Does anyone here build their own receiver battery packs? My plane came with a Sanyo 4.8V 600mah battery pack. I don't get a lot of flying time from it. My instructor recommended getting some rechargable 2300mah Nimh cells from Wal-Mart to solder together and make my own higher capacity battery pack. Not hard to do, but does it work well? He had a couple he had built. Just wondering if anyone here does that?

You can build your own packs by soldering them together, but there is a huge word of caution that should go with it. Batteries such as this are very easy to ruin. If you get the top of the battery cell too hot it will melt the seal of the battery cell which could cause the battery to fail in flight. Trust me, it doesn't take too much heat to melt that cell. A couple of seconds can sometimes be too much. If you're interested in doing this there is a website dedicated to EVERYTHING about RC batteries. You can find it at [link=http://www.rcbatteryclinic.com]R/C Battery Clinic[/link]

Hope this helps

Ken

there are a couple of sites..cheapbatteries.com is one I think where they will custom make you any size/cell configuration you want and put whatever connectors you want on it...Rog

IMO RC batteries can be gotten relatively cheap and I don't think it would be worth the chance and risk of trying to make your own. Serious burns if you rupture the batteries in your attempt at it. Personally I would not attempt it.

Battery pack is one of the most important things in that plane, so don't skimp. There are plenty of good packs out there for reasonable cost. The charger that came with your radio is only good for about 800 MIL. If you go bigger you will need to buy a charger. I would stick with NICAD batteries if you don't have a weight issue. Your transmitter battery would also need tobe upgraded if your planning on flying a tremendous amount as well. You could also invest in a field charger and top up your plane at the field. Buying cell's from Walmart is just a good way save $5 and spend hundreds when you crash due to a battery failure. Leave this one to the pros.

I'd be afraid of ruining the batteries with too much heat. Here is one good source of RX and TX packs. They also sell a wall wart charger, for about 20 bucks, that puts out about 180 mah for overnight charging of high capacity packs.

http://www.hangtimes.com/nobsbatteries.html

how much time are you getting from your current pack?usually 600 mah on a trainer is good for an hour to an hour and a half of safe operation depending on the number and model of servo used.Astalled throttle servo will drain a pack extremely fast.Also do you cycle your batteries to see what the actal capacity of your pack is?

Greetings from a less cold Sweden!
Here are some humble suggestions and questions from a nordic beginner that has not (yet) flown....:-)

What about those plastic frames where you insert AA-batteries??
They could be got in several configurations,2,4,6 & 8, etc...and are quite light too. I got one as batterypack for my Hitec Flash 5X,since I have found a Tjeck dude that sell AA-NiMh batteries that contain 2950 Mha and AAA-batteries with 1450 Mha on the Net. For the reciver I also found an english site that sell batterypacks and bought one 2200 Mha-6volt.However, isn´t the objective to have as much electricity available as you possible can??
If using frames,the eventual danger with soldering is moot and the charging could also be done in an ordinary charger as well as a field one, and if for some reason one battery turns bad, one can replace the one and not the whole pack.
Sincerely yours,
Mikke

I use 600 mAh batteries for my Tx and Rx and charge them for 16-18 hours with a Wall Wart 50 mA charger. I flew 2 times 2 days ago and 1 time today. I got home and turned on my transmitter and receiver and it took "3" hours for both to go almost completely dead. You must not be charging your batteries properly.

Depending on what type of plane you are using and number of servos makes a difference. You should get at least 5 flights with the average plane and still have some juice left in them. Other wise, maybe you didn't cycle your batteries properly when they were new or you're not charging them right or long enough.

Good Luck

I highly recommend against this type of battery holder for use in a plane. Vibration, dirt and oxidation between cells can lead to intermittant contact between cells. Of course, if you can tolerate intermittant crashing? Stick with soldered connections. If you don't feel comfortable about doing it (be honest with yourself about your skills) let a pro do it. The "big boys" don't solder cells together either. They are actually spot welded.

I don't know for certain how long I can fly with the batteries I have. When charged they read around 5.3v - 5.4v. After a couple of short flights today the receiver battery read around 4.9v. I didn't notice any problem but I don't really know how low is TOO low to fly with. Also, right after I got the plane, I charged them for the recommended time period and then left the switch on later after I finished playing around with the flight controls. It completely drained the battery pack. I don't know if that hurt it in any way. I just figured why not go with a higher capacity battery. I will stay away from soldering them together though. It was recommended to me and that's why I asked about it.

I agree that using the battery holder wouldn't be a great idea. If a battery got loose or popped out that would be bad news. I am very confident in my soldering skills but don't know how much heat the batteries can take....I can afford to just purchase a higher capacity battery pack, I just thought making my own sounded like a fun idea...turns out it's probably not such a great plan.

When my first airborne battery pack on my Futaba FP-4FN died, I went to Radio Shack and picked up one of those 4-AA holders that the batteries just clip into and has the 9V style connector on it. I got a 9V wire to clip on it, and tool the connector from my old battery pack and soldered them together. I used a rubber band around the batteries to make sure they wouldn't come loose, and one lengthwise around the connector on the end of the case to make sure the connector wouldn't come loose. The only soldering involved was to connect the wires and cover them with heat shrink. This way I could charge the batteries with the wall wart charger and flew that way for several years until the throttle stick broke off the TX. Today you can replace the Ni-Cads with NiMh but the usability will be the same. I use this same method with my RC sail boats today and have had no problems with it at all.

