LiPo Ready - Is My Rifle LiPo Ready? How can I tell?

[m102404]

I've gotten these types question over and over.

"Is my rifle LiPo ready?"
"I want to run a LiPo...will that destroy my mechbox?"
"What do I need to do to my rifle so that I can run LiPo Batteries?"
"Is this rifle or that rifle ready to run LiPo's?"

And the only definitive answer I can give at that moment is...I don't know.....with the following explanation

1. You need to decide what you want to do with your rifle and what you're trying to achieve.
- LiPo's are great for stuffing a lot of power into a small space/package
- you can often get lots of Voltage and Amps out of a LiPo to build up really fast Rate Of Fire (ROF) rifles

2. You need to understand batteries and some particulars of LiPo's
- I'm not going to rewrite it here...there's already at least 2 good threads on this forum and some other great write ups out there. If you can't use the search feature and Google...you are too lazy to use LiPo's

3. Bigger isn't alway better, you need to match the battery to what you're trying to achieve.
- a 7.4v 2000mAh 20C battery isn't a "crazy" battery....it's like a large 8.4v 3000mAh NiMH (guesstimation)
- a 11.1v 1100mAh 15C battery isn't all that "crazy" either...it's like a large 8.4v 3300mAh NiMH (guesstimation) as well
* see point two if you don't understand why
* now the two batteries will perform very different. The 11.1v will seem a bit "spiffier" but is not suitable for long burst in a high powered rifle. It's better suited to semi-auto with a mid level powered rifle. If you don't know why...see point 2. But...the 11.1v will tuck into a M4 stock tube

4. Here it is...the answer to the big question...
Any AEG is LiPo ready. But you need to understand what's going on in an AEG and why that statement is true. Forget the externals of the rifle...that's just a shell holding all the mechanical bits in place. The mechbox is made up of a bunch of gears, driven by an electric motor, spinning around against spring pressure. At best, the whole system starts to wear out as soon as you start to use it. Good quality parts, assembled well...wear out slower and can operate at higher forces (i.e. faster, stronger).

So a LiPo is just a battery...a source of power to drive the motor, which turns the gears against a spring. If your mechbox is buit nicely...it'll work and it may last for as long as it would with a "normal" battery as it would with a properly sized LiPo. If your mechbox is shit...it'll work/last as long as a shitty mechbox would with a "normal" battery. If you "super-size" your LiPo to the mechbox...then you'll increase the risk of toasting it quickly (maybe even just 1 trigger pull). If you way under spec your LiPo to your mechbox...then you'll starve the system of power and run into the same problems as you would with an under powered "regular" battery.

*********
So...clear as mud? If you find yourself asking the questions at the beginning of this post...do everyone a favour and think through the rest of it and rephrase your question with more detailed information.

You might even answer your own question.

Tys

[ThunderCactus]

Good post.
I've tested my 7.4v 20C LiPo against my 9.6v 1600mah NiMH, and they had pretty well the same ROF (~30RPM)
It's important to note that the size of your cells doesn't affect your ROF as it does with NiMH cells. For example, a large NiMH battery will make your gun shoot faster than a mini NiMH battery. But with LiPo batteries, every 7.4v 20C LiPo should give you the same ROF regardless of the size of the pack or the amperage.

This is a lot to take in for a new player, remember that gunsmiths don't WANT to work on broken guns, we'd MUCH rather be upgrading than fixing. And advice is always free
So before switching to LiPo, PLEASE ask a gunsmith for what you need to convert to LiPo, and what you need to be aware of.

Speaking of which, I should send a LiPo noob info sheet to Strelok so he can make a copy-paste cleverly animated informative poster lol

[medhatboy]

So I take it my pre-built systema M120 mechbox with systema magnum motor will be ok with the 7.4v 4400MaH Lipo I just ordered.

