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Batteries: how many... and tips for making them go further

Posted: Fri Jun 08, 2018 5:59 am
by csc
I am about to embark on a 6/7 day backpacking trip with my mirrorless A6000 and I am bringing 5 batteries with me as well as a small solar/battery/USB charger (has about 3 batteries worth of charge already in it, and it may be able to do a little solar charging, but at a little over 1 watt of solar, I'm not expecting much). It seems like a silly amount of battery weight, but we like to take a lot of photos and the mirrorless batteries drain fast. This set up will give us a little less than one full battery per day + however much the little solar charger can produce (maybe another battery worth or so).

So I'm wondering... for those of you using mirrorless cameras, how many batteries do you take? Do you take a USB or solar charger as well?

Here are some tips I learned to get more out of my batteries:

The Sony OEM batteries are 1020 mAh, but some of the third-party brand batteries hold 1500 mAh, which means more shots per battery.

Some battery saving tips I've learned are to turn down the screen brightness, turn off or minimize the time that auto-review pictures pop up after shooting, and turn on airplane mode, so there is no wi-fi. I would guess AF-S uses less battery than AF-C, although I am nut sure by how much. I would guess that using non-power zoom lenses would save battery, but I'm not sure by how much.

Do you have any additional tips to extend battery life?

Re: Batteries: how many... and tips for making them go furth

Posted: Fri Jun 08, 2018 7:27 am
by SirBC
I have an a6300. I haven't taken it backpacking but one thing I've noticed is that it will drain battery overnight even when it is turned off. Others have seen this behavior as well and I've tried the recommended "solutions" to no avail. If I ever do take that camera backpacking I would be sure to remove the battery from the camera at night.

Have you considered bringing a battery bank instead of a solar charger? Anker has a 20K mAh battery bank that weighs around 12.5 Oz. which you could also use to charge things like a headlamp, phone, GPS, etc.

Re: Batteries: how many... and tips for making them go furth

Posted: Fri Jun 08, 2018 7:38 am
by csc
Thanks, SirBC, for the tip on removing batteries. I would not have thought of that.

I would love to have a big battery bank like that! I'm just working with what I have right now (solar/battery was a sweet freebie from a conference!), but prepping for this trip made me curious about how others approach it.

Re: Batteries: how many... and tips for making them go furth

Posted: Fri Jun 08, 2018 11:59 am
by bobby49
I agree. A battery bank is often the best solution for a backpacker.

Solar panels can be effective, but not so much if you are moving on the trail. If you go to one spot and then set the solar panel up for optimal sun angle for several hours, then it can be much more effective. Also, when I've used a solar panel, I don't get them into full-fledged operation unless they are rated much higher than what I actually get out of them. The exception would be if I operate the solar panel in Palm Springs or Phoenix.

Also realize that just because some batteries have a factory rating in milliampere hours, that doesn't mean that they are actually that good. Many lesser known companies overrate their batteries.

What I do with camera batteries is to take the first battery that came with the camera and use that as my standard. Then I measure the milliampere hours from three or four cheaper batteries to find which ones are good and which ones aren't. I've never found a cheaper battery that was significantly better than the first one that came in the camera, but I've found some that are close, and they are much cheaper. Also, some of those batteries will look good for the first 5-10 charge cycles, and then they degrade. Some are almost unusable after 20 charge cycles. I don't know whether that is something fishy in the battery chemistry, or some unexpected interaction with the charger. Equally strange is that some batteries will get better after the first 5-10 charge cycles. Go figure.

Re: Batteries: how many... and tips for making them go furth

Posted: Fri Jun 08, 2018 1:03 pm
by rlown
I sleep with my batteries. I like to keep electronics warm. Even the delorme goes in the bag at night.

Re: Batteries: how many... and tips for making them go furth

Posted: Fri Jun 08, 2018 5:05 pm
by SSSdave
For 9 day trips carry 15 batteries for my A6000 plus a 6k battery bank. Over decades I've never come close to running out of battery power causing a need to be conservative as I make sure I have enough battery power after strenuous backpacking effort

I don't use image stabilization motorized lenses and never the LCD (only EVF). However the majority of my shots use spot auto focus that does motor a lens. Low power mode is after 2 minutes. Tend to turn the camera off every time I finish shots for subjects if I don't expect to immediately shoot. Don't review images or bother deleting images until I return home unless have a good reason to. And most importantly rarely use flash while backpacking. Different batteries lose capacity with use at different rates. Some of my batteries seem to be discharging quickly so I need to set up a metered discharge test again.

Re: Batteries: how many... and tips for making them go furth

Posted: Fri Jun 08, 2018 6:13 pm
by csc
Bobby and Dave, how do you test the output of the batteries?

Thanks for the good tip on not deleting images until home.

Re: Batteries: how many... and tips for making them go furth

Posted: Fri Jun 08, 2018 7:07 pm
by SirBC
SSSdave wrote:
I don't use image stabilization motorized lenses and never the LCD (only EVF).
My understanding is that the EVF actually uses more power than the LCD on the Sony a6XXX line.

Re: Batteries: how many... and tips for making them go furth

Posted: Fri Jun 08, 2018 8:28 pm
by bobby49
csc wrote:Bobby and Dave, how do you test the output of the batteries?
If you have a milliampere-hour meter, that is a start. Some high-end battery chargers have that feature built in, although seldom for camera batteries. You can tell a little with a digital multimeter. The fully charged voltage between two batteries can be compared, and then the fully discharged voltage between the two can be compared. Note that the fully discharged voltage is not Zero. It is normally the cutoff voltage where the camera shuts down, and it is in the range of 2 or 3 volts per cell. Some cheaper batteries have a high self-discharge rate, and that contributes to being a poor one to use. If you charge a battery up full, then measure the voltage. If you leave it laying on the table for a month, you should be able to come back and measure it and it will be 99% or 100% of full. However, after one month if it is 90% or worse, then you've got a dog.

Re: Batteries: how many... and tips for making them go furth

Posted: Wed Jun 13, 2018 6:03 pm
by SSSdave

Well not so simple but then I'm an old electronic tech. My A6000 NP-FW50 batteries are 7.4 volt Li-ion. There is no way to read the actual voltage in camera and connecting to its tiny contacts are difficult. Just putting a camera into some mode and getting consistent results as to how long a battery lasts are subject to many unknowns. Thus a poor testing choice.

Have digital volt/resistance/curret meter aka DVM and clip leads.
Have 20 ohm load resistor. 7.4/20= 370 milliamperes
Open up spreadsheet and create chart of battery number on each row and times in column where one will record voltages.

Drill holes in battery charger plastic case to get at battery contacts. Solder wire to the contacts that one can connect meter leads to.

Mark each battery with a number.
Fully charge one battery.
Place into camera. Deselect power off timer.
Run till Replace Battery warning appears.
Measure voltage. That is the battery low threshold.

Fully charge each battery.
Record battery voltage after charging.
24 hours later after no use record battery voltage.
Place battery into modified battery charger.
Connect DVM to contacts.
Connect load resistor across charger contacts and log date time.
Every periodic time check and log voltage. Say every 15 minutes.
Stop when voltage decreases to battery low threshold level.

For the tech savvy, for $59 buy one of these data acquisition boxes that can do all the monitoring with more samples:
https://www.dataq.com/products/di-1100/