Extended battery life for remote shooting

Sdack

195

« on: 10 / November / 2017, 00:05:04 »

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Hi folks,

Inspired by AHull's fascinating and diverse thread on the "quick waterproof case", which wanders deep into battery solution territory

https://chdk.setepontos.com/index.php?topic=10284.40

I've been assembling items for the remote battery solution of my dreams, for off grid, extended time-lapse.

The below item arrived from china last week and seems reasonably sturdy.. Sorry folks.. I'm not quite game for a teardown.. might not get it back together again!

ebay link here
https://www.ebay.com.au/itm/121957836096

For batteries, having read of the overblown marketing claims for 18650 batteries on ebay, I decided to go with a local (ie. Australian), supplier and a brand name batteries which came up on special a couple of days ago..

Genuine LG HE4 2500mah 20A Lithium Rechargeable battery

https://www.techaroundyou.com/Vape-Batt ... upply-bulk

and a 6 slot charger to go with the 6 batteries

https://www.techaroundyou.com/Chargers/ ... CD-Charger

Total cost AUD $95, which seems a lot but the charger was $55 of that. The batteries only cost $6.50 each. I went for 'high drain' ones having read they're more capable. Even though there were some 2600mah 30A Sony's available for only a dollar more each.

https://www.techaroundyou.com/Genuine-V ... upply-bulk

I have just started looking at the microprocessor which I hope will be the master power supply for both the camera (Ixus 160) and a Raspberry Pi Zero W

https://www.raspberrypi.org/products/raspberry-pi-zero-w/

A tiny linux computer, which will controll the camera via CHDK-PTP, and then resize and upload the images as they are taken, to my webspace.

With help from Manoweb and Reyalp, I've got a working version of the scripts to achieve this. I'm only lacking the 3/4 G connection hardware to make this work away from a router with wireless.

Any suggestions would be most welcome on this project. I'm keen to make sure the hardware and batteries don't suffer when the power gets low. Hoping I can find a way to monitor the remaining charge remotely.
Best wishes
Sdack

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c_joerg

1247

Re: Extended battery life for remote shooting

« Reply #1 on: 10 / November / 2017, 03:03:36 »

Quote from: Sdack on 10 / November / 2017, 00:05:04

ebay link here
https://www.ebay.com.au/itm/121957836096

The 9V output looks interesting to power my g1x and EOS M3.
But not sure if the 9V/1.1A on startup time is enough.

Quote from: Sdack on 10 / November / 2017, 00:05:04

I'm keen to make sure the hardware and batteries don't suffer when the power gets low. Hoping I can find a way to monitor the remaining charge remotely.

That could be a problem when the cam goes off immediately.
Reply #4
https://chdk.setepontos.com/index.php?topic=13164.0

Quote from: Sdack on 10 / November / 2017, 00:05:04

the camera (Ixus 160)

I would power the cam directly with the 18650 cells. Then the power goes slowly down.

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Hardware_Hacker

322

Re: Extended battery life for remote shooting

« Reply #2 on: 10 / November / 2017, 20:33:13 »

Quote from: Sdack on 10 / November / 2017, 00:05:04

"...I've been assembling items for the remote battery solution of my dreams, for off grid, extended time-lapse..."

Any suggestions would be most welcome on this project. I'm keen to make sure the hardware and batteries don't suffer when the power gets low. Hoping I can find a way to monitor the remaining charge remotely.

Ref #1:- Reply #1 by c_joerg
"... I would power the cam directly with the 18650 cells. Then the power goes slowly down..."
"...But not sure if the 9V/1.1A on start-up time is enough...."

That is what I would also do. Some additional stuff to consider (i.e. camera don't suffer):-

a/ System reliability, powering the camera directly of a battery (parallel bank) will have a greater
peak current (reserve) capacity. i.e. The Camera could, at times, draw peak currents, beyond
the ability of the inbuilt voltage converter stated specification.

b/ When a Camera "peak current event" occurs on a camera with direct battery power the lower
internal resistance of the direct battery power supply results in only a very small drop in the
cameras supply voltage.

c/ When a Camera "peak current event" occurs on a camera with converter battery power the higher
internal resistance of the converter battery power supply results in a higher drop in the
cameras supply voltage.

d/ As demonstrated by "Bug Splatter" in the "a560 Camera Battery and Current Measurements".
here https://chdk.setepontos.com/index.php?action=dlattach;topic=12334.0;attach=11946
The camera's, internal power management, attempts to to compensate when a "peak current event"
occurs (which then results in a sudden camera supply voltage drop) by then drawing additional
current. With the lower internal resistance of the direct battery power supply there is no problem
until the direct battery are almost flat. i.e a controlled camera power down.

c/ With a converter battery power supply, when a Camera "peak current event" occurs, on a camera
there is a MUCH greater probability of a UN-controlled camera power down.

d/ The above stuff is the basic reason for random UN-controlled camera power down issues with
cameras powered via cheap Chinese Mains supplied battery adapters.
i.e. "High Internal Resistance" and "NO" additional filtering components.

