A word about receiver batteries
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- Опубліковано 8 лют 2025
- If you fly an RC plane that isn't electric powered then you need to give thought to the type of battery technology you use to power the RC gear.
The old AA size Nicad or NiMH packs simply are not suitable for many of today's larger glow/nitro, gas or turbine-powered RC planes because they can't reliably deliver enough current to support the demands of hi-torque or hi-speed digital servos.
Lithium battery technology has made the older Nicad/NiMH batteries all but redundant because it offers a cheaper, more reliable, higher current option without the problems of "memory" or high self-discharge.
These days I'm increasingly using LiFe packs for my receivers/servos and have yet to experience a failure. A123 packs are also based on LiFe chemistry but have "nanotech" construction which effectively gives them a higher 'C' rating so they can deliver more current.
Given that LiFe a 1100mAH pack costs under $4, a 2000mAH pack can be bought for under $15 and a 4200mAH pack for around $30 -- it makes no sense to rely on older technology batteries that may not be up to the task in your larger non-electric RC planes.
Getting back in to the hobby...your videos are invaluable. I honestly had no idea that battery technology had changed so much. Thank-you.
I pulled a 220mah cell with a wrong polarity from a "toy" RC motorcycle I have. My friend purchased a... not so great glider using non-micro servos and a 4 x AA pack!
Swapping the leads on the switch harness allowed me to thoughtless continue to use the original charger for the battery, and it saved a considerable amount of weight. Who knows how long a flight time we'll get, but this time around I think it does actually have a chance of flying!
Great post Bruce, keep em coming. You are right, too many people who have been flying a long time don't move forward with the technology ( which actually battery wise, is way cheaper than what they use now )
And all over sudden, i feel old. It is 2019 now and i do fly a 250g Parkflyer with a 24g Motor, 2 Servos (3.7g) on my trusty 35 Mhz Multiplex Europa Sprint Transmitter.
Nothing wrong with a great name brand VHF system. I've gone back to them myself, due to multiple reboot issues with 2.4ghz stuff in my area. It really is the most cluttered, poorly regulated RF band there is. Wifi, a wireless home thermometer, bluetooth....completely cluttered and not bulletproof like it was 10 years ago. I use PCM Futaba and JR radios, and no problems since.
@@guerrillaradio9953 can you still use old radio's at the fleld?
Love your old videos , you look so much younger , har ha!
I power all my receivers with a lemon and a zinc rod.hasn't failed me yet although I am thinking of upgrading to that new fangled lead and acid technology for my next masterpiece.
PS I am not a crackpot.
Awesome video Bruce.
These past couple of weeks have been sweet and sour for me regarding you. I hate you're not flying, but at the same time, you're cranking out a lot of videos, so we all love it!
The problem here is not with the NiMH batteries. Depending on the model you may draw 10A peaks from them.
The problem is VOLTAGE. At such tough loads the voltage will drop down to below 0.9V/cell. So you start out with 4*1.2V=4.8V which already is marginal, but when you start stalling 2, 3 or even 4 servos then you're down to 3-4V. This is a dangerous territory as receivers will turn off in this range.
Just adding 1 more NiMH and you'd be fine. Starting out with 6V, dropping down to 4.5V with multiple servos stalled.
It's nice to learn something new every day. This video has today covered, thanx
Using better quality battery helps keeping the voltage in between safe values, but it's far far away from something you can call "a safe power source and feed to the electronics".
High power servos also put a lot of stress on the receiver if they are sucking power from there, so a second step on safety is wiring the servos to the receiver with signal only, and powering them directly from battery.
Than, you may want to overcome a battery failing (dual battery array), and many other aspects...
Well done Bruce,you made a talk on batteries interesting + I learned something as well.
Cheers mate.
Great video, Bruce. Solid technical advice that keeps us coming back to your channels. I guess we ALL have something to learn. Even MFNZ members. Thanks for pointing out that nobody is perfect.
Good informative video Bruce.
I liked the info on the alternative shape and size of the LiFe packs, they look interesting, a no nonsense, makes sense battery, with good power.
Nice one mate..
Cheers Steve
Hi Bruce
I have now flown with life battery for 5-6 years without regulator, with std servos,, which is marked 4.5-6v. never had problems, no servos have burned.
Got a cheap $20 NiMh receiver pack from amain for our new RC trucks. Figured those are the easiest to work with, safest, and the tried & true battery type when I was into the hobby over a decade ago. First charge it blew up. I coughed up some $$$ and only run Spektrum LiFe packs now.
