Geoff Smith 1 Posted January 3, 2011 Share Posted January 3, 2011 Hiya all, my first question so be gentle. I have purchased my first model, an Art Tech Cessna 182 500 class RTF. It came supplied with a 2400mAH -11.1v Li-Poly battery. Maximum flight time of 10 minutes, I take this to be at full chat. Now my question is that 10 minutes is not what I would call a pleasant Sunday afternoons flying. Ok I know I can purchase more batteries but at £40 a throw it don't come cheep. What does everyone else do to get a decent days flying? Cheers my friends. Geoff Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted January 3, 2011 Share Posted January 3, 2011 Hi Geoff, well you will need more than one battery really - but two or three would do. Basically most electric flyers I know have a 12 lead-acid "leisure battery" in the back of the car. They then either connect their charger directly to that or connect via a 12/240v inverter. With that set up and say 2-3 batteries you can fly pretty well non-stop all day! One battery in the plane, one charging, one waiting to go on charge. BEB Quote Link to comment Share on other sites More sharing options...
Steve W-O Posted January 3, 2011 Share Posted January 3, 2011 For £40 you can buy 3-4 batteries from HK. (2200mAh) Quote Link to comment Share on other sites More sharing options...
ericrw Posted January 3, 2011 Share Posted January 3, 2011 What are the consequences of putting a battery with the same number of cells but a higher number of mAH, other than using the recommended size, with a stock power set-up ? Does it increase the duration of flight ? Eric . Quote Link to comment Share on other sites More sharing options...
Steve W-O Posted January 3, 2011 Share Posted January 3, 2011 I now have six of t h e s e , buy them 3 at a time to get the best value for postage, three leaves you 65g to the next post level, so I usually buy some glue or small parts to use up that 65g. They have been working well, and balance quickly. Quote Link to comment Share on other sites More sharing options...
Steve W-O Posted January 3, 2011 Share Posted January 3, 2011 Posted by eric loakes on 03/01/2011 10:41:52:What are the consequences of putting a battery with the same number of cells but a higher number of mAH, other than using the recommended size, with a stock power set-up ? Does it increase the duration of flight ? Eric . Yes, but the extra weigh also takes power. If the plane can fly and balance with the extra weight (many can't move the battery enough to get the CoG right) then it will give extra time. Quote Link to comment Share on other sites More sharing options...
Alan B Posted January 3, 2011 Share Posted January 3, 2011 Hi Geoff As BEB & Steve has commented. You could also use eg these CLICK HERE next day delivery (Normally!) if you didn't want to wait for Hong Kong delivery eg Hobby King. You do not need to pay Art Techs silly prices! They are 15c rating but should be ok for cruising around. Al Quote Link to comment Share on other sites More sharing options...
Geoff Smith 1 Posted January 3, 2011 Author Share Posted January 3, 2011 Wow! thanks for this info my friends this will surely help. BEB These Li-Poly batteries worry me (getting old and careful) Haven't I read somewhere that these batteries must be charged through a dedicated supply and not one which is running something else? Connectors, are all Li-Poly battery connectors the same or does one have to change them to suit your model? Don't worry lads I will get the hang of it soon. Geoff Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted January 3, 2011 Share Posted January 3, 2011 Well, I'm no expert on electric flight - I only have two electric models - so others might want to comment here as well. But for what its worth.... Sure Lipo's are potentially more hazardous than other battery technologies. But provided you are sensible they are fine. After all, a couple of gallons of methanol is a fairly volitile thing to have around the place as well and if mistreated will also cause problems! My rules for Lipo are: (and I haven't had any problems yet - touch wood!) 1. Always charge them with a proper balanced charger, with the battery in a fireproof bag. Don't leave them unattended when charging. Personally I always charge at 1C - but that's just me - I'm sure its OK to charge at 2 or 5C as long as the battery says it can do that. 2. I store them in a ceramic container in a metal cabinet. I not saying this is essential - I just happen to have a metal cabinet I picked up from an offlice/lab furniture auction and its handy. But I think the ceramic or eathenware container is a good idea, I fit heat shrink to right to the ends of the "sockets" perminantly and then temporarily in storage fit little lengths of fuel tube over the ends as well to be certain that there is no way the terminals can accidentally touch. 