I've really been looking forward to this video, thanks very much for sharing this invaluable information, this is incredibly useful. I fell into the trap of buying the Panasonic 18650B batteries in 4S which had roughly a 6A limit which resulted in the quad dropping after a two minute flight. I've since been using the Molicell 21700 P42A which have worked perfectly.
Great video 👍🏻 For 7” LR I use the Molicel p42 21700 and the Samsung INR21700 40T both in 6s2p configuration, and they both yield almost identical flight times. Both great cells I find. I also have several of the GNB 4Ah 50c lipos you have for shorter flights, and really like them.
@@PerchEagle pls don't use 6s1p for quad you will burn your battery pack 6s2p is recommended. you can use 6s1p for glider & other applications. Also 6s1p can be beneficial for toothpicks 'cause they consume less current.
I wrote a commend and got removed ! I don't know why. But my question was do you recommend a good brand for a drone or a terrain robot ?@@hardikyadav5277
On the most longest flights I did so far (5km away and 1km in height) were with these beautiful Molicel P42 Liions 21700. Best battery for long range in extreme conditions! Great informational video! Thanks
So far I'm not having luck with long flight times with bought & DIY li-ion packs. The best performer so far is that Gaoneng 4000 mah lipo which gives me around 20min flight times just going around in long circles.
Ya its a great lipo. The new 4200 90c is even better. I almost always use my 18650 6s packs two at a time in parallel, its about 30 or 40 grams heavier than that lipo.
Hey Falconrad, thanks for the information on Li-Ion packs! I'm planning on building a 7" LR in the summer and was thinking about which battery configuration would be best for me. This video helped a lot with that. Quick tip for you videos: Put your audio into mono channel, it is a bit weird to listen to your voice with headphones because it is biased towards the right channel.
Do you happen to have a configuration for a 6s2p or a 6s3p pack? I've built a few 1p packs but I'd like to build at least a 6s2p with the Molicel P45B cells for my Helion 10
Ya the safety difference between li-ion cells and lipo's is a big deal if flying in the summer months. A li-ion cell has a metal "can" around the whole thing and goes through crushing tests and so on. If a lipo gets poked by a branch sometimes it'll bust into flames.
Thank you so much for the video! I'm about to build a 7" quad for long range and I feel frustrated about what battery to choose. Do you think its better to use 21700 or 18650 packs? I dont want high speed, I want to fly for as much time as I can. Thanks for your valuable information
Ok, I'm convinced. It's time to switch to lion for long range. Just the issue of fire risk is enough add the weight savings and its a no brainer... Unfortunately I bought some very expensive 6s pre made packs from pyro and don't think they have the specs I need :( back to the drawing board....
Sorry to hear that. I'm not sure what companies are using to make li-ion packs but it shouldn't be so hard for them to just pick the good cells. I guess it's down to cost and something almost as good is about 25% cheaper so...
I've landed at 2.4 - 2.8 volts very often. It'll bounce back up to about 3.2 or so after sitting for 5 minutes after landing. It drops quickly after 3.0 volts though.
I hear ya, I keep squeezing my batteries into 250 mm straps. For my big 2170 packs I actually use long zip ties even. I just bought 280mm TBS Swagger straps yesterday. THEY ARE GARBAGE!!! The velcro is setup so that it only works as a 250mm strap, how does that get screwed up so bad? Still looking for 280 - 300 mm straps for myself. Of course you could order RJX straps from china. They make pretty good ones but it'll take a while for shipping and the logo's will just be RJX based.
That was a great primer for building your own packs. I have used the Molicel 21700 P42A to make a 6S pack. I think another interesting thing to look at would be the cost per capacity, P42A vs P28A. One of the questions that I have is why you fly/build 2 packs to run in parallel rather than just building one 6S2P? (12 cells). Is it mostly just the form factor or are there other reasons? You may show it in the next video but do you solder or spot weld them together? I have been using the BIFRC DH20 Pro and really like it.
Thanks for the comment. I run two separate 6s packs so that I can use one at a time on small quads, or one on top and one underneath, or both on the top plate. Depends which quad I'm using. I do a lot of experimenting so the versatility of having 6s2p in two separate 6s1p packs is useful. I solder my li-ion packs. Every time I look at getting a spot welder I can not find sufficient information on the required nickel strips. From what I have found it seems it would probably need four pieces of 15mm X 0.2mm nickel strips stacked up for every connection. But will a spot welder actually weld a 3rd and 4th 0.2mm strip to the cell? The standard silicone insulated multistrand tin coated copper wire is way more efficient at carrying current. I know it's possible to make a good quality spot welded li-ion pack but I think it might be best done with expensive spot welder that can make use of even thicker nickel strips. But most nickel strips for sale are really thin and only rated for 3 to 6 amps.
@@FalconRadFPV It's also possible to use copper strips for spot welding. 0.1mm or 0.15mm strips, topped with a small section of nickel strip to provide enough resistance for the weld to occur, is doable with a kWeld or similar device. A kWeld is much pricier than the ones found on Amazon (up to ~US$800 depending on how you set it up), but the cheap Amazon spot welders don't put out nearly enough power to handle copper, and probably not enough to weld more than two nickel strip layers.
