What battery should I go for?

[Knocturnal]

I will be receiving my Echo1 ER25K tomorrow, so I will be going to the local store to purchase a better battery. What I would like to know is... Considering I will be using this rifle as a sniper, I will eventually upgrade the spring and other internals to increase my fps, though, I am not looking for a faster ROF, but rather strength for the motor to support the springs higher tension. Am I looking for a higher voltage, or amperage? Will a Lipo due to my crane stock be the better choice or a smaller nihm battery?

[iKliiu]

A high torque motor and a 11.1 LiPo will give you instant trigger response. Make sure you get a mosfet if you are using a 11.1 LiPo, or say goodbye to your trigger contacts.

[MultipleParadox]

Think of it this way:

If electricity would be a river, the width of that river would be the voltage, while the flow of water would be the Amps.

More Voltage will allow for more electricity to get to your motor at the same time, and would make it spin faster under low load (forget the water analogy here, a waterwheel would not be the best of example, I now realize :P)

More Amps will be drawn by the motor from the battery to make it spin harder/stronger. This is what you want more in your case.

But don't confuse mAh and Amperage, or more precisely, discharge rate of the battery (higher discharge rate means more current delivered at once).

mAh's (milli ampers per hour) will reflect the amount of electricity the battery hold. A 7.4V 1000 mAh battery can have a low or high discharge rate regardless. It will just last longer with a low discharge rate than a higher one.

So to put it shortly;

NiCd battery (nickel cadmium): old technology, you don't want this. heavy, not efficient.

NiMh battery (Nick Metal Hydride): Good compromise between efficiency, price, and bulk. Usually round like CR123, AA (like the NiCd too). Usually the discharge rate of these batteries is not mentioned anywhere. You'll only have Voltage and mAh's rating. I'm not sure if it is just because, or if all NiMh are considered to have the same discharge rate.

Lipo/LiFe battery (Lithium Polymer / Lithium Iron, and other lithium based batteries):
More modern tech, will usually be more expensive but also much more efficient for similar sized batteries (compared to NiMh). Usually Square-shaped wrapped in some black plastic.
Needs to be handled with care, especially the LiPo's, while they're still comon and more and more widely adopted despite the "risks" they involve (lots of threads on ASC already)
Usualy requires a attery monitor of MosFet installed on the gun, and be sure to have a good charger especially made to handle Lithium-based batteries.

Regardless of that battery you buy, get a good charger like the iMax B6 or similar. IT will allow you to keep your batteries longer, and one charger will be able to charge most if not all types of batteries if you decide to change in the future.

Hope this help clear a few questions you might have. Note that I am no specialist on the matter and might be wrong or mistaken here and there, others will probably correct me the case being.

[dutch13]

Do your research on them. I always run nimh but that's because I don't want to change over all my aegs. Lipo may be a bit more maintenance but better performance out of your aeg.

[ThunderCactus]

You messed up the metaphor
The speed of the flow of water is the voltage
The amount of water in the river is the amperage
Rocks are resistance
The motor in your AEG is like a water mill, takes a specific amount of v and A to turn. Not enough water in the river means there isn't enough torque to move the wheel.

and read this if you're considering LiPo; http://airsoftcanada.com/showthread.php?t=99899

[Knocturnal]

So, I'm not sure I got this part right, but a higher mah means the battery holds more while discharging more? Which all in all boils down to "more power" (amperage)? Say I get a 8.4v 5000mah battery (given that my rifle will most likely always be set to semi auto), I will have a slower ROF (than a 9.6v) but will have a faster response (than a 1600mah)Correct me if I'm wrong, this is just how I have understood the info. My next question, what stats am I looking for in a battery for my case (semi auto sniper, which faster response is better) whether it be a nihm, or lipo?

[venture]

Lipos are now cheaper than nimh batteries. Go with Lipo

[MultipleParadox]

Originally Posted by ThunderCactus

You messed up the metaphor
The speed of the flow of water is the voltage
The amount of water in the river is the amperage
Rocks are resistance
The motor in your AEG is like a water mill, takes a specific amount of v and A to turn. Not enough water in the river means there isn't enough torque to move the wheel.

and read this if you're considering LiPo; http://airsoftcanada.com/showthread.php?t=99899

Damn you're right lol
Thanks for the correction hehe

To OP:
More mAh does not equate more power. Just more energy stored in the battery. The Power would be rated as a "C" unit (for "Current I guess?)

The higher the discharge rate, *combined* with a high mAh rating does equate to more Amps delivered at once:

A 20C battery with 2000mAh would be:
(2000/1000)*20 = 40 Amps (Constant, not peak)

A 30C battery at 5000mAh:
(5000/1000)*30 = 150 Amps

And so on

[ThunderCactus]

Because a NiMH doesn't provide all the amperage your motor needs, there's a few factors that contribute to ROF

So another cool metaphor goes like this;
The battery is your gas tank. The Mah rating is the gallon size of the tank, the amperage is the energy potential of the fuel, and the voltage is how fast that fuel gets to the motor.

