systema m120 vs m120s
 

hi I have some queastion for y'all
if you go to this URL: http://velocityarms.ca/index.php?mai...systema+spring
there is two types of m120 spring.
I just want to know what's the difference between them.
thanks

also I do have another queastion as well
it's not realted to systema spring but what is an li-po ready bettery anyway???
thanks again

the lipo battery ready mean that the gun can take li-po's without a modification

so what is lipo then?????

li-po is a battery that goes into your gun

way better than your Ni-cd or Ni-h

li-po battery's need to use a certain type or charger for it to be safe to use.

Li-po is a differant batery chemistry then Ni-cd and Ni-hm, the two most common airsoft battery compositions.

Li-po batterys can give you insanely high rates of fire, much higher then a normal battery but if your mechbox isn't propperly re-enforced, a lipo can tear it appart pretty fast.

Li-po batteries also need special chagers.

so then if I wanted to put lipo bettery to a AEG that isn't lipo ready.
what mechbox do I have to upgrade in order to put lipo battery.
does some mechbox says that????

Read this: http://www.airsoftcanada.com/SpringChart.php

thanks for the spring info

IMO LiPo ready is a bunch of marketing crap. my stock TM M4S ran fine with 7.4 LiPo, my TM P90 (yeah i know v6 is sturdier) stock is running lipo 7.4v without any problems either.

When people talk about Lipo most people if not all are thinking 11.1v not the 7.4 packs, and with 11.1v packs you want to have higher quality gears and depending on your spring a reinforced gearbox.

Some manufacturers are charging a premium for "lipo ready" nonsense. KWA seems to be the only company i've found that truly is lipo ready. Built in low voltage cut off, reinforced gears out of the box etc.

The most important part of running LiPO batteries IMO is having a low voltage cutoff circuit, if the Lipo pack is drawn below 3v per cell then you run a risk of ruining your cells, IE they will never charge again or burn, smolder when charged.

is that right eh???

That's all IMO.

again IMO i think most guns are Lipo ready at 7.4 V packs.

Goto a RC shop and pick up your Lipo gear. I bought a low voltage cut off for 4.99. airsoftparts is charging 20 dollars. The difference is that the cutoff from Airsoftparts is made by a Airsoft manufacturer (or rebranded I dunno), and mine is generic who knows who made it but it gets the job done.

Better yet goto a RC shop and talk to a guys who fly electric planes and race electric cars and get the real info on LiPo yourself.

your TM guns are running with 7.4v li-po with no problem, so is 7.4v li-po about same voltage with 9.6v ni-mh battery??

the trigger response and ROF is higher with the 7.4 lipo over nimh and nicd both at 9.6 small pack. (i dont have large packs to test with).

My Custom M4 (not the stock M4S):
Systema 120 gearbox replaced piston piston,
magnum motor
9.6 G&P style crane batter NIMH

gets 17 RPS, with the 7.4 lipo it jumps to 22.

short answer yes.

thats awesome. did you need cut circuit for 7.4v li-po?? or just plug in.

sorry,, I do not really understand the electronic things.

I am going to test the need for a cut off with a 7.4. With an upgraded spring 120+ and upraded motor, i don't *think* a discharged 7.4 lipo is able to turn over the spring.

I recommend that you use one anyways since they are so cheap. and the risk of not ever being able to recharge your battery is not worth 4.99 for a cutoff.

LiPo's are also cheaper. RC guys are constantly throwing away their lipo's when the next gen battery comes out that gives the extra 1c discharge. you can buy really high end packs off these guys for 20-30 dollar, but don't hold your breathe hoping to find a pack that will fit into your gun.

thanks =)

Here's my take so far on the LiPo-mystery/myth/magic...

With "normal" NiCad, NiMh batteries...most people didn't sweat them much. 8.4v was "regular", 9.6v was "fast" and anything more was insane. Large batteries lasted all day and resulted in a higher rate of fire than a mini battery pack. If the pack was overcharged...you ended up with a gooey mess on the table. Charging/discharging them incorrectly would kill/ruin the pack...but it's simple to plug it in and let the charger finish automatically.

