If you are using an AEG, you are going to need batteries to power it and these come in a number flavours shapes, sizes, power levels and cell types. They are generally defined by:

• Voltage – The amount of voltage the battery can hold. You can see Voltage as the force or “pressure” that can be applied. The higher the voltage the higher the potential force used, and with AEGs that means the amount of potential force used to spin the motor. The value shown will actually be the “nominal” value, half way between minimum and maximum, and that varies between cell types. A LIPO cell will have a maximum voltage of 4.2v BUT the nominal value will be 3.7v, so you will generally see LIPO’s in 7.4v (2 cell) and 11.1v (3 cell) configurations.
• Amperage – Defined in milliamp hours (mAh), the “capacity” of a battery, the larger the number the longer the battery can last. You may also see values for Discharge rate, which is measured in current (C) and Pulse-discharge. The discharge rate (often referred to as continuous discharge) is how much Amperage (A) it’s safe to draw from the battery at a given time. It’s calculated as A = mAh * C. If we use the example of a 1000 mAh 20C battery, that could safely pull 1000 * 20 = 20000 milli-amps, or 20 amps. If you pull more than the discharge rate, the battery can become unstable and even blow up. However for a VERY short period (like milliseconds), the battery can go above that, which is where we see the term Pulse-discharge.
• Configuration – The shape of the battery itself, or how the cells are connected / secured together. This can be important to know for the configuration that will fit in your RIF. Common configurations include:
  • Block – standard oblong shape
  • Stick – thin, long and round
  • Crane / Nunchuck – 2 long cells connected together at one end, either cylinder shaped or flat
• Cell type – The Cell technology or material used, each have their advantages and dissadvantages which will be explained below. There are 4 main types Nickel-Metal- Hydride (NiMH), Lithium-Polymer (LiPo), Lithium-Ion (Lion) and Lithium Iron Phosphate (LiFe).
• Connectors – There are two main connection types, Mini Tamiya and Deans. The type you need will depend on what connector your AEG has, although you can get adapters. Deans are a much better choice of connector and are becoming much more popular due to their lower resistance and better safety.

General Safety

There are a few safety precautions that are worth following regardless of the type of battery you use.

• Never leave a battery unattended while charging.
• Always use a charger that is intended for that battery type
• When charging a battery, do so in a fire-safe environment, and always use a heat resistant charging bag. These bags can be bought for a few pounds, and will provide precious seconds should a charging battery ignite.

What power battery should I use?

There seems to be a lot of “Jeremy Clarkson” advice on the interwebs and social media telling people MORE POWER. But that isn’t often the best advice, and if you ask a good tech they will tell you to get your RIF in better shape rather than just going for maximum voltage.

Often a 7.4v lipo or 9.6v NiMh will work fine and in many cases stepping up to an 11.1v just invites trouble, with the biggest problem then being motor burn-out or even gearbox issues. Some RIFs however will need more, but if so it’s worth trying a 9.9v LiFe first (if there is suffient room as they are chonk) as that CAN be a nice middle ground, providing more power than a 7.4v Lipo but without going full Clarkson with an 11.1v.

How long should a battery last in a game?

That’s going to depend on that Amperage figure mentioned above. The bigger the mAh figure, the longer that battery will last. It will depend on the RIF (power of motor) and also on your style of play. It’s important to consider that single shot fire takes more power than quick bursts. If you are spending all day at an event it’s always a good idea to take two batteries with you as a minimum. An afternoon of CQB, you are likely to not need to change they battery, unless you are doing some frantic speedSofting.

How long do batteries take to charge?

You should find that good quality chargers will turn themselves off / stop charging when the battery is full.

You can however work out roughly how long it should take by dividing the total mAh by the charger mAh rate. So a 2000 mAh battery on a 800 mAh charger would take 2 1/2 hours to fully charge (2000 / 800 = 2.5), of course that’s assuming the battery was completly drained, which should be avoided.

Nickel-Metal Hydride (NiMh)

These batteries are generally considered “old School” but are still worth thinking about. Some of the more budget AEGs will even still come with batteries of this type, although they are generally of poorer quality than after-market versions. Note: DON’T use the chargers they come with, as they are universally dodgy.

The batteries are generally bigger and bulkier than Lipo or Lion, and not as powerful, don’t hold as much charge.

So why bother? Well they are reliable, much less volatile than Lithium and not as fragile. They are also usually cheaper, and will often outlive Lithium equivalents.

You will generally find them in 8.4v and 9.6v voltages.

Lithium-Polymer (LiPo)

Currently the most popular choice for Airsoft, these batteries are smaller and lighter than most batteries, have soft cells so can be used in many different shapes and offer a higher capacity to density so when compared to NiMh they can be smaller but last longer and povide more power on a lower vaultage due to their higher discharge rate.

They come in 7.4v (2 cell) and 11.1v (3 cell) varieties. A 7.4v Lipo is comparible to a 9.6v NiMh (but will perform better).

They are a lot more delicate and volitile than the NiMh however. If you let the battery completely discharge, they may never charge or work again. Some AEGs will provide an alarm when the battery power is low, others will stop working to prevent permanent battery damage.

There is also a small chance they may overheat and combust when charging. When being charged, they should never be left unattended, and should be done so in a heat resistant charging bag. If they ever become bloated or expand, they should not be used and disposed of appropriately. When not in use, they should not be left connected to a RIF.

Always use a charger that is designed to charge Lipo’s, don’t ever use a NiMh charger as these will not know when the battery is fully charged.

Lithium-Ion (Lion)

These types of battery actually have the largest capacity but with a low discharge rate (often around 15C). They also have the pecularity of discharging themselves when not in use. So they have more capacity, discharge slower, but discharge all the time.

They are also still Lithium, so come with all the fragility / volititlty as as Lipo. They REALLY don’t like being over-charged, even more so than the average Yorkshire person and will errupt just as explosively.

There have also been a lot of reports about general reliabilty being pretty poor, which makes sense if they, like Lipo’s, don’t like being undercharged, but yet discharge when idle.

Lion batteries come in 7.4v (2 cell) and 11.1v (3 cell).

Lithium Iron Phosphate (LiFe)

Still a Lithium type battery, which means fragility / volitility, and they have less storage capacity than a Lipo and Lion. As a result they are bulkier, but generally a little more robust as a result.

They also come in 9.9v voltage and have a reasonible discharge rate, which makes them a nice bridge between a 7.4v and 11.1v Lipo.