Li-Ion Batteries, not li-po

Stercus Accidit

http://ebaybanned.com/product_reviews_info.php?products_id=1107&reviews_id=281

I had a brief read of wikipedia on these as they got a recent mention over on arnies, are they good?

Are they good meaning with the circuit shown on the one I linked too, will they be as much hassle as a li-po or be more like a ni-cad or ni-mh?

I haven't heard them mentioned before in airsoft, I know they can be used in power tools sometimes.

Being a stick battery, it may suit the ak type aegs I'm going to be using from now on, and will allow for real steel furniture without hollowing out the stock.

So anyone with practical experience in these or an interest in using them, please post your experiences,

Thanks.

Puding

have nit used them myself, i did see them on ebaybanned ( only came across them today really ) and they where down for trial to go with my ak, i still think you will have the same issues and with li-po they seem to have the same advantages and disadvantages, will be interesting if anyone can add to this thought and tell use any differences.

Hivemind187

Actually energiser have had a model out for a while now (bloody brilliant lifespan). The dfference is something to do with the way the charge is stored in the medium. Not sure but Dex could probably explain (as could Fiach or ay of hte other engineering boffins).

zero19

Hmmm never seen those before, if they are safer to use than Li-Po then it could be the way to go

Beast ASI

The best technology available for airsoft is really LiFe, well as far as lion technology gets. it is cylindrical which works well for airsoft and it's the same as A123.

It's 3.6V per cell if I can remember, but it's quite new so I don't think it's widespread.

Personally, I use the Li-po's and they're fantastic - the Firefox ones anyway - so I'd have to say that the li-ion's are good as well.

There's something about them though not being good for airsoft?

liamo333

Beast ASI wrote: »

The best technology available for airsoft is really LiFe, well as far as lion technology gets. it is cylindrical which works well for airsoft and it's the same as A123.

It's 3.6V per cell if I can remember, but it's quite new so I don't think it's widespread.

Personally, I use the Li-po's and they're fantastic - the Firefox ones anyway - so I'd have to say that the li-ion's are good as well.

There's something about them though not being good for airsoft?

There dangerous! Arrragh.

ED E

Beast ASI wrote: »

The best technology available for airsoft is really LiFe, well as far as lion technology gets. it is cylindrical which works well for airsoft and it's the same as A123.

It's 3.6V per cell if I can remember, but it's quite new so I don't think it's widespread.

Personally, I use the Li-po's and they're fantastic - the Firefox ones anyway - so I'd have to say that the li-ion's are good as well.

There's something about them though not being good for airsoft?

Ehh, the whole voltage situation means they're either way under, dangerous, or way over I think.

Li-Ions are what are used in phones, camcorders and mp3s. Never headr of them being used for higher voltages though.

Stercus Accidit

the latest model on ebaybanned has a cut off circuit built in for low voltage afaik.

ED E

Motosam wrote: »

the latest model on ebaybanned has a cut off circuit built in for low voltage afaik.

Nice.

Puding

well i have one on order will be nice to see how they come out

Stercus Accidit

where are kd, dex etc., the electronics nerds.

I mean nerd in the best possible way mind, its a compliment here.

Puding

rsov seem to have some interesting new products im looking to try and buy one to see how they perform

A.C.M. Li-Polymer battery cells voltage monitor and alarm buzzer
http://www.rsov.com/product/0/1656/p_ACM-Li-Polymer-battery-cells-voltage-monitor-and-alarm-buzzer.html

and because rsov is very very ........very slow at this moment in time......


and

A.C.M. Li-Polymer battery cells voltage indicator
http://www.rsov.com/product/0/1652/p_ACM-Li-Polymer-battery-cells-voltage-indicator.html

Beast ASI

I've used Lipoly's for a while and they're fantastic - Better performance than Nimh in an alot smaller size.

I've just never used Li-ion's - What I was saying above is that is there a difference in the chemistry. I've been told by a battery retailer that Li-ion isn't that good for airsoft, while Lipoly obviously is.

What's the difference really, apart from the obvious.

liamo333 wrote: »

There dangerous! Arrragh.

Ehhh, no they're not, as long as you know how to charge them properly - Don't leave them unattended and charge them with a proper charger

Puding wrote: »

A.C.M. Li-Polymer battery cells voltage monitor and alarm buzzer

You don't really need this.

All you need is to get is a balance charger, that will auto cut off etc.

I'd recommend the Tenergy one that's available from www.all-battery.com.

If a li-poly battery does not have a balance tap on it, don't buy it because it will be VERY dangerous

Stercus Accidit

I have a regular smart charger with auto cut off,
What way should a li-po be charged then?

Beast ASI

Motosam wrote: »

I have a regular smart charger with auto cut off,
What way should a li-po be charged then?

Li-po's need their own charger, because if they are charged in a regular nimh charger, they will blow up

Just by making sure that all cells are getting equal voltage etc.because if they don't, they'll explode etc. - Charging in a plant pot or something would always be recommended.

