Airsoft FAQ: How do I install a Battery in my M4?
How to Install a Battery in an Airsoft M4/AR15 AEG
To many who have been into Airsoft for years, this can seem like a no-brainer, but it really isn't that obvious! We're here to help make the transition from a normal person to a mighty Airsoft skirmisher easier for the new players by explaining in the simplest terms we know, how to install the battery in the most common M4/AR15 AEGs out there today. Let's get straight into it!
Battery installation: M4/AR15 AEG Crane Stock battery compartment
The most common battery compartment currently available on many M4/AR15 AEGs is the Crane Stock battery compartment. This stock is based on a real-world design intended to provide better comfort for users and allow CR123a batteries to be stored inside, and Airsoft manufacturers saw this as a great opportunity to mount bigger batteries inside their M4s.
The battery we recommend for this type of stock is a 7.4V 1300mAh LiPo battery in nun-chuck configuration or a 9.6V 1600mAh NiMH battery, also in nun-chuck configuration. Most Crane stocks should look like the image above, and how to access the battery compartment isn't super obvious to the casual observer so don't feel bad if this was a mystery to you upon opening your new gun! Instructions on how to access a Crane stock battery compartment can be found below:
- Squeeze the two tabs at the toe of the stock together (shown below), after which the butt plate can be lifted free. Sometimes the butt plate is connected to the piece which plugs the battery compartment and prevents water/dirt ingress, sometimes it is a separate piece.
- With the butt plate and battery plug piece removed, you should be able to see into the rear of the buffer tube and find the battery connector (in this case, a mini-Tamiya connector) sitting inside.
- The next step is to connect your battery to the connector and place the two cell groups of your nun-chuck/Crane battery into the now open tubes on either side of the stock. The cell groups should easily fit inside, and it is important that you do not squash the cells to avoid damaging your battery.
- With the battery sitting snugly inside you can now reinstall the battery plug and butt plate.
- Eye-pro on, load up and it's time to shoot!
Battery Installation: M4/AR15 AEG Buffer tube battery compartment
If you have a slimmer stock design on your M4/AR15 AEG but it is rear-wired, the buffer tube is where your battery belongs! Accessing a buffer tube battery compartment is simple in theory, but it depends on what type of stock you have installed. Our instructions will account for most stocks out there, but if yours is a little different you should be able to apply the principles of these instructions to your stock and figure it out! As always, if you are having trouble you can contact our player community using the "Ask Players a Question" button on each product page, or email us at sales@patrolbase.co.uk
Above is an example of the type of stock which is far too slim to house a battery, and as such, the battery compartment for this M4/AR15 is in the buffer tube. Read on for instructions on how to access the buffer tube battery compartment and install your battery!
- Remove the stock by holding the adjustment lever out (pull it the opposite way when adjusting the stock) and sliding the stock off the buffer tube to the rear.
- With the stock removed, you should either see the inside of the buffer tube or a cap on the rear of the tube. If your buffer tube has a cap you can unscrew it, if not you should see the battery connector inside.
- Now is the time to hook up your battery to the connector, and insert it into the buffer tube. It can sometimes be easier to insert the battery and then connect it up, depending on the wire length. If your battery sticks out of the end of the buffer tube slightly no need to worry, just make sure you do not collapse the stock all the way to avoid squashing it.
- With the battery inside you can reinstall your stock the same way you removed it; pull and hold the adjustment lever out and slide the stock on from the rear of the buffer tube.
- You're ready to go! Goggles/glasses on, mag in, and let rip!
For buffer tube battery compartments we recommend a 7.4V 1300-1450mAh LiPo battery for an easy fit. NiMh batteries will not fit inside buffer tubes so you will have to make do with the extra trigger response of a LiPo! Poor you! Some Crane stock AEGs also have the option of using the buffer tube battery compartment. In this case, you can choose whichever fits your battery type and whichever is easiest for you!
Battery Installation: Front-wired M4/AR15 AEG Handguard battery compartment
Front-wired M4/AR15 AEGs are a bit of a rarity since LiPo batteries became common for Airsoft, but the guide wouldn't be complete without covering this!
Most front-wired M4/AR15 AEGs house the battery inside the handguard or externally inside a vertical grip or PEQ battery box. The instructions below will cover M4 AEGs with a standard polymer two-part handguard as well as two-part RAS handguards and MOE-style handguards:
- The first step is to remove the lower half of the handguards by sliding the delta ring (shown below) towards the receiver. With the delta ring in this position, you should be able to pull the lower handguard downwards and off the rifle. It can take some force to pull the delta ring back due to the strong spring holding it forward so if you are struggling to remove the handguard the delta ring may just need to be pulled back more.
- With the lower handguard removed, you should now see the battery connector inside. Hook your battery up and then you can reinstall the lower handguard.
- Pull the delta ring back again, index the lower handguard inside the front handguard cap, and then push the rear of the handguard up to meet the delta ring. The lower handguard should meet the upper handguard, after which you can release the delta ring and it should slide forwards and over the rear of the handguard to hold it in place. Keep an eye on where your wiring is as you don't want to trap the wires between the handguards!
- Following this, you are ready to shoot. As always, eye-pro on, mag in and stay on target!
For this type of battery compartment, the recommended battery can vary in size and shape so we suggest checking the product description of the specific AEG you are using where we will have stated the recommended battery. If your front-wired M4/AR15 AEG uses a PEQ or vertical grip battery compartment you should have an easy time fitting it, simply connect up the battery connector and mount the PEQ or grip to your rail.
Battery Installation: M4/AR15 AEG Fixed Stock battery compartment
Rear-wired M4/AR15 platforms with fixed stocks like the M16A2, MK12 SPR and others are much easier to install a battery inside than examples with a sliding stock.
Whether your AEG has an A2 or an A1 stock the following steps should clue you in on how to install a battery, if it wasn't obvious already!
- Check the butt plate, you should see a port with a hinged door. If you don't, grab your screwdriver as you're going to need to remove the butt plate.
- Open the port door or unscrew the butt plate screws and remove the butt plate. Inside you will see the battery connector.
- Connect the battery, slide it through the port and close the door. If your stock doesn't have a port you can just throw the battery inside (not literally!), connect it up and reinstall the butt plate.
- Grab your goggles/glasses, load your mag and get shooting!
Hopefully, this has given you the intel you need to get your M4/AR15 AEG up and running, ready for action! If you need some intel on Airsoft batteries and advice on which to choose you can check out this PBTV Beginner Guide on Airsoft Battery Connectors to fill in any knowledge gaps. If you arrived looking for an M4/AR15 AEG you can check out our selection via the button below!