3. If they are not going to be used for over 1 week, charge them to the special "storage" charge level. 4. Never completely discharge them - aim to land with a bit of juice in the battery. 5. Never use/charge/keep any lipo which looks physically damaged and/or swollen. Instead remove the connectors (you can reuse them), soak it in a bucket of salt water overnight and then dispose of it. An obvious point - but worth making - is never cut the connectors off a battery by just cutting across the two wires in one go - well not unless you really like loud bangs and flashes of light! Regarding connectors - the two main choices seem to be "Deans" connectors, like two blades at right angles to each other, or "Bullets", basically cylindrical plugs and sockets. Bullets come in a range of sizes - typically from 3mm up to 6mm+. Its a personal choice but you really need to standardise on one type for interchangability. Personally I use 4mm bullets. If you use bullets should also adopt a "convention" like "plugs on the battery positive, sockets on the battery negative" and do all systems like that. That way any battery will fit (electrically at least) any model. You'll need a similar convention for Deans connectors if you use them - like battery positive always goes to the "horizontal" blade or whatever. Hope this helps. One of the "leccy" experts will now post and probably tell me I'm going it all wrong! But it seems to work for me! BEB Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted January 3, 2011 Share Posted January 3, 2011 Here's another battery option here, bit more than HK but normally next day delivery. Also you can charge at 5c (5 x 2.3A = 11.5A) if your charger is up for it, so recharge in less than 15 mins. But if you are using the charger that came with the plane, these are usually a low amp charging unit that charges through the balance socket so recharges could take well over an hour. I also have a couple of the Turnigy batteries noted about from HK and these have been very good also.Edited By Biggles' Elder Brother - Moderator on 03/01/2011 18:00:43 Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted January 3, 2011 Share Posted January 3, 2011 They're the batteries I use Frank - I've found them very good. BEB Quote Link to comment Share on other sites More sharing options...
Geoff Smith 1 Posted January 3, 2011 Author Share Posted January 3, 2011 Thanks my friend. I am worried about the connectors, I take it that you (me) have to do the plug changing, There by could be a problem. Strewth if I keep on like this you gonna think I'm a right wimp. I have little or no experience of soldering or the like, would it be easy for me to pick up? also what about the balanced charger connections, those little white 4 pin plugs look a different kettle of fish. From your description I appear to have a battery with a Deans connector. It appears from reading the blurb that when the charge to the motor reaches a certain point it will power down the motor, a useful bit kit for me. I hope you lot don't mind these questions, they may seem trivial but I don't want anything to go wrong when I get my first flight in. Many thanks to all for your help and it is really appreciated. Cheers my friends, Geoff Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted January 3, 2011 Share Posted January 3, 2011 Yeap - long term you are going to have to either learn to solder - or make very good friends with someone who can! Usually the white balance connectors are fine - they are pretty standard. Its the main connector you will sometimes have to change. If your happy with the Deans connector standardise on them. The only reasons I prefer bullets are: 1. I think they solder neater and easier. 2. I have fingers like sausages (!) and I struggle sometimes to separate Deans connectors. I find bullets easier. But I stress its a personal choice - you'll find lots of other flyers that swear by Deans connectors! Soldering isn't difficult - its a knack and once you've mastered it you'll find it straight forward. Soldering connectors is particularly easy because most battery leads are pre-tinned and the connectors are gold plated - so the joint is easy to form. Just remember; plenty of heat (applied to the job not the solder!) and get it really clean! There are several threads on here about soldering (you can find them in the search box at the top of the page), and there are several good videos on You Tube that teach soldering. For general reading, if you haven't do so already, you might want to look at this page. If you go down close to the bottom you'll find a section called "Electric Flight for Beginners" - lots of good tips there. BEB Quote Link to comment Share on other sites More sharing options...
