A word about receiver batteries

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.

[@DaveStroble]

Getting back in to the hobby...your videos are invaluable. I honestly had no idea that battery technology had changed so much. Thank-you.

[@Metal-Possum]

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!

[@gavansexton9234]

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 )

[@falconeaterf15]

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.

[@Elnufo]

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.

[@guerrillaradio9953]

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.

[@edmundooliver7584]

@@guerrillaradio9953 can you still use old radio's at the fleld?

[@punkrocker1984]

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...

[@steveone9375]

These were great we need more

[@brucestivaletta2782]

Love your old videos , you look so much younger , har ha!

[@jackhammell1926]

It's nice to learn something new every day. This video has today covered, thanx

[@xnoreq]

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.

[@Cyberdactyl]

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!

[@alexstromberg5865]

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

[@davedeja]

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.

[@hb4596]

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.

[@jjkulick]

Thank you very much for this advice. Just what I needed!

[@RobFRC]

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.

[@philg311]

Well done Bruce,you made a talk on batteries interesting + I learned something as well. Cheers mate.

[@steveevans1247]

thanks for the info I had not heard of these before

[@SteenPedersen]

As usual, very interesting.

[@jacobhendrickson8935]

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.

[@MrWarwick15]

Wise words Bruce! Rich.

[@RoboTekno]

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 :-)

[@scottfillier7929]

Lol thanks for the advice I’m gonna put a 3s lipo on my Tmaxx😂😂😂😂

[@davefost]

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

[@richardmiddleton7770]

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.

[@rl2109]

I sure got a charge out of this video! Thanks for posting! ;)

[@TilmanBaumann]

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.

[@edmundooliver7584]

my old futaba use's Nicd 4.8v for the receiver can I use lipo batterys

[@thefakemaker]

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.

[@gabysande]

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!!

[@HeliEye]

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

[@DarrenFollows]

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

[@arcteryxxx]

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.

[@Rumblebum100]

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.

[@mrfourtysevenman]

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

[@LeighHart]

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.

[@rynair_winklair]

I use two LiFePo AA batteries for my small gliders

[@amtpdb1]

Thanks, I will take a look at it.

[@priito]

Keep up the tech people!

[@TheValkyrie1968]

Barry for lord supreme rc air commander!

[@willsherwood1189]

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 :)

[@shannonnewman3091]

Thank you for the info, You Rock !

[@nwck1]

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.

[@scotty1004]

Did you ever get an answer i have the same question

[@RodrigoSotoCastro]

@@scotty1004 And now I have the same question haha

[@paulb8188]

He's not answering questions. I guess he has a lot on his plate

[@thenerdyouknowabout]

Thank you very much Bruce, very informative video!

[@Diabolical.-.]

Thank you for the information. What chargers can be used to charge life batteries?

[@frazermann1448]

great video, thanks for uploading it :)

[@pukki34]

Btw you are totally right, today my controller alerted me about the "a1 voltage critical". Im using digital servos with nimh.... bad idea

[@SuperSpuddo]

Bruce as always very informative. Thanks so much. Now if you guys could stop beating us at Rugby, everything would be fine. Keep well.

[@UAVfutures]

5 years ago. wow. crazy to see a different back drop

[@brendongyde]

I like this back drop than the new one he uses. Does not change the quality content I guess.

[@808GT]

Excellent info Bruce, as always!

[@infi84]

Sorry Bruce, but I have to disagree with you there, the Eneloops you're showing in the video are definitely not 90's technology and are very different from older batteries, yes they are not made for power-demanding applications like lipos or life, but they certainly don't suffer from memory problems and especially not high self discharge rates, quite the opposite, that's one of the strong points for Eneloops, they keep their charge for a very long time.

[@tonyl9516]

i really learned alot thank you,,, do you need a special charger for life or can you se a standard lipo charger

[@Toysrme]

That's crazy. 4s 600ma nicd's are $8-10usd and 2200-2400nimh nimh packs are $30-35usd. NZ has some crazy markups.

[@dermotgorman]

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?

[@crunchied8]

the gas engine you have to regulate lipo for gas ignition A123 doesn't need to be regulated on the gas ignition

[@rcandfitness3812]

Mad scientist.. you the man lol

[@demietrilazarakis283]

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?

[@pedrojtmartins]

6.6v LiFe is a direct replacement of 6V NiMH. Both batteries, when fully charged, will be at 7.2V!

[@hugoboss3096]

Thank you sir!

[@usukie1]

love your work :) i had issues with these in cars lol

[@davidwatkin1484]

Bruce, you didn't cover the mAh capacity for a receiver pack.......suggestions ?

[@richardhill2451]

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

[@Toysrme]

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).

[@DavesRc]

Thanks for the video. So if I'm running all high voltage high torque servos. Do you think staying with the 2 cell lipo would be good?

[@alpeshsoni]

Hi, which is the right battery for my Glow engine Rc plane and 4 servos? using Spektrum receiver.

[@trevorice6499]

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 ,

[@iman80skid91]

Hi, I'm starting out with gas planes now and have 8 servos to run.. so what voltage is your liFe battery that you have there

[@thercdude9382]

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

[@KasunTalwatta]

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.