Just got into 1/8 4wd nitro buggy pick up a thunder tiger eb-4 s3 pro and im installing 2 7.4v 20kg servos for steering and throttle and definitely knowing now I'll get a 2000+mah 2cell lipo to running my 2 highvoltage servos
Fair point on the voltage of the freshly charged 5 cell NiMh packs but with LiFe being a consistent 6.6V does this not put extra stress on the electronics in the servo (e.g. motor windings)?
Totally agree on the LiFe for my receiver duties and try to share the info as much as possible but a lot of people are still stuck on using a BEC. On my surface electric vehicles I might use a BEC only if the ESC's BEC totally sucks.
LiFe batteries are also quite convenient compared to LiPo for this application, due to their voltage levels. 3.3V nominal per cell and approx 3.6V when fully charged. Which means a 2S LiFe is between 6.6 and 7.2V - compared to a 2S LiPo (7.6V-8.2V) - 3.8V nominal per cell and approx 4.2V when fully charged.
I know this is well old by now. New to the model game. Originally was running my 6v model on a lipo but have swapped to LiFe now. Peace of mind. Only issue is I’m having to make xt60 adapter cables but hey ho. Getting better at soldering in the process.
Thank you very much for this advice. Just what I needed!
The only issue is the cable size with those rx packs, you can just use 2 of them to split the power between the two.
Oh Nutts! ive just bought x2 5cell 2300mah enloop batterys to power my Hangar 9 60 size P 40 with a laser 100 four stroke engine! 1 to power rx servos etc and 1 to power retracts! Ive anways used them with my IC stuff and had no problems! Also have a 30 cc Edge with a 2s lipo and bec! May change that though! Cheers Bruce
Battery types are a minefield. I fly a 76cc Bidule tow plane and when on the 'tow' every servo in the model bar the release until flipped, is working very hard maintaining correct attitude, bank and yaw - so the fingers are busy.. I have always used 3000mah LIfe 2S batts x 2 until recently when they seemed to suddenly (overnight) degenerate to a stage where they will only accept about 70% charge. Being desperate I flew with these batts... two flights towing, I lost signal at the same height and same direction of flight and distance from me. The tug rolled over and dived and I guess within 2-3 seconds I had control back - twice. On checking the batts once safely back on the ground, both gone from 70% (being maximum charge) to under 50% in two very short flights. Lesson learnt but I am now changing back to Lipos.
I was just considering making a regulator for one of my new DLGs, but you bring up a good point about adding more points of failure. I'm planning on using four DS285 servos, although the specs have a torque range of 4.8 to 6.0 volts, is it safe to put a LiFe's 6.6 volts on the servos?
Thanks Bruce, another informative video that could save my models :-)
Nimh batteries are generally fine for most applications expect high draw situations as Bruce said. A real problem is that people charge a Nimh battery like a Lipo e.g. charging a 2000mah Nimh at 2A doesn't charge the battery at all because all chargers nowadays are delta peak and are only waiting to see a peak in the voltage. So charge your nimh's as slowly (e.g. 0.1a)as possible and it will be fine :)
As usual, very interesting.
Quite many servos, including the Hyperion Atlas DS09 servos are rated at 5.5V maximum. This means that you still need to use a BEC with a LiFe to bring the voltage down to a spec level. After all the 2S LiFe is 7.2V fully charged.
Wise words Bruce!
Rich.
I like the cylindrical LiFePo4 for gliders. If you choose the components right you can run the whole ship on one cell. Or use two. They still fit most fuselages.
Pouch type LiFePo4 are much lighter and bigger. If you have the space for them I guess they are the way to go. And you don't have to solder the cells together.
thanks for the info I had not heard of these before
spent 900 on a .50 heli, used a nimh pack for 4 high torque analog servos. when I gave it throttle, 4 of those moved causing a brownout. into the sky it went never saw it again. it was NUTS
Hi there,quality videos! as usual, but I have to just give my thoughts about bec's, Im a guy who likes simple setups as you mention, more stuff more to go wrong, but looking few years back were all the lipo tech started, I been flying all sort of electric planes, small big, helis, and never ever had a bec going wrong, only in one case the speed controller gave up, but rc still working, and on todays massive hi tech 600 700 class helicopter using huge servos and massive lipos, for the Rc they still using a good quality bec, and those choppers could be quite dangerous out of control!, again there are not many cases apart from the odd wrong connected battery, For my 50cc gas planes I like to have some redundancy used in some twin regulators using 2 2s lipos, heavy duty switches plus using twin 2100 mah batteries you end with 4200 mah to power your plane for the whole weekend although I like to charge up before going up! some setups are in a reasonable price range without going in to the expensive power boxes field which I thing they are too big for a 50cc plane, yes for a 100cc with two servos per aileron 2 for the rudder etc, any experience with the dualsky vlr twin reg?.