Now here's where it gets tricky, as you increase the physical size of an NiMH or NiCd cell, the surface area for chemical reaction increases, that by some magic formula that increases the amount of amperage the cell is able to produce.

NiMH/NiCd
more voltage = higher ROF
larger cell size = higher ROF

LiPo
more voltage = higher ROF
larger cell size = doesn't matter
higher C rating = reduces internal resistance of the pack, gives you a bit higher ROF
If your motor only draws 8A, then supplying 200A won't make it go any faster than supplying 16A
But your constant draw from your motor has to be less than what your pack can provide, otherwise you can damage the LiPo.

For a benchmark, an 8.4v large (sub-C cell) battery will give you about the same ROF as a 9.6v mini (2/3A cell)
And due to it's ability to supply all the amperage you need, a 7.4v LiPo battery CAN provide the same ROF as a 9.6v mini.
The 9.6v will often provide higher ROF when directly compared, but the 7.4v provides more torque allowing you to run a higher ratio gear set.

I bet you thought batteries weren't so complicated eh? lol

[Knocturnal]

Not all that bad... Ok so, I imagine a higher torque may require stronger parts such as the gears? I want to get the quickest response time, I really could careless about the rof due to using my aeg on semi for sniping.

Also I would like to add that shopping at evike might not be as bad as it used to be. At least from what i have heard... My whole order was quickly processed by customs, now i just need to go pay the duty txes and pick up my package at the post office.

[m102404]

The way to go is generally (oversimplifying a bit)
1. Get the largest capacity (mAh) battery you can fit into your setup...that's going to be the deciding factor unless you change parts of your setup.
2. Large cells provide power longer than small cells (i.e. SubC vs. 2/3A). LiPo's are a bit odd to compare to other battery chemistries when comparing cell size.
3. Non-memory cells/chemistries are more convenient (i.e. NiMh, LiPo, LiFe)
4. Go with the lowest voltage that will result in your desired performance...it's different for every setup

So...if you've got one of those crane stocks that only fit mini (2/3A) NiMh battery...you're typically relegated to a 9.6V 1400-2000mAh NiMh battery. They're just fine for most setups but will suffer for applications where 1) there's a lot of full auto sustained fire...the small cells struggle to keep up the supply 2) there's a lot of shooting over a long day...the small cells just don't have that kind of staying power when compared to larger batteries (because they're not as efficient).

Of course there's 8.4v mini NiMh batteries that will fit too...if the mAh's the same, what you'll notice is that there's more trigger lag and slower ROF compared to a 9.6v of the same type/rating. All other aspects (vs. larger packs) will be the same. But I'd take a quality 8.4 pack over a no-name cheapo 9.6v pack.

Old simple solution...have spare batteries charged up and ready to swap in.

Again...that said either may work just fine in your setup. If you're taking 20 shots the whole day neigther is going to hold you up. If your rifle is shooting 300fps...no problems.

The "only" other option you have is to go to a LiPo pack...because its form factor is very small (relative to other batteries). In that case you're looking at a 7.4 or 11.1v packs. Again...#1, it's got to fit your setup...or you have to change your setup. What you'll find is that with the 7.4v packs you'll typically get larger mAh sizes than with 11.1v packs of the same physical size. That's because each of the 7.4v packs' cells (2) are bigger than the cell of a 11.1v pack.

7.4v 2000+ mAh 20C pack....you'd probably have no problem pulling a M120 spring all day (or weekend...again depending on how much you shoot). It'd probably be equivalent to somewhere between a large 8.4 or mini 9.6 so far as ROF goes...but it'd last like the large NiMh pack.

Same as with the NiMh pack...go from 7.4 to 11.1 and you'll have a quicker trigger response and higher ROF. Wear and tear would be accelerated with the 11.1v and 9.6v.

So, if you made it this far.....what to do?

I'd say get the largest 7.4v 2000+ 20C lipo you could fit into your stock and have at it. If it shot well...I'd pick up a spare (always have a spare battery for games).

[MultipleParadox]

Great explanations;

I would add, if you go lipo and want quick response, get an ASCU or similar control unit. Will cost between 75 to 120$ approximately, and will provide not only a way to monitor and prevent damage to the battery, but also provide a much quicker trigger response.

They basically replace the trigger contacts with a microswitch; Day in night if you ask me. Some also have active breaking, 3 round burst mode, etc etc

[Knocturnal]

Thanks for the explanation I figure that Lipo will be the way to go because of the physical size and because of my crane stock. Now, if only I could get the age verifier to answer me... Also, I got my order, thing is, the screw that holds the crane stock to the rifle is too short... Hence, I cannot install my crane stock... Sigh... Anyone know of a place to get specific screws? Where I'll need to match thread size and diameter, and of course a longer format.