@@FalconRadFPV I have tried the multi-layer spot welding. I used 7mm X 0.3mm niclke strips and stacked around 7-8 layers which is slightly more than whats required. I welded one layer on top of another. The weld is very strong that I can say. Its a lengthy process but did not take more than half a day for my pack.(First 6s pack and first time spot weld user) I havent fully tested the amp draw yet, still caliberating and testing. I was debating with myself over spot welding or soldering for a month and decided to go this route as I had already purchased the spot welder and in the end the welds are cleaner compared to soldering. The spot welder I use is a cheap BIFRC one and use 2 3s 3.3Ah lipos in parallel to power. And later use them in series for the 7" :P Love your work, please keep it going :) Cheers
I am still soldering my packs. I don't know enough about spot welding and layering nickel strips 4 high seems an odd solution for spot welding and getting enough nickel to manage the amps.
cant there just be a capacitor of some sort as peak amp draw safe be installed ? i mean you never need constant high current when cruising only short punches, when needed. so if one could make a Capacitor as peakamp dampener for the li-ions wouldnt they be way more forgiving for relativly normal fpv cruising flights. ? thoughts ?
Great information, thanks very much for this video 😁👍. I‘m just for 3 days now in the air with my Chimera 7. Before I’ll send it on long range I tested my 6S LiPo‘s (3.300/60C and 4.200 mAh/75C) and my 6S Li-Ions (4.000 mAh/40A and two in parallel=8.000 mAh) in GPSrescue mode with the factory settings. I got some weird results. Go rescue (the flight back) worked like expected with the 8.000 mAh Li-Ion and the 3.300 mAh LiPo. It failed with the single 4.000 mAh Li-Ion and the 4.200 mAh LiPo. The quad lost too much altitude after the first ascend (+ 50 meters) in rescue mode and I could rescue it only with kicking out GPSrescue before it crashed in the ground and raise throttle. That really confuses me … do you have similar experiences ? Does every pack need a special Go rescue setting in Betaflight with minimum/maximum throttle and hoover throttle ? Because I could rescue the quad by manual throttle it seems that every pack can deliver enough amps 🤷🏻♂️. The 4.000 mAh-packs are made by Farin Frames, the 3.300 mAh LiPo is from HRB and the 4.200 mAh from URUAV. Any tipps highly appreciated 😉🙏
I believe it's an issue with the newer version of GPS rescue. Back with betaflight 4.1.7 GPS rescue was fast and never flew towards the ground before gaining altitude. I'm tempted myself to go back to BF 4.1.7 just for the better GPS rescue mode. BF 4.2 always goes to low throttle for 5 or 6 seconds before starting to gain altitude, I have no idea why.
@@FalconRadFPV Hi FalconRad, thank you so much for your answer 💪💪. I didn’t know that there is a different behavior in GPSrescue between the different Betaflight versions 😲. From the perspective of control engineering the PID‘s in BF 4.2 must be totally wrong in the flight mode which the flightcontroller uses during the Go rescue flight. That means for me that I‘ll use for long range only the battery packs which work properly so far and that I must hope to have enough altitude when rescue is triggered … a horrible scenario for every LR pilot 😮💨. Thank you again, I highly appreciate the effort you put into your videos and comments. Best regards from Germany.
@@mog59 Why dont you try iNav? I have just built Chimera 7 with iNav. Still in testing though. But I feel for long range purpose, it is more reliable and in some instances superior. We dont need the flight dynamics of Betaflight, and essentials like GPS rescue, or pos hold(cuz you have to scratch your nose mid flight) and other nav parameters and sensors support helps greatly I believe.
@@hemanthkrishna5343 Hi Hemanth, thanks for your comment 👍. 14 month ago I entered fpv as a newbie and climbed the ladder from a 1.6‘‘ analog whoop to 7‘‘ digital. I don’t know where my fpv ladder will end … a CRSF diversity receiver is waiting to be installed on the 7‘‘ … and I‘m following people who are flying wings. iNAV is on my list when I have the feeling that my skills are appropriate. Hopefully not so far in the future 😅😉
It depends on how many amps your build is going to need. For higher amps I like to use 6s2p 18650. For more moderate amp draw I'll use 6s1p 21700. For extra range I'll use 6s2p 21700 but it's really heavy.
Hello FalconRad, how high do you charge your Li-Ion in terms of volts? I charge them up to 4.10V only; would it also be good charging them up to 4.20V regularly? Also, can I have a 3000mAh and 4200mAh (45C and 35C respectively) in parallel without trouble? Thank you, you're channel has been very helpful.
Yes I charge my li-ion packs to 4.2 volts. I'm not sure about mixing different battery sizes and C ratings for parallel use. I have always used matching packs to run in parallel. I usually label them into pairs that I always use together.
