Lipo Batteries: Sources and Charging Methods

[mistajingles]

Where are some of your best places to get li-pos? I've never really needed a place to get them but now that I am getting into multirotors I need some sources that aren't too expensive. With my heli i would buy 3 at a time and run them in the worst way possible until they die. I would rather not do that when my quad arrives.
So also, what charging methods for your li-pos do you use? Other questions that have come up are: How can i maintain the best discharge rate for my quad? How can i prolong a batteries life? I've heard a few different ways of charging them from friends and online websites.

 

[Mike]

Hobbyking is a good source for lipos. They have a lot of selection and warehouses all over the place. It would be smart to invest in a good charger that can also discharge and has programs for charging up or discharging down to "storage" levels.

The iMAX B6 is good for the price. I just bought a pair of the B6AC with the built in power supplies for about $30 each on ebay.

As far as discharge rate goes, it really just depends on your power system on your quad and how much power it's going to draw. You'll typically spec out your power system, then buy a battery with a proper discharge (C) rating.

This is a good place to start for info on what battery specs mean:

http://multicopter.forestblue.nl/lipo_need_calculator.html

Overall, not ever discharging your battery too much, and always storing it at a proper storage charge is going to prolong the life. Also, getting the proper battery with the proper discharge rate will save you from burning through batteries.

Lastly, definitely get some lipo charging/storage bags. Lipos are unstable, especially damaged ones, and can randomly burst into flames and burn your house down - especially when charging or discharging... and even more especially if it's done improperly.

 

[glowingturnip]

what is the correct charge to have when storing them for some time btw? I assume from your post that you don't store them with a full charge - can I store them as they are after a flight, so about 10.8-11v for a 3-cell ?

 

[mistajingles]

I'm very new with lipos so I could be wrong.
A storage charge is usually slightly higher voltage than the standard voltage. So standard being 3.7v per cell, I keep mine at 3.8v. If your going to be storing for a while I would take them out like every week or 2 and cycle them with a multifunction charger. If you don't have one then it's the best investment you will make towards your lipos. Most charger literally any battery. I use mine to charge car batteries mostly. I did a little research since this and it seems the best charge amperage is what the mAh rating is.
So my 11.1v 1500mAh I charge at 1.5A. I know electricians are laughing at me for not putting the mAh and amp relationship but I'm learning still.
So yo answer your other question, no u would not leave the batteries at the ending voltage because it conditions them to that voltage. You want them to be conditioned to their original voltage. 3.7v/cell
After figuring this out I cycled all my lipos at the correct amerpage for that battery and the performance difference is crazy.
Google Lipo battery break in. That might help.

 

[GJH105775]

I'm very new with lipos so I could be wrong.
A storage charge is usually slightly higher voltage than the standard voltage. So standard being 3.7v per cell, I keep mine at 3.8v. If your going to be storing for a while I would take them out like every week or 2 and cycle them with a multifunction charger. If you don't have one then it's the best investment you will make towards your lipos. Most charger literally any battery. I use mine to charge car batteries mostly. I did a little research since this and it seems the best charge amperage is what the mAh rating is.
So my 11.1v 1500mAh I charge at 1.5A. I know electricians are laughing at me for not putting the mAh and amp relationship but I'm learning still.
So yo answer your other question, no u would not leave the batteries at the ending voltage because it conditions them to that voltage. You want them to be conditioned to their original voltage. 3.7v/cell
After figuring this out I cycled all my lipos at the correct amerpage for that battery and the performance difference is crazy.
Google Lipo battery break in. That might help.

Mostly correct, scientificlly agreed storage voltage is usually 3.8 per series (or cells if you must), but almost all manufactures say to store at 3.7, which is the voltage they put on the pack. A 3S LiPo will say 11.1v on the pack, when in reality at full charge it is ~12v. When possible you should slowly charge LiPos, fast charging diminishes the life of the battery; even when they are made to quick charge.

 

[glowingturnip]

a lot of good info on this site, thanks very much guys. So 3.7v it is, and will charge my 2200mAh batteries at 2.2A (had been using 3A at random). I've got a lipo fireproof bag that they live in unless they're on the quad

 

[holtneil]

Hi mate most of my li-pos are over 2 years old , Like George said store at 3.7v a cell , I never fly mine below 3.7v a cell most say 3v a cell, but this makes my li-pos last for years if your not going to fly for over a week then fly to a store charge or store change them , let a battery rest after a flight before you charge about 5 mins to let it cool down , Always balance charge if you have the time the li-pos will love you for it

 

[mistajingles]

I have one "waste battery" for my blade heli and for my Syma. Waste meaning its one battery usually with a storage charge that i use to fast charge when i want to fly as soon as possible but have nothing charged. I charge them usually at double their normal charge on only those baateries. That way I'm not abusing all my batteries. Just a few. Of course the discharge quality on them is really bad. Usually i have almost half the flight time and the lifespan is very short but it keeps me from doing this to a random battery every time so i do not destroy them all.
Being an anxious 18 year old that just wants to fly, I would always but my batteries immediately on the charger after a flight no matter the temp of it. Then i read online that it causes the cell to charge disproportionately as it cools. i also read that a steady ambient temp is best for keeping batteries alive.
Thanks for the info guys. Its always better to have other opinions then to blow up some lipos.

 

[mistajingles]

This seems like a really great website for drone info. But i feel like more threads like this need to be made. Telling people who have little experience things that the experts hardly even think about. I am completely new to quads but not to RC so if i think of anything I'll make a thread for it so we can compile as much info as possible about the subject.

 

[mistajingles]

Anyone know why the 3rd cell in both my 11.1v batteries is higher than the other 2 even after balancing?

 

[GJH105775]

Anyone know why the 3rd cell in both my 11.1v batteries is higher than the other 2 even after balancing?

Try discharging it and recharging it. It can either be imperfections n production, or un-evenly discharged.

 

[holtneil]

Hi mate George has done a thread on C rate I will do one on Lipos

 

[mistajingles]

I just got a Venom 11.1v 2100mah 20C battery off of amazon for $20 and it came with a booklet with all the info on lipos anyone could need. Plus they have a really awesome replacement plan. Tomorrow morning I'll scan it and post it here. There's everything from explaining C rates, mAh, charging amperage, new lipo break in, discharging, etc. It basically answered every question I have ever asked myself about lipos.

 

[holtneil]

Hi mistajingles that sounds great if you can post it here I will copy it and make it sticky on the newbie section

 

[mistajingles]

Here it is. I had to do it in 2 parts because it was so long that the file size came out to be over 1GB. The most surprising part of this is the battery disposal method. Everything i know about batteries tells me that is a horrible idea but i guess it works. I have a few dead lipos i need to completely drain and trash.

 

[chillware]

Another vote for HobbyKing, I use nothing but Turnigy Nano-Techs and have never had any issues with them and I run them hard! I've had a few get puffy (I think that's unavoidable with any lipo) and they keep on trucking!

 

[GJH105775]

Here it is. I had to do it in 2 parts because it was so long that the file size came out to be over 1GB. The most surprising part of this is the battery disposal method. Everything i know about batteries tells me that is a horrible idea but i guess it works. I have a few dead lipos i need to completely drain and trash.

I am currently at MEPS and can't download anything on this tablet. The discharge method, is it the salt water method?