Frank Skilbeck Posted April 24 Share Posted April 24 10 hours ago, Peter Jenkins said: Toto, LiPos hold charge for weeks. So, charging a day or so earlier is no problem. They do, but it's not a good idea to leave them at 100% for an extended time, especially if they see big temperature fluctuations. I've had a few swell up that have been left fully charged, so no put them on a storage charge when I get back from flying and then top them up the day before, whem I know the weather is going to be conducive for flying. 1 Quote Link to comment Share on other sites More sharing options...
Christopher Wolfe Posted April 24 Share Posted April 24 Toto, after a year of of adventures then your signature tune should be Learning To Fly as along with many beginners the line 'What goes up must come down' is very important. Best of luck with your 'A' certificate Regards * Chris * Quote Link to comment Share on other sites More sharing options...
Christopher Wolfe Posted April 24 Share Posted April 24 A few years ago I used to teach some new aeromodellers to fly R/C models and I was always asked why I concentrated on landing approach, distance, height, throttle and speed before teaching them how to take off. My usual reply was 'What's the use of of teaching you how to take off if you can't land the model on the strip' * Chris * 1 Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted April 24 Share Posted April 24 50 minutes ago, Frank Skilbeck said: They do, but it's not a good idea to leave them at 100% for an extended time, especially if they see big temperature fluctuations. I've had a few swell up that have been left fully charged, so no put them on a storage charge when I get back from flying and then top them up the day before, whem I know the weather is going to be conducive for flying. Hi Frank Please explain what you mean by extended time. My message was that it's OK to charge up LiPos a day or 2 days early since they will not lose any charge over that period. It's the same with LiFe and Enelope NiMH but not other NiMHs. I don't make a habit of it but if I don't use all my packs then I'll leave them fully charged for up to 2 weeks. If it's going to be longer, then I'll stick then kn my charger and didchafge to storage voltage. I've run 5S 5000 mAh 25C packs for the past 14 years and, as I'm sure you've found, some packs swell up early while others soldier on for ages even from the same label. I don't use high C packs as my flying rarely demands more than 80-85 A - that is in 10S configuration - and then only demand that for around 6 - 7 secs at any one time. That equates to around 2,800 W max demand although in my current setup the max power I've seen was 3,600 W at 98 A. That was a test early on to check with the manufacturers figure of a max 99A draw on a 23 x20 props. It did what it said on the tin! I should emphasise these readings were taken with telemetry while airborne with max/min figures stored for inspection. I no longer check max power while the aircraft is tethered on the ground as my testing showed that you can pull 25% more power out of electric motors in such circumstances. I aim for a minimum of 100 cycles per pack but have had cheap Turnigy ones reach 200 and expensive packs die at 60 cycles. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted April 24 Share Posted April 24 "Big temperature change" is an important point. The maximum charge a LiPo can accept is affected by temperature. They don't like the cold. A fully charged LiPo at 20 degrees will become over charged if allowed to drop to say 5 degrees. The damage done to the capacity of the cells in this situation may only be a small proportion of the total but it is permanent. If it is repeated the damage is cumulative. Unless you can be sure the temperature is kept constant it is a valid reason, apart from any safety concerns, not to leave a LiPo fully charged for any longer than necessary. Quote Link to comment Share on other sites More sharing options...
Cuban8 Posted April 24 Share Posted April 24 My only concern with leaving Lipos fully charged is all that energy has to go somewhere in the case of a fault during storage (rare, but not unheard of by all accounts). It's a pain to have a charging marathon prior to a days flying and of course batteries can catch fire whilst charging, but I feel more comfortable knowing that my batteries are depleted whilst being stored. I'll either keep them at storage level, or simply leave them as they are after a full flight. As far as I've found over the years, storing at a safe voltage below the 'storage point' has no detrimental affect on them. Comments would be welcome on that. Risk during transport to the field? well yes, so fire resistant container(s) for the batteries and the means to get them ejected easily and PDQ from the vehicle if the worst should happen. I always load my battery tin last and at the rear right behind the tailgate. One of our club members had his workshop severly damaged by a lipo fire a while back - he's not one to take safety with a pinch of salt, yet he was still caught out. Quote Link to comment Share on other sites More sharing options...
toto Posted April 24 Author Share Posted April 24 I may have to do them tonight as on Friday ( my usual battery maintainable night before flying the Saturday ) I'm already committed to a " wedding speech " night ahead of my daughters June wedding. I don't want to leave it until tomorrow night if it can be avoided because although it's free, things are constantly changing at the moment and I don't want to be caught out. We'll see Toto 3 Quote Link to comment Share on other sites More sharing options...