With LiPo batteries there's a lot of stigma around them blowing up, killing your mechbox, gassing you to death, etc...

Here's what I've found so far (NOTE: I am not a be-all-and-end-all fact sheet for batteries...there's lots of other good information out there. But hopefully what I write is comprehensible and correct).

- much of it has to do with the C rating. A 11.1v 1100mAh 15C battery is very different from a 11.1v 2000mAh 20C battery...the first one can provide 16.5Amps and the other 40Amps. There will be a big jump in ROF going from one to the other.
- a 7.4v 2000mAh 20C battery does seem to be about the same as a large 8.4v 3600mAh battery. It does not rip your mechbox apart (unless your mechbox gets destroyed by "normal" batteries :D)...in and of itself. Maybe a little quicker...but nothing like a large 9.6v 2200mAh NiCad
- a 11.1v 1100mAh 15C battery is quick like a small 9.6v 1400mAh mini pack...faster ROF than a 8.4v large. Maybe similar to a 9.6V large.
- Rapid firing with a lipo (i.e. lots of semi or long bursts of full auto) does heat up the battery more noticeably than with NiMh/NiCad batteries. Getting it really, really hot (i.e. too hot to hold in your bare hand) can't be a good thing.
-- I had a "run-away" gun from a pinch wire...it probably cut loose a 1000+ shots before I got into the stock and unplugged the battery (11.1v 1100mAh 15C lipo). The battery was EXTREMELY hot...and took a long while to cool down. The voltage of the pack was still above threshold...but the heat generation was a bit unnerving.
- preserving the integrity of the LiPo battery casing (i.e. the plastic wrap it comes in) is important. It's the only thing that prevents it from venting, exploding etc... NiCad/NiMh batteries are in little metal cans...LiPo cells are basically baggies of chemical goo.
- LiPo cells should be charged up to a max of 4.2v per cell and never discharged below 3v per cell. So a 3 cell 11.1v battery has a max of 12.6v and a min of 9v.
- Continuing with the example 11.1v lipo pack example...If a cell in the pack is "dead" and isn't taking a charge...and then you charge up the pack to a total of 12.6V...you've overcharged 2 of the cells, driving them up into (and maybe past) the danger zone where the cell packaging bursts and all the firery demons come out and burn down your house. Same thing happens with NiCad/NiMh batteries...but you don't get flames and toxic gas...you get a chemical mess of battery acid.
- If a cell in the pack is worse than the others...it may discharge quicker. So when your total Voltage is 9V (for a 11.1v 3S pack)...two of your cells might be higher than 3V and one under (killing it more). Then you go to charge it up and BOOM.
- Balancers and the capability to check the individual cell voltage is important. Balancers monitor the voltage of each pack while it's charging and adds power to individual cells to "balance" them out. It does not guarantee that when discharging one cell is "dying off" faster than the others.

Hope that helps,

Tys

Ni-Cd (Ni-Cad) = Nickel Cadmium
Ni-MH = Nickel Metal Hydride
LiPo = Lithium Polymer

LiPo batteries are the same kind used in your cell phones and most modern portable electronics these days, but they require a lot of care, as they are quite volatile and can explode quite violently if mistreated in use or in charging.

If you're pulling an M120 type spring, just make sure the LiPo pack you're getting is rated for at least 20C. 25C recommended. Stick with 7.4v = 11.1v will be too hot for your mechbox.

As for the Systema springs, the standard M120 is an oil quenched steel, whereas the M120S is Stainless steel (hence, the "S"), and the M120S is more suited for a skirmishing gun that goes through full auto cycles. It seems to return springiness faster than an M120 does and is what Systema recommends for the common skirmisher. The Stainless spring also seems to push out a slightly higher velocity than the standard M120.

I'm not so sure that C rating is all that important as long as it's above 15, ideally 20.

THe motor pulls power from the pack and with airsoft motors that maxes around 60amps (or so i'm told). i've seen RC packs up to 68C 3000 mah, If you want insane lipo packs look at the ones for choppers and planes.