[CJay]

if it pushes the spring lol - 7.4's tend to to have some probs pushin heavier springs but I have no experience with PTW's so I'm not the best person to offer advice - u mught be better with an 11.1v

like Tys said the mAh rating on lipo's mean next to nothing when it comes to trigger response - that's the voltage that counts and higher voltage will push the motor with more ease...for example - I had an indoor rated P90 firing nice and snappy with a 7.4v lipo but when I put that in my outdoor P90 shooting 430 it wouldn't push it whereas the 11.1v lipo more than happily powered it. also I dont think it has been said but the main reason lipo's are seen as dangerous is that they can speed up the rotations inside the guns etc and that increwases ur wear and yes it will break down more quickly - but with a normal battery this may also happen - it'll just take longer as the motor isn't cycling as fast.

[m102404]

I wrote this so I wouldn't get asked....

7.4v/4400mAh/???C rating....probably in the 35C range (so 154A on tap)...I'll bet it'll be a sweet screamer.

I'd check the motor engagement first with a lower powered batt when you're setting it up...get it in the sweet spot first...then go for it. Some guys swap off the pinion gear from Magnums....I've never had one fail, but I guess others have.

[Schwag]

My 2 cents.

I have yet to see a stock gun that can run an 11.1v lipo reliably for long. 2 of the supposedly lipo-ready KWA m4s blew their boxes in no time at our field. Not even a summer's worth.
If you want to run lipo, you need a tough box perfectly assembled.
It puts a lot of strain on gears, pistons and cylinder heads.

Before putting both my guns on 11.1 lipo I added sorbo pads, double o-ring cyl heads, sorbo piston heads, sector gear clips(otherwise you probably wont be able to load bbs)
Titanium tooth pistons, metal bearing spring guides, solid metal bushings, stronger anti-reverse spring and a perfect shim job.
A box moving that fast also has alot of vibration within the shell. Proper body/shell fit will increase the life of your box.
V3 is stronger than V2 and better suited to lipo.

With this setup I have run my guns for over a year with only 1 issue. That is arcing.

On my mp5k, the lipo causes arcing between the trigger contact and blades. This scorches them and builds up a residue that will eventually stop it from working. Need to strip it and clean the contacts every few months. This has only happened on one gun. My other has no arcing. Don't know why.
This can be fixed with a mosfet.

Also remember that regular mini connectors(tamiyas) limit the amount of juice so your 11.1 won't be super efficient until you upgrade wiring and go to deans connectors.

The short answer is that if you can't build a gun(or aren't friends with a very generous gun doc) you probably should avoid lipo and stick to 9.6v regular batteries.

If you build a gun to handle it, it is awesome. Instant trigger response, great rof, I have never run our of juice and the cold doesn't seem to affect them as badly.

I have been using king arms stick and small pack in a peq. Can't recommend them enough. King arms rocks.

[medhatboy]

Originally Posted by m102404

7.4v/4400mAh/???C rating....probably in the 35C range (so 154A on tap)...I'll bet it'll be a sweet screamer.

Forgot to mention its 20c.
http://shop.ehobbyasia.com/bb-batter...m-battery.html

used to run it on a 8.4v 3300Mah NIMH, but wanted a smaller buttstock on it.

[ThunderCactus]

a 7.4v 20C will push 400fps no issue what so ever.
My M4 shoots 380 and it gets 1000rpm on a 7.4v 20C LiPo
The thing is, as long as your LiPo isn't rated UNDER your needed amperage, it really doesn't matter what the C rating is since your already pulling 100% of the amps your motor needs. It's not 'how much amperage is my battery giving me?', you have to think of it as 'how much amperage is my motor taking FROM my battery?'
So a 20C and 50C LiPo will give you the same ROF. But if you have a 10C and you need atleast 15C, your battery will go up in flames.

Things you REALLY should have for a 7.4v LiPo:
upgraded piston
upgraded wiring harness
deans connectors
MOSFET or SW-COMP and a PCB

Things you NEED for an 11.1v LiPo:
upgraded piston
upgraded wiring harness
deans connectors
MOSFET or SW-COMP + PCB (Don't use a triggermaster with an untuned magnum motor)
sorbo pad (for V2 mechboxes)
upgraded and shimmed gears
tuned motor (absolutely mandatory to tune those P.O.S. systema magnum motors)
upgraded tappet plate

The triggermaster SW-COMP allows you to slow down your motor speed (and therefore ROF), it comes in handy with 11.1v LiPo's not just for mechbox wear, but incase you have problems feeding at high ROF
And IMO magnums are crap, I've heard of 5 pinion gears failing and seen one fail myself, although it's less common with prometheus gears. And every magnum I've put a triggermaster on has NEEDED to be tuned, as it was so badly tuned from factory it was causing the triggermaster to overheat in semi auto. The G&P M140s and M160's are superior and consume less amperage even after tuning the magnum.

