** LIPO BASICS ** Read me first!

[litehawkdown]

Originally Posted by Slyster

What charger do you have?

For your packs a 1C charge would be .8A per lipo... so four packs in parallel you would set it to 3.2A.

But with Gens Ace you can certainly charge at 3C to save time... so set it at 10A. All four packs will finish in around 20 minutes or so.

Parallel charging is the way to go these days. Don't worry about it.. just make sure your packs are all healthy and have roughly the same number of cycles... and if one won't balance well or if puffing.. pull it out of the loop and charge it by itself.

I have one of these.

[Slyster]

50W output That's is as low as they come.

Many of us are using 1000W chargers these days... that is 20 times the output of your charger... so I have no idea how fast you will be able to charge your packs in parallel... not very... are they 3 cell lipos? Set the amps as high as it goes and see what it reaches.

[litehawkdown]

Originally Posted by Slyster

50W output That's is as low as they come.

Many of us are using 1000W chargers these days... that is 20 times the output of your charger... so I have no idea how fast you will be able to charge your packs in parallel... not very... are they 3 cell lipos? Set the amps as high as it goes and see what it reaches.

LOL My LHS guy said it was all I would need

Yes they are 3 cell.

This battery stuff smashes my pea. Think I need to read up more.

[litehawkdown]

Well I was trying it at 0.4 I got a time out stop at 74 minutes So I got her going again at the same setting. I just stopped it at 54 minutes. I only had 11. 95 v in there. I pumped it up to max. 5.0 and since I started typing it is up to 12.19

[litehawkdown]

And we are done. Only took 21.12 minutes to go from 11.95 to 12.60. Too fast? If not I guess I will keep it to the max and see how it goes. These batteries and charger are cheep enough for me to experiment and learn on. I just don't want to burn my apartment down is all Thanks for the help.

[DominicD]

50W charge ... all you need .... sounds like you need a new LHS.

[litehawkdown]

Originally Posted by DominicD

50W charge ... all you need .... sounds like you need a new LHS.

LOL I get the feeling that he plays dumb to the dumb so he can up sell later. He wanted to sell me the same charger in 4 port. Basically a 4 in one charger. To be honest my town is quite cheap. He is just supplying the demand for cheap. In his defense I said to him. "I need something cheap to charge my 250 batteries. I think they will be the biggest batteries I ever get." And so far this holds true. I don't really have a need for a bigger heli.

1. When it is windy I kiteboard

2. There is no designated flying field anywhere around me.

So I think I should be fine with this setup for awhile. My fleet consist of a MCPX the 250 and soon a 130x.

[desertstalker]

Originally Posted by litehawkdown

LOL My LHS guy said it was all I would need

As long as you never want to charge more than 1 pack for a 450 sure

I bought a 10A charger (250W) thinking it would be plenty . Just bought some 6S packs for a protos build... now im looking at a PL8 (might as well go all out).

[litehawkdown]

Originally Posted by desertstalker

As long as you never want to charge more than 1 pack for a 450 sure

I bought a 10A charger (250W) thinking it would be plenty . Just bought some 6S packs for a protos build... now im looking at a PL8 (might as well go all out).

When and if I go bigger it will be Nitro. Then I won't need no stinking charger

[nivaldin]

Hi folks,

How long a battery can last in good conditions when is not in use.
I mean, if I buy a battery and not use it immediately, how long can I hold it with no use, and with no performance lose.

Thanks.

[REVOJohn]

oK depends on performance loss definition.
BUT in general if you don;;t use the battery it should last years. It'll probably lose about 3 - 5% capacity per year upon aging

[Slyster]

I thought this was good enough to copy/past here so it doesn't get lost.

This is a quote from Gitbse from a post on the main forum.

-----------------------------------------------------------------------

So at IRCHA I sat down with Dave at progressive rc for quite awhile. He did a couple seminars, and I also happened to share a tent with those guys. Lemme tell you, aside from being a really cool guy...Dave knows his s***.

Lipos *must* be stored at 3.7-3.8 per cell, if you want to retain the power capacity. It's "simple" chemistry.
Battery breakdown, and puffing, is all about the electrolytes between the cathode and anode of the battery. The electrolytes are organic materials, and breakdown over time, releasing gasses as they do so. As the e.lytes breakdown, they will not allow electron transfer as easily, therefore losing their power output. Internal resistance goes up, so the energy has a harder time going through the system. This does two things. One, it decreases the power output of the battery, and two, heats up the pack more. Puffing is caused by the gasses being released from the breakdown of the e.lytes.
The e.lytes breakdown under two conditions, heat being #1, and general current being #2. He told us the danger zone is around 140 degrees, and you need to keep your batteries under that. Now here's where storage comes into play. The charge of a battery basically determines how fast the electrons are wizzing around in the packs, and the faster they move around, the faster the e.lytes break down. It's that simple. The packs won't lose 6% capacity over a year, it's more like 60%. And if you don't believe me, I have some used thunder powers I bought for cheap from somebody, with about 20-30 flights on them. He stored them at full charge. When I look at the logs on my esc, from a full charge they drop to nominal voltage (44.4v) RIGHT WHEN I HIT IDLE UP. <--- They maintain 39-44v through the flight, and the largest output I've seen is 4200 watts. On a 4525le... a 9600 watt burst motor.
Leave your batteries at 3.7-3.8v and store them in the fridge or freezer, and they should maintain 85-90% capacity or more for a very long time.

