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I have just brought some new lipos for my EDF Jets 

I normally just charge them up and put them in my EDF and fly. I have now been told by one of our club members not to do that. He said I should charge the new lipos  up at least 5 times before putting them in a EDF and flying them. 

I have never done that before. I just charge up the new lipo and fly them 

Is he right???? 

 

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I agree there is a lot of history left over from the nicad days when we would do anything that might get us any little bit of extra performance. 

Now I just do a single charge/discharge cycle to check that the batteries actually have the expected capacity and a reasonable IR. After that - charge and fly! 

 

Dick

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I also just use them, but for reference Overlander's Instructions are:

 

"4) For the first discharge, use low discharging current and keep the the discharging time to a 6-minute session with 15-minute break."

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Posted (edited)
6 hours ago, tigerman said:

I have just brought some new lipos for my EDF Jets 

I normally just charge them up and put them in my EDF and fly. I have now been told by one of our club members not to do that. He said I should charge the new lipos  up at least 5 times before putting them in a EDF and flying them. 

I have never done that before. I just charge up the new lipo and fly them 

Is he right???? 

 

 

Simple answer- ask him to quote a referenceable source, if he can't them I'm afraid it's just more lipo FUD... ?

 

https://batteryuniversity.com/article/bu-701-how-to-prime-batteries

 

Lithium-ion

Some battery users insist that a passivation layer develops on the cathode of a lithium-ion cell after storage. Also known as interfacial protective film (IPF), this layer is said to restrict ion flow, cause an increase in internal resistance and in the worst case, lead to lithium plating. Charging, and more effectively cycling, is known to dissolve the layer and some battery users claim to have gained extra runtime after the second or third cycle on a smartphone, albeit by a small amount.

Scientists do not fully understand the nature of this layer, and the few published resources on this subject only speculate that performance restoration with cycling is connected to the removal of the passivation layer. Some scientists outright deny the existence of the IPF, saying that the idea is highly speculative and inconsistent with existing studies. Whatever the outcome on the passivation of Li-ion may be, there is no parallel to the “memory” effect with NiCd batteries that require periodic cycling to prevent capacity loss. The symptoms may appear similar but the mechanics are different. Nor can the effect be compared to sulfation of lead acid batteries.

A well-known layer that builds up on the anode is the solid electrolyte solid electrolyte interface (SEI). SEI is an electrical insulation but has sufficient ionic conductivity to allow the battery to function normally. While the SEI layer lowers the capacity, it also protects the battery. Without SEI, Li-ion might not get the longevity that it has. (See BU-307: How does Electrolyte Work?)

The SEI layer develops as part of a formation process and manufacturers take great care to do this right, as a batched job can cause permanent capacity loss and a rise in internal resistance. The process includes several cycles, float charges at elevated temperatures and rest periods that can take many weeks to complete. This formation period also provides quality control and assists in cell matching, as well as observing self-discharge by measuring the cell voltage after a rest. High self-discharge hints to impurity as part of a potential manufacturing defect.

Electrolyte oxidation (EO) also occurs on the cathode. This causes a permanent capacity loss and increases the internal resistance. No remedy exists to remove the layer once formed but electrolyte additives lessen the impact. Keeping Li-ion at a voltage above 4.10V/cell while at an elevated temperature promotes electrolyte oxidation. Field observation shows that the combination of heat and high voltage can stress Li-ion more than harsh cycling.

Lithium-ion is a very clean system that does not need additional priming once it leaves the factory, nor does it require the level of maintenance that nickel-based batteries do. Additional formatting makes little difference because the maximum capacity is available right from the beginning, (the exception may be a small capacity gain after a long storage). A full discharge does not improve the capacity once the battery has faded — a low capacity signals the end of life. A discharge/charge may calibrate a “smart” battery but this does little to improve the chemical battery. (See BU-601: Inner Working of a Smart Battery.) Instructions recommending charging a new Li-ion for 8 hours are written off as “old school,” a left-over from the old nickel battery days.

 

Edited by MattyB
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4 hours ago, Dickw said:

I agree there is a lot of history left over from the nicad days when we would do anything that might get us any little bit of extra performance. 

Now I just do a single charge/discharge cycle to check that the batteries actually have the expected capacity and a reasonable IR. After that - charge and fly! 

 

Dick

 

This is sensible advice, but I always check the IT before I have even charged it, as some manufacturers wil do whatever they can to wheedle out of a replacement. I remember having to show IR and voltages in a video to get HK to give me a refund once, then after all that they asked me to dispose of the pack and jsut credited my account.

