Mavic Pro Battery Mod

[CyberNate]

At any point when you tuned back did the signal improve face towards you.

Yes, the signal was better on the way back. On the way out I had complete disconnects. The signal is spotty out here with the wifi interference, but I don't normally get complete disconnects like that where you see "RC Disconnected" messages.

 

[MacIak]

Yes, the signal was better on the way back. On the way out I had complete disconnects. The signal is spotty out here with the wifi interference, but I don't normally get complete disconnects like that where you see "RC Disconnected" messages.

Im sure at these distances the signal gets picky and blocking it will cause issues. Getting the batteries out of the way is a good idea id think.

 

[CyberNate]

Im sure at these distances the signal gets picky and blocking it will cause issues. Getting the batteries out of the way is a good idea id think.

Yes, perhaps I can simply turn the battery to an angle to get the front part of the battery up, away from the front legs. It's also possible I just had bad signal for that flight. It happens. The route is not precise.

 

[cruzroy]

 

[MacIak]

The videos look great @cruzroy ! will check them after work.

Can anyone explain again why we need LiHV again? If I compare the multistar LiHV to a normal LiPo, te LiPo's generally have a much higher discharge rate..

 

[CyberNate]

The videos look great @cruzroy ! will check them after work.

Can anyone explain again why we need LiHV again? If I compare the multistar LiHV to a normal LiPo, te LiPo's generally have a much higher discharge rate..

Lipos are fine. It is only the multistar lipo that doesn't work well. The advantage of Lihv is more power to weight ratio. Lihv cells also match the Mavic better because Mavic uses Lihv as well which has peak cell voltage of 4.35v rather than 4.2v for lipo. The downside for Lihv is that you need to be careful when charging to slightly undercharge it to only 4.32v/cell or less. If you don't there is a chance that the voltage will exceed the Mavic battery which can cause Mavic to switch off the main battery. The symptom is that you're flying and notice the battery gauge is not dropping. This means the Mavic battery is off.

This only happens (in my experience) right at takeoff, so you'll see battery stuck at 99%. Just a fyi as 2 of us lost our Mavic this way, by continuing to fly and later having the external battery run out suddenly with a critical landing which is more like a controlled crash landing.

 

[MacIak]

Lipos are fine. It is only the multistar lipo that doesn't work well. The advantage of Lihv is more power to weight ratio. Lihv cells also match the Mavic better because Mavic uses Lihv as well which has peak cell voltage of 4.35v rather than 4.2v for lipo. The downside for Lihv is that you need to be careful when charging to slightly undercharge it to only 4.32v/cell or less. If you don't there is a chance that the voltage will exceed the Mavic battery which can cause Mavic to switch off the main battery. The symptom is that you're flying and notice the battery gauge is not dropping. This means the Mavic battery is off.

This only happens (in my experience) right at takeoff, so you'll see battery stuck at 99%. Just a fyi as 2 of us lost our Mavic this way, by continuing to fly and later having the external battery run out suddenly with a critical landing which is more like a controlled crash landing.

I think i'll stick to LiPo since im not aiming for extreme range, not even sure my old Hyperion charger accepts LiHV. Too bad the multistar LiPo's are "bad".. the 4000 mAh seems to have great dimensions for piggyback.
I will be getting an extra battery tonight, first need to see what my .0200 firmware does with this. If no issues I prob will get another one and cut 2 of my older batteries for an ER mod.

edit: I think it will become Turnigy 2x 1800mAh 20c Lipo. 300g total and 10cm long. Would be perfect. OR 2x 2200 mAh. 70g more weight but same length, total width 5cm.
Not too bad id think..
I d like to use 1 4000mAh pack but these are around 15cm long...not good.

 

[CyberNate]

I think i'll stick to LiPo since im not aiming for extreme range, not even sure my old Hyperion charger accepts LiHV. Too bad the multistar LiPo's are "bad".. the 4000 mAh seems to have great dimensions for piggyback.
I will be getting an extra battery tonight, first need to see what my .0200 firmware does with this. If no issues I prob will get another one and cut 2 of my older batteries for an ER mod.

edit: I think it will become Turnigy 2x 1800mAh 20c Lipo. 300g total and 10cm long. Would be perfect. OR 2x 2200 mAh. 70g more weight but same length, total width 5cm.
Not too bad id think..
I d like to use 1 4000mAh pack but these are around 15cm long...not good.

I shouldn't say the Multistar lipos are bad, but there is a lot of internal resistance. If you run your Mavic battery all the way to zero like Unknown Caller does, you can get most of the energy out of them, but that's pretty hard to do. Unknown Caller just went nearly 46,000ft with a single Multistar 5200mah lipo, but he runs his batteries WAY down.

 

[digdat0]

I always had great results with both the lihv and lipo multi star batteries, but most of mine were 4s not 3s like for the mavic. I used to run a pair of 4000mah lipos on my p3 and got great numbers, they would burn down at the same rate without any issues. I'm optimistic still about them for the mavic, cause the multi star 4000 3s lipo has the best mah to grams weight ratio of all 3s batteries I could find.

