Li-ion rechargeable batteries suddenly drain

Frank van der Most

@Frank_van_der_Most

FileMaker developer with a passion for nature.

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Camera Traps

I am currently testing a camera trap with rechargeable Li-ion batteries and untill a week ago they were doing much better than the NiMH rechargeable batteries that I used before. The camera has been working for about 5 months, taking on average at least 2 images and 2 20-second videos during daytime ( in fact taking many more, including night time images and videos but I don't have any averages readily available in my head ) and a week ago it still reported three bars out of three on the battery indicator.

Today, I checked the camera trap and the batteries were completely drained. 6 out of 8 were completely drained, down to about 0,015V, and 2 still had a charge of 1 V.

What puzzles me is that it happened in the time of a week. Some hypothesis:

It is how this type of batteries behave?
The camera trap's indicator is faulty. Could be but it is a new one, so I don't think so ( Coolife H881 old model without any wireless capability, no wifi, no bluetooth, no mobile. )
This is only the first cycle of the batteries which were bought in July ( Security Zone A2U-22 23000mAh / 3400mWh ). I don't even know if these batteries need to go through a couple of charges before they reach their optimum.
The weather ... it has been raining steadily for a couple of weeks. Almost daily, between 3 to 5 or more hours. For sure it has been far more humid in January than in previous months. However the camera has an IP rating of 67. That does perhaps not say a lot about resistance against air humidity, but it should be good for something - or should it not?

I would appreciate any and all feedback.

Akiba

@Freaklabs

Freaklabs

I'm an engineer and product designer working on wildlife conservation technology.

3 February 2024 2:53am

Hi Frank.

Just wondering but is it possible you got lithium-ion batteries in the AA form factor and voltage? If that's the case, the batteries have an internal switching regulator which will keep the voltage output constant until the batteries no longer have enough charge to meet the minimum operating requirements of the power supply. Then the power supply will shut off. It would look like the voltage drops off a cliff. It sounds like this is what is happening.

[Updated] Oops, scratch that. I just saw the part number and they are indeed lithium-ion batteries in the AA form factor and outputting the AA alkaline voltage. Hence there is a power supply on them.

Akiba

Frank van der Most

3 February 2024 2:53am

Hi Akiba,

Thank you very much for your helpful reply. So, what happened is how they typically behave. Which means one can not see the shutdown coming by looking at the battery indicator. Right?

Then I have a follow up question, if I may:

The 8 batteries are grouped in two parallel groups of 4 ( one can either load 4 or 8 batteries ) In each group there was one battery that still had a charge of 1 V whereas the other 3 had virtually nothing. Following your explanation, those 3 had their regulator shutting them down. But what about that other one. Was it about to shut down? Was it a coincidence that in each group there was one with still 1 V? Could it have to do with the order in which the 4 batteries are in series? ( I failed to notice where they were in their respective group ) I am trying to get at : would it make sense to occasionally change the order of the batteries?

Craig Rackstraw

3 February 2024 2:53am

Hi Frank,

The battery showing 1V charge probably doesn't mean much, it is likely in an imperfect shut down state, unlike the other three in each group. Changing the battery order won't help you really, you only need one cell in the group to switch off to cause your operating voltage to come crashing down which will put the remaining cells under much greater pressure (if they remain in circuit) and they will quickly follow suit.

The battery indicator is just working off a measured voltage level, so it will see either full voltage, or nothing with the type of cells you are using. A normal alkaline battery would have a graceful deterioration from about 1.8V down to around 1.2V per cell which would register better on the indicator. The camera would need to use a charge counter to be able to deal with a lithium ion based cell rather than a voltage measurement.

Frank van der Most

3 February 2024 2:53am

Hi Craig,

Thank you for clearing that up. It's kind of weird, isn't it, how these Li-ion rechargeables seem an improvement, except not in a world of devices that were not designed for them.

I am a big fan of rechargeable standard batteries, so it was a disappointment to find out that most camera traps don't work or don't work well with them. Then I got all enthusiastic about the Li-ion batteries, but they are not the silver bullet I was hoping for. Still they seem to do better in camtraps than the NiMH rechargeables.

Craig Rackstraw

3 February 2024 2:53am

Hi Frank,

Yes, I agree. There is a halfway-house solution if you take a look at the Energizer Ultimate Lithium range of batteries. They have superior life to alkaline batteries (3.5Ah in a single AA cell), though they are of course still one-time use. They would also work a little better with your battery monitor since they have a graceful degradation between 1.8V down to 1.5V, but then they fall off a cliff ;-)

Amanda Matthes

@Amanda_Matthes

12 February 2024 11:22am

Hi Frank,

Your question has already been answered, but I thought it would be useful to add this plot to the comment section. It shows the expected voltage vs capacity for that battery model.

This is consistent with what you observed and also shows you that battery charge indicators don't even work that well for NiMH batteries.

I pulled it from this website: https://www.bol.com/nl/nl/p/4-stuks-oplaadbare-aa-li-ion-batterijen-a2u-22-aa-1-5v-usb-oplaadbare-lithium-ion-batterijen-3400-mwh-security-zone/9300000112911034/

So without any further modifications your battery indicator just isn't useful for the Lithium batteries. But now you know how long they will last with that configuration. Expect that the batteries will get worse with age, though.

If you are using this camera trap model a lot and would really benefit from roughly knowing how long they would last with some arbitrary configuration, it is possible to estimate that. You would need to use a power analyser to measure the idle current as well as energy consumption for each image and video.

Hope this helps you or others stumbling across this thread.

Amanda

Frank van der Most

12 February 2024 11:22am

Hi Amanda,

Thank you for adding the image and the link. This is exactly where I bought exactly this brand and model. Pity that they can not be delivered anymore because they were the cheapest available in the Netherlands as far as I could find out.

You are right that at least now I know how these batteries work for this model and settings, and can make some estimates. When you write power analyser, would a multi meter suffice? Because I could try that.

cheers

Frank

Amanda Matthes

12 February 2024 11:22am

A multi meter would probably not be enough, unless you have a very fancy one. To get the energy use, you need to be able to integrate the current drawn over time. Something like this: Otii Arc Pro

I don't know how much you paid for these, but Amazon Basics has a line of rechargeable AA batteries, including a high capacity version which can store 2400 mAh which is a little more than the ones you're using. (I've seen even more capacity with other manufacturers.)

You might also want to consider avoiding batteries with USB ports in the future. It seems to me like just an additional thing that can break, especially if moisture could be an issue.

Frank van der Most

12 February 2024 11:22am

Thanks for the link, Amanda. The price of $900 is a bit too steep for me, but at least I now know a bit better what you meant with a power analyser.

I can't remember either what I paid for the batteries, but I try to avoid buying stuff from mr. Bezos, because he is rich enough as far as I am concerned.

The moisture issue slipped my mind when I was in Europe. As far as I remember, I liked the usb ports because I bought the batteries as a test and I didn't want to buy a separate charger, as I thought one needed one designed for Li-ion batteries. The usb ports made that possible.