toto Posted April 24 Author Share Posted April 24 In the shed ..... Batteries on charge ..... 4 no ... John Smiths in hand ..... 2 no ... Toto ..... 1 no ... 2 Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted April 24 Share Posted April 24 (edited) 9 hours ago, Peter Jenkins said: Hi Frank Please explain what you mean by extended time. My message was that it's OK to charge up LiPos a day or 2 days early since they will not lose any charge over that period. It's the same with LiFe and Enelope NiMH but not other NiMHs. I don't make a habit of it but if I don't use all my packs then I'll leave them fully charged for up to 2 weeks. If it's going to be longer, then I'll stick then kn my charger and didchafge to storage voltage. I've run 5S 5000 mAh 25C packs for the past 14 years and, as I'm sure you've found, some packs swell up early while others soldier on for ages even from the same label. I don't use high C packs as my flying rarely demands more than 80-85 A - that is in 10S configuration - and then only demand that for around 6 - 7 secs at any one time. That equates to around 2,800 W max demand although in my current setup the max power I've seen was 3,600 W at 98 A. That was a test early on to check with the manufacturers figure of a max 99A draw on a 23 x20 props. It did what it said on the tin! I should emphasise these readings were taken with telemetry while airborne with max/min figures stored for inspection. I no longer check max power while the aircraft is tethered on the ground as my testing showed that you can pull 25% more power out of electric motors in such circumstances. I aim for a minimum of 100 cycles per pack but have had cheap Turnigy ones reach 200 and expensive packs die at 60 cycles. The articles I've read have noted that the cells degrade more quickly if stored at 100% charge and elevated temperature, if you charge them up at lower temperatures and then they warm up there is some minor degradation which accumulates over time. But yes there are lots of reasons why lipos die early so it is probably me being a bit over cautious. Edited April 24 by Frank Skilbeck Quote Link to comment Share on other sites More sharing options...
toto Posted April 24 Author Share Posted April 24 And still worth the post. We all seem to experience different situations and I'm glad to hear all. thanks for the post. toto 1 Quote Link to comment Share on other sites More sharing options...
toto Posted April 26 Author Share Posted April 26 (edited) So ..... here we are again ..... Friday .... the weather has been favourable for most of the week with some lovely blue skies .... albeit with a degree of light wind. Battery charging duties are complete with my tranny's being done last night and Lipo's the night before. A quick look over my Supercub and all is good. Wind forward to Saturday morning ..... what are we going to get ? So far all is good. I have a date for eleven o'clock at the East Fortune flying field with my mentor, Cub and no less than eight suitable battery packs ....... the big question is ..... how many will I get to use. Circuits, circles, figure eights, aborted approaches, landings ........ the big question is ....... Will I be able to improve enough to enable a questimate as to how far I am to achieving my first attempt at a solo flight. ..... Its that challenge and mindset that forges me on and provides the target / goal I need to make me try to push myself and improve ..... we all need a goal. Stay tuned in for my field report on my success or failure. Hope you all have a great flying weekend. Toto Edited April 26 by toto 4 Quote Link to comment Share on other sites More sharing options...
GrumpyGnome Posted April 27 Share Posted April 27 Fingers crossed toto. I am currently listening to the rain falling, and watching the wind steadily increasing. No flying for me today, I suspect, although if the weather window opens just a crack...... Quote Link to comment Share on other sites More sharing options...
JOHN MOSLEY 2 Posted April 27 Share Posted April 27 How cold is in sunny East Yorkshire ?? Quote Link to comment Share on other sites More sharing options...
GrumpyGnome Posted April 27 Share Posted April 27 4° at the moment, about 15 mph wind.... 1 1 Quote Link to comment Share on other sites More sharing options...
leccyflyer Posted April 27 Share Posted April 27 Perfect morning here in Central Scotland, so hopefully Toto has the same conditions. Other commitments for me today, so fingers crossed that it's similar tomorrow. I look forward to reading the flight reports later today.👍 2 Quote Link to comment Share on other sites More sharing options...
toto Posted April 27 Author Share Posted April 27 Yes ...... its looking good. Car packed and ready to go. Just need to pick up a lunch from the shops on the way and I'm all set. Hoping this is the start of a nice spring / summer with loads of regular stick time. Have a great day all Toto 1 Quote Link to comment Share on other sites More sharing options...