No, you should not connect 3000 mAh, 45 A, and 4200 mAh, 35 A lithium-ion batteries in parallel. The cells have different capacities, which means they will discharge at different rates. This can lead to overheating issues and potentially result in a fire.
hy i've got some sony murata 3100 mah 35A curent cells to make a 6s2p pack , my concern i about how many nichel strips do i need to get 35A per series pack (35 per pack will lead to 70A discharge total 2p config), i have some 0.2x8 mm pure nichel strip that i've heard and tried that it doesn't like to stack multiple layers, and some nichel plated steel that weld better more buttery. Are 4 layers enough ? should i alter the strips to have steel nichel steel nichel ... also i think it is better to connect the cells in parallel using the strips, at each joint of 2 parallel cells instead of just at the end like if they were 2 separate packs, it should help with balance, but i ask just to be sure. Also even if i stack enough strips on top of each other, all of them will interact with the cell using the tiny spot welds of the first strip that conects all of them to the battery trough it, are they gonna be enough, those spot welds ?
I don't use a spot welder, I solder my packs. Specifically for that reason, nickel strips are not very good conductors and it would take 3 or 4 layers to be sufficient. I know one company solves it by using copper strips but it requires a very expensive laser welder. Sony doesn't make a 3100 mAh 35 amp cell. Sony doesn't make any cells rated for 35 amps, there's a 30 amp rated one but it's only 2100 mAh. Not sure which ones you are referring to. Watch out for the cell ratings, some store will misrepresent stats and say the burst rating is the constant rating. it'll say 15/30 amp rating then it's only rated for 15 amps constant and for short 30 amp bursts or else it'll get way too hot. Yes its better to make one big pack with 12 cells in 6 pairs connected in series. BUT then the pack is huge and only fits on a drone with a huge top plate which isn't great for aerodynamic efficiency.
Thanks for sharing your experience with us:) Would you think 21700 in 6s2p has worse efficiency than 18650 6s2p? Would a 7.5" with slightly bigger motor like 2808 would help for the 21700s? I went for the 21700's and now im wondering if I should increase the prop size for better efficiency. Also why dont you use iNav? If you have not tried it, maybe you can give it a shot and share your experience.
21700 6s2p is less efficient than 18650 6s2p. The weight gets a bit much for a 7" prop and then necessary increase in motor RPM decreases the efficiency. With 18650 6s2p I get about 4km per 1000mah so max 20km on 5000mah 18650 6s2p. With 21700 I get about 25km so roughly 3.1km per 1000mah. The lighter the load the better the ratio of km per mah will get. I use 21700 6s2p for when I really need good range or if I want to be in the air longer and do several attempts at a specific GoPro shot. For the avg. long range flight I will use 18650 6s2p for a lighter craft with better maneuverability. As for firmware, I'm always bust with TH-cam videos and working on new frames designs so I don't really change firmware very often. I have only updated my crossfire for instance 2 or 3 times in 5 years, and only because I had to to get new features to work. If I was more interested in the automated GPS stuff I would be using INAV for sure. But ya, I should give it a try, I'm sure a basic setup isn't much more work than with Betaflight.
@@FalconRadFPV I'm having a hard time deciding between 21700 and 18650. You told me the other day to buy Molicel brand but I forgot to ask which size. So based from your response to Hemanth above, it looks like for my 7" quadcopter, I should buy 18650 cells. However, I got confused about this text you wrote above "I use 21700 6s2p for when I really need good range". I can't figure out how you arrived at 25km. What was the mAh on your 21700 6s2p setup? Then you also wrote that if you want to be in the air longer, you use your 21700 6s2p. Thanks a lot in advance!😊
Yes that should be fine but the motors are pretty high kv, you should limit motor output by about 20% or so. and make sure your amp draw is resonable for the limits of the li-ion battery.
Great insights into batteries from a long range perspective. I thought about setting motor output limit to not accidentally surpass the amp draw limit catching a dive. That probably means getting used to a different throttle stick position. What do you think about that? Also how bad is it to go higher? Will the battery die during flight or just not last as long in the future?
In my experience the li-ion batteries will just sag really badly if the amp draw gets too high. Or with brnd new cells it will put out the amps but get quite hot. In the end the pack shouldn't suddenly die in flight, but it will reduce the lifespan as well as the total mah that can be output. This is why I use two packs in parallel at 6s voltage. It keeps my amp draw below 1/4 of what my molicel li-ion packs are rated for, at least most of the time. If using 8s on a 6s setup you for sure want to use the motor output limit rather than just a throttle limit.
What do you think about other form factors of LiIons ? Is 18650 still the king for the usecase, or do other formfactors (shorter&thicker) allow for ex. higher mah/g ? I am really looking forward to your guide, so i can mid range my AOS 5.5 and use its higher disc loading! Cheers from Munich :)
I only use 21700 and 18650 cells. Which ones depend on the weight of the build the range that I'm looking to get. Most of the time I use 18650 6s2p but I do some flights with 21700 6s2p if I need more range.
The weight savings is only a small amount maybe 20 grams. Having a top plate big enough to carry a 6s2p li-ion battery and a gopro will create a lot of drag in the air. For the best range drag needs to be kept to a minimum. With my RAD Li-ion frame one battery is carried on the top plate and another one underneath, this helps to reduce drag quite a bit.
