3 different battery test

[Tankdude]

I am not the first to do this, but you can't have too many examples



Volts are not everthing when it comes to batteries. Another case in point.
Gun has standard gears, classic army super torque motor, and a PDI 150%


The order in the movie.

7.2 3300 nimh
8.4 1700 nicd
9.6 2000 nicd

The nicds were discharged and charged twice to regain full mah. All were at room temperture.


And yes I was watching in the footsteps of binladin

[ILLusion]

So what was your personal conclusion of this test?

[Tankdude]

My main goal was to prove you can use 7.2 volts batteries in an upgraded gun.

1. You could use all of them for gaming.
2. You can use a 7.2 volt battery in an upgraded gun.
3. Rate of fire change was not that big, I am guessing maybe 2 bb/s for the 8.4v and maybe 3 bb/s for the 9.6.

Save your money and instead of buying those extra two cells just go for more mah.

[LUTNIT]

CDN_Stalker has been telling me the same thing in a couple conversations weve had on msn. The battery with the higher mah will have a higher rate of fire usually, regardless of voltage. A 9.6V 3300mAh will still have a higher rate of fire than an 8.4V 3300mAh but not by that much (noticable but not a drastic increase) and 8.4V 3300mAh will have a higher rate of fire than a 9.6V sub-3000mAh. It all seems to make sense, gotta go get me a 7.2V 4300mAh to test out now...

But when you consider the price of batteries the extra two cells to get it up to 9.6V compared to 7.2V is maybe $85 instead of $70 (using IB 4200mAh SC NiMH cells) and when you consider the price of airsoft in general that is a very small difference, true the gain in rate of fire wouldnt be too large but for only $15, I dont mind.

I guess my point is, why do people use batteries that aernt the max mAh for the size? I see people running around with $50 1700mAh large batteries and wonder why they didnt spend the extra $20 to get a 4200mAh battery, it just doesnt make sense to me. I only have 3300mAh batteries instead of 4200 or 4300mAh because 3300 was the max mAh I could find when I was shopping around, only later did my friend show me some R/C car sites where I can get up to 4300mAh batteries. I know some people prefer NiCd's to NiMH and that I respect but it isnt always the case, people just seem to go cheap on batteries. My P90 came with a 1700mAh J-battery when I know the same size cell is avaliable in 2500mAh to give a higher rate of fire, and I know there are many people that use 2-3 600mAh mini's in their guns instead of 1400mAh minis that cost only a fraction more.

[Guardian]

Originally Posted by LUTNIT

... people just seem to go cheap on batteries. My P90 came with a 1700mAh J-battery when I know the same size cell is avaliable in 2500mAh to give a higher rate of fire, and I know there are many people that use 2-3 600mAh mini's in their guns instead of 1400mAh minis that cost only a fraction more.

Are the larger rated mini cells relatively new? They didn't appear to be readily available a couple of years ago when I bought my batteries. Maybe time for me to start spec-ing replacements anyway.

[sherlockbonez]

I saw a 1400mah NiMH minis, 8.4V. It had a very good firing rate, a very small.

[ILLusion]

Originally Posted by Guardian

Are the larger rated mini cells relatively new? They didn't appear to be readily available a couple of years ago when I bought my batteries. Maybe time for me to start spec-ing replacements anyway.

They've been around for a while now, but they are Ni-MH. You'll need a supporting charger.

Personally, I'm still not a fan of Ni-MH, especially if you plan to play in any environment that is 5 degrees or colder.

[cjfield1129]

I was consider getting 7.2v li-poly. I wonder if similiar results would apply. I bet the 7.2v at full charge would produce 8 or more volts. Hmmmm....

[Tankdude]

lipo is 7.4

[LUTNIT]

Originally Posted by ILLusion

Personally, I'm still not a fan of Ni-MH, especially if you plan to play in any environment that is 5 degrees or colder.

NiCd's are better in the cold? This subject has never come up before in anything that I've read, I have no experience with it, and my R/C racing friend doesnt exactly race in the snow...

Are the chemicals in NiMH batteries retarded in the cold so their output drops or something? I always chose NiMH because the mAh capacity is almost always a lot larger and you dont have to worry about memory effect (even though I know its still there to a small degree and NiCd's can often be recovered from the memory effect.)

