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

[Gary Seven]

@Bartman, This is OT to the thread, but how were you able to post such a large photo? I just now posted a photo in another thread which was over 1.5MB in size, but once uploaded the forum software says it's 49KB! Of course, this makes for a small photo, even when you clic on the thumbnail!!

 

[Bartman]

not sure, it might be an admin permission. i can look into it when i have time.

 

[Gary Seven]

sorry guys but it's impossible to say if the batteries are at fault without having internal resistance numbers.
<<snip>>
Gary, are you using the battery monitors from HobbyKing with the digital readout or just the alarms? the digital readouts will tell you the voltage of each cell and yes, one bad cell will cause those monitors to chirp.

Yes. I'm using that little gadget called, "LiPo Battery Voltage Tester Low Voltage Buzzer Alarm." And yes, you're right. When I bring my quad down and hover it right in front of me I can see the readout. If I throttle up slightly, I can see two cells drop from say 3.65 to 3.59 (or 3.6 even), while the remaining other cell drops to below 3.4V.

Yeah, it appears I'm dealing with a bad cell in at least one (of the two) Multistars. Thanks for the hint.

 

[PeteDee]

Shawn,

The best you can do when trying to save money on a charger, IMHO, is to save by using the computer server power supplies (available on eBay) while still buying a high quality brand name charger. Here's a pic of my set-up using two Dell power supplies in series to get 24 volts but with an iCharger 206B. Probably not what you wanted to hear but a low quality charger can destroy your expensive batteries and maybe cause a LiPo fire. I've heard of other HobbyKing chargers lasting only a few charge cycles. The iCharger 306B is about $160 and with the two power supplies it's around $180 depending on what you pay for the power supplies.
Probably not the reply you were looking for, sorry!
View attachment 22063

Yes it would have been nice to see the difference in the IR from when they were new to what they are now. My main charger is a PL6 with 60A E-Fuel supply, great for testing.

I decided not to buy any of these packs, decided the risk was too great.

 

[Bashedcrab]

I have a couple of them on my dji F650, they are 4s 5200mah, they weigh the same as my old 3s 5500mah packs which is around 433 grams each. I have only put a few full flights on them but so far they have met my expectations. On my f650 with 12x5.5 props and 3508 700kv motors with an AUW of 2600 grams I am getting a good 20-23 minutes mixed flight out of 2 batteries in parallel. When I charge them I put in around 8200-8500 mah, they do not charge as fast as regular lipos at around 100 minutes for a single battery around 80% depleted. I intend on keeping charging and flight records for these batteries to see if they stand the test of time.

 

[PeteDee]

Interesting that you say they take longer to charge, I would have thought that if you are charging at 1C then it would take the same but might be that these packs take more work to balance?

 

[Mactadpole]

I just wanted to report back that I now have 11 flights on the (2x) Multistar 4S 8000mah 10C packs I mentioned earlier in the thread. Still getting great flight times and they seem to be taking acceptable mah numbers back in. No puffing at all. Been out of country so haven't put a lot more on them beyond a few flights but just wanted to let you guys know.

I have decided to go with the Multistart 6s 8000mah 10C packs for my upcoming build. I'll post back on those too.

BTW - Just ordered an iCharger106B+ with a parts order.

 

[Mactadpole]

Wanted to come back to this topic and say that the Multistar 4S 8A are now being used on my quad and they are still flying great. But they are under very little stress with this setup.

I did however just do a flight with dual Multistar 6S 8A 10C on my new large hexacopter and they hardly changed temp at 70 F air temp. I measured the IR before flying them and one was at 23 and the other 28.

 

[Motopreserve]

That IR seems high. No?

 

[Mactadpole]

That IR seems high. No?

That is the sum of all six cells. Highest individual cell on any battery was 6. I'm not real familiar with what is good and bad. I just know it was requested here.

I should mention I am having an issue with a new iCharger106B+ charger that is in another post. It won't charge for more ~3 minutes.

 

[Motopreserve]

Ah. That makes more sense.

My batteries are typically very low - closer to 3. But they go up as they age.

 

[tstrike]

I just got some of the 4s 6600's and I've got to say, WOW! I've been using the zippy blues in the 4k variety and was getting a solid 6 minutes with one on my quad that weighs in at 2400g's . With these new Multistars I'm getting 13 minutes before my voltage alarm starts screaming and it's set at 3.6 so I still had more in the tank if I needed it.
I've never flown for so long before, it got kind of boring because I wasn't expecting that much of an increase. I thought it'd be great if I got like 9 minutes so I never really went out to far.
I did originally order 2 3s 5200's thinking I go to a bigger prop but one of them had dodgy cells and got sent back. HK just yesterday sent my replacement but I think I'll end up using them for a monitor set up instead, they're so skinny!

 

[Gary Seven]

Wanted to come back to this topic and say that the Multistar 4S 8A are now being used on my quad and they are still flying great. But they are under very little stress with this setup.