@FalconRadFPV Thanks man for the info, that's an important point. Then how about doing a 6s in one line ? I know it's going to be tall for a 5" quad. But how about a 7 " one ? I haven't tested or done any drone build but it's coming very soon. Haven't purchased the parts but most of them in the cart.
That's hard to answer. It depends on the drone and what you want to do with it. As far as a battery for a 7" long range drone, I think the molicel P28A or P28B cells are my personal favorite. The best cells for flights packs are not the ones with the highest capacity as the video will tell you. You want a pack that can manage the current draw of a drone, the highest capacity cells are only good for flashlights and low current uses. For a 21700 size cell I suggest the molicel P45B or the samsung 50S.
Trying to make my 5" freestyle into a long range drone and I'm wondering whether 4S or 6S is better for efficiency. I feel like my old 4S builds were much more efficient on the low end.
I believe 3s and 4s are most efficient as far as watts vs thrust. I only use 6s because the higher voltage lowers the amp draw which allows me to run li-ion cells without them getting hot.
Don't know why there isnt sony vtc6 or vtc5a, I have tried moly cells and they suck compared to sony, also you didn't mentioned that you use 21700 not 18650 that is big difference compare to weigh.
I use both 21700 and 18650's. I showed both size packs in the video. The first time I tried a sony cell it performed badly. Lol, I guess the opposite experience from yours. The sony is rated for less amps also. The Molicel put out the amps that they claim. I have pulled over 80 amps from 6s2p 18650 packs with molicel P26A cells.
@@FalconRadFPV moly has more total capacity, but at the end it's sagging very fast compared to sony vtc6 and added all that weight I don't know which is better. Maybe in the future you will make video sony vs moly endurance test. Also watch out for fake one's.
More great information. Thanks, Conrad. Glad I've been watching your channel for a while and watching what you're using for cells. Bought some Samsung 40T/21700/4000 and some Molicel P28A/18650/2800. Made several batteries and the first one was the hardest. Just getting your head around how things connect and good wire location and length. Doubt I'll buy any more lipos as most of my flying is cruisy and I have a bin full if I feel the need to blast. So whadya think? Should we build up 10 of your li-ion frames with goggles, chargers, radios and batteries and send them to Ukraine for long range reconnaissance? Bet we could fundraise and get donations of equipment and parts. You have my number.
It's a great idea but 10 frames alone is over $1000. It would be about $6000 worth of gear to do that, I'm lucky if I get one FC and one ESC for free every three months or so. Most companies don't even answer emails from me!
I've really been looking forward to this video, thanks very much for sharing this invaluable information, this is incredibly useful. I fell into the trap of buying the Panasonic 18650B batteries in 4S which had roughly a 6A limit which resulted in the quad dropping after a two minute flight. I've since been using the Molicell 21700 P42A which have worked perfectly.
Glad it was helpful!
I've been waiting for this beautiful video.👍
You taught me som really useful info so thank you 😊
Great video 👍🏻
For 7” LR I use the Molicel p42 21700 and the Samsung INR21700 40T both in 6s2p configuration, and they both yield almost identical flight times. Both great cells I find.
I also have several of the GNB 4Ah 50c lipos you have for shorter flights, and really like them.
Isn't 6s2p 21700 a bit heavy?
would you recommend 6s1p 21700 or 6s2p 18650?
@@PerchEagle bro that is a 7-inch quad and has higher thrust than 5 inches.
@hardikyadav5277 Thank for the information 👍
@@PerchEagle pls don't use 6s1p for quad you will burn your battery pack 6s2p is recommended. you can use 6s1p for glider & other applications. Also 6s1p can be beneficial for toothpicks 'cause they consume less current.
I wrote a commend and got removed ! I don't know why. But my question was do you recommend a good brand for a drone or a terrain robot ?@@hardikyadav5277
A perfect guide to lithium cells👍
Thank you, FalconRad!
Thanks and you're welcome!
Very good informaion man, thatnk you. I learned enough to start looking at making my own packs. Keep up the good work
The new Molicel P30B 18650 is an excellent cell. I recently built a 4s1p pack for my Flywoo Explorer LR4 and it performs great. 30A rated and 3000mAH
Ya those cells are way better than the sony ones. Molicel is a great choice for long range packs. glad to hear its working well for you!
On the most longest flights I did so far (5km away and 1km in height) were with these beautiful Molicel P42 Liions 21700. Best battery for long range in extreme conditions! Great informational video! Thanks
Couldn't agree more!
Just ordered some p42 and a 60$ prime day battery spot welder cant wait to try out liion for the first time
@@lililililililili8667 You're gonna be happy with it, trust me! Just don't give them hell but play nice with them and you can go miles! 😊
So far I'm not having luck with long flight times with bought & DIY li-ion packs. The best performer so far is that Gaoneng 4000 mah lipo which gives me around 20min flight times just going around in long circles.