Cheers!!
I sure got a charge out of this video! Thanks for posting! ;)
Excellent info Bruce, as always!
That's crazy. 4s 600ma nicd's are $8-10usd and 2200-2400nimh nimh packs are $30-35usd. NZ has some crazy markups.
Bruce as always very informative. Thanks so much. Now if you guys could stop beating us at Rugby, everything would be fine.
Keep well.
Thank you very much Bruce, very informative video!
Btw you are totally right, today my controller alerted me about the "a1 voltage critical". Im using digital servos with nimh.... bad idea
Bruce, What are your recommendations for figuring out the mAh for LiFe batteries? I can work out the math, but I wonder if there's any tips or tricks you have? BTW: Love the videos! Dave
I've been out of the game for 10 years, now all my receivers & my hand set are out of date . . All i have left is my servos. I have to start over from scratch,
TY on the info on the batteries, I’m now looking for info on tx battery chargers ,
great video, thanks for uploading it :)
Lol thanks for the advice I’m gonna put a 3s lipo on my Tmaxx😂😂😂😂
I use two LiFePo AA batteries for my small gliders
Bruce, is it correct to say that since the servo position is sent in pulses the motor windings are only seeing ~6.6V for the width of a pulse (~1.5ms) and at a rate of 50 times a second for an analog servo i.e. duty cycle is low? Also is it reasonable to assume the motor windings are the sensitive part of the servo and not the electronics?
Keep up the tech people!
5 years ago. wow. crazy to see a different back drop
I like this back drop than the new one he uses. Does not change the quality content I guess.
Bruce:
I have never used a life battery and would like to know more about them. Maybe a video on them including what not to use them on and why and what to look for so that we don't blow thinks up? How many volts are they?
Thanks
6.6v LiFe is a direct replacement of 6V NiMH. Both batteries, when fully charged, will be at 7.2V!
Thank you for the info, You Rock !
Thank you for the information. What chargers can be used to charge life batteries?
love your work :)
i had issues with these in cars lol
my old futaba use's Nicd 4.8v for the receiver can I use lipo batterys
i really learned alot thank you,,, do you need a special charger for life or can you se a standard lipo charger
@tom reid, doubt its the 1 5th scale vampire that dh100 is showing on the mfnz website. But i am worried about a nimh pack eing uesed in a turbine plane with 14 plus servos.
the gas engine you have to regulate lipo for gas ignition A123 doesn't need to be regulated on the gas ignition
Thanks for the update I am running 4.8 to 8.4v servo and was wondering if those 6v pack would work so I checked the spectrum receiver voltage it's about 4 to 9v so I just bought a spectrum Rx 2000 7.4v receiver battery do you think that will work cheers Rick
I am thinking of buying some sort of a 1/4 scale Super Cub and am looking for engine options, something a little different. I will have to to some investigating online. Thanks Bruce
Hey great video Bruce. Can you use Nimh and lifepo together in the same RX? How bout if I plug in two nimh into one RX. Is there a way around two switches? Or will I always need two switches? Thanks for your videos great stuff.
I am curious also to see Bruces response to the LM7805 question.. Its a simple voltage regulator...but 'm not sure it can handle the current of large servos. I was thinking of using it for the 5 volt regulator for some cams and transmitters in FPV. I bought some nice regulators ...but they produced lines on the video... and I think the LM7805 may not do this.
Try a 338 adjustable regulator
More advantages nicds have against lipos. In my experience nicd's have a useful life span of about a decade. Lets talk durability (lipos cant touch nickle). And let's talk cell failure. A nicd pack has a cell fail, you still get your power out of the remaining batteries in the pack. A lipo cell fails. You might continue getting power out of the pack. (Ive had them go fail both ways).
LIPO's are undesputed king of powering your motors
Nicd's can not be beat powering R/C gear
Keep flying Bruce!
Hey Bruce love your work have watched hours of your content . This might be a stupid question but will my 4.8v to 6.0v servos take a 6.6v liFe? Thanks for any help you can give me.
Did you ever get an answer i have the same question
@@scotty1004 And now I have the same question haha
He's not answering questions. I guess he has a lot on his plate
I have heard of redundancies used in battery hook up and I would like your opinion. "Power Box" idea seem like a great idea but the expense is ridiculous. I have a 90" AeroWorks Edge 540. I have been out of the Hobby for 15 years and it certainly is a different world than I left. I have two thoughts about power distribution. (1) Is the idea that using the receivers last aux input will isolate is one battery fails, but does this stop one battery from trying to charge the failed battery. I want the redundancy but will this work. (2) I think a circuit built with two power rectifier diode in series with each of two LiFe 2250 Mah batteries is the better idea and I can see and understand it would work. Does the receiver idea really work?
