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Mar 11, 2019, 04:22 PM
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if the first time they send me genuine cells for me is ok.
with your configuration you probably drawn more than 24A (2A x 4P x 3C) since according to the specs EMAX 2213 on 3S and 1045 should draw 38.4A (9.6A x 4 motors at 100% throttle)
Last edited by miky94; Mar 11, 2019 at 04:29 PM.
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Mar 12, 2019, 10:58 AM
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what about buying cells with presoldered nichel strips and solder them toghether using a normal iron soldering?
Last edited by miky94; Mar 12, 2019 at 12:28 PM.
Mar 12, 2019, 08:25 PM
The QuadFather
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Quote:
Originally Posted by miky94
I'll do a try, if motors get hot I'll buy new ones 4S compatible.

I have a buzzer directly connected to the balance charge plug.

for charging I always use a iMAX B6 Mini, I meant only on holidays to charge by car.

with the 4S I'll be near 1250g , can I safely remove the hard case pack to earn a few grams? can I do something to improve efficiency?
Getting around your battery subject, can your engines swing a 1045 prop (room-wise) Your gonna be losing some efficiency on those 8" props, I run 2212 Sunnys on 4S and have for years now and never had one get hot, or experience failure with that combo. I run 4000 and 5000mah batteries.
Mar 13, 2019, 10:45 AM
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I abandoned that build, on 330mm frame I couldn't mount 10" props
now I'm looking for 6S2P 18650 pack
and easier than using cells with presoldered nichel strips , what about combining slots, solder XT60 plug, and then charge the cells separately using a normal charger? I'm not sure the slots can handle 30A or more
Last edited by miky94; Mar 13, 2019 at 11:23 AM.
Mar 20, 2019, 01:12 PM
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Quote:
Originally Posted by miky94
I abandoned that build, on 330mm frame I couldn't mount 10" props
now I'm looking for 6S2P 18650 pack
and easier than using cells with presoldered nichel strips , what about combining slots, solder XT60 plug, and then charge the cells separately using a normal charger? I'm not sure the slots can handle 30A or more
Those battery holders are crap. There fine for low power electronics, but steel contacts, 30AWG wire, and high contact resistance will simply not work for something demanding more than an couple amps or so. They also do not work at all with flat-top 18650s. They require protected button-top cells.
Mar 20, 2019, 01:14 PM
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Quote:
Originally Posted by miky94
what about buying cells with presoldered nichel strips and solder them toghether using a normal iron soldering?
That might be fine, although I have not tried that. Spot welders are expensive, so it is understandable not to get one just to build a single pack. Although they are essential tools if you build lots of custom packs.
Mar 20, 2019, 01:24 PM
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Quote:
Originally Posted by miky94
if the first time they send me genuine cells for me is ok.
with your configuration you probably drawn more than 24A (2A x 4P x 3C) since according to the specs EMAX 2213 on 3S and 1045 should draw 38.4A (9.6A x 4 motors at 100% throttle)
My point was you cannot trust most sellers. It's a lottery. If you assemble your pack and you have even a single mismatched cell, that could spell disaster for your quad. (falling like a brick and exploding cells, fumes, and class D fire.) It's critical to have identical cells, ideally from same batch and carefully binned. Untrustworthy sellers cannot be trusted to provide this ever.

That said, if you have a means to test their capacity at a high load (10A constant current discharge) and plot the discharge curve of each cell to verify they all have similar characteristics, then you should be fine. High current discharge is necessary because some "fake" cells will actually perform to close to their rated capacity under very light load. (genuine cells but lower tier; low-power high-energy chemistry). Others will perform well under load but be well but have lower rated capacity, usually because you actually get a re-wrapped lower-tier cell. Like Sony VTC4 instead of VTC6.
Mar 20, 2019, 03:21 PM
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Quote:
Originally Posted by Power Max
My point was you cannot trust most sellers. It's a lottery. If you assemble your pack and you have even a single mismatched cell, that could spell disaster for your quad. (falling like a brick and exploding cells, fumes, and class D fire.) It's critical to have identical cells, ideally from same batch and carefully binned. Untrustworthy sellers cannot be trusted to provide this ever.

That said, if you have a means to test their capacity at a high load (10A constant current discharge) and plot the discharge curve of each cell to verify they all have similar characteristics, then you should be fine. High current discharge is necessary because some "fake" cells will actually perform to close to their rated capacity under very light load. (genuine cells but lower tier; low-power high-energy chemistry). Others will perform well under load but be well but have lower rated capacity, usually because you actually get a re-wrapped lower-tier cell. Like Sony VTC4 instead of VTC6.
I meant battery holders with nickel contacts, I can replace the wires anyway I opted for cells with presoldered nickel terminals from LiitoKala
according to this video (imho trustable), they should be good enough, so I'll give a chance.
https://www.youtube.com/watch?time_c...&v=q2o3Wc-0fVk
I'd like to place them inside the arms like the image, can you show me a diagram of how the wiring should be in a 6S2P with XT60 charge/discharge and JST balance plugs? I'd make 4 3S packs (one for each arm), then pair them in 2 6S, and finally in a 6S2P, or is it not possible beacause of balance leads ?
is there an order in which to proceed when soldering to avoid damages?
Last edited by miky94; Mar 20, 2019 at 04:24 PM.
Mar 20, 2019, 06:43 PM
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Quote:
Originally Posted by miky94
I meant battery holders with nickel contacts, I can replace the wires anyway I opted for cells with presoldered nickel terminals from LiitoKala
according to this video (imho trustable), they should be good enough, so I'll give a chance.
https://www.youtube.com/watch?time_c...&v=q2o3Wc-0fVk
I'd like to place them inside the arms like the image, can you show me a diagram of how the wiring should be in a 6S2P with XT60 charge/discharge and JST balance plugs? I'd make 4 3S packs (one for each arm), then pair them in 2 6S, and finally in a 6S2P, or is it not possible beacause of balance leads ?
is there an order in which to proceed when soldering to avoid damages?
Are the batteries going to be put into some sort of frame? I assume carbon fiber tubes with an inner diameter greater than 18mm. If so, that would be pretty clever! Otherwise I think a hard landing would result in stresses applied to the joints between cells and it may be difficult to keep them secure and in place. If you go with 3S and use (aluminum or titanium) metal tubes, then you could actually use the frame as a return path for current, similar to the body of many tactical flashlights. That configuration would probably lend itself fine to the cells with pre-welded nickel tabs. This approch will make replacing the integrated battery a real hassle.

