Battery Box for Altus Metrum 850mAh LiPo: Fit and Care

By High Power Model Rocketry | Published: 2026-11-01

Category: Tips & Care

Learn how to install and care for the Battery Box for Altus Metrum 850mAh LiPo. Get a fit check, mounting tips, and battery retention advice for your avionics bay.

Quick answer

Mount the battery box securely to your avionics sled, confirm the battery fits without forcing, and route cables through the corner exits. Always perform a fit check before flight and inspect the box and battery for damage after each flight.

Why the box size matters for your sled layout

The Battery Box for Altus Metrum 850mAh LiPo comes in single and double versions. The single box measures 72.5mm x 37.9mm x 12.5mm externally, while the double is 72.5mm x 37.9mm x 17.6mm. Internally, the single provides 49.8mm x 31.8mm x 6.6mm, and the double provides 49.8mm x 31.8mm x 11.6mm. These dimensions dictate how much space you need on your sled and how many batteries you can carry. Choose the single if you need one battery; pick the double if you want a spare or redundant power source. Remember that colors may vary, so plan your build around the dimensions, not the appearance.

Battery care that prevents in-flight surprises

LiPo batteries require careful handling. Before each flight, inspect the battery for puffing, punctures, or damaged wires. Store batteries at storage voltage when not in use, and never charge them unattended. Inside the box, ensure the battery cannot shift; the box helps contain it, but you still need to secure the battery with foam or tape if there is any play. After flight, check the box for cracks or loose mounts, and verify the battery voltage before recharging.

Step-by-step installation and care

Choose the right box size: Decide whether you need the single or double version based on your battery count and sled space. Measure your sled to ensure the box dimensions (72.5mm x 37.9mm x 12.5mm for single, 72.5mm x 37.9mm x 17.6mm for double) fit without interfering with other components. Double-check that the box height clears your nose cone or coupler.
Perform a dry fit: Place your Altus Metrum 850mAh LiPo battery into the box. It should slide in without force but not rattle. If it is too tight, do not trim the box; instead, verify you have the correct battery model. If it is too loose, add a small piece of foam tape to take up slack. Never force a battery into the box; a tight fit can damage the pouch.
Mount the box to your sled: Use the appropriate fasteners or adhesive to secure the box to your avionics sled. Ensure the cable exits are oriented toward your altimeter to minimize wire strain. Test the mount by gently tugging; it should not move. Avoid over-tightening screws, which can crack the 3D-printed material.
Route and secure cables: Feed the battery cable through the nearest corner exit. Leave a small service loop so the connector can reach the altimeter without tension. Secure the cable with a zip tie or tape to prevent it from snagging during recovery. Check that the cable cannot be pinched when the sled is installed.
Pre-flight inspection: Before each flight, verify the battery is fully charged, the box is securely mounted, and the cables are undamaged. Look for any signs of wear on the 3D-printed box, such as cracks or loose corners. Replace the box if you find cracks; a failed mount can disconnect power mid-flight.
Post-flight care: After flight, remove the battery and inspect both the battery and box for damage. Clean any debris from the box. Store the battery at storage voltage and keep the box dry. Log your battery cycles to track aging and plan replacements.

Product facts

Battery Box for Altus Metrum 850mAh LiPo: The box is sized to fit one or two Altus Metrum 1S 850mAh LiPo batteries and features a cable exit at each corner. The corner exits let you route power leads neatly to your altimeter without stressing the cables, simplifying your sled wiring.
Battery Box for Altus Metrum 850mAh LiPo