Bruce, you didn't cover the mAh capacity for a receiver pack.......suggestions ?
Would have liked a link to the 123 pack build video.
Mad scientist.. you the man lol
Great video
Thanks, I will take a look at it.
Recently, while surfing videos of RC models I ran across a critique of a new camera. The camera was small and was separated fromits electronics by 10 inches of wire. It was HD and the cost $150. You know the name?
Very good video as always, Did that Jet crash while Rex Kenny was in town?
Good day sir, nice video. What is the best for Futaba 6J receiver-helicopter (light and powerful).
Great Site.I came upon it by accident.Glad i did.
Q. I have a 1000w hub motor for my ebike which says i should use a 48v battery.I have linked 4 sal batteries to make up 48 v but performance is poor under load.What would you recommend + - 14 a123 battery cells joined to achieve 48v, or existing battery packs as sold by hobby king .what charger would you recommend ?Looking forward to you reply
Thanks
John H
Hi Bruce,
I tried using a LIFE receiver pack on my FRSKY gear :
Receiver Specification:
Operating voltage: 3.5~10.0V
Power consumption: 100mA
Analog voltage: 0~3.3V
Only to find that it cooked all of my servos in a brand new HK RTF model (FPV Raptor) and subsequently had servo lockup in flight with crash following shortly there after??
I read the receiver spec and believed that the analog voltage would represent the voltage coming out of the receiver to the servos ?
Did I miss something ???
LiFe are 6.6v. But my servos are max 5-6v. How would i be able to use 6.6 v LiFe batteries. I am using nimh 6v 2300mah for all my planes and they are getting biger up too 80" wing span
So how much amps your servos drew? It has to be massive if caused problems with eneloops. Strange.
Hi Bruce with the 6v battery for a nitro motor which one should i us a 700mah. or 1100.mah hope you can help me as this is my fist plane
hi Bruce when are you going to make the frsky taranis review?
I appreciate your wanting to help. This is a very technical subject and requires a technical presentation. Are you up for constructive advise? Yes.... great.... no.... well sorry its coming anyway. Were you only about speaking to NOT USING AA batteries, and the rest of the facts one would have to figure out for them self? IF that is the case then you made your point. A few things added would have helped. Please speak a little slower. Your accent is touch for some of us. You said the same things over and over. Granted it was said in different ways, but the time could have been used to present more facts. A lot more needs to be said. For some one to employ LiFe batteries, they most certainly should google and get some thorough info. But you are 101% correct. Pilots have no choice but to keep up with the changing times. In all honesty, its not that much to learn but it does take time and commitment ! Thanks for the video. I am sure it will help.
Hi. I watch your vid.s and enjoy them. However, I am an American and our accents are quite different. I am an old man and have a little trouble hearing and understanding everything you say, but I get most of it. The last battery you described went right past me, twice. So,,,what type of battery was it? I would really like to know.
Thank you for all the information you give out
Richard.
LiFe Battery(this is the common abbreviation). Full name is actually Lithium iron phosphate. It's confusing because there are a lot of lithium battery chemistries and abbreviations. NOT to be confused with the other common type, LiPo (Lithium Polymer)/Lithium Ion(which are also and abbreviation for same battery in different physical packages, nominal 3.7v/cell). LiFe have much higher energy density (smaller/lighter) and current output compared to NiMh packs. LiFe Batteries have nominal voltage of 3.3V/cell , so a LiFe 2S (2 cell) pack has nominal 6.6V. LiFe batteries also have a flatvoltage discharge curve similar to Nickel batts, even better than LiPo's, These reasons make them a good replacement for the 5 Cell NiMh receiver packs.
I can't understand half of what he is talking about. He talks too fast on many of his highly accented words, ands crushes the pronunciation.
Barry for lord supreme rc air commander!
Bruce when you get the time and budget can you please do a proper comparison between Sony FPV cameras and GoPros ? Im building a multicopter so it would be awesome to know what youd think to take aerial videos and pictures. I read GoPros have a weird wide angle and most people prefer to fly Sony cameras instead. Your thoughts. Please thumbs up so he can see.
Well, if in doubt use HV servos. But no, in practice most servos don't care squad about a few volts more or less. Your mileage may vary.