Ya its a great lipo. The new 4200 90c is even better. I almost always use my 18650 6s packs two at a time in parallel, its about 30 or 40 grams heavier than that lipo.
Great bit of info there mate
Hey Falconrad, thanks for the information on Li-Ion packs! I'm planning on building a 7" LR in the summer and was thinking about which battery configuration would be best for me. This video helped a lot with that. Quick tip for you videos: Put your audio into mono channel, it is a bit weird to listen to your voice with headphones because it is biased towards the right channel.
Thanks for the audio tip!
Fantastic info, dude! Thanks a bunch! 😃
Stay safe there with your family! 🖖😊
Thanks! very much my friend! Will do! 👍👋
Thanks for sharing with us this information 🙏👍
Hey Aragorn23! You are very welcome. I'm glad to see you still around watching this channel, thank you, you've been a subscriber for quite a while!
Great info. I just started using lion packs so this was perfect timing.
Glad it was helpful!
Thanks for sharing your knowledge
Great video bro
Do you happen to have a configuration for a 6s2p or a 6s3p pack? I've built a few 1p packs but I'd like to build at least a 6s2p with the Molicel P45B cells for my Helion 10
Can we use in 5 inch drone with this cell battery pack --> Samsung INR18650-25R 2500Mah (8C) Li-Ion Battery
You NEVER one talked about RECOVERY. My bird deploys a dye pack, 2 buzzers and a strobe
Oh nice, a dye pack! That's a great idea. I had thought about a tiny servo that could be triggered to release a florescent pink marking ribbon.
@@FalconRadFPV I'm the guy that wanted to chat. I'll hit you back in a couple weeks.
Never thought about the safety factor before now. Flying mostly forested areas it’s a major concern of mine.
Ya the safety difference between li-ion cells and lipo's is a big deal if flying in the summer months. A li-ion cell has a metal "can" around the whole thing and goes through crushing tests and so on. If a lipo gets poked by a branch sometimes it'll bust into flames.
Thank you so much for the video! I'm about to build a 7" quad for long range and I feel frustrated about what battery to choose. Do you think its better to use 21700 or 18650 packs? I dont want high speed, I want to fly for as much time as I can. Thanks for your valuable information
Ok, I'm convinced. It's time to switch to lion for long range. Just the issue of fire risk is enough add the weight savings and its a no brainer... Unfortunately I bought some very expensive 6s pre made packs from pyro and don't think they have the specs I need :( back to the drawing board....
Sorry to hear that. I'm not sure what companies are using to make li-ion packs but it shouldn't be so hard for them to just pick the good cells. I guess it's down to cost and something almost as good is about 25% cheaper so...
How do you determine what pvc battery shrink wrap to buyt Im trying to do a 21700 6s2p and don't know what size to order
I think 120mm for 21700 6s packs.
So when Molicel says 2.5v minimum, that means it will be destroyed at lower voltage, right? So you land at like 2.8v with those still?
I've landed at 2.4 - 2.8 volts very often. It'll bounce back up to about 3.2 or so after sitting for 5 minutes after landing. It drops quickly after 3.0 volts though.
Where do you get your straps from and what straps are you using? I'm having a hard time finding anything quality over 250mm.
I hear ya, I keep squeezing my batteries into 250 mm straps. For my big 2170 packs I actually use long zip ties even. I just bought 280mm TBS Swagger straps yesterday. THEY ARE GARBAGE!!! The velcro is setup so that it only works as a 250mm strap, how does that get screwed up so bad? Still looking for 280 - 300 mm straps for myself. Of course you could order RJX straps from china. They make pretty good ones but it'll take a while for shipping and the logo's will just be RJX based.
Would I be right in thinking that there is basically no disadvantage to just buying batteries with 45a rating? Apart from cost.
There is no disadvantage to having a high amp rated li-ion cell. They generally perform better than lower amp rated ones.
That was a great primer for building your own packs. I have used the Molicel 21700 P42A to make a 6S pack. I think another interesting thing to look at would be the cost per capacity, P42A vs P28A.
One of the questions that I have is why you fly/build 2 packs to run in parallel rather than just building one 6S2P? (12 cells). Is it mostly just the form factor or are there other reasons?
You may show it in the next video but do you solder or spot weld them together? I have been using the BIFRC DH20 Pro and really like it.
Thanks for the comment. I run two separate 6s packs so that I can use one at a time on small quads, or one on top and one underneath, or both on the top plate. Depends which quad I'm using. I do a lot of experimenting so the versatility of having 6s2p in two separate 6s1p packs is useful.
I solder my li-ion packs. Every time I look at getting a spot welder I can not find sufficient information on the required nickel strips. From what I have found it seems it would probably need four pieces of 15mm X 0.2mm nickel strips stacked up for every connection. But will a spot welder actually weld a 3rd and 4th 0.2mm strip to the cell? The standard silicone insulated multistrand tin coated copper wire is way more efficient at carrying current. I know it's possible to make a good quality spot welded li-ion pack but I think it might be best done with expensive spot welder that can make use of even thicker nickel strips. But most nickel strips for sale are really thin and only rated for 3 to 6 amps.
