PatR
Premium Pilot
The answer to that is easy; provide minimum acceptable performance at the lowest possible production cost, enabling maximum profitability at reasonably inflated price levels.
**** Battery build **** What do you think?
- Thread starter cabinfourus
- Start date
And - now we know why DJI used Lion 18650's in their new Mavic Mini.
I just did a side-by-side stack of 8 18650's & a retired H LiPo.
This could be made up as a 4S2P pack.
Hmmm...
I just did a side-by-side stack of 8 18650's & a retired H LiPo.
This could be made up as a 4S2P pack.
Hmmm...
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PatR
Premium Pilot
The 18650 double stack is actually longer than the H battery. The H battery has a PC control board in front of the battery and the tapered portion of the case contains the plug assembly. When that double stack is fully assembled it would be longer than the H battery.
The battery in the picture was in a crash and I retired it.
When I repaired it, I discovered It had no control board at all, only the power & balance wires in the nose.
Maybe that's what you get with an off brand battery?.
I'm curious about what your 20 amp test rig looks like.
My 150 watt discharger only draws a little over 9 amps from a 4s LiPo..
By the way that other drone company is using 18650's in their light weight "mini" quad for >25 minute flights.
PatR
Premium Pilot
If the need to possess a case structure that locked into the airframe was eliminated I think experimenting with use of 18650 cells for the battery pack would be a good idea. The true limiting factors for an "H" battery are voltage, weight, and having the dimensions necessary to fit within the airframes battery well.
I have been very busy for the past few days. As soon as I can get this done I will post the results.
PatR
Premium Pilot
Although time consuming and a little expensive to make, a multi bulb light strip is a great way to create a variable load test fixture. A lot of 12v light fixtures in a series allows adding or subtracting bulbs as needed to obtain a desired load value. the concept has been used to create a fixture to switch back and forth between 20A and 100A loads in duration/performance testing.
HI Sure shot,
I built a similar pack that actually just fitted into a 3d printed battery shell and had it working.
It lifted off and hovered for about 2 minutes then went I to low battery mode. Landed it and watched the voltage recover and started the props again and that was it. The 18650 cells are Panasonic
18650B 3400 mah, the biggest mah capacity of any 18650 cells produced. If you buy off eBay or else where and they claim a higher mah rating it is not true, before spending money on cells do some research into the manufacturers of the cells you wish to buy. Unless they are made IN JAPAN be very cautious of the advertised ratings. I am looking at some new ones to come to market that have a 20 amp draw capacity. Also the controller has to be changed to handle the lower voltage that you can drain them down to. I am also in contact with a university and solid state batteries. It is a very interesting project and I am keeping my involvement with new research. I have been using a LiPo hv 7400 mah NXE Power battery with very good test results so far, Another 3 months of tests and flying in my business and the conversion will be shown on here.
Unless we keep trying something new and different we will be held captive to OME replacements and high priced ones at that. Johnno Hennessy. Keep flying on the green side of the grass.
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I owe a big thank you for the 18650 test.
I was about to order those same 18650B 3400mAh cells and would have gotten the same disappointing results.
It seems the definition of high drain overlooks voltage sag.
Thanks again,
-Bill
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OK, I got the cells in the mail today. The cells I ordered are INR26650. I am posting a picture of the spec sheet that came with the cells. Now, these are only 20 amp cells, so I am going to order the 30 amp cells next. I tried them in a 3d printed battery case I have printed and the pictures are also here. I am waiting on my tabs so I can connect these cells together and test them. I plan to load them up and discharge them hard. I will post the results. If you look at the drone picture, you can see that the extra length can be removed since the cells only take up 70 percent of the space. Let me know what you guys think about
this. I can get 30 amp in the same cell.
this. I can get 30 amp in the same cell.Me also. I was looking at the 18650 cells next. Glad someone ran this test for us.
That's OK Sureshot (Bill)or (Wild Bill),
I am using the batteries in some torches for my worksites. It seems like what PatR said along time ago that the 'c' rating that Yuneec gives you at 8 'C' does not stack up. I am also looking at capacitors in blocks to see if they also work. The small mod that I did with the wiring in the H is working out very well and using batteries that are 1/2 the price.
If we don't try we won't be able to change. Johnno Hennessy.
PatR
Premium Pilot
You should leave the stock main connectors in the shell if you intend to mate the shell with the airframe power plug. Just cut away the 24awg balance wires as they link to nothing in the aircraft. If you aren’t going to make use of the shell connectors there’s not much point in using the shell.
Leaving the stock connectors in the shell provides you with a board to solder the power leads to. Alternate; you could leave the balance wires in place but you would have to figure out how to make use of them when charging/discharging non OEM battery cells.
Leaving the stock connectors in the shell provides you with a board to solder the power leads to. Alternate; you could leave the balance wires in place but you would have to figure out how to make use of them when charging/discharging non OEM battery cells.
Yuneecs C rating is 8c for sure. This would mean the stock battery would handle 40 amps at 5400mAh. The numbers Yuneec gives us are correct but the correct C rating has to be for the motors under a load and this would jump it up to around 18c. I am not sure of the 18650 cells you used. Were they high drain?
UPDATE
I have ordered the 45 amp 5000mAh high drain 26650 cells for my build. These cells are designed to handle the current and power required by the Typhoon H. They fit inside the case nicely. I will update everyone once I get the new cells in and am able to test them. I like the 26650 cell over the 18650 due to size and safety. If you decided to try this, make sure to buy protected cells.
I have ordered the 45 amp 5000mAh high drain 26650 cells for my build. These cells are designed to handle the current and power required by the Typhoon H. They fit inside the case nicely. I will update everyone once I get the new cells in and am able to test them. I like the 26650 cell over the 18650 due to size and safety. If you decided to try this, make sure to buy protected cells.
The cells arrived today!!! I will be building the battery pack today and testing it this week. I will post the results.
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