Discharging AEP Lipos?

[Impulse]

Hey gang, just wondering how people discharge AEP lipo batteries? My fancy-pants Turnigy 6 Accucel charger hates them, since they charge via the balance lead which my charger dislikes (my charger requires you to plug in the balance lead AND the normal lead).

 

However, storing lipos at full charge is bad and will burn my house down and explode and make the frogs gay and it seems like the chargers that will charge my AEP batteries will not discharge them. How can I make sure I can discharge and store my AEP lipos at the safe voltage levels, since I can't just stick my Turnigy on "storage mode" like I can with my other lipos.

 

Plz halp am scured 😢

[Rogerborg]

Er, I don't, any more than I discharge any other of the many lithium based grenades surrounding me each night, whether airsoft, phone, tablet or laptop.

 

Are we talking these AEP lipos, the drop in replacements for the stock nihms?

 

 

I guess if you reeeeeeeeeeeeeeeeeeeally care, you could make a connection between the main battery contacts and the charger power lead.  I'm seeing pictures of that Turnigy charger coming with a lead ending in a couple of crocodile clips.  If you have that, or can fettle up something similar, you can stick the ends to the battery contacts with magnets - that's how I use my B6 to charge 18650s and similar.

 

Heck, you could do it with a couple of bare wires and a clothes peg to hold them on.  That's guaranteed to end in a towering inferno, but then you at least wouldn't have to worry about the potential for that any more.  

[Impulse]

13 minutes ago, Rogerborg said:

Er, I don't, any more than I discharge any other of the many lithium based grenades surrounding me each night, whether airsoft, phone, tablet or laptop.

 

 

Do you not find your lipos get damaged? I can only get out to play every fortnight, so I'm concerned I may just have to run a couple hundred BBs through my mp7 if I have a fully charged battery.

[Cannonfodder]

I only get to play once a month and I've never had a lipo go tits up from leaving it fully charged. In fact the only time I've had one stop working was when I discharged it too much 

[Impulse]

Reassuring to hear. Thanks guys, I'll stop worrying then. TM MP7 is the first "AEP" I've bought, so it's all new territory for me.

 

I was starting to feel like I should've just bought some TM nimhs instead 

[EDcase]

All good chargers require connecting the balance connector AND the main lead.

I have an AEP LiPo for the MAC10 and I made an adaptor from the old charger base so I can connect it to the main leads on an IMAX B6.

 

I think discharging to 'Store charge' is more of a concern for larger capacity packs, perhaps 11.1v and higher if unused for months at a time.

I've never discharged a 7.4v battery and they are all good according to the meter.

 

Edited October 7, 2021 by EDcase

[AirSniper]

There is a reason for discharging LIPO's that are not being used.

Typically, you charge,  use and then if not being used again, you check the voltage and then charge if needed otherwise you can elect to do a storage charge.

What this does is stop the collection of oxygen at the anode and lithium ions at the cathode and prevent the lithium oxidising and going nuclear when the lithium oxide causes an internal short.

The storage charge prevents this, keeping a cell on full charge and not using it leads to cell degradation early.

Remember that you get about 150 to 200 cycles out of a cell, so caring for them is helping keep them in peak condition and able to deliver the currents demanded of them. safely.

Capacity of your cell or number of cells do not matter, it happens to all Lithium even 18650''s

Edited October 7, 2021 by AirSniper

[Rogerborg]

17 minutes ago, AirSniper said:

What this does is stop the collection of oxygen at the anode and lithium ions at the cathode and prevent the lithium oxidising and going nuclear when the lithium oxide causes an internal short.

 

Thanks, that's the first time I've ever seen anyone actually provide an explanation for why you shouldn't leave a lithium battery fully charged.

 

On the other hand, every other lithium battery in everything else that I own, including the laptop I'm typing this on, gets kept at 100% as much as possible. Why come none of them have gone critical?

 

Do you have a reference for that?

[Gonz.]

I'm pretty chill about lipos in general, but I always keep them at storage voltage when not being used for more than a week or 2 at the most. And I have lipo's that are over 10 years old that work perfectly fine. 

 

Things that will reduce the performance and lifespan of a lipo include keeping them at high/full, voltages. In fact, lipos in long distance satelites are never charged to 100% at all. I don't recall the optimal figure, but I believe it's somewhere around the 80% mark. 

 

You have to take into account that most of energy stored in a lipo is in the middle range of voltage, say 3.6 - 4.0v. I don't recall exact numbers, but something like 4.0 to 4.2v accounts for something like 5% of storage capacity but 20% of voltage range, and 3.2 - 3.6v accounts for about 5% of total battery capacity.