If instead you are thinking about using 12 of those battery holders, I still have by doubts that would work. Nickel and steel are very similar in a lot of ways so telling them apart is tricky. Even if you found battery holders that are made with nickel contacts, you still deal with the problem of contact resistance and some cells possibly not making a good connection. God forbid if a cell somehow falls out during flight!

Battery packs are going to be built in a way where you have 'P' number of cells in parallel, then you take those 'P' number of cells and place them 'S' of them in series. If the cells are properly matched, very little current should flow between parallel cells, since they (should) have similar voltages throughout the charge/discharge cycle. make sure all cells are at the same voltage before connecting in parallel. The connection is necessary for balancing in the case the cells are not completely identical.
Mar 20, 2019, 07:06 PM
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Quote:
Originally Posted by Power Max
Are the batteries going to be put into some sort of frame? I assume carbon fiber tubes with an inner diameter greater than 18mm. If so, that would be pretty clever! Otherwise I think a hard landing would result in stresses applied to the joints between cells and it may be difficult to keep them secure and in place. If you go with 3S and use (aluminum or titanium) metal tubes, then you could actually use the frame as a return path for current, similar to the body of many tactical flashlights. That configuration would probably lend itself fine to the cells with pre-welded nickel tabs. This approch will make replacing the integrated battery a real hassle.

If instead you are thinking about using 12 of those battery holders, I still have by doubts that would work. Nickel and steel are very similar in a lot of ways so telling them apart is tricky. Even if you found battery holders that are made with nickel contacts, you still deal with the problem of contact resistance and some cells possibly not making a good connection. God forbid if a cell somehow falls out during flight!

Battery packs are going to be built in a way where you have 'P' number of cells in parallel, then you take those 'P' number of cells and place them 'S' of them in series. If the cells are properly matched, very little current should flow between parallel cells, since they (should) have similar voltages throughout the charge/discharge cycle. make sure all cells are at the same voltage before connecting in parallel. The connection is necessary for balancing in the case the cells are not completely identical.
yes I'd place the cells inside the frame as in the video, the frame will be composed of 2 aluminium squared tubes crossed
considering:
- 18.5mm maximum cell diameter
- nickel strip
- 2x 3mm diameter 16awg positive and negative wires of 1 2P
- 1x 3mm diameter 16awg negative wire of 3rd cell (I don't consider the positive which will stay in the cell diameter)
- 2x 3mm diameter 16awg balance wires (negative of first 2P, positive of 2P, as above I don't consider the positive of 3rd cell)
- 3x 2mm diameter 18awg motor wires
total area of 313,57 mm2, so I'd stay on 20x20 mm internal square (400 mm2), 1mm thick.
Mar 22, 2019, 03:54 AM
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OT
using round tubes as arms, do motors stay flat using just 2 screws? in this image it seems so
and does carbon fiber ravel by cutting it? I'm not familiar with it and I need to cut 2 tube in the center to fit them together
Mar 22, 2019, 04:18 PM
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Quote:
Originally Posted by miky94
OT
using round tubes as arms, do motors stay flat using just 2 screws? in this image it seems so
and does carbon fiber ravel by cutting it? I'm not familiar with it and I need to cut 2 tube in the center to fit them together
The only thing I would caution you is to ensure the connections on the cells are well isolated from conductive carbon fiber. I would have a connector leaving each arm and a custom wire harness or better, custom power distribution PCB for connecting the cells in the config you want.
Apr 02, 2019, 08:31 AM
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Quote:
Originally Posted by Power Max
The only thing I would caution you is to ensure the connections on the cells are well isolated from conductive carbon fiber. I would have a connector leaving each arm and a custom wire harness or better, custom power distribution PCB for connecting the cells in the config you want.
I think I'll cover all the terminals with shrink tape or maybe is better some hot glue to keep them in position and avoid overheating since I'll push them near limits because of low discharge current than LiPos.
Apr 03, 2019, 12:26 AM
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Quote:
Originally Posted by miky94
I think I'll cover all the terminals with shrink tape or maybe is better some hot glue to keep them in position and avoid overheating since I'll push them near limits because of low discharge current than LiPos.
Hot glue is never the answer in such an application! It will certainly melt and provide no electrical protection when the cells are pushed. Heatshrink would be your friend!
Apr 03, 2019, 01:28 AM
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Thread OP
Ok, I thought about hot glue because I've seen use it to cover solder joints the DJI's video on how to assembly flame wheel arf kit.
having the cells inside the arms I think this would be the best solution for the wiring diagram, what do you think about it?


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