From the Bench - Lipo Batteries, C Rating, and Tips for Best Battery Performance
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- Опубліковано 12 лип 2024
- One of the questions I get quite often at events is what kind of batteries do I use in my aircraft. I've been flying large EDFs and electric warbirds for a long time and good quality batteries are essential to performance. So here's a little discussion on the batteries that I currently use and what I go for in terms of C rating as well as what my best practices for maintaining battery performance over time. Article available at: wp.me/p5LuFX-1qf
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The all-important Time:Fun ratio. Haha! Very good point. Thanks for helping to broaden my understanding on the LiPos. I've always just thought "if the battery comes out just a little warm, you're at the right C rating"... and I too ALWAYS charge at 1C. Great video, Chris!
Good points in this video and this is a deep subject on many sub topics to get the best from your investment. My personal experience is from producing packs and dealing with the manufacturer plus lots of testing and evaluation for the RC market.
Top Tip: get a Data Logging system or Telemetry wether in an ESC or a stand alone unit. It provides invaluable data so you know exactly what’s going on. Save the data from each pack so you can track the life and health of each pack.
Temps: from testing and practice the packs under load, cold, get up to about 100F or so before they actually start to push to their potential. In all weather make sure your pack is at 90 to 100F starting temp and you will not waste time or capacity in the first moments of the flight.
Soldering Connectors: make sure you have nice clean glossy solder joints on the bullet plugs or Deans plugs. This can be a source for failure if not done right. From experience...
From data logging and telemetry what you want to see is Voltage Under Load. When you add power and the load increases the best sign of a packs performance is voltage under load or VUL. The single most significant increase in performance to an electric vehicle is voltage. The best point to see what that value is at peak load. From one pack to another the best one will deliver the highest VUL and operate within temperature parameters.
C rating is the packs ability to deliver the power under load. In a 3D helicopter or plane or in an RC car if you watch the voltage under load between low and high C packs you will understand the difference and why it justifies the extra cost of a higher C pack. Otherwise for longer constant power demand flights like EDF you can use a lower C rate pack and maximize capacity for increased flight time. As Chris said though, it’s a balance between battery size/weight and the airframe. In most cases when a company claims insane high C cell ratings it’s done in a lab and the numbers are not practical. The suggested amps or volts are too extreme for the packs own tabs to handle let alone the wires and plugs. So in the case of typical RC planes a lower C rate is just fine and more economical.
Tam Jets tested our 20C 5000mah packs against 30C and 40C packs in his Sky Master F-86 using his own EDF unit and found our 20C packs could perform as well or better than others.
Ultimate pack performance on a bench test should reveal 3 data points coming together simultaneously. Peak temp, 120F, max capacity and max voltage under load. While testing the pack cannot exceed 120F before fully dumping. If the pack fully dumps but maintains its temp then you want to see the max voltage it sustained. The pack cannot then exceed 140F - 145F after it fully dumps. This is the exotherm cycle after the pack stops pushing amps, the molecules are still active and giving off heat. If it passes this stress test then you have a good pack. The LVCO or low voltage cut off should be set to 3V per cell on the ESC. I have tested to 2.9V and 2.8V but this is extreme.
Balancing packs I found is harmful if you do it every time you charge. Monitor the difference between cells always and balance charge as needed and at least every 3rd to 5th cycle. LiPo packs do not like trickle charging for long periods of time. They like to charge at 1C as soon as possible and discharge as soon as possible. LiPo chemistry is not designed for long term storage because it has a pretty high energy density and wants to repeat cycles and be active. For storage applications like radios Tx/Rx look to LiFe and LiOn packs. Do not exceed 0.5V but a couple tenths of a volt between cells is ok.
High rate charging is bad for packs, from the horses mouth, literally. Even battery manufacturers will tell you it’s not good on the overall life span of a pack designed to take high rate charging. If your not racing or not sponsored then save your money and charge at 1C. Plus it’s safer.
Storage: store at the nominal pack voltage or 3.7V per cell and at a temperature of 60F to 75F. LiPo packs hate the cold in use and in storage.
Basically, information is key to succeeding at LiPo power systems and I cannot stress enough the importance of a Data Logger or Telemetry in all your applications. It’s just smart and much safer than guessing about how your set up is working.
Who am I? Former head of R&D for Venom Racing and I developed the battery program for the company from the beginning in 2005 until 2012.
Thanks to Chris Wolf for his undying support of the RC hobby, keep up the good work!
Great info Chris, thanks for posting!