If it's not a balance charger, then the cells will not be charged evenly which could lead to your battery on fire.

Stercus Accidit

To hell with that!

I have a 3300mah battery at 7.6 volts, It came with an ak I bought, but I want to up the voltage using a bit or re-wiring, and the battery space in the top cover.

What type of cell could it be?

I think there is 6 of them, 7.6 v and 3300 mah between them.

Edit: just tried 15.6 volts, fcuking brilliant

Puding

All you need is to get is a balance charger, that will auto cut off etc

this unit is not for charging as it uses the same plug as the charger would it can be used in game for example to let you know when the lipo has discharged to low , well that my interpretation of the info anyway

Beast ASI

Puding wrote: »

this unit is not for charging as it uses the same plug as the charger would it can be used in game for example to let you know when the lipo has discharged to low , well that my interpretation of the info anyway

No, a balance charger is to make sure that all the cells are being evenly charged, because if they are not it will explode.

The same goes with guns, if one cells voltage messes up, it'll explode.

kdouglas

Beast ASI wrote: »

No, a balance charger is to make sure that all the cells are being evenly charged, because if they are not it will explode.

The same goes with guns, if one cells voltage messes up, it'll explode.

The unit that they have on rsov.com is a buzzer which sounds when the individual cell voltage drops below safe levels, so it could be installed in an aeg (if you had the room) to warn you when to stop firing, given that a 11.1v lipo would still turn over an aeg when it was at/below safe level, then something like that could be handy

Puding

The unit that they have on rsov.com is a buzzer which sounds when the individual cell voltage drops below safe levels, so it could be installed in an aeg (if you had the room) to warn you when to stop firing, given that a 11.1v lipo would still turn over an aeg when it was at/below safe level, then something like that could be handy

its the same kinda unit that people talked about on boards in the other lipo thread (that i could not find sorry or i would have posted the first post in there) in that example we talked about a cut off at a set power level, but a audio or visual warning to me would be just as good and goes some way to limiting the risks that can come with the lipos

No, a balance charger is to make sure that all the cells are being evenly charged, because if they are not it will explode.

i have a balance charger i know what one is :P

extremetaz

...sorry, just saw this thread.

Right - here the skinny with Li stuff.

the whole "they explode" thing is thrown way out of proportion. Yes, if they are incorrectly charge they can rupture and catch fire or set fire to any combustables in the direct vacinity - but it's not a shrapnel inducing rapid-expansion reaction.

now - the complication with charging Li cells is this.

NiMh, NiCad, lead acid, and any others you can come up with are all relatively easy to charge as the basic charge cycle simply involves passing current into the cell current up until peak voltage and then stopping (charge rate depends on current)

overcharging will cause the batteries to heat up and, put simply, damages the ability of the cell to reconvert the energy effectively.

As such, it is perfectly possible to charge any of the above cell types with a simple DC power supply at the correct voltage and delivery an acceptable current level.


Lithium technology cells however, require that the charger monitors:
-the current flowing into the battery
-the voltage at which this current is flowing


this is known as CCCV (Constant Current Constant Voltage) charging and it requires smart chargers on account of the tempermental nature of the beast as it were.

As little as a 2% undercharging of an Li cell can mean as much as a 10% loss in the stored energy in the cell, whilst as little as 1% overcharging can result in its failure!

and it's not just as simple as charging the cell to voltage either. The cell must first be charged at constant current, to precisely the peak voltage and at that point, the current must be pulled back and the voltage maintained for a set period of time in order for the cell to absorbe the charge.

SO - simply charging them at known current for X time and using an alarm to tell you when voltage has peaked is insufficient as at this point, the voltage must be maintained and the current reduced in order for absorption to occur. This in itself required propportional control as the current must be dialled back according to how much is needed in order to maintain the peak voltage during absorption.

Now, why not use Li in airsoft - In the early days, Li was used primarily because it holds charge incredibly effectively. you can charge one today and in 20 years time it will still be charged. Hence they were used for things like watches and CMOS circuits in computers (CR22 et al).

BUT - they didn't like high current draw - that's where the "they explode" thing comes from. Li get *VERY* hot during high current delivery, hence, why you're also supposed to discard them if they ever get short circuited as it does massive damage to the internals and can lead to them catching fire in the future.

These days however, they are happy to supply anything up to 6A at 20V - so the question then becomes, how much current doesn your AEG draw at 9.6V

...and remember, 6A and 9.6V will generate significantly more heat than at 20V, so you'll have to scale the current available accordingly.

extremetaz

ps: Beast is right about the definition of a balance charger.

and another point of note on them - they are unapplicable to combination cell battery packs as they have no way of accessing each individual cell to ensure consistant charge capacity.

what they can do is ensure that two packs get exactly the same charge, and they will contain the necessary intelligent circuitry to control an Li charge - although whether or not they're rigged to do it is another matter entirely.

