Panasonic S1[HR] have very high power consumption when "off"; Panasonic S5[ii] have relatively high power consumption when "off".
To the extent that Panasonic S1[HR] require unusual handling to minimise damage to the camera [sic] and its batteries, apart from simply to ensure that the camera has usably charged batteries. S5 and S5M2 require a little care, but are much less problematic.
I expect Panasonic MFT cameras have similar power management and power supply behaviour.
I've made some measurements of this, because, at least for S1[HR], it's been noticed as a practical problem by many users. I also measured Nikon D7200 and D7100 (APS-C DSLRs) by way of comparison. I previously posted measurements that were spread over various DPReview.com threads. I re-measured all the cameras, adding S5M2.
Summary
Estimated main battery lifetimes when "off":
- Panasonic S1R: 24 days
- Panasonic S1: 26 days.
- Panasonic S5: 190 days.
- Panasonic S5M2[X]: 130 days.
- Nikon D7100: 500 days.
- Nikon D7200: 700 days.
These figures are: (nominal OEM main battery capacity in mAh) / ("off" current at 7.5V battery voltage).
Bluetooth on/off and LCD on/off make no material difference.
So What?
So the battery goes flat? Just put another one in and charge up the flat one.
There are a couple of problems with this:
- The cycle life and capacity of Li-Ion batteries are reduced by deep discharge. Hopefully, the batteries' internal protection circuitry disconnects the battery cells before the batteries are discharged beyond the point at which they can be safely recharged. S1 & S1R will discharge main batteries to the point at which the batteries' internal protection circuitry is activated.
- After the main battery is discharged, the rechargeable ML421 Manganese dioxide Lithium clock/configuration battery [Datasheet link at end] will start to discharge. This is an internal cell, soldered to a Printed-Circuit Board ("PCB"). This battery technology is far less tolerant of cycling and deep discharge than the main Li-Ion battery [See Application Note at end]. Regularly allowing the main battery to run flat sharply reduces the life of the clock battery. An ML421 battery costs maybe $0.70 in bulk, but replacing it in a camera will cost 100s of $, unless you happen to be set up to tear down and rebuild cameras.
What to do about it?
One suggestion has been to remove the batteries when not using the camera. But, as noted above, this has another problem: you start discharging the (rechargeable) Manganese dioxide Lithium ML421 cell that Panasonic uses to maintain the real-time-clock, and other data. And these Manganese dioxide Lithium cells like deep discharge even less than the main Lithium Ion (Cobalt Oxide) batteries, and really, really don't like deep discharge. Lifetime can be roughly 30 deep discharge cycles, so replacing ML421 batteries in Panasonic cameras is a thing.
My take on all this is that the least worst solution is to store the camera with the camera powered from USB. A less convenient, but technically superior solution would be to store the camera with a powered dummy battery. This way, there isn't a main Li-Ion battery being repeatedly charged to full capacity (storage at a high state of charge reduces battery life, particularly at higher temperatures).
For the S5 cameras, where the problem is less bad, a routine of recharging the batteries in unused cameras every month would work, but will you remember?
If you are using all your camera bodies every day, or even every week, you're fine.
What could Panasonic do?
- Fundamentally rethink their power management strategy. So that won't happen.
- Introduce a "maximum charge" setting for in-camera charging. Could be a percentage of capacity relative to charging to 4.20V, or just a switch that disables charging above - say - 65%. That would improve battery life for cameras left connected to USB power.
Comments
- The Nikon D7200 DSLR doesn't have a problem. Put it down (charged). Pick it up 18 months later - it works.
- When S5M2 was released, Panasonic let it be said that the slow startup was because of complaints about battery life. It seems that the problem was the increased power consumption of the chipset. With S1[HR]-like power management, the battery would last about 13 days.
Methods
Previous measurements were based on a mains-powered dummy battery which outputs 8.98V @ 5mA; 8.88V @ 0.9A. That's a bit higher than a real battery.
I had assumed that the cameras used a low-power Switched-Mode Power Supply ("SMPS") with roughly constant efficiency over a 6.0-9.0V supply range.
I now have a bench power supply which allows more detailed measurements over a range of supply voltages.
This has shown that my previous assumption of constant efficiency for the Panasonic power supplies was false - when "off" they behave as if inefficient linear power supplies are used. The Nikon cameras tested behave more as if they have constant-efficiency SMPS. To be clear, when operating, the S-series camera power supplies do appear to have nearly constant efficiency - operating current is close to inversely proportional to supply voltage, in a given use case.
