Battery Powered Arduino Projects

I know the project I have in mind will run from a Arduino Uno, I'm hoping to be able to use a Mini or Pro Mini to reduce size (would a 5V version as one of the components requires 4-7VDC power input).

In the meantime, I'm trying to decide on how to power the unit. It will be portable so it will be battery powered.

I know I could use 9V batteries, but (a) I don't know yet how long it would run and (b) I don't want to keep buying batteries.

I was thinking of using one of the external cell phone power packs. As I recall most are 5VDC out at 1amp-hour or more. Has anyone tried this plan? How were the results?

How are you powering your portable battery powered Arduino projects?

Here is a page about power saving that may intrest you.

Those cell charger battery packs can have a circuit in them that shuts off the output if the current drawn is low ie. the phone has charged. One that I have will shut down if the current is under 30mA.

I have used the 2 x 14500 3.7v 2500ma in parallel with a cheap 3v to 5v step up converter from e-bay for 1.59GBP(cheaper than just buying the inductor alone) my project comsumes 37-45Ma little bit more if I turn the lcd back light on runs for ages 27hrs in a continuous useage and use it for 1hr a day and still going strong. I'm yet to go through the stuff to get it to consume less power just wanted to get it working first, that's the next stage

This may sound obscure but I'd go for a Ni-Cd battery pack. The nominal voltage will be closer to 5V with 4 cells (4.8 ) as opposed to lithium anything (3.7 or 7.4 with a regulator) and you can recharge the battery when it gets low without fear of any damage to the battery. The voltage is also inherently more stable that almost any other battery chemistry so you don't even need any power regulation. A fully charged 4 cell pack will be around 5.6V and taper down to 4.8 where it will stay until it's pretty much dead. I think any logic high will register above 4.5 so the battery will be above that for 95% of its useful charge but never high enough to overload anything.

The sensor to be attached draws 60mA alone, plus the LCD and the Arduino. Hence the concern over battery life. I would love to have a 16-18 hour run time, but half that (8-9 hours) would be the minimum.

Not Ni-Cd - I'd go for Nickel Metal Hydride, NiMH. Similar voltage, but without NiCad's memory problem. Can get 2500mAH AA cells, last a long time.

Logic High in or out will depend on Vcc. A '328P will be fully in operational compliance at 16 MHz with Vcc down to 3.78V, and things may or may not get funny below that. Vih & Voh are dependent on Vcc, with a valid high in needing to be 0.7 x Vcc, and a high out guaranteed to be 0.8V to 0.7V below Vcc, Vcc & load dependent. See section 32, 32.2. Common DC Characteristics of the datasheet, the latest is dated Nov 2016 http://www.atmel.com/devices/ATMEGA328P.aspx

Or C cells for more capacity.

CrossRoads: Not Ni-Cd - I'd go for Nickel Metal Hydride, NiMH. Similar voltage, but without NiCad's memory problem. Can get 2500mAH AA cells, last a long time.

Logic High in or out will depend on Vcc. A '328P will be fully in operational compliance at 16 MHz with Vcc down to 3.78V, and things may or may not get funny below that. Vih & Voh are dependent on Vcc, with a valid high in needing to be 0.7 x Vcc, and a high out guaranteed to be 0.8V to 0.7V below Vcc, Vcc & load dependent. See section 32, 32.2. Common DC Characteristics of the datasheet, the latest is dated Nov 2016 http://www.atmel.com/devices/ATMEGA328P.aspx

I stand corrected on the logic levels and NiMH is certainly a more "energy dense" battery but every other characteristic of NiMH is inferior. Most people nuke them just trying to charge them. They are very poor at handling fast or overcharging whereas NiCd can be recharged over 1000 times at up to 4C safely and will provide long life even when abused. AA cells are also available in a 600 mAh capacity which should yield the 10 hr min the OP is looking for. Given the 5V requirement of these boards, a battery with 1.2V nominal voltage is more convenient than any other battery type (fact) because you don't need to regulate it at 4.8V and if you go to 3 decimal places, these batteries often hover a little above that at low discharge rates of 1/10 C. Compare this to alkaline (4.5V), lead acid (4V), lithium (3.7V) and it's clearly the closest match. Plus you can:

-operate the battery in the most extreme range of temperatures -discharge it to 0V without damaging it -maintain a safe operating voltage for most of the batteries life without voltage drift -use it over and over again for at least 1000 cycles -charge it quickly (4C) without any damage

NiMH basically has the advantage of greater capacity but has none of the other benefits

The nefarious "memory" effect was observed in space satellites on a charge cycle that coincided with its fixed orbital period after many cycles and the only effect was a momentary drop in voltage at the point where the charge normally terminated. This effect is 100% reversible by deep cycling and is very hard to reliably reproduce in consumer applications because the phenomenon only shows itself with repeatable and frequent incomplete charging. It is mostly popularized hype with negligible importance in real-world battery usage.

