HK Multistar high capacity, 10C batteries made for MR: Opinions from the experienced?

[Gary Seven]

Hello everyone.

I follow HK on their YouTube channel and see that they are introducing a LiPo "especially designed" for MR use. In a nutshell, they have lowered the C-rating to 10 (ie, 10C) to increase the mAh capacity for the same physical size. I'm posting a link to their video giving a rather pedestrian "technical" presentation, but would really appreciate the opinions from some of the more experienced folks here at MultiRotor.

link: http://youtu.be/ouH6Y4PmjVA

Thanks!

 

[Motopreserve]

Lower C ratings are definitely appealing for the weight savings.

Not sure there will be too many experiences with these yet - they were just recently introduced. You need to do the math for your MR to determine whether 10C would be enough. You can figure that out by finding the hover amps and max amp draw your motors would need. Then you divide that by the battery Amp hour. Many (but sadly not all) motor product pages have a spreadsheet with various data where you can find this info.

For example:

My SunnySky 3508-580kv motors draw 2.5A at hover using a 12x3.8 prop. I have them on a hex. So 2.5A x 6 = 15A draw at hover. I use a single 5000mah (or 5A) battery.

15A/5 = 3C discharge rate required for hover.

For my motor 100% throttle max/burst: 14.1A x 6 = 84.6A
84.6A/5 = 16.92C required at max throttle (or burst).

These calculations are also done using ideal conditions - and presuppose that the provided data is correct. I have read often that C ratings are often inaccurate, and without personal testing we can't know if the motor manufacturers are providing accurate data either - so adding a buffer of 20% may be safest.

Im im more comfortable with a little headroom. I've just recently ordered my first 20C batteries. That should save me some weight compared to the 35C I have.used in the past - but still provide me with peace of mind.

If you end up trying these new batteries, please let us know how it goes.

Good luck and fly safe.

 

[kloner]

the higher density is the trend in multi rotors. they don't usually have huge amp swings so it's easier to do this with them. it'll give longer flight times, same thing Tattu from gens ace just did....

 

[Motopreserve]

the higher density is the trend in multi rotors. they don't usually have huge amp swings so it's easier to do this with them. it'll give longer flight times, same thing Tattu from gens ace just did....

MIT definitely makes sense. It seems to me maybe the current Lipo C ratings are holdovers from the airplanes??? I would assume a single motor/ESC setup would need a heck of a lot of juice to do the 3D style flying.

The Tattu batteries seem like a good deal for the capacity. Have you tried them yet?

 

[kloner]

no but this is the technology ferdinand plays with a lot, it's what has our arm kits doing 45+ minutes on discos

 

[Motopreserve]

no but this is the technology ferdinand plays with a lot, it's what has our arm kits doing 45+ minutes on discos

I watched the video from the range video guys doing 1+ hour with their super low-C battery. Not sure it is applicable for many applications - but it was cool to see people messing around with the specs and technology. That's the only way we will get the next gen power systems.

EDIT: it was actually only 45 minutes. They're working on it

VIDEO:

 

[Gary Seven]

Thanks for the quick lesson. [MENTION=11354]Motopreserve[/MENTION]; If I buy one of these to try I will indeed post back.

 

[PeteDee]

I like the idea of more power in a smaller size but very concerned that the packs will not last so long, my 450 sized quads draw around 18-19 amps in the hover so at almost double the continuous rating. I would also expect that these packs will taper more slowly and simply deliver very little near the end of the discharge cycle, a higher C pack will hold the voltage better and so have more "oomph" left at the end and so make it home.

I would be more than happy that these packs do live up to the promise but I just have the nagging thought that Hobby King are cooking the numbers just a bit, perhaps in a really lightweight machine they will be good enough.

Pete

 

[kloner]

Trappy has a similar pack that's 15c, 6s 4000 mah that fits in the trunk of a disco if that's what it's for. kinda spendy but is what it is

 

[PeteDee]

Yes but a 6S setup will draw less anyway and I trust Trappy's 15C rating way more than the HK 10C rating.

HK have them in pack sizes suitable for "standard" setups, flyers will be buying them as direct replacements.

So for my Disco Pro setup on 4S, the TBS 4500 30C packs are 433 grams, exactly the same as the HK 5200 10C packs, so 700mah more capacity, allowing for the 20% rule that gives about 500mah more usable capacity in theory, I want that extra capacity and will buy one to test when they come back into stock but I still suspect that they will not have the punch when needed and will sag at the end more than higher C packs. The TBS packs just keep on giving, they cost lots but they can be depended on.

Pete

 

[Motopreserve]

It would be interesting to test the theory of less punch at the end of the pack. You would hope that with enough discharge headroom (which this would be less of for all but the motors with very little draw) the lower C rating wouldn't come into play at all - as long as you're not pushing full throttle hard at the end of the pack.

But having had higher C rated batteries need a little more throttle than I'm comfortable with to land at the end of packs, I'm afraid Pete is right - and the promise of light packs is still a ways off...

 

[Nola26]

I bought 2 of the 4S 5200 Multistar batteries. At first they were great. I was getting 8-10 mins of flight time on my F550 with gimbal/ gopro FPV setup on one battery. After my flights I was putting in 4000 MaH back into the batteries. Then on my 10th or so flight, I was about 3 mins into flying when it happened. I was about 50m high and about 50m out. I was hovering over a tree and the hex began to decend. I tried everything to gain altitude including putting it in FS. Nothing worked and the hex crashed into the tree. I was able to retrieve the bird and there was little damage. I noticed the battery was vey warm and puffy. I put my cell checker on the battery and it showed an error on cell 1. It showed 4.0v on the other cells. Charger would not read cell 1 and it would not charge. After contacting HK and requesting a warranty replacement, they made me submit 2 videos and 3 pictures before they finally determined it was a faulty battery and are sending me a new one.

