Mavic2 Battery Mods

[lolo780]

I attempted a flight the other day with HS8000 but it was too cold(27°f). Flight started out good at 90% I was over 18000 feet out. Once I got out about 45K I could tell the cold was getting to the batteries and my power level was dropping faster than I like, so I turned around at 48K and managed to get back with 31%.

I can’t wait for so spring to get here.

You should have good air density in that temp. How hot did the batteries start at? One trick I used on the M1P is using the hot exhaust to heat the external batteries.

With the M2s rear/side exhaust outlets it's a bit more work but you should be able to make that heat work for you. Extra battery insulation is also worthwhile, and preheating as hot as 60c goes a long way. Make sure to give plenty of time to heat all the way through the pack. Insulating the top and sides of the stock battery makes a measurable difference as well.

I make a single pack, wrap in a thin air tight layer and then insulate with closed call foam. Make sure there are zero air passages through wires or anywhere for heat to escape. Extra packing on the front side doubles as an aero device as well.

 

[beanbubba]

You should have good air density in that temp. How hot did the batteries start at? One trick I used on the M1P is using the hot exhaust to heat the external batteries.

With the M2s rear/side exhaust outlets it's a bit more work but you should be able to make that heat work for you. Extra battery insulation is also worthwhile, and preheating as hot as 60c goes a long way. Make sure to give plenty of time to heat all the way through the pack. Insulating the top and sides of the stock battery makes a measurable difference as well.

I make a single pack, wrap in a thin air tight layer and then insulate with closed call foam. Make sure there are zero air passages through wires or anywhere for heat to escape. Extra packing on the front side doubles as an aero device as well.

I ignored Lolo in the beginning and figured he also wore tin foil hats in his basement bunker.

I finally did everything he listed above and it makes a HUGE difference (finally listened after a known/repetitive flight came up way short and didn't make it home on a cold night).

Here is the foam and 2 sizes of filament tape that is highly recommended from Lolo too:

https://www.amazon.com/gp/product/B06XSBWDHF
https://www.amazon.com/gp/product/B01LZ5JQ51
https://www.amazon.com/gp/product/B01FYJKGS2

Using the wider tape, you can optionally securely encase the whole thing without the need for another wrap layer and this makes it air tight. There are many good methods, this is just one I settled in with.

PS - I personally still see benefits even with warmer temps up into the 50F's by insulating/heating all the batteries.

 

[SkyNinja]

I've been lucky had a mild winter so far . The HS is a beast I had to have 2

The winter here has sucked it been raining, snowing and very windy.

I also have a couple of the HS batteries they’ve been very good. But you know I am kind of battery junkie alway testing new ones trying to find something better.[emoji846]

 

[SkyNinja]

You should have good air density in that temp. How hot did the batteries start at? One trick I used on the M1P is using the hot exhaust to heat the external batteries.

With the M2s rear/side exhaust outlets it's a bit more work but you should be able to make that heat work for you. Extra battery insulation is also worthwhile, and preheating as hot as 60c goes a long way. Make sure to give plenty of time to heat all the way through the pack. Insulating the top and sides of the stock battery makes a measurable difference as well.

I make a single pack, wrap in a thin air tight layer and then insulate with closed call foam. Make sure there are zero air passages through wires or anywhere for heat to escape. Extra packing on the front side doubles as an aero device as well.

I ignored Lolo in the beginning and figured he also wore tin foil hats in his basement bunker.

I finally did everything he listed above and it makes a HUGE difference (finally listened after a known/repetitive flight came up way short and didn't make it home on a cold night).

Here is the foam and 2 sizes of filament tape that is highly recommended from Lolo too:

https://www.amazon.com/gp/product/B06XSBWDHF
https://www.amazon.com/gp/product/B01LZ5JQ51
https://www.amazon.com/gp/product/B01FYJKGS2

Using the wider tape, you can optionally securely encase the whole thing without the need for another wrap layer and this makes it air tight. There are many good methods, this is just one I settled in with.

PS - I personally still see benefits even with warmer temps up into the 50F's by insulating/heating all the batteries.

View attachment 59812

I was being lazy, it was kind of a rush flight I saw that the weather was not raining or snowing with calm winds. I heated up the batteries before I left the house for about 30 minutes I think they outer temperature was around 90°F. place the batteries on my seat warmers with the heating pad over top of them. Didn’t have any insulation on the stock battery. I tried some different than I normally do with the Xternal battery. I put insulation directly against the cells and then try to shrink wrap over top of it. I messed up and heated the shrink wrap too hot and it melted a lot of the insulation during the process.

