Short answer: the TG-6 uses the LI-92B, not the LI-90B, and the two are not interchangeable. A 45-60 minute recreational dive usually consumes half to one pack, so two packs cover a day of two dives plus shore shooting, and three is more comfortable. Cold and frequent flash use speed the drain considerably; for winter outdoor work, plan on 1.5 times the room-temperature count. As for flooding, the great majority of incidents have nothing to do with the battery — they come from sand under the O-ring, a door not latched properly, or opening the compartment underwater.
Settle the model question first, then talk about the plan.
1. Get the model right
The TG-6 belongs to the generation after the TG-4, and its battery is the LI-92B, rated 3.6V and about 1350mAh. The LI-90B is the earlier model used by the TG-1 through TG-3 and by the SH-1 through SH-3; its shape and latch differ, so it will not go into the TG-6’s compartment. The used-market claim that “all TG bodies take the same battery” simply is not true, and checking the label before ordering saves a lot of trouble.
If you still have a TG-3 or an SH body, the relevant notes are on the Olympus LI-90B category page, where the full mapping between the two series is listed.
2. How power is spent underwater and in the cold
Underwater power use looks different from dry land: the screen stays on, autofocus hunts repeatedly, the flash fires often and the body is under constant pressure. The table below gives references for common ways of shooting.
| Scenario | Duration per session | Estimated use | Advice |
|---|---|---|---|
| Snorkelling | 30-45 minutes | About 1/3 of a pack | One pack covers two sessions |
| Recreational dive (within 15 m) | 45-60 minutes | About 1/2 to 2/3 | Swapping per dive is safer |
| Mostly underwater video | 20-30 minutes | About 1/2 | Turning off stabilization extends it |
| Liveaboard, multiple dives | 3-4 dives a day | About 2-3 packs | Rotate per dive |
Underwater video is the big consumer. The TG-6’s electronic stabilization runs continuously underwater, and with high-bitrate recording a single pack often yields only about 60% of the stills-mode time. If video is the priority, keep each clip to three to five minutes and leave cooling gaps between them.
Cold follows a completely different curve. Below freezing, usable capacity falls off markedly — that is electrochemistry, not a quality problem. Skiing, winter beaches and high-altitude hikes commonly produce a jump from 40% straight to a warning, followed by a partial “recovery” once the camera warms up. For how the decline behaves, see the method recorded in our minus 10°C battery test.
The response is simple: keep spare packs in an inside pocket warmed by your body; tuck the camera inside your jacket when not shooting instead of leaving it hanging in the cold; and avoid charging in low temperatures, waiting until the pack is back at room temperature indoors. Condensation may form on the pack as it warms, so dry it before opening the compartment.
3. Flood risk and three compartment details
- Dry hands before opening. Do not open the battery door with wet hands, a wet body or wet hair. A single drop running in past the door is enough to write off the camera.
- Inspect the O-ring. Before every dive, run a finger around the seal and check for sand, hair and salt crystals. Replace the ring when it hardens or shows fine cracks.
- Latch the door properly. The TG-6’s latch has a definite locked position, and no gap should be visible once it is closed. Make a habit of tugging it once before entering the water.
One more point that gets overlooked: do not change batteries in a wet environment. On a boat with wind and swell, many people open the compartment on deck to save time, and that is exactly when flooding happens. The safer routine is to get back into the cabin, dry your hands, and swap there.
4. Putting a spare plan together
- Day-trip snorkelling: two packs, one in the camera and one in a dry bag, is enough.
- Liveaboard with many dives: three packs, numbered and rotated by dive, all charged together in the evening.
- Winter outdoor: room-temperature count times 1.5, carried in an insulated pouch and kept away from metal items such as crampons.
- Long trips: a USB-capable dock charger is more useful than extra in-body charging cables.
Carry spares in individual sealed bags, which keeps moisture out and stops the terminals shorting. On flights, lithium batteries must travel in the cabin and cannot be checked; the rules are set out in the lithium battery flying guide. A YO LI-92B compatible pack works as a spare, while it is worth keeping one first-party pack in the primary slot for the steadier voltage curve on deep or cold dives.
FAQ
Can the TG-6 use an LI-90B?
No. The TG-6 takes the LI-92B, while the LI-90B is the battery for the TG-3 and earlier bodies and the SH series. The shapes differ.
Should the battery be fully charged before a dive?
Yes. At low charge the voltage falls faster, and cold water further compresses usable capacity, which makes an early shutdown more likely.
Can a flooded compartment be saved?
Switch off immediately, remove the battery and card, rinse the exterior with fresh water and dry it thoroughly, and do not power it on to test. Whether it recovers depends on how much water got in; sending it for service is the safer route.
Is one battery enough for a dive?
For most recreational dives, yes. But if you are shooting video and using the flash heavily, swap between dives to avoid meeting a warning at depth.