@@FalconRadFPV It's also possible to use copper strips for spot welding. 0.1mm or 0.15mm strips, topped with a small section of nickel strip to provide enough resistance for the weld to occur, is doable with a kWeld or similar device. A kWeld is much pricier than the ones found on Amazon (up to ~US$800 depending on how you set it up), but the cheap Amazon spot welders don't put out nearly enough power to handle copper, and probably not enough to weld more than two nickel strip layers.
@@FalconRadFPV I have tried the multi-layer spot welding. I used 7mm X 0.3mm niclke strips and stacked around 7-8 layers which is slightly more than whats required. I welded one layer on top of another. The weld is very strong that I can say. Its a lengthy process but did not take more than half a day for my pack.(First 6s pack and first time spot weld user) I havent fully tested the amp draw yet, still caliberating and testing. I was debating with myself over spot welding or soldering for a month and decided to go this route as I had already purchased the spot welder and in the end the welds are cleaner compared to soldering.
The spot welder I use is a cheap BIFRC one and use 2 3s 3.3Ah lipos in parallel to power. And later use them in series for the 7" :P
Love your work, please keep it going :) Cheers
Great information! I've been building my packs with the Moxcell cells as well. Are you spot welding or soldering your packs together?
I am still soldering my packs. I don't know enough about spot welding and layering nickel strips 4 high seems an odd solution for spot welding and getting enough nickel to manage the amps.
cant there just be a capacitor of some sort as peak amp draw safe be installed ? i mean you never need constant high current when cruising only short punches, when needed. so if one could make a Capacitor as peakamp dampener for the li-ions wouldnt they be way more forgiving for relativly normal fpv cruising flights. ? thoughts ?
To be of any real help the capacitor would have to be quite large to hold more than a few milliseconds worth of power.
Great information, thanks very much for this video 😁👍. I‘m just for 3 days now in the air with my Chimera 7. Before I’ll send it on long range I tested my 6S LiPo‘s (3.300/60C and 4.200 mAh/75C) and my 6S Li-Ions (4.000 mAh/40A and two in parallel=8.000 mAh) in GPSrescue mode with the factory settings. I got some weird results. Go rescue (the flight back) worked like expected with the 8.000 mAh Li-Ion and the 3.300 mAh LiPo. It failed with the single 4.000 mAh Li-Ion and the 4.200 mAh LiPo. The quad lost too much altitude after the first ascend (+ 50 meters) in rescue mode and I could rescue it only with kicking out GPSrescue before it crashed in the ground and raise throttle. That really confuses me … do you have similar experiences ? Does every pack need a special Go rescue setting in Betaflight with minimum/maximum throttle and hoover throttle ? Because I could rescue the quad by manual throttle it seems that every pack can deliver enough amps 🤷🏻♂️. The 4.000 mAh-packs are made by Farin Frames, the 3.300 mAh LiPo is from HRB and the 4.200 mAh from URUAV. Any tipps highly appreciated 😉🙏
I believe it's an issue with the newer version of GPS rescue. Back with betaflight 4.1.7 GPS rescue was fast and never flew towards the ground before gaining altitude. I'm tempted myself to go back to BF 4.1.7 just for the better GPS rescue mode. BF 4.2 always goes to low throttle for 5 or 6 seconds before starting to gain altitude, I have no idea why.
@@FalconRadFPV Hi FalconRad, thank you so much for your answer 💪💪. I didn’t know that there is a different behavior in GPSrescue between the different Betaflight versions 😲. From the perspective of control engineering the PID‘s in BF 4.2 must be totally wrong in the flight mode which the flightcontroller uses during the Go rescue flight. That means for me that I‘ll use for long range only the battery packs which work properly so far and that I must hope to have enough altitude when rescue is triggered … a horrible scenario for every LR pilot 😮💨. Thank you again, I highly appreciate the effort you put into your videos and comments. Best regards from Germany.
@@mog59 Why dont you try iNav? I have just built Chimera 7 with iNav. Still in testing though. But I feel for long range purpose, it is more reliable and in some instances superior. We dont need the flight dynamics of Betaflight, and essentials like GPS rescue, or pos hold(cuz you have to scratch your nose mid flight) and other nav parameters and sensors support helps greatly I believe.
@@hemanthkrishna5343 Hi Hemanth, thanks for your comment 👍. 14 month ago I entered fpv as a newbie and climbed the ladder from a 1.6‘‘ analog whoop to 7‘‘ digital. I don’t know where my fpv ladder will end … a CRSF diversity receiver is waiting to be installed on the 7‘‘ … and I‘m following people who are flying wings. iNAV is on my list when I have the feeling that my skills are appropriate. Hopefully not so far in the future 😅😉
Are Lipos cheaper? Coming from Vaping, I'd have always tried 18650 or 21700 in these way before I ever thought of Lipos?
no li-ion packs are cheaper usually. For sure way cheaper if you make your own packs.
@@FalconRadFPV My dream right now is a 2S 21700 drone using Molicel P45B cells...
great video, thank you! can you help me decide between 18650 vs. 21700 cells?