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I'm regarded by some in my club(s) as a complete vandal when it comes to flight batteries.  I'm sure that if they sold after run oil for LiPos they'd be using it by the gallon!

 

My history dates back to DEAC cells through to currently using very high C packs in freestyle multirotors.  I fly several times every week, usually more days than not in any week, usually 3 hour sessions.  Now while still flying FW and Heli's, flying said MRs in aggressive freestyle mostly, I'm running 160-200C 4S  and 6S packs.

 

I never use storage, don't deliberately cycle use of packs across the set.  Don't "run in" packs.

 

A flight session might see me come away with around 9-12 packs to charge.

 

I usually charge that evening under close by observation while on computer.

 

They might then be used next day, they might be left for several days while I fly different sized MRs, so using different sized packs.  Might even be a fortnight.

 

I won't go on, but generally do most things regarded by some as "bad" for pack life. 

 

Sub 850mAh packs get used down to 3.00v per cell. Above that capacity down to 3.4V per cell under load.

 

SO why am I just getting to have to replace packs bought as long ago as 2017 and 2018???  (and makes that have disappeared)

 

Answers on a postcard, please, to.....................

 

Personally I have found there is more to the manufacturing quality than to anything else. Gens Ace?  Rubbish....... Turnigy? Rubbish 

 

Good manufacturers come and go, and I'm no more going to tell you which ones I buy currently than give you my car or house keys, especially in these shortage limited times, but I doubt my extremely high current short flight duration usage would suit many of your differing purposes anyway.

 

I will say I regularly test the waters with sample buys of many brands, find a good current producer/seller and concentrate solely on them.

 

 

Seek and you will find.............. ?

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12 hours ago, Dave Bran said:

I never use storage, don't deliberately cycle use of packs across the set.  Don't "run in" packs.

We have heard this before but my observation is that you are in a minority. Like most I charge, fly and return to storage ready for the next flying session. 

 

Steve

 

 

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TBH I’m a bit like Dave, I fly, then the batteries get left in whatever state they come back from the field in (usually >35% capacity remaining) until I need them again then I’ll charge them up the day before. This means that some packs, if not used, are left fully charged sometimes for weeks. It doesn’t seem to have badly affected any packs! Most of my batteries (3s - 6s) are HK supplied, so Turnigy and Zippy but most of the recently bought ones are CHNL (really nice packs). I have tried 3x cycle charging new batteries but it doesn’t seem to have made any difference!

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13 hours ago, Dave Bran said:

I'm regarded by some in my club(s) as a complete vandal when it comes to flight batteries.  I'm sure that if they sold after run oil for LiPos they'd be using it by the gallon!

 

My history dates back to DEAC cells through to currently using very high C packs in freestyle multirotors.  I fly several times every week, usually more days than not in any week, usually 3 hour sessions.  Now while still flying FW and Heli's, flying said MRs in aggressive freestyle mostly, I'm running 160-200C 4S  and 6S packs.

 

I never use storage, don't deliberately cycle use of packs across the set.  Don't "run in" packs.

 

A flight session might see me come away with around 9-12 packs to charge.

 

I usually charge that evening under close by observation while on computer.

 

They might then be used next day, they might be left for several days while I fly different sized MRs, so using different sized packs.  Might even be a fortnight.

 

I won't go on, but generally do most things regarded by some as "bad" for pack life. 

 

Sub 850mAh packs get used down to 3.00v per cell. Above that capacity down to 3.4V per cell under load.

 

SO why am I just getting to have to replace packs bought as long ago as 2017 and 2018???  (and makes that have disappeared)

 

Answers on a postcard, please, to.....................

 

Personally I have found there is more to the manufacturing quality than to anything else. Gens Ace?  Rubbish....... Turnigy? Rubbish 

 

Good manufacturers come and go, and I'm no more going to tell you which ones I buy currently than give you my car or house keys, especially in these shortage limited times, but I doubt my extremely high current short flight duration usage would suit many of your differing purposes anyway.

 

I will say I regularly test the waters with sample buys of many brands, find a good current producer/seller and concentrate solely on them.

 

 

Seek and you will find.............. ?

Sounds like your packs are in pretty much constant use and, whilst some of your usage may be taking certain packs a little low, compared to some recommendations, in practice 3.4v/cell under load is often bang on 3.8v/cell off load, at least in my experience. It's clearly working well for you - so more power to your elbow.