[m102404]

So...quick summary of some great points to keep in mind...

- having Amps on tap is great...as long as you have more than what your motor is going to draw

- 11.1v (really 9.6v+) will cause arcing of your trigger contacts...mosfets relieve that (go search re. mosfets...here and through google...search for DonP ASC's mosfet friendly pusher)

- matching your wiring (16AWG+) AND connectors is required (DEANS)

- gotta have your mechbox sorted out or kabloowy

- Thundercactus does not like Systema Magnum motors

[ThunderCactus]

Alright, for anyone who wants hard numbers, here they are!
Both batteries tested on fully upgraded M4, prometheus double torque gears (properly shimmed), prometheus piston, 380fps spring, TUNED motor, low resistance silver plated 18 gauge wire, triggermaster MKIII SW-COMP, deans connectors, bearing piston head and spring guide.
Readings are after a full charge on NiMH and LiPo
The 11.1v LiPo was first tested at 50% motor speed (920rpm), then at 70% I didn't crank it up any higher because there's simply no point in risking internal damage.

11.1v 20C 4900mah LiPo (AT 70% MOTOR SPEED)- 1052rpm
9.6v 4200mah NiMH - 1212rpm

7.4v 20C 1600mah LiPo - 910rpm
9.6v 1600mah NiMH - 1066rpm

[m102404]

do you have a smaller mah lipo to run some comparitive numbers?

I.e.

11.1v 20C 4900mah vs. 11.1v 20C 2000mah @ same gun setup

[ThunderCactus]

They have the exact same ROF. Mah has nothing to do with the rate of fire on a LiPo.
The physical size of NiMH affects the drain, and the amperage it can supply, that's why you get higher ROF from large batteries.
But LiPo's already supply 100% amperage, so only the voltage changes your ROF.
So a 7.4v 20C LiPo will have the same ROF whether it's 1600mah or 6000mah.

[m102404]

I get your point ...just wanted to see if you had a different battery...

A buddy of mine has a high speed setup and runs 4 different batteries, the biggest one is a 11.1/4000/45C brick....the next size down is a 11.1/3000/35C smaller brick. Since the "smaller" one can sustain ~100A...I had a hard time thinking that his rifle wanted to draw more than that since there's a noticible increase in the ROF with the "bigger" one. Those ratings are from memory, they might be the peak rates instead of the constant rates of the batteries...still, it's monstrous. I doubt he has the setup any more...at least in one piece

Perhaps a different question that will help others who read this post...aside from just trying bigger and bigger batteries until your ROF levels out...what is a safe reliable way/location to measure the draw of a setup?

[ThunderCactus]

Well a fully upgraded airsoft gun, at 400fps, firing around 1200rpm (really fast), with a tuned systema magnum (draws the same if not more than an untuned motor), will draw ~17A. So it's safe to make all your guesstimations to 25A for high power setups, and 20A for normal 400fps, 1000rpm setups.

If your LiPo doesn't supply enough amperage for you motor, your LiPo goes up in smoke.

Although every 7.4v 20C LiPo has the same output, there IS a factor than can cause a change in ROF on a gun; and that's the wire gauge of the battery.
If you have two batteries, one with 18 gauge leads and one with 12 gauge leads, the 12 gauge is going to offer a higher ROF because the wire has less resistance in it.

For example, I have 3 different 7.4v 20C 1600mah LiPo batts, a turnigy and 2 intellipacks. All having differing rates of fire due to the 20, 16 and 14 gauge leads.

[Timely A.]

What if the gun is LiPo ready, then do I have to get a LiPo? or will it work with a "normal" battery?