Welcome to the hobby and the forums. Its awesome to see you are already up and flying, most beginners come in absolutely green, like myself at one time.
Your charger though you said it wont charge past 3.9? That is odd, it should go to 4.2. If thats the case then i do have to ask what your flight times are like? A couple mins?
Thanks! It took me a good amount to tries and repairs to finally enjoy and fly hehe. But I'm pretty thorough and everytime I get into something I spend hours and hours learning and reading.
I might not explained correctly. I can charge my bateries and balance them perfectly to 4.2, is just that if I select storage mode, it charges them above 3.8 first, and then discharges them to 3.8. Another fellow just answered below that this is the normal behaviour of these "smart" chages, so that's what I needed to know
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I'm flying a custom plane I found in youtube and mixed with some flitetest parts (the rudder and stabilizer for example). It's about 450g with a 800mah 3S + 1806 2280kv motor + 6.4 prop. It took me a while to find out the best combo hehe.
The old battery argument AGAIN!
I still have batteries in service that I purchased over 2 years ago and they are still within 90% of their original capacity.
As a battery only has a set number of cycles in it and each charge and discharge cycle generates some heat and reduces the battery life I treat my batteries very differently, (and nor so do my students).
We chill our batteries before charging and we NEVER use storage charging UNLESS we are not the use the battery for a year or more.
After charging we keep our batteries in the refrigerator at around 4 degrees Celsius.
We always chill our batteries before charging and only ever balance charge and we also never charge a warm battery or run our batteries to where they are actually hot.
Nett result is that we only buy battery replacements every 2 or more years unless we damage them in a crash or the like.
I got my students to have 2 sets of batteries and one was treated as I teach and the other was following the standard practices. The batteries that were subject to standard practices needed to be replaced after 12 months whereas the chilled ETC batteries were still going strong at 2 years. My students all now chill their batteries religiously.
Please note; I live in Australia with a sub-tropical environment and so battery heat is a definite battery killer, (even at storage charge).
Just what works for me!
have fun!
Thanks for the tips!!
Right now my usual ritual is, charge the batteries to 4.2 the day before flying. I have my buzzers setup at 3.5, so as long as it beeps I put the plane down (I haven't had any issues if I have to do a couple more circles if I can't land right away) so they usually end up between 3.6 and 3.7.
Go back home, and either charge them back to 4.2 if I plan to fly next day or charge them to storage voltage if the weather forecast is bad. No issues up here with the warm weather (sadly) hehehe (Canada).
It all depends on your battery choices. The lower c rated packs fixed wing pilots fly are more susceptible to damage from excessive heat, mismatched chemistry, brand.. etc.
Sounds like you are doing pretty good at managing their use. Things to think about.. if your packs are always coming down feeling more then slightly warm to the touch they are being degraded with each flight and will shorten the life span little by little. Again this is where brands and types of packs comes into play. Some handle this better then others. As they need replacing over time like all batteries will consider buying a higher c rated pack and you will find heat management less of a problem.
As for the storage voltage thing it is normal the "intelligent" chargers charge to 3.9 to 4.0 V and then drop them back to 3.8. This is to balance the pack better for longer term dormancy. "Balance" charging is not so picky as that is the usual method to cycle packs to fly again so the tolerance between cells may not be so tight to conserve time on charge. The time it takes to do any type of charge being the same is that it defaults to 1c charge rate and they dont discharge as hard as when under actual load. All done with that thing called maths and if you are like me we dont do maths on the weekends.
And thank you too. That was what I was looking for. At this moment when I land the batteries are slightly warm, not hot at all. I have one big lipo bag where I store my 6 batteries but I just ordered a few small bags more to separate them between each other. I have read a lot about how delicate these batteries are and I don't mind expending a few hundreds bucks to prevent any accident.