One more theoretical explanation he gave us about breaking in batteries too. It made perfect sense, and he said it has been "tested," although it's still ..theory.
The surfaces of the "cells" in the batteries contain carbon nano structures. I've heard beforehand that this is one of the biggest research fields in batteries nowadays, and it is. That's what "Nano-Tech" batteries mean, and the thunder power logo kinda uses a representation.

Here's the beef, and why I will always.... *always* break in a battery for 5 cycles on a charger first. And this is straight from Dave, I mean the guy is a genius. And hang with me cause like I said, and I apologize in advance for all the "quotes."it's still "theory."
The nano structures have little "pockets" where the electrons rest, and the more pockets the cells can fit, the more power it can contain. That's why lipo capacities are skyrocketing now into the 10-12mah range. Each electron has a certain spot it rests in from first charge on the anode. When the electrons move from anode(+) to cathode (-,) (also known as current,) they develop certain pathways through the structures and through the e.ytes that they like to take *every time*. Same thing on charge and discharge. The electrons create their pathways, and travel along those back and forth from cathode to anode, and back again. On charge and discharge, they also "look for" the exact same resting spot on the nano structures. This is where the break in comes into play. Slowly charging and discharging, i.e. cycling on a charger for 3-5 cycles, allows the electrons to create more solid pathways, and to allow them easier access back and forth from anode to cathode. Internal resistance stays low, so it allows for easier power transfer, so the temp also stays low. This in turn keeps the e.lytes from breaking down as easily, so the batteries won't puff so much, and still maintain power.

[surferman]

Thanks Slyster, nice to hear from an electric engineer 'ProgressivRC' I heard also that he knows his stuff!


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[clough42]

The process you're talking about during break-in is called cell formation. When done slowly for the first few cycles, the surface layer that builds up on the cell materials is smooth and even. When it's done rapidly, the layers are not deposited evenly and the cell performance and longevity do not reach their maximum potential for the cell design.

Some manufacturers (often premium brands with higher prices) perform this process at the factory, resulting in a cell that you can use right out of the package without major negative effects. Other manufacturers (often bargain, low-price brands) do not spend the time to do this during the manufacturing process and their cells can show great benefit from a break-in procedure.

Depending on the economics, price may not align perfectly with the need for break-in. There are of course some low-priced gems out there and some high-priced junk. In any case, I don't think you can go wrong breaking in your cells. It won't hurt a quality battery, and it could help a lot if the manufacturer took shortcuts on formation.

[clough42]

Here's a short article that gives some actual numbers for capacity loss under different conditions.

http://uterc.org/files/LipoStorageTips.pdf

The short of it is that at room temperature, you should expect 4% capacity loss per year for cells stored about half full vs. 20% or more for cells stored fully charged. Storing at low temperature helps, too, though there is lots of confusion (debate?) about temperature transitions for fully charged cells.

[cloud kicker]

Good helpful info in this thread.

I only started electric flight this year and I've only been using the Turnigy LiPo's.

I'm thinking of getting some better quality LiPo's. On one of mine, Turnigy 6S 5000mAh 40C, I did my 18th charge yesterday, flew with it, then when removing it I noticed that it was really puffid.

I fly the T-Rex 700E 3GX, so two 6S LiPo's in series.

What are good quality Lipo's, even if I have to pay a bit more?

[Slyster]

If it puffed that early (18 cycles) you are over discharging them!

Gens Ace at the best value today. www.hobbypartz.com

[cloud kicker]

Until this thread I'd just read not to go below 3.2V/Cell, but this thread mentions mAh. After charging one of my 6S that was used in series with the puffed from yesterday, the charger, iCharger 208B, put in 4742mAh. Way to much according to some posts in this thread.

[Liduno]

Originally Posted by cloud kicker

Until this thread I'd just read not to go below 3.2V/Cell, but this thread mentions mAh. After charging one of my 6S that was used in series with the puffed from yesterday, the charger, iCharger 208B, put in 4742mAh. Way to much according to some posts in this thread.

It's putting back in what you let out, you are letting out too much.

[Slyster]

I time my flights to end at around 40% (roughly 3.75v/cell)... that way the packs aren't too stressed and also I don't need to do a storage charge.

3.70-3.90 is the happy place for packs to sleep at.