Well now I am nervous about these batteries. I put my cell checker on my other battery and although cell 1 registered, it was several points off from the other cells. I ran a balance charge on the pack and it is now reading 4.1 volts and the other cells are reading 4.4 volts so that is better I guess. I will continue to fly with this battery but I will keep it low and slow until my confidence in these batteries is won back.

 

[Motopreserve]

Before you fly it again you may want to try discharging it on your charger, and balance charge it again. Make sure it's done supervised - and maybe outside or in ammo box if you can.

The fact that it won't recharge to the same level as the other cells is a concerning. Are you able to check the IR on your charger? If be curious to see what it reads.

 

[fltundra]

I bought 2 of the 4S 5200 Multistar batteries. At first they were great. I was getting 8-10 mins of flight time on my F550 with gimbal/ gopro FPV setup on one battery. After my flights I was putting in 4000 MaH back into the batteries. Then on my 10th or so flight, I was about 3 mins into flying when it happened. I was about 50m high and about 50m out. I was hovering over a tree and the hex began to decend. I tried everything to gain altitude including putting it in FS. Nothing worked and the hex crashed into the tree. I was able to retrieve the bird and there was little damage. I noticed the battery was vey warm and puffy. I put my cell checker on the battery and it showed an error on cell 1. It showed 4.0v on the other cells. Charger would not read cell 1 and it would not charge. After contacting HK and requesting a warranty replacement, they made me submit 2 videos and 3 pictures before they finally determined it was a faulty battery and are sending me a new one.

Well now I am nervous about these batteries. I put my cell checker on my other battery and although cell 1 registered, it was several points off from the other cells. I ran a balance charge on the pack and it is now reading 4.1 volts and the other cells are reading 4.4 volts so that is better I guess. I will continue to fly with this battery but I will keep it low and slow until my confidence in these batteries is won back.

What brand charger are you using? If it's charging them to 4.4 volts per cell, that's your problem. 4.2 absolute max.

 

[Motopreserve]

What brand charger are you using? If it's charging them to 4.4 volts per cell, that's your problem. 4.2 absolute max.

Good catch tundra! I was so focused on the fact that one was lower that I didn't even notice the others were at .... explosion

 

[Gary Seven]

I bought 2 of the 4S 5200 Multistar batteries. At first they were great. I was getting 8-10 mins of flight time on my F550 with gimbal/ gopro FPV setup on one battery. After my flights I was putting in 4000 MaH back into the batteries. Then on my 10th or so flight, I was about 3 mins into flying when it happened. I was about 50m high and about 50m out. I was hovering over a tree and the hex began to decend. I tried everything to gain altitude including putting it in FS. Nothing worked and the hex crashed into the tree. I was able to retrieve the bird and there was little damage. I noticed the battery was vey warm and puffy. I put my cell checker on the battery and it showed an error on cell 1. It showed 4.0v on the other cells. Charger would not read cell 1 and it would not charge. After contacting HK and requesting a warranty replacement, they made me submit 2 videos and 3 pictures before they finally determined it was a faulty battery and are sending me a new one.

Well now I am nervous about these batteries. I put my cell checker on my other battery and although cell 1 registered, it was several points off from the other cells. I ran a balance charge on the pack and it is now reading 4.1 volts and the other cells are reading 4.4 volts so that is better I guess. I will continue to fly with this battery but I will keep it low and slow until my confidence in these batteries is won back.

Holy s**t I have two of these batteries sitting here in my office (Multistar 3S, 4000 mAh) waiting to be used for the first time. Still doing my F450 build and haven't gotten to the power/flight test stage yet. Ok, NOW I'm nervous.

p.s. I did however also buy two Zippy Flightmax 3S, 4000 mAh batteries "just in case", but of course I have to cut and change the discharge connectors. :-(

 

[fltundra]

Holy s**t I have two of these batteries sitting here in my office (Multistar 3S, 4000 mAh) waiting to be used for the first time. Still doing my F450 build and haven't gotten to the power/flight test stage yet. Ok, NOW I'm nervous.

p.s. I did however also buy two Zippy Flightmax 3S, 4000 mAh batteries "just in case", but of course I have to cut and change the discharge connectors. :-(

Gary,
I wouldn't worry to much, these lipos are fine. User error mostly. Mine is holding good IR numbers.:tennis:

 

[Motopreserve]

Gary,
I wouldn't worry to much, these lipos are fine. User error mostly. Mine is holding good IR numbers.:tennis:

I think to assuage fears - you could always do a few cycles of charge//discharge and check the IR and cells to see how they're doing before putting them on a craft. I have a couple of these 6S 10000 mah I have been waiting to try on a new build. I may do a few cycles on the bench to see where I'm at. I'll report back.

 

[edgarmillennium]

I have 1 4s 8000 and Im getting about 15 minutes on my F550 with 10" props and video gear. My pack is pretty well balanced and the IR is about the same on all cells. So far no complain, I just ordered 3 more.

 

[Gary Seven]

[MENTION=13488]fltundra[/MENTION]; [MENTION=11354]Motopreserve[/MENTION]; [MENTION=16112]edgarmillennium[/MENTION]; thanks for the feedback. With my Multistar 4000mAh 3S 10C I am getting 15-20 min. flight time on my F450 (DJI E300 system and Naza M V2). Of course it's only the quad, no camera gear or landing gear or anything. mY concern is that the batteries seem to be very warm at the end of flight. Just posted a thread over at "General Discussions" about my concerns about how many mA I'm putting back into the batteries, even when I land with a voltage alarm set at 3.6V.