Thanks mate. I did not know that balance charging every time was bad. Will stop doing that. 👍🏻👍🏻🙃🙃
@@matk4731 its not the worst thing you can do but it has been observed to reduce the life of the packs we tested and purposely abused. Just watch them closely and you will catch a lazy cell before it gets too bad and causes issues.
Chris Nicastro
Thanks for the advice its always appreciated 👍🏻
Thanks Chris for this great video, I agree the proper care is key and I love my review charger as well. Always keep batteries warm on colder days and try not to let them get to hot on the hotter summer days, there like us....they like a nice normal range temp as well. Thanks for all you do for this great hobby 👊🏼👊🏼👊🏼👍🏼👍🏼👍🏼
Good tips on battery temperature! Makes a world of difference on performance and getting the most cycles from the packs. Thanks for watching! :)
Been flying electric for 17 years ,still learned something , thanks Chris
Thank you!
Thanks for sharing the your ideas on proper lipo care and maintenance.
Thanks for watching!
Well done comparison of maximum current regarding bigger c-rating vs. bigger capacity. But from my experience, an I heard It from some EDF pilots as a rule of thumb: If you discharge your battery in less than 5 minutes, and all of this small EDF foam-jets can do that, you will hurt your battery. You can calculate by yourself, how much time you have, if you discharge let’s say with „only“ 35C. And most manufacturers indicate the c-rating as max continuous current. With an EDF you can easily prove that as wrong and destroy your LiPo battery. So I agree to rather choose a bigger capacity than a bigger c-rating.
Im right on board with your perfered choice of batteries Chris.Ive got 5 and 6 year old Roaring Top Batties that have at least 500 flights on them by now and they just never die for me i had planned on replacing them 2 years ago but they just havent given me reason too. oh as a side note i do something nobody ever does cause their terrified to and that is i always leave my batteries fully charged even in storage in my home fire safe and i have had one go bad yet out of around 40 betteries so there is alot of misnomer about lipo,s from what i can tell from my own personal long term performance testing.....Cheers and thanks for the video....Sorry to blow a hole in everybodies therory but my personal experiance proves the whole storage voltage thing incorrect just call them as i see them
I ordered 4 packs from them today. Really good info on Lipos, I also out more faith in personal experiences with a product than brand loyalty. Their pricing was very good as well.
Awesome! I hope they work as well for you as they have for me!
Great video man. Roaringtop batteries and Andy are awesome.
Thanks man! Yeah, love me them RT packs. 😎
Lol, love the biscuit scene!. Also good info!
haha, thanks!
This is all I run now thanks to you thank you very much very happy with this brand customer service also great
Awesome man, so glad you loving the packs!!
Thanks Chris great video mate 👍🏻👍🏻🙃🙃
Great video sir 👍
Thanks!
Thank you
I too am a fan of Roaring top.
Good video and great information. I'm looking for batteries for my new FMS FUTURA V3 80mm. I don't see that you mention SMC (Superior Matching Concept) LiHV batteries -- any particular reason?
Mostly because at the time I made this, I hadn’t used them before. Even still, I don’t have much experience with the smc packs, but I’ve heard very good things about them. My only recommendation would be to make sure your power system can handle the additional power. You’ll get increased peak current and power, so make sure the motor and esc can handle it.
Personal experience matters more to me than just sticking to a brand. I appreciate the honesty!! I have been a huge fan of Roaring Top for a couple years now! And thanks for your thoughts on lower C packs... I have been saying this for a really long time! My fave packs are 30-40c packs!! My fastest edf which is almost doing about 140mph and on a 30c pack!!! And my new fave set up runs best on a 30c!! The 5800 and 6200 35c packs are awesome!! Great info and I totally agree with everything you are saying!! Good stuff!
