Short answer: the Osmo Action 3 and Action 4 use the same battery, rated about 1770mAh, and are fully interchangeable; the Osmo Action 5 Pro moved to a new model, the BCX204, at about 1950mAh, with different dimensions and communication protocol, so it will not work with the previous generation. In other words, upgrading from an Action 4 to an Action 5 Pro means replacing your spare packs and charging hub as well. Confirming the camera generation before buying matters more than comparing capacity figures.
An action camera battery looks like a minor accessory, but it determines continuous recording time, cold-weather usability and how much of your kit carries over. The relationships across the three generations are set out below.
1. Battery fitment across the three generations
DJI established the cold-resistant battery plus magnetic quick-release scheme with the Action 3, and the Action 4 reused the same battery and housing, so accessories are highly compatible between the two. The Action 5 Pro changed the body structure, sensor and cooling, and the battery changed with it.
| Body | Battery model | Nominal capacity | Compatibility |
|---|---|---|---|
| Osmo Action 3 | Previous-generation cold-resistant battery | About 1770mAh | Interchangeable with Action 4 both ways |
| Osmo Action 4 | Previous-generation cold-resistant battery | About 1770mAh | Interchangeable with Action 3 both ways |
| Osmo Action 5 Pro | BCX204 | About 1950mAh | Not compatible with Action 3 / 4 |
One caveat: shell printing can vary between batches and sales channels, so fit should be judged by the shape of the camera compartment and the official compatibility list. When you see the word “universal”, check whether it means between the Action 3 and 4 or whether it quietly includes the 5 Pro — the latter is usually a seller being vague.
2. Why the two generations do not mix
Externally they are both magnetically attached square packs, but the differences sit in the details, and almost every one of them affects usability:
- Dimensions and latch: the 5 Pro compartment was adjusted slightly, so the old pack will not go into the new body and the new pack will not go into the old one. This is physical incompatibility.
- Communication protocol: the fuel gauge and temperature protection communicate differently as the platform was updated, so even forced contact may leave the body unable to read the charge, producing jumps or errors.
- Charging hub: official hubs are generation-specific, with different contacts and bay dimensions. An Action 3/4 hub cannot charge a BCX204, and vice versa.
- Water sealing: waterproofing on the Action series depends on the door and O-ring working together, and a pack of the wrong model breaks that seal. Confirm before you get in the water.
So “does it fit in the slot” is not the test; “does the body recognise it and does the door seal” is. The cost of mixing is usually not that it fails outright, but a sudden shutdown or water ingress at the worst moment — and neither is easy to recover from on an action camera.
3. How many to buy, by use case
The official runtime figures (about 160 minutes maximum for the Action 3/4 and about 4 hours for the 5 Pro) all assume 25°C, low bitrate and some features disabled. In real skiing, cycling or diving, expect 60-70% of that. Configure in this order:
- Confirm the generation first: Action 3/4 take the previous-generation pack, the 5 Pro takes the BCX204. Get this wrong and everything after it is wrong.
- Size to your shooting rhythm: two packs is enough for short-clip editors; for continuous capture (cycling, fishing, long vlogs) start at three and rotate through the charging hub.
- Consider cold use: for winter or altitude, favour the official cold-resistant spec, since third-party low-temperature cutoffs are generally more conservative and shut down earlier.
- Then think about charging: multi-battery users are better served by a hub than charging one at a time in the body; single-battery users can simply use a PD power bank.
Third-party packs are another option. Brands such as YO make separate Action 3/4 and 5 Pro versions by generation, usually at modest prices, which suits use as a supplement to first-party packs. Two things matter when choosing: whether the specific generation is named, and whether the temperature-sensing contact is retained — that directly affects false warnings in the cold.
4. Two things beyond runtime
The first is cycle life. Action camera packs are small with high discharge rates, and storing them full or fast-charging them often accelerates wear; after a year or two, a pack with the same rating may deliver only 70-80% of its original time. Getting into the habit of storing at around half charge after a shoot clearly extends service life.
The second is flying and transport. Lithium batteries must travel in the cabin and cannot be checked — a general civil aviation rule that has nothing to do with brand. For capacity arithmetic and declaration requirements, see our guide to whether camera batteries can fly; the logic applies to action camera packs too. For cold-weather behaviour, compare against our minus 10°C battery test, where the method and conclusions reinforce each other. More accessories for this model are collected on the Osmo Action battery category page.
FAQ
Can an Action 4 battery be used in an Action 5 Pro?
No. The two generations differ in dimensions, latch and communication protocol, and the Action 5 Pro uses the new BCX204. It does not work in reverse either — a 5 Pro pack will not fit an Action 3/4 compartment.
Are the Action 3 and Action 4 batteries identical?
They share one spec at about 1770mAh and swap in both directions. The two bodies use the same pack and magnetic quick-release structure, and the charging hub is shared as well, which is why Action 4 owners keep their accessories when upgrading.
Does a third-party battery affect waterproofing?
It can. Waterproofing depends on how precisely the door and O-ring mate, and if a third-party shell is out of tolerance the door may not compress fully. Use a first-party pack for diving or heavy water exposure; for ordinary dry-land use the impact is small.
How should a battery be stored when not in use?
Discharge to 40-60%, keep it somewhere cool and dry, and top up every three to six months. Storing full or completely empty accelerates wear, and a pack that has swollen or deformed should be retired immediately — do not charge it or fit it again.