battery charging and storage

[Rogerborg]

that locks the charge limit to 85%

But you use 100% of that?  Oh, mate, no, never go over 70% of your 85% limit!

 

[Sewdhull]

I apologise if this is TMI but lithium batteries are clearly confusing.

All lithium rechargables are lithium ion. Marketing confuses things. Cylindrical cells are called lithium ion. Pouch cells lipos. Chemistry is very similar, pouch cells have a paste, cylindricals have a liquid.

Pouch cells puff, cylindricals vent and are less likely to be damaged when it happens.

Storage charges are useful, but so long as the cell isn't full or empty (30% SOC either way is good) all should be well. This also applies to cylindrical cells, I can't imagine that titan think differently. This voltage is 3.7v for lithium's that aren't life cells.

Storing any lithium battery empty is really bad for it's longevity and safety.

Titan batteries have the same chemistry as other batteries. They are still damaged by over or under charge and high discharge currents and catch fire.

Metal cells are resilient and difficult to damage.

Lithium iron phosphate (life) are the only resilient and safe lithium battery, tolerant to overcharge and need to reach 270C to make fire.

They hold less charge but have a very long life. I have some that are 10 next year.

3S batteries are 9.9v.

If you look after lipos (pouch cells) they will last a reasonable amount of time, but they are fragile.

Cylindrical cells are physically robust, won't get stuck in a gun, but other wise have the same issues as pouch cells.

Other than life cells all the others suffer thermal runaway at pretty low temps so if they get hot (from 80C to 130C), they get hotter until fire. Careful charging and use can avoid the cells getting hot.

 

[RostokMcSpoons]

Thanks @Sewdhull sadly my old farty brain can't seem to cope with much new information, so that is TMI for me but I guess the takeaway message is that LiFe batteries would be great to use.   

Except (and please correct me if I'm wrong, or indeed the manufacturer is talking bollocks) that Double Eagles witht their Falcon Control Units are specificied as incompatible with LiFe batteries. 
Which rules 'em out for me (as I did go looking a month ago)

Please note that the gun's EFCS system is only compatible with LiPo Batteries, and is not compatible with LiFe or NiMh batteries.

 

[Gunboat Diplomat]

I storage charge all my LiPos when not in use (I have FPV quads as well as airsoft kit so have quite a lot of batteries). 

Aside from longevity reasons, if I storage charge them UP from a low voltage state after a game then it will save 20 mins or so of charge time before game day.  If I bring them DOWN to storage levels (say if I haven't used them) then they are significantly more chemically stable so less likely to suffer a LiPo fire, plus the stored energy is lower so in the worse case scenario the reaction is smaller.

Fortunately I seem to find that half a day on the field brings a battery down to storage voltage naturally, so usually I just plug them into a cell checker at the end of the day and find they at 3.7v per cell so good to go back in the box.

The relatively small low stress LiPos I've got for my RIF aren't really a concern, but the big 6S packs that suffer huge current drain and multiple crashes on my FPV quad I treat as a riskier proposition.  

 

[Lozart]

The relatively small low stress LiPos I've got for my RIF aren't really a concern, but the big 6S packs that suffer huge current drain and multiple crashes on my FPV quad I treat as a riskier proposition.  

I think that this is the critical bit most people miss. The horror stories about LiPos mostly come from the RC scene where there are much bigger batteries and a higher chance of kinetic disassembly. The more likely culprit in airsoft is either user error whereby the user charges them on a cheap POS charger or user error where they just wilfully mistreat them.

Thanks @Sewdhull sadly my old farty brain can't seem to cope with much new information, so that is TMI for me but I guess the takeaway message is that LiFe batteries would be great to use.   

Except (and please correct me if I'm wrong, or indeed the manufacturer is talking bollocks) that Double Eagles witht their Falcon Control Units are specificied as incompatible with LiFe batteries. 
Which rules 'em out for me (as I did go looking a month ago)

Sounds like bullshit but if they have set up any sort of voltage level checking in their mosfet they might just refuse to work with anything of too high/low a voltage. My G&G SR25 doesn't like 7.4v LiPos and beeps like mad before deciding not to play. Haven't tried it with a LiFe yet but just an example for you.

 

[RostokMcSpoons]

Sounds like bullshit but if they have set up any sort of voltage level checking in their mosfet they might just refuse to work with anything of too high/low a voltage. My G&G SR25 doesn't like 7.4v LiPos and beeps like mad before deciding not to play. Haven't tried it with a LiFe yet but just an example for you.

Well exactly, it seems a bit odd that that something that falls neatly between 7.4v and 11.1v should not work, as both are supported by the Falcon unit (though I do remember someone having a problem with one or the other, a while back).  I can understand the Nimh perhaps, but surely the voltage detection on a LiFe battery is the same as on LiPo? 

 

[Lozart]

Well exactly, it seems a bit odd that that something that falls neatly between 7.4v and 11.1v should not work, as both are supported by the Falcon unit (though I do remember someone having a problem with one or the other, a while back).  I can understand the Nimh perhaps, but surely the voltage detection on a LiFe battery is the same as on LiPo? 

Yeah, volts are volts. The EFCS can't tell what it's coming from unless it's set up to detect specific voltage ranges as being acceptable. That might form part of its battery protection for example so that it knows not to keep running and deep discharge your battery. In theory it may be possible that they have set two specific levels for that function (ie 7.4 and 11.1) so it can't work out where to stop with a 9.9v battery but that just seems like piss poor design. Oh...wait....airsoft. That'll be what it is.

 

[Sewdhull]

Thanks @Sewdhull sadly my old farty brain can't seem to cope with much new information, so that is TMI for me but I guess the takeaway message is that LiFe batteries would be great to use.   

Except (and please correct me if I'm wrong, or indeed the manufacturer is talking bollocks) that Double Eagles witht their Falcon Control Units are specificied as incompatible with LiFe batteries. 
Which rules 'em out for me (as I did go looking a month ago)

It will be the voltage monitoring shutting off the gun that's the issue.

Nominal cell voltage for life is 3.2v Vs 3.6 for most others.

It's worth trying it with a life I think. The cutout for a lipo will be 3v. Life can go lower but the discharge curve is pretty flat.

It depends how sensitive the system is to voltage sag under load.

 

[RostokMcSpoons]

That explains it, I think, @Sewdhull

Cheers!

 

[RostokMcSpoons]

I just happened to be watching this video...

.. and I noticed the new control unit has support for LiFe batteries.  The commentary mentions 'correct battery voltage detection' 

It's a shame the DEX / DEK guns are a bit 'fuggly' (with apologies to anyone who likes the super-stubby honey badger look), but I think this unit also exists in the AEX 15 (for those who like a futuristic M4 variant)

 

[Caj109]

I know this is an old thread just thought to put my input. I have two 7.24 lipos that have been in storage mode for the past 2-3 years from when I played last using the skyrc charger.

Plugged them in recently and still reading 3.81v per cell on both batteries, charged and discharged fine ready for airsoft next year. My understanding storage mode puts the cells to 3.85v

No bulging in them either, just stayed within a lipo safe bag.