I would like to say that AA sized (450-500-600ma) nicd packs were NEVER a problem for larger fuel planes because NOONE in the world ever used such small packs flying giant scale, or with servos larger than Standard size. (40-60oz). Entry level IMAC legal giant scale fliers typically would use 5s 800-1100mah nicd packs. This is enough to run five to six heavy duty standard sized servos (50-110oz).
just a little question
i have a stock losi raminator nitro and it has the losi 6v pack i think 900 mah also. and i have a 7.4 volt 1300 mah dynamite battery to upgrade with. but the orignal battery has a jst connector and the reciever area has the jjst female plug (obviously) how do i change that? i dont want to fry something. and the wire gauge is also much larger. thanks
I'm building a 55" spitfire. 80 amp esc with 5 amps for the radio gear. Seven standard analog servos. Will that ESC provide enough power for seven servos?
i have a life battery in my p-51. it has only one charge wire. it is a j connector. it has a balance wire. one cell is very low. it is a life 6.6v 2200 mah 2 cell battery. how can i balance the cells?
I drive cars and trucks so not much of an issue hasn't someone come up with a backup supply just to land the planes ie a cheap 4 cell old type so when the power goes off a switch jumps into the backup just to land the craft?.
Fx 1C Yes, they sell a very simple device that does just that. I do use an "old" 4.8v nicad as my back-up. It only gets switched on if the esc/bec fails or the lipo (2S or more) drops below the 4.8v. The 600mAh is plenty to make what would be a deadstick landing.
thanks bruce.
The Life batteries are rated at 3.3 volts per cell. most seem to use 2 cell, so 6.6.
There was a warning on one battery site that some of the smaller 17 gram servos are rated 6 volts or below and that 6.6 will reduce the life.
Do I need worry?
www.helifreak.com/showthread.php?t=567539
Thank you sir!
I received a fpv mariner in the case and there is a 6 pin connector which appears to plug into the lipi battery second wire (small voltage wire, I think) My question is -Should I connect this or go straight for the direct connect and keep the transmitter receiver seperate all together
Get in contact with the guys on the openrcforums forum for that. A lot of the developers hang out there. They would love to see what you have to say and answer questions.
Hey i am putting together a 40 size nitro piper cub. I have the spektrum ar6210 receiver and am wondering what type of battery i need to power my reciever and servos? How many volts and mah? I think j have a 2000mah nimh now but it is no good.
Hi. I am building the Giant 2metre wingspan LX Mitchell B25 Bomber. I will also fit the 'model sounds incorporated' sound system with the recommended 3 inch speakers.
The sound system will work independently and directly from a Lipo as it has a voltage range of up to 24volts. So no problems for that.
The Bomber itself has 10 servos and additional cabin area LED's, and I have been advised to power the receiver independently.
The main battery, a purpose built flat pack designed for the model by LX. power the twin 600kv motors.
I watched your piece on the Lithium Iron Batteries (LiFePO4) and wanted to get your thoughts on the size required.
The main issue will be weight as I will now have 3 batteries.
I really enjoy your vids. They are interesting and very informative.............keep up the good work.
regards
Can I use a 2.4g receiver and remote, and install 9V batteries ?? I’m really new to this and building my own stuff.
I use a typical receiver system, powered by a typical BEC attached to my typical ESC. How does my typical receiver manage to start operating at up to 10 volts when it's only supply is 5 volts ?
Hi, which is the right battery for my Glow engine Rc plane and 4 servos? using Spektrum receiver.
What about the CDI ignition modules of the Gas engines, do the 6.6V Life batteries pose a problem there? I'm using a regulator to cut my life packs back to 6V. Is that necessary?
I have 2 planes. They both carry hitec optima receivers, one airplane has 7 digital servos, the other has 5 with 3 electric retracts i think their eflite retracts. What battery for my recivers do you recommend i really need help. Thank you.
Thank you for the information, I have watched many of your videos on RC. I am newbie in RC. I am stuck on a few questions and couldn't find any reasonable answer so far.
My question is.. on the receiver end, how do i determine battery voltage Amps etc?
if there are ...
FlySky 9x Receiver and ...
2 motors with propellers on both side wings connected parallel with speed control,
2 servos (I don't know its required volts) on both Ailerons,
1 servo on Elevator,
1 servo on Rudder,
1 servo on Landing Gear,
1 servos with Flash light.
Now how much volt of current and in what direction i will need to put connection with batteries.
That's lot to ask as a you tube comment mate. Go to rcgroups (google it) which is more appropriate to find such info and ask such questions.
Basically you need to look at specs of your equipment and calculate it.