 

We're not talking about memory effect here, it's just that lipos are not so happy with extremes. That incudes extreme discharge or charge rates (relative to C rating), extreme charge states or internal temperatures. 

 

Now most people aren't going to lose sleep over a £10-£20 airsoft battery compared to a 6 cell, 16,000mah lipo costing £180+ or a lipo on a satellite, but a lipo will last longer if charged slowly and not fully charged or kept with a high charge for extended periods. In the real world, an airsoft battery used once a fortnight or so is still going to last a good while; just it will last longer if stored at 3.7 - 3.8v between uses/charge cycles.

 

I've even bored myself now, but to answer the OP question, chargers typically discharge lipos very slowly. I personally have a couple of car bulbs wired in series to discharge lipos faster than a charger will, but still not too high a discharge rate. Airsoft batteries will be fine with a single battery and my rig can split into 2 x single bulb sets for 2-3 cell lipos. Leave a lipo alarm set to around 3.65v and job done. 

 

 

[Samurai]

I had a few lipos go puffy because I stored them fully charged.

[Gonz.]

22 minutes ago, Rogerborg said:

On the other hand, every other lithium battery in everything else that I own, including the laptop I'm typing this on, gets kept at 100% as much as possible. Why come none of them have gone critical?

 

Do you have a reference for that?

 

It's not always just about going critical. The capacity to hold a charge reduces over time when lipos have a hard life. My laptop, tablet and mobile phone batteries will hold a decent charge a lot longer than yours if you keep them at 100% most of the time, because I don't keep them at a high charge. 

 

One of the craziest trends is for devices, especially mobile phones, is to have faster and faster charging times. Each charge cycle reduces the performance of your battery. Fast and superfast charging accelerates this deterioration, but device manufacturers aren't going to lose sleep if you end up replacing your battery or your phone after a couple of years, are they?

 

A lipo battery can last 10 years or more if looked after and I have plenty of batteries that have done 1,000 charge cycles. Now they clearly won't hold the same charge they did when new, but they will still hold maybe 70-80%. As an example, I vape and use 18650 batteries. I charge them to 90% and they get me through a whole day for about 2 or 3 years. After that I replace them and use the old batteries in other devices like torches, power banks or RC transmitters. 

[Asomodai]

4 hours ago, Impulse said:

Hey gang, just wondering how people discharge AEP lipo batteries? My fancy-pants Turnigy 6 Accucel charger hates them, since they charge via the balance lead which my charger dislikes (my charger requires you to plug in the balance lead AND the normal lead).

 

However, storing lipos at full charge is bad and will burn my house down and explode and make the frogs gay and it seems like the chargers that will charge my AEP batteries will not discharge them. How can I make sure I can discharge and store my AEP lipos at the safe voltage levels, since I can't just stick my Turnigy on "storage mode" like I can with my other lipos.

 

Plz halp am scured 😢

 

 

I have the same charger and its why I got this.

 

https://www.taiwangun.com/battery-chargers/adapter-for-li-po-aep-batteries-ipower

 

 

[Impulse]

1 hour ago, Asomodai said:

 

 

I have the same charger and its why I got this.

 

https://www.taiwangun.com/battery-chargers/adapter-for-li-po-aep-batteries-ipower

 

 

 

Ugh, I can't afford £140 on an order right now, but this is totally something I'll look at getting in the future when I can justify the order.

[concretesnail]

The parts to make up that harness are dirt cheap and it's easy to do if you have a solder iron. If you don't fancy that you should be able to buy an off the shelf 2s parallel board which will work to.

 

I've made a few different sets for using different batteries a rifs and still matching my charger, personally I prefer xt connectors over deans, I found they handle weather better.

Edited October 8, 2021 by concretesnail
addition

[Impulse]

13 minutes ago, concretesnail said:

The parts to make up that harness are dirt cheap and it's easy to do if you have a solder iron. If you don't fancy that you should be able to buy an off the shelf 2s parallel board which will work to.

 

I've made a few different sets for using different batteries a rifs and still matching my charger, personally I prefer xt connectors over deans, I found they handle weather better.

 

Yeah, it looks incredibly simple, but I neither have a soldering iron or any experience with electronics beyond building my PC. I'll see if anyone at my local site has experience with electronics and get some help with it.

[Ebeneezer Goode]

Interesting reading.

 

I was always under the impression that keeping Li batteries fully charged when stored was better for battery health as it stopped them degrading. My cordless drill has a Li battery and the instructions actually recommend storing it fully charged.

 

The problems with Li batts seem to stem from keeping them on charge permanently with non-smart chargers (happens with laptop batteries). Boeing had a slot of bother with the batteries in 787s due to this happening...

