Li-Po batteries - The truth is out there... but where?

ambro25

Morning lads and ladettes,

Seeming as I'm currently down to one shotty springer, one 7,2V "proprietary battery/charger" MP7 and eagerly awaiting my first TM AEG, but without an Nimh/Nicd charger at hand, I'm ogling all that new-fangled Li-Po batteries stuff that's starting to make some noise in the Airsoft world.

I'd be looking to get a 7,4V Li-Po battery small enough for the MP7 front compartment, and an 11,1V Li-Po battery small enough for the SIG552 front compartment (just about big enough for a 7-cells 8,4 nimh/nicd mini-type).

The questions trotting 'up there' atm are manyfold:
_ do I need to upgrade the MP7 innards for the 7,4V? I'm thinking 'not', as it's only a 0,2V difference, after all
_ has anyone ever seen a site with battery dimensions anywhere? (can't seem to find )
_ is there a Li-Po charger that can do both 7,4 and 11,1V?
_ what needs to be upgraded on the SIG552 to accomodate the 11,1V (aside from a mag-sized BB factory )? Gearbox? Piston? Everything? (Note - I've already got a Systema 1J spring coming in with it)

Fallschirmjager

i searched a bit for these before and i seem to recall fiach knows a bit on these, well at least i think it was fiach...or it may have been KD...might be worht to ping them on this..


there is a li-po that does 10.something but all of them would require big upgrades to the internals. there seems to be a belief that it would be okay if you stuck to small bursts and single fire, but tbh, i am not sure i buy that.

currently even the systema top range would grind out. there is also an issue that the mag would not be able to keep up with the piston and piston teeth would be vulnerable also.

you also need a different charger as li-po is very different then nimh. there are some that do all but you would need to be shelling out a lot for them, a couple of hundred dollars last time i looked.

the general consensus is stick with nimh and a very high MAH to get you thru the day. li-po will come, but i think the engineering tolerances and the price point for aegs are not matching to support it.

thats what i got from quite a bit of searching

if you find out any more ambro, i am all ears. i would be interested as they seems to be very small in comparison.

kdouglas

just did a quick bit of searching on arnie's, found the threads below
http://www.arniesairsoft.co.uk/forums/index.php?showtopic=120163&hl=lipo&st=0
http://www.arniesairsoft.co.uk/forums/index.php?showtopic=113680&hl=lipoly

and links to some guides on ebay:

http://reviews.ebay.co.uk/LiPo-LiPoly-buying-and-usage_W0QQugidZ10000000001234231
http://reviews.ebay.co.uk/Safety-with-LiPo-Batteries_W0QQugidZ10000000000990408

off for lunch now, but ill read up a bit more on it this evening and see what i can find

i would say just go ahead and try it, but 11.1v could easily destroy your piston/gears without mods and lipo's can be dangerous if mistreated

ambro25

Thx for these (and for some reason, Search on Arnies doesn't seem to work for me ).

Seems to be some conflicting reports about useability of 7,4V - I've seen a number of posts on Arnies and AirsoftRetreat, wherein the users are claiming no difference in ROF between a 7,4V lipo and an 8,4 nicd...and that's with a M120 spring :eek: ...which I find hard to believe.

May not be worth it, then - will be cheaper just buying an nicd/nimh charger altogether.

Hivemind187

ambro25 wrote:

Thx for these (and for some reason, Search on Arnies doesn't seem to work for me ).

Seems to be some conflicting reports about useability of 7,4V - I've seen a number of posts on Arnies and AirsoftRetreat, wherein the users are claiming no difference in ROF between a 7,4V lipo and an 8,4 nicd...and that's with a M120 spring :eek: ...which I find hard to believe.

May not be worth it, then - will be cheaper just buying an nicd/nimh charger altogether.

Depends on the efficiency of the battery.

A NiMH battery might be able to have a peak output of 8.4v but chances are that you are getting a lot less average or actual output due to power fluctuations.

If a LiPO battery is more stable in its current flow then you could quite easily be getting the same performance at a lower voltage because you are not making up for the same ammount of power loss due to frequency dips.

... all this electrical stuff makes my head hurt.

ambro25

From perusing a few RC Forums, doesn't look like LiPo stability offsets inferior voltage in terms of performance - consensus seems to be that Lipo > Nimh/Nicd for weight, but power ratio not quite there unless Lipo voltage (11,1) > Nimh/Nicd voltage (8,4) (of course).

Anyone can point me to a cheap 8,4/9,6 nimh/nicd charger/discharger as a stop-gap?

Hivemind187

ambro25 wrote:

From perusing a few RC Forums, doesn't look like LiPo stability offsets inferior voltage in terms of performance - consensus seems to be that Lipo > Nimh/Nicd for weight, but power ratio not quite there unless Lipo voltage (11,1) > Nimh/Nicd voltage (8,4) (of course).

Pfffffbbbtttt!!! Forums! sure, who would believe anything you read on a forum

It was merely a suggestion for explaining the variation in claims. I would be interested to see frequency reading from the different battery types though.