Hi Chris, need to add additional information here on the C rating. As you say the C rating is the number of amps the battery can deliver for a given charge value. Most people believe that that Current is available from the battery throughout the flight. This is not 100% correct. As an example a battery at 50% charge will have (The same example you give) 5000mah 35C is 175 Amps, at 50% charge it is a 2500mah Battery and can only deliver 87.5 Amps. And when 0% charge its 0 amps. Fairly linear as far as I am aware. Pilots normally time their flights and ensure that they land at about 3.8V per cell. Mostly on a fixed wing Prop or Electric this loss of max current as the battery discharges won't be noticeable. What will happen if you throttle up is that the demand on the battery will exceed its ability to deliver current. This will not damage the battery as the individual cells can withstand the full charge C value current rating. Something has to give, Ohms law prevails. V=IR. R the resistance is the load (The ESC / Motor Resistance at your throttle setting) which will be fixed value for any particular throttle setting. So as V=IR and resistance is a constant the request to the battery is throttled by the C rating at that charge level, hence the V Voltage drops. This is called a "Brownout", not a big deal as I said for Fixed Wings as it will manifest as lack of power. (assuming you have a good quality BEC in your ESC or run a seperate Flight Rx battery {Highly recomended}). If you have a poor quality BEC it is possible that it also will brownout and depending on your RX /FC setup this can cause issues. It is possible that demands on the battery the BEC can cause a reset of the RX or FC. If you are using a Promiscuous RX it could be a problem as you will lose the bind. If you are using a gyro you could lose the current Gyro setting. As I keep repeating not a big issue for Fixed Wings. Now if you fly everything, like I do this is an issue for Helis and Drones. If you are flying helicopter 3D at this time and the FC gets a reset you will lose your Heli. If you are at altitude, most likely have time to recover. And helis can glide, a drone can not. Drones glide the same way a brick does. Brownouts on drones will either cause a fall from the Sky or as with some GPS based return to home drones they will fly off in a random direction, never to be seen again.
My general battery philosophy is to buy batteries that have a C rating that will still provide full power and current supply at 50% Charge. So a 5,000mah battery and an ESC / Motor / (Prop / Props / Fan) combo that draws 200 Amps on full throttle will require a 200 / 5.000 = 40C, For things like my 12s scale helis I work this out as a peak, the same as the Peak settings of the ESC. My 200Amp ESCs will peak at 400Amps. So I would use 80C. It's a how large a margin do you want to have and what is the cost of the margin. I recently purchased a bunch of 5,000Mah 100C Batteries from China. I am going to put them to the test on a 12S 105mm JP fan on a test stand and see how they perform. Weight wise they are about the same as a 50C nanotech battery. All Lipos come from China including your Roaring Tops I believe. Good work here in this post and your vblog. Just wanted to provide a more detailed view of the specifications and impacts for your subscribers. I provide online support for a Drone manufacturer members site. Its amazing how many people lose their drones as they don't understand the battery technology. They treat the manufacturers max flight time as a recommendation. I never fly my batteries under 50% charge. Keeping the Charge Recharge cycle above 50% extends the number of possible charge cycles hence life of the battery.
Finally, (Everyone breath a sigh of relief) higher C ratings do not improve the performance of a Fixed Wing at full charge. As the limitation is the request for Current from the ESC. But as the battery charge / voltage drops the higher C rating will deliver more current to the ESC as it will not brownout as fast. So the higher C rating will appear to give better performance. So anecdotally people are correct, but for the wrong reason.
Yup, good stuff!
I love my 6s RT’s in my CZ Cessna 150
Good stuff!!
thanks Chris, a lot of good info. when will you be doing a review on the Scale Dynamics AT 6 say an unboxing see what's inside. mike
Well, I've not started the kit unfortunately and I've been dying to do so. Once I get started, I'll get the videos going for it. I have a big VQ warbird B-24 on the bench needing to be finished first.
I like the way you explain that you are just using the packs, not trying to be scientific
Thanks! Ultimately, how they perform in their intended use is what matters.
Thanks for making this. I wish someone would make a how to store your lipos safely. How do you store yours? Indoors outdoors away from the house? What causes batteries to explode? Is it mainly over charging them, charging them incorrectly? Thanks
I store them in ammo cans and lipo sacks and in a storage state. Battery incidents almost always are a result of over charging or over discharging, so it's important to keep any eye on the cell voltages as you charge.
Outside. I make ion battery packs. Polymer is No joke. Never overcharge Never leave unattended Never store OPENLY. SOME SORT OF METAL CONTAINER. COMMMON SENSE
Excellent video. Can you tell me the exact model of this charger and also the power supply you are using please. I start about 5 month with electrics planes and now EDF's . I need an charger upgrade for this 2021. It takes forever to charge my 10 6S packs LOL. Thanks
Thanks! I'm using a maxamps 24v power supply and a revolectrix Dual PowerLab 8 charger. It's not cheap, but is a fantastic charger setup!
@@Thercgeek
Excellent. The progresive RC website show it rated at 1350W per channel. How powerfull most be the power supply in this case. I ask because I saw couple of 24V PSU. Thanks
You’ll want the higher power 24v supply. Progressive rc is a great source btw!