 

[CyberNate]

I always had great results with both the lihv and lipo multi star batteries, but most of mine were 4s not 3s like for the mavic. I used to run a pair of 4000mah lipos on my p3 and got great numbers, they would burn down at the same rate without any issues. I'm optimistic still about them for the mavic, cause the multi star 4000 3s lipo has the best mah to grams weight ratio of all 3s batteries I could find.

If you live nearby, you can have mine for free. I have 5 multistar lipos and they all perform terribly for me as compared to the LiHV. Perhaps if I had directly wired power leads like you they would work better. I see such a drastic difference in voltage sag between the lipo and lihv. Even charging there is a drastic difference. When you approach the final voltage of 12.6V, it takes forever for them to finish with the current tapering down slowly. This is due to the high internal resistance. With the LiHV, you get the the final voltage of 13.05, you see a sharp decline in current at the end.

 

[MacIak]

Still i do not like the 10c of the multistar. Rather go for 25c turnigy 2200mAh. 2 of them should fit like a glove with @cruzroy his mount. I will use additional velcro to secure the mount and hook n loop the batteries. Gonna try this after the weekend as soon as i modded a battery.

 

[CyberNate]

Still i do not like the 10c of the multistar. Rather go for 25c turnigy 2200mAh. 2 of them should fit like a glove with @cruzroy his mount. I will use additional velcro to secure the mount and hook n loop the batteries. Gonna try this after the weekend as soon as i modded a battery.

The LiHV may say 10C, but it is not. There is very little resistance in that battery. Now the LIPO, yeah, it's not good.

 

[CyberNate]

So I did a flight with my dual Multistar 3000mah lihv batteries today. Very good performance from these. I flew nearly 84,000ft to 11% battery in a decent cross wind. I had a flight time over 33 minutes and a projected flight time of around 36-37 minutes. There's a good balance of performance to flight time with the 3000 lihv. The 4000s are a little too heavy if there's any wind to deal with.

One mistake I made today, I routed the battery wires OVER the front arms. It looked like there was enough clearance, but apparently there is enough flex in the props that I managed to take off the insulation on one of the wires. That's was a little too close for comfort. Don't route wires OVER front arms if running batteries on the sides. Need to go under.

 

[digdat0]

If you live nearby, you can have mine for free. I have 5 multistar lipos and they all perform terribly for me as compared to the LiHV. Perhaps if I had directly wired power leads like you they would work better. I see such a drastic difference in voltage sag between the lipo and lihv. Even charging there is a drastic difference. When you approach the final voltage of 12.6V, it takes forever for them to finish with the current tapering down slowly. This is due to the high internal resistance. With the LiHV, you get the the final voltage of 13.05, you see a sharp decline in current at the end.

i'm in oregon, if your serious i'll cover shipping up here. Why not right?

 

[digdat0]

So I did a flight with my dual Multistar 3000mah lihv batteries today. Very good performance from these. I flew nearly 84,000ft to 11% battery in a decent cross wind. I had a flight time over 33 minutes and a projected flight time of around 36-37 minutes. There's a good balance of performance to flight time with the 3000 lihv. The 4000s are a little too heavy if there's any wind to deal with.

One mistake I made today, I routed the battery wires OVER the front arms. It looked like there was enough clearance, but apparently there is enough flex in the props that I managed to take off the insulation on one of the wires. That's was a little too close for comfort. Don't route wires OVER front arms if running batteries on the sides. Need to go under.

thats terrific time, i was thinking 45k would be a good target for 2x3.0 lihv on a windless day. I need to fly some more and get used to sport mode and how it drains battery. When you use it, you use the tach and don't go full throttle do ya???

 

[CyberNate]

thats terrific time, i was thinking 45k would be a good target for 2x3.0 lihv on a windless day. I need to fly some more and get used to sport mode and how it drains battery. When you use it, you use the tach and don't go full throttle do ya???

I use sport mode with tail wind. I use full throttle unless tachometer is above 80. I throttle down to just under 80% as needed. Usually full throttle if tail wind is over 6mph and tachometer is around 60 to 70%. I followed same rule into wind in the way it, watching tachometer, even in p mode. Keep under 80%. Usually p mode is under 80 unless strong headwind. You save a lot of battery and put less strain on escs and motors.

 

[MacIak]

Someone else made a thread posting a link to this: Not my picture but it clearly shows the PCB on top. Gives a good indication where to drill relatively safe if you want to hardwire on the battery. It would be really cool though if these solder joints could be pinpointed on top and drill 2 holes there...solder> fill up with sugru> done!

]

 

[Natedoggz]

Someone else made a thread posting a link to this: Not my picture but it clearly shows the PCB on top. Gives a good indication where to drill relatively safe if you want to hardwire on the battery. It would be really cool though if these solder joints could be pinpointed on top and drill 2 holes there...solder> fill up with sugru> done!

]

I think I can eyeball it!

 

[MacIak]

I think I can eyeball it!

Haha! I had to bury many things cause I thought I could eyeball. Still have a couple of days before my stuff arrives...hopefully "someone;0" will get the measurements before I make the battery meet my dremel.

 

[cruzroy]

I think I can eyeball it!

retract