[Scarecrow]

Originally Posted by LUTNIT

NiCd's are better in the cold? This subject has never come up before in anything that I've read, I have no experience with it, and my R/C racing friend doesnt exactly race in the snow...

Are the chemicals in NiMH batteries retarded in the cold so their output drops or something? I always chose NiMH because the mAh capacity is almost always a lot larger and you dont have to worry about memory effect (even though I know its still there to a small degree and NiCd's can often be recovered from the memory effect.)

Well, in my experience, both NiMH and NiCAD suck in the cold, NiCAD is just marginally better. Plastic hopups are even worse in the cold as they tend to shatter. Generally rule of thumb is when it is cold, find a way to keep the gun warm, or you risk breaking your gun. I used to winter game, but, 3 or 4 hopups later, I don't anymore.

There is no question that NiMH is not as good a performer for pushing a battery in the same voltage and amperage as NiCAD however, when you have space limitations and you can get a 1100mah NiMH in the same space as a 600mah NiCAD, the NiMH is (in my experience) the better option. As you get larger, I think this changes. If you have the space to spare, get the NiCAD.

[Scarecrow]

P.S. Maybe someone in the know can answer this one, but my assumption was the voltage basically overcomes the friction of turning the motor and thus all the gears, and the tighter the setup, the more voltage is consumed in that push over friction. So if you have a good shim job, its easier on the motor and the battery and the battery will last longer. Bad shim job, more friction, shorter bat life. And in all this mah just dictates rate of fire... is this a correct characterization?

[LUTNIT]

Yeah, thats what I was told by a couple different people, upgraded spring = shorter battery life because more force is required from the motor, same thing if theres extra friction.

Rate of fire is determined by voltage and current. mAh stands for mili-amp hours, how I understood this is if there is a 1000mAh charge that means the battery will last for 1 hour at a draw of 1000miliamps or 1000 hours at a draw of 1miliamp. Rate of fire is determined by both voltage and avaliable current, higher voltage = faster motor cycle and more current = faster motor cycle. I wont go into details as I'm sure I will get them wrong but that is essentially (I think...) what CDN_Stalker told me. Think of a taser, they have incredibly high voltage and next to no current, thats why they aernt nearly as fatal as jabbing a fork into a wall socket. The voltage is the amount of electricity but the current is how fast its moving (or maybe I got that backwards...)

[Gryphon]

I made a video to this effect several months ago to quell the naysayers on Arnie's Airsoft that a 7.2V wouldn't even turn over a stock gun. Not only did it work just fine, an 8.4V gave only 1 round per second extra speed over the 7.2V.

In fact, I use an Intellect 7.2V 4200 mAh pack in my M249 with a 400 fps spring, no other mods. I get probably close to 900 RPM on that battery. Going back down to a stock spring yields an even faster ROF that borders on wasteful.

The only 8.4V I own is an Intellect 1400 mAh mini for my MP5.

Originally Posted by Scarecrow

P.S. Maybe someone in the know can answer this one, but my assumption was the voltage basically overcomes the friction of turning the motor and thus all the gears, and the tighter the setup, the more voltage is consumed in that push over friction. So if you have a good shim job, its easier on the motor and the battery and the battery will last longer. Bad shim job, more friction, shorter bat life. And in all this mah just dictates rate of fire... is this a correct characterization?

That is correct though it's amps you're consuming, not voltage. The more resistance you put on moving parts the harder the motor will have to turn, and thus draw more current. Bear in mind that current (amps) are not really something that is 'given' by the battery, it's something that is 'taken' by the device being powered. The harder a device has to work, the greater it's amp draw will be. If the battery cannot provide the requisite amount of current the device will not be functioning at it's full capacity. That's why the mAh rating is important, because not only will the battery have the capacity to power a high drain device but will also have a low internal resistance to provide those heavy currents.

[ILLusion]

Originally Posted by LUTNIT

NiCd's are better in the cold? This subject has never come up before in anything that I've read, I have no experience with it, and my R/C racing friend doesnt exactly race in the snow...

Are the chemicals in NiMH batteries retarded in the cold so their output drops or something? I always chose NiMH because the mAh capacity is almost always a lot larger and you dont have to worry about memory effect (even though I know its still there to a small degree and NiCd's can often be recovered from the memory effect.)