Measuring the standby (on/off switch Off) current is a bit of a pain in the neck on S1[R]. This is because it isn't constant. It fluctuates a few 10s of microamps around 5.1mA, spiking up to about 17mA every few minutes. I'm using an 80,000 count Digital Multi-Meter on mA setting to measure current. It updates at something like 2.5Hz, which perhaps gives some idea of the measurement bandwidth. I leave it in "Average" mode for a couple of hours to get a stable measurement. Even then I don't measurements as consistent as I would like. "Off"-state current on S5/S5M2 is more constant.
I do not have a full battery-breakout kit, and the cameras can tell that they are not powered by an actual battery - On S1[R] no battery status is reported on the LCD, the EVF, or the rear display. The camera software could be making power management decisions on the basis that it believes that it is mains-powered. Then it certainly isn't running at full power, and power management seems to be happening. With a dummy battery connected, the Panasonic cameras will not start up at a dummy battery voltage below about 8.75V. Below 8.75V, the cameras will boot, butdisplay "This battery cannot be used" if turned "on", and return to standby. After the camera has been running for a few seconds, the dummy battery voltage can be reduced to 6.0V, without apparently affecting operation. 8.75V is somewhat above the maximum possible output voltage for a standard battery charged in a conventional charger (8.40V) - charging a standard battery to 8.75V would be hazardous.
Raw current measurements with camera "off", at a dummy battery Voltage of 9.0V:
- Panasonic S1: 5.12mA (3050mAh DMW-BLJ31 battery).
- Panasonic S1R: 5.46mA (3050mAh DMW-BLJ31 battery).
- Panasonic S5 (first roughly 6 hours after shutdown) 2.5mA (2200mAh DMW-BLK22 battery).
- Panasonic S5 (more than roughly 6 hours after shutdown) 0.49mA
- Panasonic S5M2X (first roughly 3 hours after shutdown) 7.03mA (2200mAh DMW-BLK22 battery).
- Panasonic S5M2X (more than roughly 3 hours after shutdown) 0.72mA
- Nikon D7200: 0.097mA (1900mAh EL-EN15 battery).
- Nikon D7100: 0.125mA (1900mAh EL-EN15 battery).
Raw current measurements with camera "off", at a dummy battery Voltage of 7.5V:
- Panasonic S1: 4.93mA (3050mAh DMW-BLJ31 battery).
- Panasonic S1R: 5.27mA (3050mAh DMW-BLJ31 battery).
- Panasonic S5 (first roughly 6 hours after shutdown) 2.5mA (2200mAh DMW-BLK22 battery).
- Panasonic S5 (more than roughly 6 hours after shutdown) 0.48mA
- Panasonic S5M2X (first roughly 3 hours after shutdown) 6.97mA (2200mAh DMW-BLK22 battery).
- Panasonic S5M2X (more than roughly 3 hours after shutdown) 0.71mA
- Nikon D7200: 0.097mA (1900mAh EL-EN15 battery).
- Nikon D7100: 0.121mA (1900mAh EL-EN15 battery).
Raw current measurements with camera "off", at a dummy battery Voltage of 6.0V:
- Panasonic S1: 4.79mA (3050mAh DMW-BLJ31 battery).
- Panasonic S1R: 5.22mA (3050mAh DMW-BLJ31 battery).
- Panasonic S5 (first roughly 6 hours after shutdown) 2.5mA (2200mAh DMW-BLK22 battery).
- Panasonic S5 (more than roughly 6 hours after shutdown) 0.48mA
- Panasonic S5M2X (first roughly 3 hours after shutdown) 6.92mA (2200mAh DMW-BLK22 battery).
- Panasonic S5M2X (more than roughly 3 hours after shutdown) 0.70mA
- Nikon D7200: 0.107mA (1900mAh EL-EN15 battery).
- Nikon D7100: 0.136mA (1900mAh EL-EN15 battery).
Links:
Hitachi-Maxell: "LITHIUM MANGANESE DIOXIDE RECHARGEABLE BATTERY" (Application note): static6.arrow.com/aropdfconversion/a975e293432d8487dd4438162ed783dcbe0df75f/5ml_15e.pdf#page=4
Panasonic ML421 data sheet: www.mouser.com/datasheet/2/315/mlseries_datasheets_merged-462869.pdf#page=2