I did however just do a flight with dual Multistar 6S 8A 10C on my new large hexacopter and they hardly changed temp at 70 F air temp. I measured the IR before flying them and one was at 23 and the other 28.

Both my Multistar's have failed with at least one cell in each gone bad. Yesterday, I finally received the iCharger 406duo I've been waiting for for over two months, and once I get the thing figured out I will do IR measurements to see what's up.

I should note that I believe the battery failures were of my own doing. I received them just as I had finished my first MR build, and in my excitement to fly I ran them down way too low on more than one occasion. To add insult to injury, I made the mistake of keeping them fully charged on my shelf for weeks at a time before I got around to discharging them (flying) again. I have since changed my battery management practices completely.

 

[Mactadpole]

Update on my HK Multistar 6s 8000mah batteries. Still super impressed! I'll give the full story here.

I have 4 of these batts that I fly in parallel with the same two batts always paired together. They fly my newly built ~800mm hexacopter on Pixhawk. One set now has 4 flights and the other had three. I still haven't taken the time to research the significance of internal resistance, but my IR readings have been improving since the initial charge, discharge, charge sequence I did on them before flying.
Initial IRs:
A1: 4,2,4,4,5,4
A2: 4,4,6,5,4,6
B1: 6,6,6,7,6,8
B2:4,3,6,5,7,6

A's after first 4 flights-
A1: 4,2,4,3,5,3
A2: 4,2,3,4,2,4

B's after 3 flights-
B1: 3,2,3,4,5,4
B2: 4,3,4,3,4,4

No puffing. And only a little bit warm after ~23 minutes per flight. I have seen my flight times improve too. Pretty darn happy with these batteries so far!

 

[Mactadpole]

Just wanted to give another update on the HK Multistar 6S 8000mah batts I have detailed in this thread.

I now have 25 flights on one set and 27 on the other. I fly them down to 21.5-21.7 volts typically (about 3.6V per cell). I get between 25-28 minutes of flight time and draw 32-35amps in hover. The IR readings on both are now very low with 1-2 per cell being most common with a couple at 0 and 3. Still no puffing and they just got better with age.

 

[Motopreserve]

Those are great specs! Thanks for the update.

 

[crayfellow]

@Mactadpole what charger and PS are you using with these?

What do you think of using 2x 10Ah Multistar as opposed to the 8Ah? Only slightly more weight (1189g vs. 956g for the 8Ah). I was playing with the numbers since I could compare one-for-one with the $250 Tattu 10Ah.

 

[Mactadpole]

@Mactadpole what charger and PS are you using with these?

What do you think of using 2x 10Ah Multistar as opposed to the 8Ah? Only slightly more weight (1189g vs. 956g for the 8Ah). I was playing with the numbers since I could compare one-for-one with the $250 Tattu 10Ah.

I use an old dell tower power supply and two iCharger 106B+ chargers. I just got the iChargers a few months ago and love them. I did see your other post about what you picked out. If you are only ever going to charge 6S batteries it seems like overkill. But I'm also cheap.

I have to be honest, I'm getting a bit worried about your AUW with everything I see you putting on that copter. It may be totally fine as long as your willing to sacrifice the flight time. If it were me I think I would order a single set of Multistar 8Ah batteries and see how it flies on those. They're a cheap investment for initial testing and you can always continue to use them. I can't tell how much difference a few 100 grams can make on fight times once your at the high-end of your AUW.

 

[crayfellow]

I have to be honest, I'm getting a bit worried about your AUW with everything I see you putting on that copter.

How so? It seems like it's right in the "mid-lift", between lightweight gimbal+GoPro and big heavy lift DSLR/RED type octo. Equipment wise it seems pretty typical to me. Do you mean the addition of an FPV flight camera? Eliminating a dedicated 4S batt for the gimbal seems to balance a bit too.

Aren't there plenty of 8-1000mm carrying GH4/A7S size cameras? Or are you saying there are, and they're all only realistically flying 10min missions?

 

[crayfellow]

I use an old dell tower power supply and two iCharger 106B+ chargers. I just got the iChargers a few months ago and love them. I did see your other post about what you picked out. If you are only ever going to charge 6S batteries it seems like overkill. But I'm also cheap.

Trust me, I'm cheap too. I drive a wholly owned VW Golf diesel with 130k+ on the odometer (except for when hauling the whole family). But I also own a Fluke meter I'm always looking for the balance between cost, minimal maintenance, maximum reliability and flexibility, and reasonable travel characteristics.

The "old server PS" thing is right up my alley as a 1980's PC hacker, just not sure it's the best for this particular project when research trips will also be with our family of 6. But maybe I'm wrong, and it would be ideal for travel in the right case.

Dumb question, why dual low-power chargers like 106B vs. one high-power charger like a 306B or PL6 with a ParaBoard to charge 4 at once?