Like Scarecrow said, both chemical types begin to degrade in performance as the pack gets colder. However, you will notice the retardation sooner with Ni-MH types (around 5-10 degrees) whereas Ni-Cd can go a bit colder before you notice it (around 0 degrees). At -20, you might as well just leave your Ni-MH packs at home, unless you like playing with a ROF of 0.8 shots per second. ... and if your idea of a shoot-em-up day is being able to barely shoot off 3 lowcaps. I swapped to an external 8.4v 2400mAh Sanyo NiCd pack afterwards and ROF picked up, was still a bit slow but it still held up fairly well and lasted me the rest of the day.
(those numbers are based on my experience with an 8.4v GP cell 2500mAh A-cell pack in my P90.)

Originally Posted by LUTNIT

Yeah, thats what I was told by a couple different people, upgraded spring = shorter battery life because more force is required from the motor, same thing if theres extra friction.

Rate of fire is determined by voltage and current. mAh stands for mili-amp hours, how I understood this is if there is a 1000mAh charge that means the battery will last for 1 hour at a draw of 1000miliamps or 1000 hours at a draw of 1miliamp. Rate of fire is determined by both voltage and avaliable current, higher voltage = faster motor cycle and more current = faster motor cycle. I wont go into details as I'm sure I will get them wrong but that is essentially (I think...) what CDN_Stalker told me. Think of a taser, they have incredibly high voltage and next to no current, thats why they aernt nearly as fatal as jabbing a fork into a wall socket. The voltage is the amount of electricity but the current is how fast its moving (or maybe I got that backwards...)

Here is another way of looking at the issue:

Heavy upgrades also add stress to the motor - this stress also gets translated in to the battery. Any extra stress to the motor adds stress to the battery. Stresses can come from binding pistons, heavy springs, poor shimming jobs, high speed gears, etc etc. Higher torque gears will ease a lot of pressure off the motor and battery if running heavier upgrades. Personally, I always upgrade at least one torque level above standard ratio for any springs above 360fps.

Generally speaking, the main controller of rate of fire is voltage and current and the controller of how long you can shoot for is the capacity of the cell.
Larger cells (such as sub-C versus 2/3A [mini] cells) and even larger capacity similar cells (such as 4200mAh versus 2700mAh sub-C cells) have lower internal resistance within the cell. Basic physics tells us the relationship between V (voltage), I (current) and R (resistance). As resistance goes down, current is affected (since voltage stays the same) - and is why we notice a higher rate of fire with very large packs compared to smaller packs, even though voltage ratings are the same.
Even comparing a Sub-C 1700mAh pack to an A-cell 1700mAh pack, you will notice the sub-C pack has a higher ROF and seems to crank a spring with more gusto.

There are other factors that affect the rate of fire and how long the cell will last. For example, back to the 1700mAh Sub-C versus A-cell comparison again - a sub-C pack lasts longer than the A-cell. Why? Back to the internal resistance issue. The extra energy contained by the added resistance has to be released somehow. In the case of this chemical reaction, the extra energy is released as heat - wasted energy.
In a world of perfect atmospheric conditions, perfect cell production with 0% contamination and perfect cell mixtures and equality in a pack; yes... the rule of thumb of a 1000mAh charge lasting 1 hour at a draw of 1000mA or 1000 hours at a draw of 1mA. But that can only be used as a very general rule of thumb.



ALL of these reasons are why it's never recommended to jump to a high mAh pack when you have a low powered (stock) gun. I've seen pistons ripped to shreds in less than 10,000 rounds with 8.4v 2400mAh NiCad packs. Tokyo Marui's actual recommended pack for stock guns in sub-C form are 1300mAh!
Experienced tuners and shops do NOT recommend any higher than 1700mAh large packs for stock guns for this very reason! 4000+mAh packs lead to quick deaths for stock guns.

Higher capacity is NOT always better because in what I've just written above, higher capacity also means much more than just how long you can shoot for!

One way to balance it out if you MUST go to very high capacities on low powered guns is to drop the voltage level, which as the test in this thread proves, is still very effective for airsoft, even when running at 7.2V.
Depending on your size constraints, the stress to your motor and the size of your packs, your gun may be able to run at 6 volts? Who wants to give it a try?