Nice
What model is that in the background , it’s beautiful
It's my Jet Hangar Hobbies A-7 Corsair II. ua-cam.com/video/KXIhTT5Ehw8/v-deo.html
Thanks Chris. I was looking to buy my first 6S battery for my first edf (Freewing Hawk 70mm). I was thinking about going with the roaring top 4500mah 25C (4.5*25=112.5Amps). Is this ok for this edf (it has a 80Amp ESC, so guessed it draws 80Amp at max)? Did i get it correctly?
That should work, but I think you'll get a little better longevity from a 35C 4500 pack if you can swing it.
Your channel seems to attract more focused experienced people which makes your comment section usually very good, informative. do you mind if i post this link on our chollas rc flyers page?
Yeah, you can post a link or use the youtube embed feature to embed this video on a website. Thanks!
I have a question I am getting into rc boats and as water creates much more resistance then air what is a good compassity for a 120a esc? They recommend 50c but I found that the 50c batteries I have aren't quite powerful enough as they puffed a few of my rc truck lipos so I bought a much higher c rated pack and on the zeee lipos I bought it seems to struggle like the esc isn't putting out the power as well as dedicated batteries they suggest as the terminals get warm but not the batteries or the esc or the motor but I use a good brand 60c+ and the boat seems to run faster but the lipos don't get as hot but the motor and esc get toasty... lol so I went with a really good 120c racing lipos and the motor doesn't get hot and the esc isn't as hot either after a run. So what do you suggest for a brand for my type of application as the battery will be pushed harder then something flying in the air as water is much more resistant then air?? And it seems my motor and esc like pulling more juice specially on 4s as apposed to 6s where it is going faster and planes the water surface more then the lower 4s lipo setup. Like airplanes the weight is a factor as well especially for speed runs
All of these same rules apply that I’ve noted in the video. Sounds to me the system is pulling quite a bit of amps, so if you’re running lower capacity packs, you’ll need to run at a higher c rating. What capacity are you running and how many amps is the system pulling? In terms of a recommendation, The high c rating roaring tops are good stuff.
I'm converting to Roaring Top. That and RCJETWERX.COM.
I'm starting EDF flying.
I'll save money in the long run and not be disappointed in the short run.
You generally get what you pay for.
HI Mate, Agree with everything you said, from my experience as well. I have a questions for you. The C rating will define the maximum current of a Fully Charged Battery that the battery can provide. Do the calcs on a half discharged battery and see what you get.The C rating method does not actually provide a true reading of Current as the battery discharges. I don't know if it's linear or a curve. If you keep above the nominal voltage 3.7V per cell you will be OK. If you do the calc at half the rated mah for your max current. You know you will have no issues with voltage sag all the way to landing.
That is true, the C rating is really just a generic battery performance metric that the manufacturers came up. Interesting point at partial charge, but also the voltage drops as the charge depletes as well. I've seen plots of the voltage drop of lipo cells and it's actually pretty linear except at the very end where it drops off extremely quickly. So, keeping at the 3.7v/cell mark helps avoid that all together.
@@Thercgeek Those plots do not show the whole story of Voltage Sag. Its quite simple really, basic Ohms Law. V=IR. As the available current lowers as the battery depletes. (Max Current Available I=Cx[AH}) something has to give to balance the equation. The (R) Resistance of the load decreases as the throttle position opens. On a fully charged battery The battery can supply all the (I) current to keep the V=IR balanced. As the battery depletes, and It can't supply the current demanded by the ESC and Motor, The V must drop. Hence voltage sag. It then depends on what electronics are on the aircraft and their reactions to voltage sag. A Drone may just drop from the sky as its FC resets. A fixed wing can lose RX connection and go into rebinding. Or the Gyro may go into an indeterminate state. Rotary wings will lose the Gyro or Flybarless FC.
The reality of this will be when over discharging the battery inn flight that any sudden demand for power can result in a voltage sag that will as a minimum not give you the thrust you are demanding, at worst give you a (Brownout) on your electronics that will have undesirable results.
I fly with telemetry monitoring on all my models for at least battery monitoring.
Keep up the good work. Been a subscriber for some time .
Would you recommend a Zeee 4S LiPo Battery 14.8V 5200mAh 100C with EC5 Connector Soft Case for the F-15 V2 64 mm RC Airplane ?
Thank you
Great video !
Honestly, I have no experience with that brand, so can’t really say. Which F-15? A 5200 might be too big depending on which model we’re talking about.
Sir which one is more powerful and more faster.3500kv or 3150kv both on 4s.pls help.thanks
That is not a straight forward question as it really depends on the prop. Assuming the same propeller is used, the higher kv will spin higher rpm, but also at the expense of higher amp draw. However, in trying to match power draw, you may find the lower kv to be faster as you can run a higher pitch propeller.
