Short answer: the three common sources for an LP-E17 T series, a power bank, a phone charger, and a car charger, all supply 5V, so the difference in charging time comes mainly from output current rather than from the type of source. At 5V/2A a full charge usually takes between two and three hours; at 5V/1A it takes three to four. A car charger tends to land in the upper part of the range because its voltage is less stable. These are working ranges, not lab figures: swap the charger on the same battery and the time can change by half.
What follows breaks down the variables behind those times, then covers how to pick each of the three sources and what to watch for.
Why only a range is honest
Charging time is set by four variables. First, the charge already in the battery: starting from half versus from empty nearly halves the time. Second, the current the charger can actually deliver, since a unit rated 2A tapers to a trickle as the battery fills. Third, the cable, where a poor USB-C cable with high resistance drags the available current down. Fourth, temperature, with charging noticeably slower below ten degrees Celsius as a protection measure.
So a claim like “this battery fills in X hours and Y minutes” is meaningless unless it names the charger, the cable, the starting charge, and the room temperature. The practical approach is to remember the ranges and leave yourself margin before you go out.
| Source | Typical output | Approximate full charge | Stability | Best for |
|---|---|---|---|---|
| Phone charger (5V/2A) | Around 5V 2A | About 2-3 hours | High | Hotel, home, cafe |
| Phone charger (older 5V/1A) | 5V 1A | About 3-4 hours | High | Overnight charging |
| Power bank (5V/2A output) | Around 5V 2A | About 2-3 hours | Moderate to high, falling as it drains | Outdoors, commuting, no outlet |
| Car charger | 5V 1-2A, depending on the vehicle | About 3-4 hours or longer | Lower | Driving between locations, location work |
The table gives ranges from nearly empty to full. If you are only topping up, say from half, the time shortens roughly in proportion, but the constant-voltage tail in the last ten-odd percent cannot be skipped, so it will run slightly longer than a linear estimate.
Power banks: work out the charge count before the speed
It is easy to shop on the milliamp-hour number and forget the voltage conversion. A bank rated 10000mAh is usually 3.7V cell capacity, about 37Wh of energy, while an LP-E17 at 1050mAh is about 7.6Wh. That is nearly five charges in theory and usually three to four in practice once boost and cable losses are counted. By the same logic a 20000mAh bank gives roughly six to eight.
On speed, look for a model that supports 5V/2A output; there is no point chasing wattage. A unit with a numeric display is more useful, since you can see how much is left and whether it is working. A bank around 10000mAh is relatively light, and paired with a spare battery it is a sensible light-travel configuration.
Phone chargers: will a PD unit damage the battery
No. A PD charger falls back to its 5V default when connected to a non-PD device, and that is exactly the voltage the T series accepts. What to avoid is a poor-quality supply rated above 5V that cannot negotiate protocols, since it may simply output its rated voltage.
Another common misconception is that more wattage charges faster. With the T series the bottleneck is the charging circuit inside the battery, and anything above 5V/2A goes unused, so a sixty-watt laptop charger will not be faster, only more compatible and cooler. For business travel, one multi-port PD charger that tops up the phone and the battery together is a convenient arrangement.
Car chargers: two easily overlooked traps
The first is voltage fluctuation at startup. When the engine turns over, the accessory socket voltage dips briefly and can even spike. A decent car charger protects against this, but repeated exposure is not good for the battery. The usual habit is to unplug before switching off, or to choose a unit with regulation and over-voltage protection.
The second is inflated output. A cheap charger rated 2A may deliver only 0.8A under load, doubling the charging time. The test is simple: after half an hour, feel the charger body. If it is uncomfortably hot while the battery is only warm, efficiency is low and it should be replaced.
A car charger is better for topping up on the move than for filling a pack. Plugging in for half an hour while you stop to eat buys a hundred or two hundred frames, which is far more realistic than expecting a full charge on the road. For how the tiers differ, see the LP-E17 capacity and compatibility guide; if you are still weighing direct charging against a dock, the T series category covers it in more detail.
FAQ
Is it normal for the battery to get warm while direct charging?
Warm is normal, especially during the high-current first half. If it is too hot to hold comfortably, or heats up noticeably and then stops partway, disconnect and check that the charger and cable match.
Can I charge the camera body from a power bank?
That depends on whether the body supports USB power delivery and is a separate matter from the battery charging discussed here. The T series has its Type-C port on the battery, so the pack must come out of the camera to charge.
What happens if I leave it connected after it is full?
The charging circuit normally stops output once full, so leaving it briefly does little harm. Long-term connection is not good for longevity and makes the state harder to judge; taking it off when full is the better habit.
Why does mine take longer than someone else’s at the same 5V/2A?
Usual causes are a high-resistance cable, a lower starting charge, a colder environment, or a different capacity tier. A 1050mAh naturally takes thirty to forty percent longer than a 750mAh.