Needless to say when you do a half assed job end up getting half *** results during your flight.[emoji20]

 

[dirtybum]

I didn't realize xt-30's were so darn tiny!
Whats the biggest wire size you guys have managed to attach to your xt-30's? Looks like 14 is almost max

 

[lolo780]

I didn't realize xt-30's were so darn tiny!
Whats the biggest wire size you guys have managed to attach to your xt-30's? Looks like 14 is almost max

14 is doable, but for the short wire runs we use plus low current draw for long range flying, 16 is plenty. Press the wires against the terminal and then solder.

 

[dirtybum]

14 is doable, but for the short wire runs we use plus low current draw for long range flying, 16 is plenty. Press the wires against the terminal and then solder.

Thank you sir. I have no problems w/ the soldering. So some of you are going as low as 16 for the a/c mod? Should be fine

 

[dirtybum]

I don't know if I've mentioned this, but I'm sure you guys already know, in which case sorry to beat a dead horse, but I use dielectric grease on my XT 60 connections. It makes them a breeze to slide on and off. And I think I'm really going to need it with these tiny XT 30s and my big blue-collar fingers[emoji41]

 

[beanbubba]

I don't know if I've mentioned this, but I'm sure you guys already know, in which case sorry to beat a dead horse, but I use dielectric grease on my XT 60 connections. It makes them a breeze to slide on and off. And I think I'm really going to need it with these tiny XT 30s and my big blue-collar fingers[emoji41]

It's worth repeating, I haven't heard it mentioned in a long while.

And at the big US auto parts stores they sell it behind the counter in tiny packets for under a dollar, but they call it "spark plug grease".

Dirtybum, I converted over to XT30's last year for everything and the smaller the plug gets, the less grease I found is needed.

 

[beanbubba]

Just finished the final jettison system on the 3D printer and made improvements from the prototype. Haven't flown yet, but completed all the bench testing. This unit replaces the entire bottom plate and the net AUW difference is +80 grams. I also got rid of the separate battery to run the servo and stepped down the voltage to run the 5V electronics. I also added a master power switch on the rear end of the unit since there is no factory battery to turn on the bird. I don't know about you, but fiddling hooking up 3 power cord in freezing cold and then your body hovering over the bird causes magnetic interference and a calibration needed. This is all solved by prepping the bird and the 3 batteries in a warm shop, wrapping in a electric blanket, then deploying in 30 seconds with the flip of a switch and no compass calibration needed!!!

 

[lolo780]

Very impressive work! I like the idea of replacing the whole lower plate. Any plans for a longer drop in rear arm?

One thought about the master switch is to make it vibration and crash proof. An insertable jumper, or a plastic pin that separates spring loaded contacts for a positive ON position no matter what happens in the air.

 

[beanbubba]

Very impressive work! I like the idea of replacing the whole lower plate. Any plans for a longer drop in rear arm?

One thought about the master switch is to make it vibration and crash proof. An insertable jumper, or a plastic pin that separates spring loaded contacts for a positive ON position no matter what happens in the air.

I don't follow, longer drop arm??

Good idea on the power switch, I didn't even consider that. But I did purposely decided on a heavy duty switch that weighs 5 grams that is very stiff/sturdy.

I also made the executive decision to use 18 gauge wire across the board on everything including the battery leads. It saves a ton of weight and we will see if it affects performance soon after I can test.

 

[beanbubba]

While I was building the jettison bird I accidentally reversed the +/- and fried something, so I ordered another quality used bird from @Thunderdrones. Kudos to these guys, they are very flexible and let me buy a base bird without a camera/props/battery/RC. I highly recommend them for any repair work or cost effective replacement parts.

Anyway, while I had the replacement bird opened up for surgery, I removed the 6 cooling vent screens (hopefully to improve airflow) and placed some micro heat sinks and thermal paster over the 12 rear motor mosfet chips. There is almost no space between the boards and this was the only location I found that had clearance. Its not perfectly/exactly on the chips, but covers most of the area that gets real hot. From all of my super heavy weight testing, only the rear motors get over heated.

