Short answer: TG-6 and later bodies charge the pack over Micro-USB without taking it out. TG-4 and earlier need the battery removed and seated on a dedicated dock. At 4.07Wh both routes finish in roughly two hours, so what really differs is whether the camera stays free while it happens. Our compatible pack is quoted at 1100mAh, 3.7V and 4.07Wh, with 1070mAh and 3.96Wh as the rated figures. There is not much energy in it, which is why a charge never drags on for half a day.
First, work out which generation your body is
On the TG-6 and TG-7 the Micro-USB port sits behind the side door, so one cable fills the pack in place and the dock can stay at home. What you spend is the camera: while it charges, it is not shooting.
The TG-1 through TG-4 generation has no such route. The pack comes out and goes onto a dedicated dock. The Stylus SH-1, SH-2 and SH-3, the SP-100, the XZ-2 and the XZ-10 are built the same way and should be treated like the TG-4 and older.
The TG-5 sits between the two generations and varies by batch and region. The check takes five seconds: open the side door and look for a Micro-USB port. If it is there, charge in the body. If not, use the dock. Do not guess from the model name.
Where the two hours comes from
Charging time is energy divided by the power that actually reaches the cell: pack energy ÷ (output voltage × output current × efficiency). In the body, at 5V and 0.5A with 0.7 efficiency, that is 4.07Wh ÷ (5V × 0.5A × 0.7), about 2.3 hours. A dock at 4.2V and 0.6A delivers 2.52W, roughly 2.0W after 0.8 efficiency, and 4.07Wh ÷ 2.0W is about 2.0 hours. Both figures are estimates, not measurements.
Add the constant-voltage tail and the camera’s idle draw and you gain ten to twenty minutes. For numbers that match daily use, read the dock as 2.0 to 2.3 hours and in-body charging as 2.4 to 2.7 hours.
| Method | Bodies | Estimated time | Watch out for |
|---|---|---|---|
| Micro-USB in the body | TG-6 and later | about 2.3 hours | Switch off, do not shoot while charging |
| Dedicated dock | All, mandatory on TG-4 and older | about 2.0 hours | 4.2V output with a proper cut-off |
| Power bank into the body | TG-6 and later | about 2.3 hours, limited by the body | Steady 5V output |
| Power bank into a USB dock | All | about 2.0 hours | Depends on the dock’s input |
Why a small pack suits dock rotation
At 4.07Wh one pack covers 250 to 300 frames in ordinary shooting, against a CIPA figure of 340 for the TG-6. Photograph at any pace and a pack is done by mid-afternoon. That is where a dock earns its place, and not for speed: two packs on a two-bay charger are both full by morning.
In-body charging cannot do that. It fills one pack at a time and it occupies the camera to do it. The workable arrangement is one pack in the body and one on the dock, swapped as you go. To build that kit, look at the pack options on the LI-90B compatible battery page and the multi-packs under Olympus LI-90B batteries.
Two rules before a dive
Charge to full before you get in the water. There is no outlet at depth, a half-empty pack cannot be topped up, and cold water cuts usable capacity further. Going down full is the only reliable option.
Do not charge a wet camera. If the seal around the side door has picked up water, sand or salt, moisture can travel into the port with the cable. Dry the body, open the door, confirm it is dry, then plug in. If you are finished diving for the day, take the pack out and use the dock.
One point that gets missed: never open the side door underwater or in spray. That door is the thinnest entry on the whole body, and most water damage starts there.
FAQ
Should the camera be off while it charges in the body?
Yes. Left on, the body heats continuously and the charge current becomes less steady, and the camera cannot take pictures during a charge anyway.
Can I use a phone charger?
Yes, if it delivers a clean 5V. The risk comes from cheap chargers with unstable output, not from the phone-charger category. Fast chargers usually drop to 5V on their own, but on an unmarked budget unit there is no way to check, so travel with one you know.
Does the dock have to come from the manufacturer?
No. A dock only has to turn 5V into a constant 4.2V and stop at full, which is not hard to do well. Look for 4.2V on the label. A two-cell 8.4V charger has no business on a single pack.
Is it bad to unplug before the pack is full?
No. Lithium cells have no memory effect and shallow cycles are gentler than deep ones. Twenty minutes before you leave buys a few dozen frames, and that is enough.