Learner Posted April 27 Share Posted April 27 (edited) Wet and windy here again and no chance of flying for a while. One of the few flyable days yesterday, but was at a funeral😪 Make the most of it toto. Edited April 27 by Learner Quote Link to comment Share on other sites More sharing options...
Cuban8 Posted April 27 Share Posted April 27 Cold and wet here in N.Essex - not much better for tomorrow or next week TBH. Quote Link to comment Share on other sites More sharing options...
toto Posted April 27 Author Share Posted April 27 Hi chaps, Back from the field a bit earlier than expected. Nice sunny weather but was windy ..... too windy. Around 20 - 25 mph. I got a flight in with relatively calm conditions then the wind picked up. I done a second in the wind and landed early as somehow my rates were not kicking in when I tried to reduce from 100% to 60 %. Somehow the settings must have been upset. Took off again with 60% rates and all was good. Done my third landing of the day and my mentor decided to take his Savage Bobber up. The Bobber took the wind conditions quire well but a dead stick forced a premature landing for him. By this time the wind was picking up further so we decided to call it a day rather than risk the models. Still a good day but just a little shorter than expected. No big deal ...... here's to next weekend. Toto 7 Quote Link to comment Share on other sites More sharing options...
toto Posted April 28 Author Share Posted April 28 (edited) Not nice at all today ...... overcast and a bit blowy. Don't feel so bad about not having a flying window. I'll get the Cub packed away into the shed now. I stored the batteries in the shed last night as if they went up in the car for any reason, I'd imagine it would be a case of insurance is void. Which leaves me with the dilemma of how I'm going to entertain myself today. If I'm seen to be at a loose end , SWMBO may well try to resolve that. Hmmmmm I had a bit of carbon rod given to me some time ago that would have let me attempt the repair on the Beavers horizontal Stabilisor but can't for the life of me find where I put it so that's out. Not that my confidence is that high in undertaking the repair anyway but I might have given it a bash. I think I may use the link provided earlier to buy a few lengths for future requirements. I'll visit the site again anyway. So for now, it looks like something to eat and then ...... make myself look busy before SWMBO takes advantage. Hope others are having a more fruitful day of flying. Cheers Toto Edited April 28 by toto Quote Link to comment Share on other sites More sharing options...
GrumpyGnome Posted April 28 Share Posted April 28 It's not compulsory to use carbon... Cocktail sticks or coffee stirrers can be used to bridge the gap, warmed epoxy can be dripped into the gap as well as fixing the sticks and stirrer. Micropore tape, with some cyano dripped onto it can reinforce the plastic to foam joint. A little white paint and the repairs will be invisible. When it'a flying. 1 Quote Link to comment Share on other sites More sharing options...
toto Posted April 28 Author Share Posted April 28 I like the idea of using the micropore tape to reinforce the plastic to foam joint as the break is in that region and ... to me... its the most vulnerable point. I may just nip out for some of that. I do have cocktail sticks at hand as well. Heating up epoxy just to get it a bit more viscose and making it easier to place ( hopefully without leaving a goey mess ) also sounds good to get maximum penetration into the joint and the foams honeycombed like nature. I may just at least have a reccy overthe job and see if I can come up with a planned approach to doing a decent fix. Thanks for the ideas grumpy. Toto Quote Link to comment Share on other sites More sharing options...
GrumpyGnome Posted April 28 Share Posted April 28 No probs - I have had to repair a few foamies along the way! If you dribble epoxy into the 'void' from above, put some masking tape on the underside to stop it falling onto your shoes, then remove before the epoxy hardens completely. 1 Quote Link to comment Share on other sites More sharing options...
toto Posted Sunday at 20:34 Author Share Posted Sunday at 20:34 Eh...... I think you mean shoes, jeans, shed floor and anything else that could possibly get in the way .... .... oh and my very best M & S Teeshirt. Never mind .... it looks so much more convincing down the field when you have some clothing with war medals on them. Paint , glue, burns etc etc..... a proper modeller. Toto 1 Quote Link to comment Share on other sites More sharing options...
aidan mcatamney Posted Sunday at 21:47 Share Posted Sunday at 21:47 Thats very true Toto. When you have a few splodges of dried up epoxy on your clothing coupled with a few japs of paint and burn marks as well., this could be viewed as a badge of honour down the flying club lol 1 Quote Link to comment Share on other sites More sharing options...
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