Geoff Smith 1 Posted January 4, 2011 Author Share Posted January 4, 2011 Many thanks for this BEB. I've had a good look at video's and read up and I think I can sort this soldering lark out with much trouble. What size soldering iron do you suggest for general all round work? Also I think I'll go the way of bullet connectors, they seem to be the best option for me. A problem I may experience with these alternative Li-Poly batteries is the size. The Li-Poly battery supplied with my Cessna 182 has the dimensions of 133 x 43 x 15mm. This fits into a purpose built plastic cage in the fuze. The alternative batteries may be a bit fat to fit. BTW, just gone through your Sopwith Pup build, excellent series, started to make my thumbs itch again. Cheers my friend. Geoff Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted January 4, 2011 Share Posted January 4, 2011 I manage battery connector soldering with a temperature controlled 25w iron. But it definatly requires a bit of skill to make that work as its not really powerful enough! For large soldering - like undercarraiges etc. - I use a 100w Weller Iron. So for batteries and general aeromodelling work, I'd really recommend a 50 to 75w iron - with that you'll get the heat into the workpiece quicker with less likelyhood of damaging anything else while your learning! Glad you like the Pup thread - she's lanquishing in the "covering shed" at the moment waiting to be finally sorted out ready for the Summer! (assuming we have one!) BEB Quote Link to comment Share on other sites More sharing options...
r6dan Posted January 4, 2011 Share Posted January 4, 2011 Concept models belongs to a mate,in the link there is some useful onfo,plus he sells lipo batterys Quote Link to comment Share on other sites More sharing options...
Geoff Smith 1 Posted January 4, 2011 Author Share Posted January 4, 2011 Many thanks for this r6dan. cracking information, I will inwardly digest this lot. Cheers Geoff Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted January 4, 2011 Share Posted January 4, 2011 Posted by Biggles' Elder Brother - Moderator on 03/01/2011 17:30:47: Regarding connectors - the two main choices seem to be "Deans" connectors, like two blades at right angles to each other, or "Bullets", basically cylindrical plugs and sockets. Bullets come in a range of sizes - typically from 3mm up to 6mm+. Its a personal choice but you really need to standardise on one type for interchangability. Personally I use 4mm bullets. If you use bullets should also adopt a "convention" like "plugs on the battery positive, sockets on the battery negative" and do all systems like that. That way any battery will fit (electrically at least) any model. You'll need a similar convention for Deans connectors if you use them - like battery positive always goes to the "horizontal" blade or whatever. Just a quicky BEB, as Timbo pointed out to me a while back - and I didn't believe until I checked - all Deans - and every clone I've checked - have polarity markings moulded on them (which may be tricky to spot once they have been soldered up) so there is already an established convention. The way I remember it is positive is a cross (across) - look at one and you'll see what I mean...Edited By Martin Harris on 04/01/2011 23:35:41 Quote Link to comment Share on other sites More sharing options...
Kozmyk Posted January 5, 2011 Share Posted January 5, 2011 Posted by Biggles' Elder Brother - Moderator on 03/01/2011 17:30:47: 4. Never completely discharge them - aim to land with a bit of juice in the battery. BEB I'd agree with you by and large except that a good residual capacity to aim for would be about 20%.This keeps you well away from the voltage drop off and prolongs the life of your lipo. "The 80% Rule" they call it.A lot of ESCs have a Low Voltage Cutoff - LVC set to 3.0V(per cell); where possible, it's a good idea to set it higher. I presently have mine set to 3.3V before LVC and a soft cutoff though some set it as high as 3.6V.Simply relying on the LVC isn't the best idea however because peak current draws can drop the voltage momentarily below the threshold when, in fact, there is plenty of juice left.Monitoring flight times against the amount of current put back in when recharging gives you a better idea.Of course you have to take account of flying style. Hard flying will take more out of your batteries than gentle flying. Quote Link to comment Share on other sites More sharing options...
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