battery charging and storage

[DanBow]

I've done a quick search of the forum but found nothing, so . . . .

 

I've got my RIF, 2 x 7.4v Li-Ion batteries and a SkyRC S65 balance charger. Both batteries have been balance charged but I wont be playing for a few weeks as I work shifts. I see on the charger that there is a storage function, do I need to keep them plugged in if I'm not going to use them for a while? Does the charge dissipate over time? 

 

What say you?

[JimFromHorsham]

I’d just put them away then charge them again a couple days before your next game tbh .

[Cannonfodder]

I only play once a month so my batteries sit doing nothing for a few weeks with no problems. Just make sure you don't run them completely flat as that's what tends to knacker them.

 

It's worth noting though that some mosfets do draw power constantly so if your gun has one you need to unplug the battery from the gun

[Haru]

I also just put them away and give them a little top up before game day, ideally you'd want to discharge them to storage levels but I dont have that luxury

[Lozart]

Storage charging is really only needed if you're planning to not use them for several months. 

[RostokMcSpoons]

If you're running Li-Ion batteries (Titan?) them you don't need to worry, it's Li-po that need storage charges, but as the guys say - it's not a big deal, unless you want to squeeze every last percent of life out of them.

[C-Diddy]

I tend to leave my batteries alone after game day, and charge them the day before I use them. 

 

Running a lipo into the ground will knacker it. Leaving it between 25-80% has no detrimental effects in my experience.

 

Worth grabbing a battery capacity tester. They're only about a tenner on Amazon

[Cannonfodder]

It's also a good idea to get into changing your battery at lunchtime on a skirmish day. Apart from helping to keep the batteries healthy it means you avoid the battery dieing right at the worst moment possible 

[DanBow]

5 hours ago, Haru said:

I also just put them away and give them a little top up before game day, ideally you'd want to discharge them to storage levels but I dont have that luxury

 

Thats an interesting one, my charger has a discharge function. 

[Dan Robinson]

I have the storage function, so I use it.  Probably OTT, but it's no effort either.

 

The storage function can put power in as well as take it out depending on the SOC of the battery. 

 

Discharge mode does just that.

[The_Lord_Poncho]

I have a number of different Lipo batteries that fit different shooters, so always use the storage charge function on them after a game day- whilst I wouldn't tend to leave it over a month between games,there is no garuntee that any particular battery wouldn't end up being left for months on end. And it's not really any hassle.

[Impulse]

I storage charge mine after every game day I use them, however I don't reliably use my batteries since most of the time I run gas guns. If I run an AEG, it's entirely possible I won't run one for months or I may run one literally the next game day, so I just got into the habit of storage charging just in case.

[DanBow]

2 hours ago, Impulse said:

I storage charge mine after every game day I use them, however I don't reliably use my batteries since most of the time I run gas guns. If I run an AEG, it's entirely possible I won't run one for months or I may run one literally the next game day, so I just got into the habit of storage charging just in case.

 

Ok, I'm confused a little.

 

When you storage charge it does that mean the charger does something other than charge it as you would normally expect? Then you leave it unplugged? I presumed storage charge was leaving it plugged in the charger like an intelligent trickle charger?

[EDcase]

No, storage charge is 40% to 50% of full and then left unplugged.

You could unplug the charger before it gets to full charge but of course that's less accurate.

 

Selecting 'Storage Charge' with an intelligent charger will actually reduce the voltage if necessary.

 

Edited September 12, 2023 by EDcase

[RostokMcSpoons]

Note that this storage charge stuff only applies to Li-Po batteries - if you really are using Li-Ion then one of the great benefits (as stated by Titan) is that they can be left in any state (except completely empty) indefinitely without affecting it adversely.

[DanBow]

29 minutes ago, RostokMcSpoons said:

Note that this storage charge stuff only applies to Li-Po batteries - if you really are using Li-Ion then one of the great benefits (as stated by Titan) is that they can be left in any state (except completely empty) indefinitely without affecting it adversely.

 

Ah, I'd missed that. Yes, definitely Li-Ion. Do I still need to balance charge them then?

[Lozart]

Just now, DanBow said:

 

Ah, I'd missed that. Yes, definitely Li-Ion. Do I still need to balance charge them then?

 

Yes.

[DanBow]

@Lozart and all others, Thanks. I won't be a newbie forever! 😁

[Rogerborg]

Mmm, while I accept that storing lipos at somewhere less than completely full will probably eke out a bit more life from them, it's not something that I bother with, for several reasons.

 

1. The recommended storage voltage / energy seems to vary by manufacturer, so how is the charger going to get it right?
2. They'll self discharge from full anyway. Which may not be ideal, but...
3. When do you not fully charge your phone, tablet or laptop using the same battery technology?  Do you worry about those?
4. Airsoft batteries are consumables, and paying the cost of a bottle of BBs every couple of years is noise compared to any other airsoft cost.

[Dan Robinson]

1 hour ago, Rogerborg said:

When do you not fully charge your phone, tablet or laptop using the same battery technology?  Do you worry about those

 

 

Funny you say that.... both my tablets and phones have a battery preservation mode that locks the charge limit to 85%.  I need all of my phone's capacity for work; but I use the feature on my tablets as they spend most of their time plugged in. 

 

My car's V2G software recommends stopping at 90%, but car batteries have all sorts of overheads and hidden capacities.

[Rogerborg]

54 minutes ago, Dan Robinson said:

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)

 

Quote

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

 

Edited September 15, 2023 by RostokMcSpoons

[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]

6 minutes ago, Gunboat Diplomat said:

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.

35 minutes ago, RostokMcSpoons said:

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.