aliceallen

The Lipo packs are lighter than the equivalent Nimh/Nicd packs. Lipo batteries are like little envelopes, and as such they are encased in a strong plastic box for gens ace batteries, to protect them from damage. They don't need to be charged just before use, you can charge them days in advance and run them without any need to repeak. They shouldn't be run completely flat, and some ESCs have a setting for Lipo to ensure you don't flatten them. You don't need to discharge them before topping up either. They are generally a bit more punchy as they can deliver more power on demand.

NiCD: And old technology that is not used very often today. They have a 'memory', so if you only use don't discharge the battery 100%, the next time you charge it, you will less capacity and that will keep on happening till there is nothing left.

NiMh: Still used today, and it for people who don't want to go the LiPo route or often recommended for beginners. Chargers and batteries are quite cheap, and are generally considered safer so long as you use a good charger. These are generally sold at 7.4v 5000mah lipo battery packs, which puts out 7.2v.

LiPo: The bees knees at the moment. They are lighter, have a higher voltage for the weight, and can give the motor more amps. Precautions do need to be taken when charging because if they are charged incorrectly, they can catch on fire. So long as you are careful and use an appropriate charger with the right settings (such as charging a 3 cell as a 3 cell, not a 4 cell) and have a voltage cut-off on your ESC you will be fine. If the voltage gets down to under 3 volts per cell, then you damage the batteries which is why you need the voltage cut-off set up on your ESC (most have this built in), which turns your cut power when it detects around 3 volts per cell.

When you are trying to compare a LiPo to a NiMh/NiCd, you have to understand that from a battery standpoint there are two things that improve your guns performance. In regard to the above batteries mentioned:

Battery A = 7.4v, 18C, 1700mah = 30a Discharge
Battery B = 11.1v, 15C, 2000mah = 30a Discharge

Now lets throw a couple other batteries in the mix.

Battery C = 9.6v, NiMh/AA, 1700mah = 20a Discharge
Battery D = 9.6v, NiMh/SubC, 4400mah = 35a Discharge
Battery E = 7.4v, 10C, 4400mah = 44a Discharge
Battery F = 7.4v, 30C, 4400mah = 132a Discharge

Lets say you have two guns, one with an ICS Turbo 3000 that uses say 18a max. Then you have a second gun with the black hole of airsoft guns known as a Systema Magnum which uses up to 40a (these are not to be technically accurate power draws for the motors, just making an example here).

In gun A, all of the batteries supplies sufficient amperage to meet the motors maximum draw, therefore it's almost purely a matter of voltage at that point. The only other catch is the fact that batteries don't put out a consistent amount of power. The lower you drain the battery, the less power it's putting out. To that end, LiPo's put out a higher voltage for longer than NiMh/NiCd's which is why they seem to perform better that you would think.

In gun B however, the story is different. Only Battery F is capable of putting out enough amperage to fully meet the motor's demand, although battery E is close. However in this situation, Battery E will outperform Battery A because it's putting out more amps. In the same manner, Battery F will likely outperform Batteries C and D because they aren't enough supplying enough amps. Even if you add more cells to Batteries C and D to increase them to 10.8v or 12v, they still aren't providing any more amps which means Battery F is still going to give it a run for it's money.

So, to say a 7.4v LiPo is close to 9.6v NiMh or an 11.1v is close to a 12v NiMh, depends on the output of the batteries and the draw of your motor. An 11.1v LiPo with a 100a discharge will slaughter a 12v NiMh that's putting out 20a in any gun that can draw more than 20a. Regardless of battery chemistry, one thing to keep in mind is that increasing the voltage of the battery causes damage to your guns entire electrical system. Increasing the amperage does not cause damage to it, however it does allow your motor to run at 100% of it's capacity which means it may fail sooner than it normally would, especially if it's a cheap motor.

For the record, my two primary batteries are an 11.1v, 20C, 4400mah and a 7.4v, 30C 5000mah battery. Those batteries put out 88a and 150a respectively in bursts. I've yet to burn out a motor.