It depends on how many amps your build is going to need. For higher amps I like to use 6s2p 18650. For more moderate amp draw I'll use 6s1p 21700. For extra range I'll use 6s2p 21700 but it's really heavy.
Hi Falcon, what do you think about the new Molicel P45B? Thank
Looks like a new cell to replace the P42A. I would think it's a good choice knowing Molicel. It's still got that great Molicel amp rating!
Hello FalconRad, how high do you charge your Li-Ion in terms of volts? I charge them up to 4.10V only; would it also be good charging them up to 4.20V regularly? Also, can I have a 3000mAh and 4200mAh (45C and 35C respectively) in parallel without trouble? Thank you, you're channel has been very helpful.
Yes I charge my li-ion packs to 4.2 volts. I'm not sure about mixing different battery sizes and C ratings for parallel use. I have always used matching packs to run in parallel. I usually label them into pairs that I always use together.
No, you should not connect 3000 mAh, 45 A, and 4200 mAh, 35 A lithium-ion batteries in parallel. The cells have different capacities, which means they will discharge at different rates. This can lead to overheating issues and potentially result in a fire.
hy i've got some sony murata 3100 mah 35A curent cells to make a 6s2p pack , my concern i about how many nichel strips do i need to get 35A per series pack (35 per pack will lead to 70A discharge total 2p config), i have some 0.2x8 mm pure nichel strip that i've heard and tried that it doesn't like to stack multiple layers, and some nichel plated steel that weld better more buttery. Are 4 layers enough ? should i alter the strips to have steel nichel steel nichel ... also i think it is better to connect the cells in parallel using the strips, at each joint of 2 parallel cells instead of just at the end like if they were 2 separate packs, it should help with balance, but i ask just to be sure. Also even if i stack enough strips on top of each other, all of them will interact with the cell using the tiny spot welds of the first strip that conects all of them to the battery trough it, are they gonna be enough, those spot welds ?
I don't use a spot welder, I solder my packs. Specifically for that reason, nickel strips are not very good conductors and it would take 3 or 4 layers to be sufficient. I know one company solves it by using copper strips but it requires a very expensive laser welder.
Sony doesn't make a 3100 mAh 35 amp cell. Sony doesn't make any cells rated for 35 amps, there's a 30 amp rated one but it's only 2100 mAh. Not sure which ones you are referring to. Watch out for the cell ratings, some store will misrepresent stats and say the burst rating is the constant rating. it'll say 15/30 amp rating then it's only rated for 15 amps constant and for short 30 amp bursts or else it'll get way too hot.
Yes its better to make one big pack with 12 cells in 6 pairs connected in series. BUT then the pack is huge and only fits on a drone with a huge top plate which isn't great for aerodynamic efficiency.
Thanks for sharing your experience with us:) Would you think 21700 in 6s2p has worse efficiency than 18650 6s2p? Would a 7.5" with slightly bigger motor like 2808 would help for the 21700s? I went for the 21700's and now im wondering if I should increase the prop size for better efficiency.
Also why dont you use iNav? If you have not tried it, maybe you can give it a shot and share your experience.
21700 6s2p is less efficient than 18650 6s2p. The weight gets a bit much for a 7" prop and then necessary increase in motor RPM decreases the efficiency. With 18650 6s2p I get about 4km per 1000mah so max 20km on 5000mah 18650 6s2p. With 21700 I get about 25km so roughly 3.1km per 1000mah. The lighter the load the better the ratio of km per mah will get. I use 21700 6s2p for when I really need good range or if I want to be in the air longer and do several attempts at a specific GoPro shot. For the avg. long range flight I will use 18650 6s2p for a lighter craft with better maneuverability. As for firmware, I'm always bust with TH-cam videos and working on new frames designs so I don't really change firmware very often. I have only updated my crossfire for instance 2 or 3 times in 5 years, and only because I had to to get new features to work. If I was more interested in the automated GPS stuff I would be using INAV for sure. But ya, I should give it a try, I'm sure a basic setup isn't much more work than with Betaflight.
@@FalconRadFPV I'm having a hard time deciding between 21700 and 18650. You told me the other day to buy Molicel brand but I forgot to ask which size. So based from your response to Hemanth above, it looks like for my 7" quadcopter, I should buy 18650 cells. However, I got confused about this text you wrote above "I use 21700 6s2p for when I really need good range". I can't figure out how you arrived at 25km. What was the mAh on your 21700 6s2p setup? Then you also wrote that if you want to be in the air longer, you use your 21700 6s2p. Thanks a lot in advance!😊
What awsome information. Very interesting Thanks for sharing. God bless 🙏 Stay safe hugs 💕
Thank you! You too!
Is it okay to use 6s 21700 for a 6inch quad for long range flying? Motors is Meps 2408 1900kv.
Yes that should be fine but the motors are pretty high kv, you should limit motor output by about 20% or so. and make sure your amp draw is resonable for the limits of the li-ion battery.
Each of your word should be carved in stone ,wow are you a teacher or scholar?
