Frank Skilbeck Posted Wednesday at 07:18 Share Posted Wednesday at 07:18 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 Wednesday at 07:43 Share Posted Wednesday at 07:43 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 Wednesday at 07:53 Share Posted Wednesday at 07:53 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 Wednesday at 08:26 Share Posted Wednesday at 08:26 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 Wednesday at 08:58 Share Posted Wednesday at 08:58 "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 Wednesday at 09:07 Share Posted Wednesday at 09:07 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 Wednesday at 12:41 Author Share Posted Wednesday at 12:41 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 Wednesday at 17:23 Author Share Posted Wednesday at 17:23 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 Wednesday at 17:31 Share Posted Wednesday at 17:31 (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 Wednesday at 17:32 by Frank Skilbeck Quote Link to comment Share on other sites More sharing options...
toto Posted Wednesday at 17:40 Author Share Posted Wednesday at 17:40 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 15 hours ago Author Share Posted 15 hours ago (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 15 hours ago by toto 4 Quote Link to comment Share on other sites More sharing options...
GrumpyGnome Posted 6 hours ago Share Posted 6 hours ago 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 5 hours ago Share Posted 5 hours ago How cold is in sunny East Yorkshire ?? Quote Link to comment Share on other sites More sharing options...
GrumpyGnome Posted 4 hours ago Share Posted 4 hours ago 4° at the moment, about 15 mph wind.... 1 1 Quote Link to comment Share on other sites More sharing options...
leccyflyer Posted 3 hours ago Share Posted 3 hours ago 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 3 hours ago Author Share Posted 3 hours ago 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 3 hours ago Share Posted 3 hours ago (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 3 hours ago by Learner Quote Link to comment Share on other sites More sharing options...
Cuban8 Posted 44 minutes ago Share Posted 44 minutes ago 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...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.