You also have to remove half the plastic cover over the main system board heat sink for this mod to work. The cover directs ~75% of the fan output to the main system board and ~25% to the ESC board. By removing this cover, all fan output is evenly distributed between the two boards and hopefully helps in the overall desired results for the mod which is to get more cooling to the rear ESC mosfet's.

 

[beanbubba]

Forgot to mention, the lower M2 plate has an embedded board that you have to extricate along with 2 cameras. The cameras are too thick for the jettison mod to work (and the bird won't take off with them removed). But you can unscrew the lens and it becomes very thin and you can tape it all down and nicely out of the way.

For those new to this forum, all these mods put you squarely in the Unlimited class

 

[beanbubba]

I just picked up this 4 battery charger and verified it supports 4.4v LiHv charge level if you need that.

ProTek RC "Prodigy 610 QUAD AC" LiHV/LiPo AC/DC Battery Charger [PTK-8517] | Cars & Trucks

View attachment 59321

FYI - this unit out of the box fixed my badly out of balance batteries. The single port version of this unit mentioned earlier had very narrow tolerances and would error out if cells were too far apart. I also like this unit because it comes with a car battery cable/clips and natively steps up/down an input voltage of 6-20 volts.

Warning, this 4 port unit has a big/loud fan. Do not purchase if that is a show stopper for you.

NOTE: the factory setting for LiHv is 4.3v. You have to go into the user settings and increase to 4.4v (max allowed).

 

[chazz]

FYI - this unit out of the box fixed my badly out of balance batteries. The single port version of this unit mentioned earlier had very narrow tolerances and would error out if cells were too far apart. I also like this unit because it comes with a car battery cable/clips and natively steps up/down an input voltage of 6-20 volts.

Warning, this 4 port unit has a big/loud fan. Do not purchase if that is a show stopper for you.

NOTE: the factory setting for LiHv is 4.3v. You have to go into the user settings and increase to 4.4v (max allowed).

I flipped a coin for this one and the 625, i ended with the 625 which never let me down.

 

[chazz]

Just finished the final jettison system on the 3D printer and made improvements from the prototype. Haven't flown yet, but completed all the bench testing. This unit replaces the entire bottom plate and the net AUW difference is +80 grams. I also got rid of the separate battery to run the servo and stepped down the voltage to run the 5V electronics. I also added a master power switch on the rear end of the unit since there is no factory battery to turn on the bird. I don't know about you, but fiddling hooking up 3 power cord in freezing cold and then your body hovering over the bird causes magnetic interference and a calibration needed. This is all solved by prepping the bird and the 3 batteries in a warm shop, wrapping in a electric blanket, then deploying in 30 seconds with the flip of a switch and no compass calibration needed!!!

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This is awesome dude! I cant wait to see the results.

I haven't touched the printer in a long time. I would have to relearn how to use it all over again....Its good to see your getting use of yours.

 

[beanbubba]

This is awesome dude! I cant wait to see the results.

I haven't touched the printer in a long time. I would have to relearn how to use it all over again....Its good to see your getting use of yours.

I can't lie, I haven't used the 3D printer since the chazzmavic and it took me several hours to get it tuned and running again. But I do have to admit once I got over the hump, it was like riding a bike and it all came back naturally.

 

[lolo780]

I don't follow, longer drop arm??

Good idea on the power switch, I didn't even consider that. But I did purposely decided on a heavy duty switch that weighs 5 grams that is very stiff/sturdy.

I also made the executive decision to use 18 gauge wire across the board on everything including the battery leads. It saves a ton of weight and we will see if it affects performance soon after I can test.

Longer rear motor arms to improve efficiency and be able to fit 9" props.

 

[SkyNinja]

Just finished the final jettison system on the 3D printer and made improvements from the prototype. Haven't flown yet, but completed all the bench testing. This unit replaces the entire bottom plate and the net AUW difference is +80 grams. I also got rid of the separate battery to run the servo and stepped down the voltage to run the 5V electronics. I also added a master power switch on the rear end of the unit since there is no factory battery to turn on the bird. I don't know about you, but fiddling hooking up 3 power cord in freezing cold and then your body hovering over the bird causes magnetic interference and a calibration needed. This is all solved by prepping the bird and the 3 batteries in a warm shop, wrapping in a electric blanket, then deploying in 30 seconds with the flip of a switch and no compass calibration needed!!!

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Your skills never cease to amaze me[emoji106]