[Jacob Wright]

Following as I’ve never had an issue with mine, charge them when I need them and leave them stored when I don’t. 🤷🏼‍♀️

[Rogerborg]

14 hours ago, Gonz. said:

My laptop, tablet and mobile phone batteries will hold a decent charge a lot longer than yours if you keep them at 100% most of the time, because I don't keep them at a high charge. 

 

Do you have a control group against which you're comparing?  Or a reference?

 

Really, I've seen this asserted over and over, but not once have I ever found or been shown a citation for it, that's not itself just more assertion.  I'd love to read one.

[Adolf Hamster]

11 minutes ago, Rogerborg said:

 

Do you have a control group against which you're comparing?  Or a reference?

 

Really, I've seen this asserted over and over, but not once have I ever found or been shown a citation for it, that's not itself just more assertion.  I'd love to read one.

 

 

it definately used to be a big thing with the old nicad/nimh batteries, hell you could recover serious performance with cycling them.

 

lipo's are much less susceptible, however the key question is how much is it worth doing?

 

eg my phone is ~7 years old now and still holds over a days charge (nearly 2), and whilst i don't use those superfast chargers it does get charged fully every night (that i remember)

 

of course after 7 years, battery life isn't what's going to kill it, what'll kill it is the charging port wearing out to the point that i can no longer charge it, and for many consumers it's less relevant even than that, as the boredom and desire to change will kick in much earlier.

 

for an airsoft gun? well batteries ain't too expensive and replacing them isn't exactly a difficult task, trying to eke out the maximum number of years service isn't worth anywhere near as much as it would be for say an electric car, where such worries about increasing charge rates etc are very much relevant.

[Rogerborg]

1 hour ago, Adolf Hamster said:

the key question is how much is it worth doing?

 

None, unless it's a real effect.  I'm minded to believe that it is, but I'd still like to see a credible source.

 

And even if it is, I'm not fussed by it, given the costs of batteries, cells and new Chinesium goods.

 

Not that I'm big into throwing things out, I've recovered a forgotten laptop power pack that had gone below 1V per 18650 and it's... well, powering the thing I'm writing this on.

 

But I prefer to deal with the problem when it arises, rather than spending time regularly fretting over keeping all my electronics at 60-80% in order to eke out an unknown number of extra power cycles.

[shadowfacex]

20 hours ago, Cannonfodder said:

I only get to play once a month and I've never had a lipo go tits up from leaving it fully charged. In fact the only time I've had one stop working was when I discharged it too much 

☝🏻This. Most LiPos are designed to retain optimal performance around 70-80%, when you store them at this level.

 

Unless you want to decommission your battery, I suggest you keep some juice in it between games, and charge them fully before each game. This should give you the best compromise without consciously trying to “optimise my battery’s life at the cost of being constantly on edge.”

 

Average lifespan of a lipo is about 3-4 years, depending on the storage conditions and number of cycles put through it. Some will start to puff a few charging cycles in (like shitty Nuprol ones) or it may last you 5 years when on good terms.

 

I recently had to buy a spare one and realised my current mini-stick has been with me through 4 years and my charger shows me still about 85% capacity available.

 

So yeah, don’t waste time on magic tricks and keep it simple. Unless you go through batteries like tea or coffee, then there’s no point in overkill.

 

Also, invest in a really good charger. ISDT does marvellous gear for RC/Airsoft.

 

1 hour ago, Adolf Hamster said:

well batteries ain't too expensive and replacing them isn't exactly a difficult task, trying to eke out the maximum number of years service isn't worth anywhere near as much as it would be for say an electric car, where such worries about increasing charge rates etc are very much relevant.

Exactly. If you were to fork out £6k for a battery replacement (cheapest battery for Renault Zoe), or £12k (BMW i3), or just scrap your car because fuck paying £30k for a replacement (Tesla), you’d think about charging cycles.

 

Paying £20 for a good RC battery once every few years is par for the course, so don’t sweat it.

Edited October 8, 2021 by shadowfacex

[Lozart]

19 hours ago, Rogerborg said:

 

Thanks, that's the first time I've ever seen anyone actually provide an explanation for why you shouldn't leave a lithium battery fully charged.

 

On the other hand, every other lithium battery in everything else that I own, including the laptop I'm typing this on, gets kept at 100% as much as possible. Why come none of them have gone critical?

 

Do you have a reference for that?

 

 

Different battery chemistry though. Not all LiPo batteries are created equal! If you abuse a phone battery or it's poorly installed you can still get 'splodey nastiness!

[Cannonfodder]

17 hours ago, Lozart said:

 

 

Different battery chemistry though. Not all LiPo batteries are created equal! If you abuse a phone battery or it's poorly installed you can still get 'splodey nastiness!