Where did you get that aircraft featured in your video?
It's my jet hangar hobbies A-7 Corsair II (my dad's design). Unfortunately, that's the one kit he no longer makes. :(
Will a 5s lipo fly a Freewing 6s jet if you aren’t looking for maximum performance? I have three just collecting dust
It’ll work in the literal sense, but I’d expect the performance to be fairly marginal. Good enough for flying around, but not much vertical if any.
I had heard that you should store your batteries at storage voltage in a fridge in zip-loc bags. I have been doing this for over three years and my batteries are fine... Is it inconvenient for the LiPos?
I've never heard that for lipos, nor have I ever practiced that.
Perhaps I heard it in an old podcasts, like All Things That Fly... but I am not sure.
Chris what do you use to power your charger at the field? Thanks!
I’m currently using a Honda eu2200 generator and love it. Before I had it though, I was using two deep cycle marine batteries wired in series to get 24v. Worked great and I could usually charge as much as I wanted for about half the day.
@@Thercgeek thanks so much!!
So, I have a 6000 mAh 2s 60c lipo battery and Im gonna buy a 70mm 6s 2300kV edf. Would this give me ideal performance?
I heard that the number of cells would affect my performance
You will want to use the recommended number of cells for the edf. Running a setup intended to run on 6s on 2s likely won’t generate sufficient thrust to fly the airplane.
Chris, what plane is on the bench? Who makes it?
It's my Jet Hangar Hobbies A-7 Corsair II (my dad's design). Unfortunately, it's the one kit my dad no longer makes.
Hi have a question here. have tried and compared 35c 45c 50c 60c and even 100c lipos in my jets and prop planes. I do not see what your saying at all sorry. What I mean is this My nephew and I have the same plane for instance the eflite Cessna 150. I used a admiral 50c 5000 and he used my 4000 60c admiral night and day way different. That 60c was doing much better and was faster. I then used my 60c admiral against his 100c zeee 6s 6000mah and he blew my tail feathers off. we started next to each other on take off and he never looked back. I tried my 60c 4000 in my freewing 90mm f-22 and flew as normal not bad. Put his in and lights out way better. I have tried 35c-45c and absolutely was a flying dog. took triple the runway and then it was just always trying to catch up to its shadow very gutless. I have been flying electric since 1998 when it was sub c batts heavy garbage and flown since 1992. I have 130 planes/jets in my mix elec/gas and did nitro. But what I need to know is why is it that I see the major difference here and you do not and others. I have about a hundred lipos from zippy,turnigy (hobbking is awful cs) eflite yak, thunder junk,glacier nope,vambat nope, admiral I do not mind OK liking the zeee lipos thus far great price and have not had any issues yet about 2 years with them thus far. I guess I do not see what your saying at all. If you see that your plane/jet is much faster than how can you say a lower c is better when its slower. I am not trying to be a kill joy just trying to show different facts I can prove on video. If you can please
I would expect the results you have noted. Putting a 40c against a 100c, you will get more speed from the 100c (or other higher crated pack of the same capacity) all day long. But you will also get more weight and more amps as well. For me, I’m looking for the best balance of weight, flight time and performance. Also, the thing to keep in mind that I mentioned is that it’s both capacity and c rating. If you’re using a 4000 in a 90mm jet, I wouldn’t expect much in the way of speed there with a 35c. Now, use a 35c 6000 and you’ll see a notable difference in performance compared to the 4000. It’s like using a higher c rated pack, but at the end of the day, you’ll get more flight time from it due to the higher capacity. Ultimately, it’s about what you’re looking to get from the airplane and what gives you the performance you want from it.
👍👍
what are the details on your charger? Who sells it?
The chargers came from fma direct/revolectrix. Unfortunately they closed down permanently a year or two ago (byproduct of the pandemic 😕). I’d recommend taking a look at the icharger duo from progressiverc.com
What balancing boards are those?
The boards I've gotten from a number of different places. ProgressiveRC.com is a great place for chargers and balance boards.
I disagree with fully charged overnight. I have had admiiral batts for 2 yrs and still run like new.
It really depends on the batteries. I did this for a number of years without too many issues, but then I started using the cheaper HK packs and they got soft pretty quick letting them sit overnight. Ultimately though, it's just safer, so that's why I maintain the practice of charging the morning of. With the right charger setup, there's really no reason not to.
A Lot of people dont know much about C rating on lipos . You dont need high c rating lipos on big warbirds or little foamy planes like people think they do. Just like theres no such thing as 100c lipos