H-H

Ref #2:- Using chdk to measure the internal resistance of the batteries in the camera
15/November/2008 by Bagger288

Edit #1 Also some time ago someone constructed a (portable) CHDK 8 camera panoramic (legacy) array that
was powered from a 12 lead acid battery with a DIY converter and a voltage regulator.
Because of the rig's poor wiring and construction the voltage regulator failed and 12 volts was then
feed to a 8 cameras which then failed.

An additional issue, in this post, is the voltage adjustment switch, which could be inadvertently be set to the wrong voltage.

« Last Edit: 10 / November / 2017, 21:44:49 by Hardware_Hacker »

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Sdack

195

Re: Extended battery life for remote shooting

« Reply #3 on: 11 / November / 2017, 03:15:55 »

Thanks heaps for your detailed input..

When you say "converter battery".. do you mean one of these, what I call dummy batteries?

https://www.ebay.com/itm/302417801125

And do I understand correctly that something you call a "peak current event" might not be able to pull enough current through a cheap device as shown above?

The USB power pack I have received, has six 18650 batteries, I believe wired in parallel, which must then go through some kind of (probably cheap as possible) step up regulator, to achieve 5volt output from 3.7 volt cells.

I guess, if I find my cameras shutting down unexpectedly, then this is likely one of the 'usual suspects'.

Would you recommend going for the genuine Canon AC adaptor, for it's superior construction?

https://shop.usa.canon.com/shop/en/catalog/ac-adapter-kit-ack-dc90

Best wishes
Sdack

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waterwingz

12138

Re: Extended battery life for remote shooting

« Reply #4 on: 11 / November / 2017, 09:15:11 »

Quote from: Sdack on 11 / November / 2017, 03:15:55

And do I understand correctly that something you call a "peak current event" might not be able to pull enough current through a cheap device as shown above?

AFAIK, H-H's comment was about an external power supply not being able to provide enough peak current. As long as your cheap device fits correctly into your camera, it should not have an issue with peak current.

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Sdack

195

Re: Extended battery life for remote shooting

« Reply #5 on: 11 / November / 2017, 16:08:55 »

That makes sense in the context of mains adaptors but my post was all about about batteries..

Perhaps he will clarify further.

It turns out that another CHDK member, AHull, who's STM32 microprossesor based project, Sunset Timer I'm seeking to duplicate, also has the ability to read the charge of the batteries and therefore offers the safety I need for the Raspberry Pi and camera. Even if the camera can shutdown on low voltage, I don't want to be supplying a hit of 'almost enough' power every ten minutes for hours or possibly days before I can get out to it.

It's also more than likely the Raspberry Pi could upload a snapshot of battery state too when it uploads the images, so I will know what's going on at a distance. If it weren't for the internet connectivity of my project, I don't think I would be game to leave a camera unattended for days and weeks. It would be like going back to cellulose film again.. I'm old enough to remember waiting weeks for rolls of holiday film to arrive in the post, only to be disappointed by entire rolls being ruined due to overexposure or some other error.

I was tempted to suggest that I am too lazy and coddled by the digital age, expecting instant results delivered to my desktop but I am putting a lot more effort into developing this project than my parents did into their holiday snaps.

S

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Mlapse

577
S95 S110

Re: Extended battery life for remote shooting

« Reply #6 on: 22 / March / 2018, 17:04:03 »

I do not know if this is still relevant.
But to give an answer to what could work for you it would be handy to know what you expect.

Do you want it to run unattended for a week, shorter or longer?
Would it be possible to use a (small) solar cell at the site?
What is the power consumption of your complete rig?
Do you have a welding tool at hand

« Last Edit: 22 / March / 2018, 17:05:54 by Mlapse »

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frustration is a key ingredient in progress

Sdack

195

Re: Extended battery life for remote shooting

« Reply #7 on: 26 / March / 2018, 20:04:44 »

Quote

Do you want it to run unattended for a week, shorter or longer?

Hi, I've made significant progress with my rig/s. One has been running since just before Christmas, documenting construction of some new classrooms at a local school. That one is mains powered with wifi connection, so it's been relatively easy going.

Quote

Would it be possible to use a (small) solar cell at the site?

This is what I'm looking at now for remote locations and I could use some suggestions for a smoothly operating (ie. spike free), solar recharged battery solution. I've read that the switching of some solar systems leaves something to be desired in this respect and don't want my Raspberry Pis crashing due to brief brownouts or overvoltages.

Quote

What is the power consumption of your complete rig?

My latest rig has an onboard hard drive as well as a 3/4G data modem. I put a Kill A Watt like device on it last week and, during daytime image shooting at 1 image a minute, it reported the following:

Min power draw - 3.4 Watts
Max power draw - 12.5 Watts
Average power draw 8 Watts

Which I think bodes well for a modest solar panel and battery situation.

I would like the security of a couple of days worth of battery, in case it's far enough away from base to be inconvenient to rush right out to fix it.

Quote

Do you have a welding tool at hand

I've got a soldering iron... I would love welding skills but don't know where to start? Is there a safe and simple entry point to learn the most useful and affordable method?

Any suggestions welcome.