Hogflyer

YellowHawk,

Are you flying that Hobbico NexSTAR Select - 46 I noticed in your dossier under "My Planes"? And also, what charger are you using?

Yes, I'm flying the Nexstar Select .46....I'm using the wall wart charger that came with it. I have not had any problems with the batteries I have, but would like to get more flying time before I have to start worrying about batteries dying.

You should get 5 to 6 flights on a full charge with that plane. Providing your servo's aren't buzzing when you operate your controls.

I sent you an email.

Good Luck

Hi

I recall trying to solder copper wire on nicad batteries years ago and found that the solder would not stick to the terminals. tried scuffing with sandpaper and using acid flux, etc. No luck. I was using electrical silver solder. What do you use if you attempt this proceedure?

G'day Mate,
You are worrying about nothing.
First off, your battery pack is rated at 600Mah @ 4.8 volts.
It is not flat until it gets to 4.4 volts, so buy yourself a field battery checker, that places a load on the battery pack, test it after every flight, & note how many flights it takes to go near the red zone, you may only fly 4 or 5 flights a day & be mentally exhausted after that, trust me, you will be concentrating hard, or you should be, & your batteries will last all day.
The next purchase you should make is a good charger/ cycler, use it to cycle your battery pack, after you come home from flying for the first couple of sessions, then you can determine how much capacity that you use in 3, 4, 5, 6, or whatever flights you had that day, & every month or so, after that, & you will know exactly what the capacity of you batteries is.

I already have an ESV to check the state of charge in my batteries...I just wasn't sure what the lower limit was for "safe flying." I do need to get a field charger and a charger/cycler though.

I made three flights yesterday on a fresh battery and it was down to 4.9v. I wasn't sure how far I could push it so I packed it up and brought it home. I'm probably packing up too early but I figured it's better to quit than to chance it and loose a plane if it's too low. I know it's rated to work at 4.8v but I don't know how much time I have at 4.9v before I start loosing power.

G'day Mate,
As I stated before, the rated voltage of nicad cells is 1.2 Volts per cell, 4 x 1.2 = 4.8.
So anything over 4.8 is a bonus, it should stay at 4.8 volts, for 600MaH, then drop very quickly after that.
So if you discharge your batteries at 300Ma, it should last 2 hours, at 100Ma it should last 6 hours, & so on, get the idea, so it is a good idea, to discharge your pack at a known rate, after flying, & see how much capacity is left.
If, on the other hand, you have a servo or two that have a lot of drag on them, ie, not smooth pushrods, then that will discharge your batteries faster, than they normally would.
This is assuming you have full capacity in your battery pack to start with, of course.

Greetings!
Thanx for all input !
This is really interesting issues ventilated here for a ignorant flyer-to-be like me.
To counter vibrations Hogflyer uses rubberband and as for dirt,etc a small plastic bag must be sufficient, since most planes have closed RX-compartments,methinks?
As for soldering it seems according to < http://www.rcbatteryclinic.com/ > not such a good idea, since it´s kinda hard to really know what the heat does to the battery´s innards,however fun it it to solder....I like soldering(as opposed to soldiering) too and take any chance to do so... ...
Contact-issues doesn´t seem to apply, since batteries can be taken out of holder quite easily, thus minimizing oxidation,etc.Charging could also be done, both in the field and also using an ordinary charger at home.
Being a novice I assumed the general idea was to aim for six volts forTX & RX and servos,etc if possible, but the reduced weight of one AA-battery could of course make a difference, depending on the plane. Personally, I will try to get as many Mha I can in my packs, just in case.
Is there any statistics available in US regarding RC-plane crashes and their causes??
In Sweden RC-veteran&legend Bo GĂĄrdstad made some inquiries into this issue if anyone is interested.
Sincerely yours,
Mikke

Whether or not you can take the batteries out of the holder easily doesn't matter too much. Most battery packs are placed in models not for ease of access, but for purposes of achieving proper weight and balance.

There's little point to trying to save a tiny amount of money by doing something unconventional when it comes to battery packs.

Go to Tower and get a VoltWatch its $10 and tests your battery under flying conditions (load) and the different colored lights show you the condition of your battery I have one either on all planes or in my flight box to check the small planes....I buy my paks from tower too except a few tiny (110Mah) batts for my 1/2a pylon racers...when Nicds start to go ie loose charge..they go fast!....Rog

Hi

I have built many battery packs up tx and rx packs.

You need a big iron that can solder the wires on quickly but with lots of heat, i use a 65 watt with a large bit.

Rouphen up the terminals with a file.

glue the cells together in whtever configouration you require with a hot glue gun

i use small lengths of 25 amp car wire for the links, make up a short bridge stripping the sleeve off each end and hold the bit of sleeve thats in middle with long nose pliers tin the battery terminal and both ends of the wire. solder one end on while gripping with the pliers then push flat with the pliers while soldering the other end in both cases make sure the wire dosn't move while the solder sets. if it does take off and do again but let the batteries cool first.

once done solder a lead on and cover with heat shrink.

I like to use clear heat shrink as you don't need to take the heat shrink off unless there is a problem ,and not if you think there may be.

Inbetween soldering a particular battery let it cool ie don't do one end then the other straight after. all the pack i have built have been fine except one which ended up with 2 faulty cells this was a aaa pack weather i overheated it or they were just faulty i'm not sure.



simon