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2 minutes ago, Ron Gray said:

TBH I’m a bit like Dave, I fly, then the batteries get left in whatever state they come back from the field in (usually >35% capacity remaining) until I need them again then I’ll charge them up the day before. This means that some packs, if not used, are left fully charged sometimes for weeks. It doesn’t seem to have badly affected any packs! Most of my batteries (3s - 6s) are HK supplied, so Turnigy and Zippy but most of the recently bought ones are CHNL (really nice packs). I have tried 3x cycle charging new batteries but it doesn’t seem to have made any difference!

Yep, that's pretty much what I do, other than I do check every pack before and after each flight. If, due to stretching it a bit the pack is down below 3.7v/cell after a flight, if I don't immediately charge it for the next flight, I might give it a wee storage charge if I'm not flying in the next week. That's a recent development though - historically I only charged at the field and the batteries stayed at whatever their state was on coming home.

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1 hour ago, EarlyBird said:

We have heard this before but my observation is that you are in a minority. Like most I charge, fly and return to storage ready for the next flying session. 

 

Steve

 

 

Are you saying that most people return their packs back into storage or manage their packs, including discharging to storage voltage ready for the next flying session? I'd be surprised if the latter was the case, but certainly wouldn't make any claim for what most people do. 

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17 hours ago, Dave Bran said:

I'm regarded by some in my club(s) as a complete vandal when it comes to flight batteries.  I'm sure that if they sold after run oil for LiPos they'd be using it by the gallon!

 

My history dates back to DEAC cells through to currently using very high C packs in freestyle multirotors.  I fly several times every week, usually more days than not in any week, usually 3 hour sessions.  Now while still flying FW and Heli's, flying said MRs in aggressive freestyle mostly, I'm running 160-200C 4S  and 6S packs.


Can I ask what the IR of those 160-200C rated packs actually is? I’ve never owned any rated that high, but when you think about the currents we are talking about I do really struggle to believe that those figure are even remotely close - you could quite imagine the solder giving way at those kind of currents!

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Posted (edited)
3 hours ago, leccyflyer said:

 . . . I'd be surprised if the latter was the case, but certainly wouldn't make any claim for what most people do. 

 

Maybe we need a poll, so we can see (a) who charges after flying, and then stores them fully charged until next flying session or (b) who leaves them at whatever charge level they finished flying at, and charges only on the next flying day (including those who reduce any unused packs down to storage voltage before storing them (or up, if they were over-discharged).

 

I'm in category (b), and several of my LiPos are over 10 years old and still giving good service.  Admittedly, I've also had quite a few that have puffed, and been discarded, well before that time.

 

Edited by Allan Bennett
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Posted (edited)
Quote

From Wayne Giles:

During the 10 years that I tested lipos, I always carried out three 1C charge/discharge cycles before subjecting them to a high power discharge run. There was a significant fall in IR values on all lipos.  Some lipos’ IR values dropped after the first cycle but all of them had fallen and settled after 3 cycles.

This means that there must be a chemical change in the cells during the first cycles .

If you subject a new lipo to a high current discharge, then it will run hotter for the first few cycles. We all know that heat is the enemy of lipo life so that there must be a good chance that it will die earlier.

 

Edited by Phil Green
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Simon is spot on correct, apart from obvious question of what use would that be think of the cabling required, even a small 1500 mah LiPo would be putting 300 amps down the wires! Now think how thick the average jump leads for a car are.

 

Manufactures C ratings for LiPo's are a complete joke.   

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32 minutes ago, Philip Lewis 3 said:

Simon is spot on correct, apart from obvious question of what use would that be think of the cabling required, even a small 1500 mah LiPo would be putting 300 amps down the wires! Now think how thick the average jump leads for a car are.

 

Manufactures C ratings for LiPo's are a complete joke.   

I agree that claimed C ratings are pure marketing fantasy but car jump leads isn't a good comparison. They are normally 2 or 3 metres in length or even longer. Resistance is proportional to length as well as inversely proportional to cross section area.

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Posted (edited)

Used in very short bursts of a second or two you can take some very high currents from quite small Lipos without degrading them. The attached data chart is from an F5B competition glider using a 9s 1500mAh Lipo. I use 6mm bullet connectors and short 4mm^2 cables and nothing has time to overheat with the short bursts and cooling time between. If you are wondering what use a two second burst of power is, then just look at the height gain from it. Usually about 12 such bursts of power in the average F5B flight and the batteries survive quite well, although we do heat them to about 35 degrees C before flying.

 

None of this has anything to do with normal usage by most (normal ?) people, but it might explain what someone means when talking about extremes - usually some additional factors not mentioned!

 

Dick

 

 

2022-06-03 23_32_43-.jpg

Edited by Dickw
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