philipfretwell]

Just a thought but if you only use only use a third of the power in the addon batteries for each flight, you could use batteries a third of the capacity and fully discharge them on one flight. The smaller capacity batteries should offer a good reduction in weight without reduced functionality. Not as handy as getting three flights out of them but you may get a slightly longer flight time...

 

[CyberNate]

Just a thought but if you only use only use a third of the power in the addon batteries for each flight, you could use batteries a third of the capacity and fully discharge them on one flight. The smaller capacity batteries should offer a good reduction in weight without reduced functionality. Not as handy as getting three flights out of them but you may get a slightly longer flight time...

Doesn't work that way. Capacity is not relate to how much you use as compared to internal. The relative percentage used should match the percentage used in internal battery unless there is significant internal resistance difference.

 

[chazz]

Too much drag for forward flight on that setup. I've analyzed all possible (sensible) battery configurations and cg positions for watt second per meter consumption with Csviewer. Up, down, sides, inline, side by side, even one straight forward off the nose.

I don't know what your talking about,, that 850 gram brick is totally aerodynamic.