[@rickknowles9620]

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?

[@FPVREVIEWS]

thanks bruce.

[@larrystorm6374]

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.

[@kokman62]

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

[@sinuemedina2550]

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.

[@warwickr.c.modelflyersgrou5461]

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

[@amtpdb1]

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

[@richardbaldwin2726]

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.

[@EpicNightCrawler]

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.

[@richardstaccone1927]

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.

[@warwickr.c.modelflyersgrou5461]

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?

[@shanesmethwick6171]

www.helifreak.com/showthread.php?t=567539

[@chillville5571]

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.

[@FPVmarko]

So how much amps your servos drew? It has to be massive if caused problems with eneloops. Strange.

[@one4stevo]

Great video

[@Hajis627]

Can I use a 2.4g receiver and remote, and install 9V batteries ?? I’m really new to this and building my own stuff.

[@dermotgorman]

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)?

[@jorgegouverneur5914]

Is it safe to use a couple of diodes and drop the 7.4 v to 6 v from a Lipo battery? I'm not using any electric motor. This us for a glider. My receiver can take from 4.8 to 6 volts. Looking for a reliable source of power for long periods of time.

[@gavansexton9234]

Jorge Gouverneur Hi Jorge, im using a 400 volt , 10 amp rectifying diode, its drops the LIFE battery voltage from its nominal 6.6 volts down to 5.9. Its super over engineered not to fail, you have more chance of a servo plug failing its maximum amp draw which is only 5 amps. Do a google search for this , NTE ELECTRONICS NTE5814HC RECTIFIER, SINGLE, 400V, 10A

[@jorgegouverneur5914]

Gavan Sexton thanks. I'm going to look it up. I think diodes will do the trick to replace a BEC

[@EpicNightCrawler]

As per video anything you add to drop voltage is another point of failure, (and using a non switching regulator circuit (minimal heat loss) is going to dissipate the power loss in the voltage drop as heat (could be a lot of heat too depending on volt drop and current), So I would not recommend this method to do it). Better to use a LIFE battery (nominal voltage is 6.6) and servo rated for 6V+ or use (2nd choice) a sbec (switching bec), (but is a 2nd point of failure too) Most 6V+ rated servos work fine on LIFE 2S packs.

[@EpicNightCrawler]

Just note any power loss across that is going to be heat. 10amps with a 1.4V drop is 14Watts of power , which is a lot of heat on that small rectifier , I would not use that method myself on a lipo if thats what he intends. Even on a LIFE battery 0.6vx10A is still 6 watts of heat (a large amount for a small surface area). Most 6V+ servos run fine on LIFE packs.

[@FlyingMerf]

Can LiFe batteries be stored fully charged, or do they deteriorate like Lipos when stored at full charge?

[@lw216316]

I'm new at this - your opinion please - I'm flying MICRO size foam planes 1-4 oz. They use 1 or 2 cell lipo. I'm using a DX6E transmitter 2.4 freq. Should the 4 pack Enelope batteries I'm using be okay ? My DX6E gives me a warning when the pack is low. I recharge the pack and that's been working okay so far.

[@Toysrme]

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!

[@triketraveler]

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?

[@EddieWNC]

Hi Bruce: I have a battery question I hope you can answer. I'm currently working on some 2.4 GhZ conversions of vijtage radio transmitters using the FrSky DHT DIY RF modules. I have a buddy who wants to use NiMH batteries in his. I purchased the batteries from HK and they fit perfectly in the battery box of our World Engines Expert transmtters. My question is ... what charge rate to use for these NiMH 2600 mah cells? I remember the charge rate for the original 600 mah NiCads was C10 or 50~60 mah. Would the same C10 charge rate (in this case ... 2 amps) hold for the NiMH cells? If so, can they be fast charged from time to time? What would be a safe rate for fast charging? I will appreciate any comment. Thank you.

[@gittarpikk]

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.

[@fly9wheel]

Try a 338 adjustable regulator

[@TilmanBaumann]

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.

[@bartdinardo3932]

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?

[@muhammadfarooqi]

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.

[@EpicNightCrawler]

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.

[@hunsteven]

where do you get your batteries from for that price? can you post a link please?

[@Flysimware]

HobbyKing or Amazon or Ebay.

[@TilmanBaumann]

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.

[@sweetpuppy1919]

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

[@francoishaha]

Bruce, what about 2s life battery pack on receiver with servo voltage range between 4.8 to 6 volts? LIFe pack fully charged isn't 7.5 volt?

[@geopapa4181]

So,is it ok to use a 2 cells life battery directly on futaba 2.4GHz FAAST receivers or through a regulator?

[@youtwoba]

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.

[@MrGolemSnatch]

Hey Bruce, can you answer a question for me. I've just moved into electric helis, 550 size, and the manufacturer of my model recommends using a separate 4 cell nimh pack as a backup to the built in ESC, plugging them both into the rx. Is this a good idea or should I disable the BEC by disconnecting the positive supply line from the ESC..