Puding

the whole "they explode" thing is thrown way out of proportion. Yes, if they are incorrectly charge they can rupture and catch fire or set fire to any combustables in the direct vacinity - but it's not a shrapnel inducing rapid-expansion reaction.

and

BUT - they didn't like high current draw - that's where the "they explode" thing comes from. Li get *VERY* hot during high current delivery, hence, why you're also supposed to discard them if they ever get short circuited as it does massive damage to the internals and can lead to them catching fire in the future.

contradict each other, lipos are a great safe battery used in the right area, unfortunately airsoft is not one these areas, the nature of a aeg and how we use (normal on auto) means that they are normally but under high strain due to the high draw. I see a lot of people buying cheap lipos not design for the job and putting them into aegs, and this is asking for trouble.

The lipos need care, the problem is most people are very used to there normal battery and there very low level off maintenance that is needed with them.

The dangers of lipos are increased in airsoft due to how there used and sorry to say this, the people that play airsoft, there a lot of people out there that lake commonsense and patience and im afraid airsoft (along with other activity ) does seem to attract more than it fair share, and this means the chances of accidents is highly increased.

NakedDex

Just noticed this thread now, coincidentally I was using a Li-Ion battery pack in one of my aeg's today that I built up in work. For a pack only marginally larger than an 8.4V mini (think a mini with a bulge on one side the size of another cell) I had a 10.8V 4.6Ah pack working perfectly. The momentary current draw flucutations were consistent with using NiMH (measured on an oscilliscope and meter) cells so the draw seems within tolerance for the Li-Ion cells on both semi and auto (though I only checked with 2 second bursts on auto, I didn't check sustained fire).

extremetaz

Puding wrote: »

and

contradict each other, lipos are a great safe battery used in the right area, unfortunately airsoft is not one these areas, the nature of a aeg and how we use (normal on auto) means that they are normally but under high strain due to the high draw. I see a lot of people buying cheap lipos not design for the job and putting them into aegs, and this is asking for trouble.

those quotes don't contradict each other. the first quote says they don't explode but they can catch fire - the second quote says they don't explode but they can catch fire.... where's the contradiction?

that aside - you're right, they are a great battery but I'd have to check the current requirement of an AEG motor before I could agree that they'd be under high strain. Bear in mind that Li technology is the preferred cell type for laptops and I am currently typing on such a machine which draws a full 6.15A from a lithium pack, and that pack has been operating without complaint for the last 3 years. (Toshiba Equium A60, P4 3GHz if anyone cares to doubt me)

as for the misuse of them, again, I'd agree - these are specialist cells, and whilst there are versions which will no doubt power and AEG faultlessly and work forever and a day if charged correctly, there are also plenty which just can't hack it.

as for the "safe" bit - they are, like most things perfectly safe once used as intended. But Li cells will not take abuse as well as the many other battery technologies which we have become accustomed to and as I have said - whilst they will not explode, they can be a fire hazard if used incorrectly. And that's a point which you can verify with many members of the small scale Model Airplane community from the early days of Li when many planes were lost due to abused Li packs catching fire. (granted, planes do present and extrodinarily high loading to the cell, but the point stands)

extremetaz

NakedDex wrote: »

Just noticed this thread now, coincidentally I was using a Li-Ion battery pack in one of my aeg's today that I built up in work. For a pack only marginally larger than an 8.4V mini (think a mini with a bulge on one side the size of another cell) I had a 10.8V 4.6Ah pack working perfectly. The momentary current draw flucutations were consistent with using NiMH (measured on an oscilliscope and meter) cells so the draw seems within tolerance for the Li-Ion cells on both semi and auto (though I only checked with 2 second bursts on auto, I didn't check sustained fire).

didn't happen to get a figure for the current draw did you dude?

NakedDex

I didn't think to mark it down and I can't remember what it was. I do remember auto fire having a very distinct pattern on the oscilloscope that I didn't expect initially. It has quite a strong "sawtooth" signal, indicating that there load fluctuates while firing. I put this down to the timing of the gearbox. IE, as the sector gear reaches it's last tooth and releases the strain of holding the piston spring back, the current draw seems to dip as the motor no longer has to fight the spring compression. The draw is fairly uniform until the sector gear re-engages the piston teeth and recycles. While this is happening, theres a notable exponential increase in current draw.
As such, you'd be better off taking an average draw current rather than a max or min, it fluctuates too much for it to be useful figure otherwise.

extremetaz

yeah, that's what you'd expect alright - although I imagine that the scope would have been showing you voltage not current (unless you have access to some *really* nifty kit ..in which case i'd be severely jealous!! :eek: ) but the relationship would be inverse so you could get the idea from it alright.

agreed again on the average value bit - taking the RMS value of the waveform will give you the most meanful power figure.