Short answer: the LP-E17 and the LP-E12 are two entirely different batteries and cannot be swapped. Both are rated 7.2V and their dimensions are fairly close, which is why they are often mistaken for two capacity versions of one battery. The real differences are the notch in the shell, the contact positions and the capacity: the LP-E12 is about 875mAh / 6.3Wh, while an original LP-E17 is about 1040mAh / 7.5Wh. Physically, one will not go into the other’s bay.
The mistake that causes most trouble is not a random purchase but a half-right deduction: “I remember my camera is an M series, and M series takes the LP-E17.” The M series includes bodies that use the LP-E17 and bodies that use the LP-E12, and the dividing line does not follow the series.
Why this is so easy to get wrong
The first reason is the shared voltage. Both batteries are two lithium cells in series at 7.2V, and the body applies the same logic to judge voltage, so the spec sheets look alike. The second is the similarity in size: length and thickness are in the same range, and photographs on a listing are hard to judge.
The third reason is decisive: Canon’s entry-level mirrorless naming is dense. The EOS M3, M5, M6 and M6 Mark II take the LP-E17, while the EOS M50, M100 and M200 are not LP-E17 bodies at all; they take the LP-E12. A string of four letters and a number is easy to confuse from memory, especially when ordering on the used market or from a third-party seller whose page says only “fits Canon mirrorless”.
So the reliable way to remember is not the series but the exact model. Read the plate on the underside of the body before buying; that beats any mnemonic.
A comparison table
| Item | LP-E17 | LP-E12 |
|---|---|---|
| Nominal voltage | 7.2V | 7.2V |
| Original capacity | About 1040mAh / 7.5Wh | About 875mAh / 6.3Wh |
| Shape | Longer and thicker, shell notch in a fixed position | Similar size but not interchangeable, different contact positions |
| Can they be swapped | No. It will not seat, or it seats without delivering power | |
| Bodies that are not LP-E17 | — | The EOS M50, M100 and M200 take the LP-E12, not the LP-E17 |
| Dock charger | LC-E17 | LC-E12, not interchangeable |
The last two rows are the important ones. People who buy the wrong battery often buy the wrong charger at the same time, because the dock charger follows the battery model. If a new battery will not go into the charger, do not assume it is counterfeit; the model itself is probably wrong.
Three checks before ordering, and what to do after a mistake
- Read the body plate. There is a model marking on the underside of the camera or inside the battery compartment. Confirm it is one of these: EOS RP, R8, R10, R50, R100, 850D, 800D, 760D, 750D, 77D, 200D, 200D II, M6, M6 Mark II, M5 or M3. All of them take the LP-E17.
- Read the print on the old battery. Take the battery out; the model and capacity are usually printed on the face. If it says LP-E17, buy LP-E17; if it says LP-E12, buy LP-E12. Do not go by impression.
- Check the compatibility list on the product page. A reputable listing names specific bodies rather than saying only “fits Canon mirrorless”. If it lists a series but no models, buy from another seller.
If any of the three does not line up, stop and confirm. A battery is not expensive, but the cost of returning the wrong one, or of discovering a flat battery on location, is far higher than two minutes of checking.
If you have already bought the wrong one: an unopened battery can simply be returned. An opened battery that genuinely will not fit should never be forced, because the bay and the contacts can both be bent, and then it is no longer just a battery problem. Put it back as it was and contact the seller about a model mismatch. If you are buying for someone else, or for a second-hand camera, the safest approach is to ask for a photograph of the old battery; the printed model is far more reliable than a verbal description.
Once you have confirmed LP-E17, where 950mAh fits
Capacity choices only make sense once the model is confirmed to be in the LP-E17 camp. The 950mAh is the middle of the three tiers, about 27% more than the 750mAh and about a tenth less than the 1050mAh, positioned as the main tier for one battery that covers most everyday shooting. For bodies such as the R10, R50 and 850D it is a well-balanced choice.
One caveat: the LP-E17 family includes both mirrorless and DSLR bodies, whose power profiles differ, so the same 950mAh will not deliver identical runtime across them. For detail, see the capacity and compatibility guide, or look at the 750mAh version for a top-up strategy.
FAQ
Will an LP-E12 fit an LP-E17 camera?
No. Although the voltage is the same, the shell shape and contact positions differ, so it cannot be seated correctly. Even forced in, the body would not recognize it. Do not try.
My camera is an EOS M6. Which battery does it take?
The EOS M6 and M6 Mark II take the LP-E17, not the LP-E12. This is often confused with the M50, which uses the LP-E12, because both belong to the M series and arrived around the same time. The plate on the body is the reliable answer.
If the voltage is the same, why are they not interchangeable?
Voltage is only one electrical parameter. There is also a mechanical bay and a set of communication contacts between body and battery, and Canon uses different shell shapes to prevent fitting the wrong one. Same voltage with different models is common across cameras.
Is the 950mAh more prone to overheating than the original?
No. Capacity affects how long the battery lasts, not how hot it runs. Heat depends mainly on discharge current and internal resistance, and a reputable LP-E17 battery stays within safe limits in normal use.