Many thanks!
Great insights into batteries from a long range perspective. I thought about setting motor output limit to not accidentally surpass the amp draw limit catching a dive. That probably means getting used to a different throttle stick position. What do you think about that? Also how bad is it to go higher? Will the battery die during flight or just not last as long in the future?
In my experience the li-ion batteries will just sag really badly if the amp draw gets too high. Or with brnd new cells it will put out the amps but get quite hot. In the end the pack shouldn't suddenly die in flight, but it will reduce the lifespan as well as the total mah that can be output. This is why I use two packs in parallel at 6s voltage. It keeps my amp draw below 1/4 of what my molicel li-ion packs are rated for, at least most of the time. If using 8s on a 6s setup you for sure want to use the motor output limit rather than just a throttle limit.
What do you think about other form factors of LiIons ?
Is 18650 still the king for the usecase, or do other formfactors (shorter&thicker) allow for ex. higher mah/g ?
I am really looking forward to your guide, so i can mid range my AOS 5.5 and use its higher disc loading! Cheers from Munich :)
I only use 21700 and 18650 cells. Which ones depend on the weight of the build the range that I'm looking to get. Most of the time I use 18650 6s2p but I do some flights with 21700 6s2p if I need more range.
Thanks for the info, i use molicel p26a aswell, what amperage do you charge your molicels at 1c?
1c at most, usually I charge them at 2 amps.
Are these unprotected or protecteed cells?
Unprotected. Protected cells might drop the quad out of the sky if you go full throttle.
@@FalconRadFPV thanks
Why to do 2x 6s1p in parallel? why not to do 1x 6s2p and save some weight?
The weight savings is only a small amount maybe 20 grams. Having a top plate big enough to carry a 6s2p li-ion battery and a gopro will create a lot of drag in the air. For the best range drag needs to be kept to a minimum. With my RAD Li-ion frame one battery is carried on the top plate and another one underneath, this helps to reduce drag quite a bit.
@FalconRadFPV Thanks man for the info, that's an important point.
Then how about doing a 6s in one line ? I know it's going to be tall for a 5" quad. But how about a 7 " one ?
I haven't tested or done any drone build but it's coming very soon. Haven't purchased the parts but most of them in the cart.
can i use 4 or 5 C li ion cells?
I wouldn't recommend it, the lower the amp rating the more they will sag in voltage.
@@FalconRadFPV so what is the minimum C value of a single cell?
👍🏻
What is best Battery in 2024r ??????????????????????????????????????????? Capacity/KG
That's hard to answer. It depends on the drone and what you want to do with it. As far as a battery for a 7" long range drone, I think the molicel P28A or P28B cells are my personal favorite. The best cells for flights packs are not the ones with the highest capacity as the video will tell you. You want a pack that can manage the current draw of a drone, the highest capacity cells are only good for flashlights and low current uses. For a 21700 size cell I suggest the molicel P45B or the samsung 50S.
Trying to make my 5" freestyle into a long range drone and I'm wondering whether 4S or 6S is better for efficiency. I feel like my old 4S builds were much more efficient on the low end.
I believe 3s and 4s are most efficient as far as watts vs thrust. I only use 6s because the higher voltage lowers the amp draw which allows me to run li-ion cells without them getting hot.
Thumbs up
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Don't know why there isnt sony vtc6 or vtc5a, I have tried moly cells and they suck compared to sony, also you didn't mentioned that you use 21700 not 18650 that is big difference compare to weigh.
I use both 21700 and 18650's. I showed both size packs in the video. The first time I tried a sony cell it performed badly. Lol, I guess the opposite experience from yours. The sony is rated for less amps also. The Molicel put out the amps that they claim. I have pulled over 80 amps from 6s2p 18650 packs with molicel P26A cells.
@@FalconRadFPV moly has more total capacity, but at the end it's sagging very fast compared to sony vtc6 and added all that weight I don't know which is better. Maybe in the future you will make video sony vs moly endurance test. Also watch out for fake one's.
Speak UP !!!
More great information. Thanks, Conrad. Glad I've been watching your channel for a while and watching what you're using for cells. Bought some Samsung 40T/21700/4000 and some Molicel P28A/18650/2800. Made several batteries and the first one was the hardest. Just getting your head around how things connect and good wire location and length. Doubt I'll buy any more lipos as most of my flying is cruisy and I have a bin full if I feel the need to blast.
So whadya think? Should we build up 10 of your li-ion frames with goggles, chargers, radios and batteries and send them to Ukraine for long range reconnaissance? Bet we could fundraise and get donations of equipment and parts. You have my number.
It's a great idea but 10 frames alone is over $1000. It would be about $6000 worth of gear to do that, I'm lucky if I get one FC and one ESC for free every three months or so. Most companies don't even answer emails from me!
I figure said and done, probably more like $15,000 if you included everything. Shit adds up fast. I wonder if the drone/quad community would kick in.
@@jimross898 This isn't the kind of drone being used in Ukraine though, they're using DJI Matrice and other huge quads with 30x zooms.