Thanks for your interest
Sdack

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Mlapse

577
S95 S110

Re: Extended battery life for remote shooting

« Reply #8 on: 27 / March / 2018, 03:02:32 »

Reading your mail you suggest that your rig needs some 200watt/day. I won't go into system losses of chargers/converters, but let's say 10% more is actually needed.

In your first post you suggested li-ion batteries...you'd need some 24x18650 per day or 1 cel per hour to make that work.
Charging those via a solar cell would need a complex charger because of the risk of overcharging li-ion while under load (think back on phones that caught fire while charging)
the other option is to build multiple packs that you exchange and charge at home.

Looking at your requirements and skills my first thought is to go for NimH or PB-gel because they can simply be put on a float charge.
I won't go into the 100 NimH per day setup, because I am thinking that is not for you.

Pb is heavy and larger than nimh but easyest to set up and stable even with a crappy wall mart charger or intermittant solar charger.
So for 200 watt you need 12V16Ah as a minimum (if you do run it dry the pb batterie will die)
Security comes with overcapactity, longetivity of PB cells with never running it below 50% of capacity. This means 12V/32Ah per day would be ideal, but 12V/20Ah would suffice.

Looking at a couple of days this suggest a truck or large car batterie (or 2), just to give you an idea of what you are looking at.

Using a buck step down converter (ebay) like the LM2596S you would be able to create a stable 4.2/8.4V for the camera and 5V for the raspberry.
And you would only need your soldering iron to attach a few leads. Is this what you mean with entry level?

If you want to compensate that with a solar panel it would suggest you need something like a 50watt panel, that is about 1/4-1/2 m2 solar panel and with a simple steca charge controller it can keep that PB batterie charged.

You could do with less depending on sun conditions in your location, but even a 50 watt panel will not manage this around xmas where I live or on heavy clouded days. (needed sun hours per day >4) However it wil be enough for 10 month a year and could possibly keep your batterie capacity slightly smaller.

« Last Edit: 27 / March / 2018, 03:05:52 by Mlapse »

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frustration is a key ingredient in progress

Sdack

195

Re: Extended battery life for remote shooting

« Reply #9 on: 27 / March / 2018, 04:39:32 »

Thanks @Mlapse. this is very helpful indeed..

Quote

Reading your mail you suggest that your rig needs some 200watt/day. I won't go into system losses of chargers/converters, but let's say 10% more is actually needed.

In your first post you suggested li-ion batteries...you'd need some 24x18650 per day or 1 cel per hour to make that work.

I thought I was onto a good thing with these 18650s but your figures put them into a realistic light.

Quote

Charging those via a solar cell would need a complex charger because of the risk of overcharging li-ion while under load (think back on phones that caught fire while charging)
the other option is to build multiple packs that you exchange and charge at home.

I like the Keep It Simple approach with generous buffer margins.

Quote

Looking at your requirements and skills my first thought is to go for NimH or PB-gel because they can simply be put on a float charge.

PB being lead, vehicle type batteries but deep cycle marine style as opposed to cranking high-torque starter motor batteries if I surmise correctly.

Quote

I won't go into the 100 NimH per day setup, because I am thinking that is not for you.

If it's dangerous, costly, or complex, you're right, it's not for me!

Quote

Pb is heavy and larger than nimh but easyest to set up and stable even with a crappy wall mart charger or intermittant solar charger.

As long as I can carry it up a ladder and mount it on a pole, I'm happy.

Quote

So for 200 watt you need 12V16Ah as a minimum (if you do run it dry the pb batterie will die)
Security comes with overcapactity, longetivity of PB cells with never running it below 50% of capacity. This means 12V/32Ah per day would be ideal, but 12V/20Ah would suffice.

Looking at a couple of days this suggest a truck or large car batterie (or 2), just to give you an idea of what you are looking at.

Something like this?
http://www.radioparts.com.au/product/03296520/c12-40dg-12v-40amp-deep-cycle-gel-battery-century#.WroBB4huaUk

Quote

Using a buck step down converter (ebay) like the LM2596S you would be able to create a stable 4.2/8.4V for the camera and 5V for the raspberry.

Yup.. can do that..

Quote

And you would only need your soldering iron to attach a few leads. Is this what you mean with entry level?

Well, I wasn't sure.. to me, welding is a bit more structural and non electrical, soI couldn't see how that was relevant. However, as I said, yes I can solder AND I'd love to be able to weld stuff together..

Quote

If you want to compensate that with a solar panel it would suggest you need something like a 50watt panel, that is about 1/4-1/2 m2 solar panel and with a simple steca charge controller it can keep that PB batterie charged.

That's exactly what I want.. Thanks for doing the math for me..

Quote

You could do with less depending on sun conditions in your location, but even a 50 watt panel will not manage this around xmas where I live or on heavy clouded days. (needed sun hours per day >4) However it wil be enough for 10 month a year and could possibly keep your batterie capacity slightly smaller.

Don't mean to boast but sunshine is good here, in Byron Bay, the most easterly point of Australia. Average temp is 75F and we get a mere 9.9 days of rain per month.
Sending you warm wishes
Sdack

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