Just ask Samsung Galaxy Note 7 owners

 

[Gonz.]

On 08/10/2021 at 11:44, Rogerborg said:

 

Do you have a control group against which you're comparing?  Or a reference?

 

Really, I've seen this asserted over and over, but not once have I ever found or been shown a citation for it, that's not itself just more assertion.  I'd love to read one.

 

@Rogerborg I understand where you're coming from. I'm no scientist and am not out to prove my opinion to everyone's satisfaction. However, I have seen you in a similar situation having your advice/opinion questioned by someone asking for non-anecdotal evidence of your opinion, when it's clear that you have a lot of experience relating to airsoft and you share your experience to help others. Having learnt much from many of your posts in this forum, I am taking your question as genuine interest rather than taking exception to being asked if I have a control group. 

 

So, I'm just sharing my opinion based on experience and bits of information I've picked up over the years. Apart from a general interest, I have 20 years experience in IT and 35 years experience in RC cars, helis, and drones.

 

Also, I did say it's not really a huge consideration when we're talking about  £10-£20 airsoft batteries, but it's general advice where lithium batteries are concerned.

 

Whilst I don't have a scientific control group, I have experience of hundreds of laptop owners whose batteries deteriorated in short order and I don't recall a single one that didn't leave their laptop plugged into the mains all the time. This includes my wife; I think I replaced at least 4 batteries in 2 different laptops, before she finally got the message not to leave it plugged in all the time. I haven't had to replace any more laptop batteries at home and my wife still uses my old Samsung Galaxy S7 Edge which I bought soon after launch in 2016, so about 5.5 years on the original battery. 

 

Like someone said to you once, this is just anecdotal, but I'll link some references below.

 

Most consumer devices will charge a battery to 100% and the good ones then cut power until it reaches 95%, then top up again. Some will keep the charge at 100%. Neither is great for battery life. 

 

Now, overcharging/discharging, fast charging/discharging and high temperatures will do more damage to lithium batteries than just holding a 100% state of charge, but 100% SoC causes degradation, particularly at higher temperatures.  I have to add that degradation from maintaining a high SoC does not directly equate to 'splodey nastiness as @Lozart so eloquently puts it 😄, it just degrades the battery. 

 

As far as a citations go, I can't find the study I read about battery care in deep space exploration vessels, but I found this NASA document, "Guidelines on Lithium-ion Battery Use in Space Applications" states "The state-of-charge (SOC) and temperature at which the cells are stored or cycled greatly affects the irreversible capacity loss in the cells."  https://core.ac.uk/download/pdf/10549369.pdf

 

When someone asked Jeff Dahn how they might make their EV battery last 10 years, his response was to charge to 70% normally, and 100% only if needed for long trips. Jeff Dahn is a Professor of Physics and Atmospheric Science, Tesla Industrial Research Chair and as one of the most renowned battery experts in the world. https://insideevs.com/news/334778/tesla-battery-experts-recommendation-for-maximum-battery-life-video/

 

Beatrice Browning, a PhD researcher at the Faraday Institution, states ". . . leaving a LiB-powered device plugged in overnight is still damaging to the battery’s lifetime . . ." https://airqualitynews.com/2021/01/12/why-do-lithium-ion-batteries-degrade-over-time/

 

This article from Michigan University recommends "Minimize the amount of time the battery spends at either 100% or 0% charge. Both extremely high and low “states of charge” stress batteries. Consider using a partial charge that restores the battery to 80% SoC, instead of 100%. If that’s not possible, then unplug the device as soon as it reaches 100%" 

 

It also claims "Nokia and Sony mention potential damage to their phones if the device is left charging after reaching 100%".  https://news.umich.edu/tips-for-extending-the-lifetime-of-lithium-ion-batteries/

 

This article from the Battery University might not be peer reviewed or detail methodology of testing, but is interesting reading.  https://batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries 

 

This article goes into some of the chemistry involved https://www.eyerys.com/articles/40-80-rule-battery-charging-dealing-lithium-based-chemical-problems

 

This article discusses parasitic reactions in lithium batteries and also references Jeff Dahn https://electrek.co/2018/05/04/are-you-killing-your-lithium-batteries/

 

I hope this helps

[Rogerborg]

7 hours ago, Gonz. said:

However, I have seen you in a similar situation having your advice/opinion questioned by someone asking for non-anecdotal evidence of your opinion, when it's clear that you have a lot of experience relating to airsoft and you share your experience to help others

 

Wut, no, I make it up as I go.  

 

Asking for citations is just a habit from my day job.  Verifiability is everything, or else you're just operating on faith.

 

To be clear, I wasn't desbelieving, I really was just after an explanation and confirmation.  Those sources look pretty compelling, thanks for providing them.