Suggested Cell: Panasonic (Sanyo) N-600AAC

http://feyelektronik.de/downloads/Datenblaetter/Panasonic/NiCd/N-600AAC.pdf

Gahhhrrrlic: I stand corrected on the logic levels and NiMH is certainly a more "energy dense" battery but every other characteristic of NiMH is inferior. Most people nuke them just trying to charge them. They are very poor at handling fast or overcharging whereas NiCd can be recharged over 1000 times at up to 4C safely and will provide long life even when abused. AA cells are also available in a 600 mAh capacity which should yield the 10 hr min the OP is looking for. Given the 5V requirement of these boards, a battery with 1.2V nominal voltage is more convenient than any other battery type (fact) because you don't need to regulate it at 4.8V and if you go to 3 decimal places, these batteries often hover a little above that at low discharge rates of 1/10 C. Compare this to alkaline (4.5V), lead acid (4V), lithium (3.7V) and it's clearly the closest match. Plus you can:

-operate the battery in the most extreme range of temperatures -discharge it to 0V without damaging it -maintain a safe operating voltage for most of the batteries life without voltage drift -use it over and over again for at least 1000 cycles -charge it quickly (4C) without any damage

NiMH basically has the advantage of greater capacity but has none of the other benefits

The nefarious "memory" effect was observed in space satellites on a charge cycle that coincided with its fixed orbital period after many cycles and the only effect was a momentary drop in voltage at the point where the charge normally terminated. This effect is 100% reversible by deep cycling and is very hard to reliably reproduce in consumer applications because the phenomenon only shows itself with repeatable and frequent incomplete charging. It is mostly popularized hype with negligible importance in real-world battery usage.

I don't believe 600mAhr will come close to a 10 hour run time, likely 4-5 at best. As listed in that post, the sensor alone draws 60mA and the LCD and Arduino are in addition.

Not to start a debate on the subject, but whatever the end game is on the NiCads. It sure looks like a memory effect and at some point even a deep cycle fails to have them recover. I have skipped the NiMh era and went straight to Lithium with their own charger. I have not attempted and do not want to attempt to make my own charge. Hence the reason I inquired on the use of the cell phone power packs. High power capacity, available charging sources, and interchangeable battery pack (providing the case is designed correctly).

Powering your project with a battery is actually harder than you would think if you want to take proper care and get the most out of it. A lot of people think you can just whack in a 9V, no problem. Your normal PP3 battery (the box shaped ones colloquially called "9 volt") actually sucks really bad for the kind of projects that people typically want to make. They are best used for applications that require very low current, like multimeters or smoke detectors. They aren't very good for things like motors or solenoids or relatively strong LEDs.

The capacity sucks too. If you don't take full advantage of power reduction techniques, the battery will be sucked dry in no time. The datasheet I have for an Energizer alkaline lists a 600 mAh capacity with a 25mA drain current. That's 24 hours of battery life at that current.

If you want any kind of usable battery life, you need to carefully plan out how you are going to regulate and control power to the different parts of the system.

I wasn't going to get into it but Jiggy kind of touched on it already. Alkalines SUCK... a lot, and they're expensive, being single use.

To be honest, if capacity and chargers are the chief concern then by all means lithium is your battery of choice. All I'm saying is that for a few bucks on ebay you can get a fast ni-cd charger and stick with the familiar AA size so you can use quad battery holders for convenience. You will NOT have any "memory" related problems and considering the tremendous advantages, I would seriously consider it.

http://www.ebay.ca/itm/LCD-Fast-Battery-Charger-for-4-AA-or-AAA-Ni-MH-Ni-Cd-Rechargeable-Batteries-/391592275771?hash=item5b2cb7ef3b:g:qB0AAOSwLF1X9U-Z

This is why I used 14500 batteries these are the size of double AA batteries as my space was tight and even at 51ma calculations say 68hrs continuous, even at 100ma you can get 35hrs continuous usage. I have 4 in total 2 are used the other 2 are charged and on standby for when the others need replacing. You could always use 18650 batteries as you can get higher amp-hour batteries in them. You could always run it of a 6v 12ah SLA battery and even get longer run time but it aldpends on space and needs.
I have also added a switch so the AA battery holder can be used in parallel for the 3.7v and in series for 2 x 1.5v AA batteries if ever the main battery pack runs flat you can always get them from any shop to get you out of trouble.

Gahhhrrrlic: Alkalines SUCK... a lot, and they're expensive, being single use.

I have several battery powered AVR based devices that are used daily; one of them is typically used for about 30 minutes three times a day. I typically get about two years out of a pair of AA batteries.

Given the up-front cost of chargeable batteries and the charger and the cost in time and money it would take decades for me to break even.

Coding badly, this is what I'm hoping for at the end, just working my way through power saving methods from nicks site for my wireless multimeter project I've been playing with.

If you're drawing such a low current that it takes 2 years to go through a pair of AA, then yes of course, the ROI is higher for disposables. However, if you are drawing appreciable current (enough to flatten disposable AAs in less than a day), the $/cycle investment is lowest for rechargeable and specifically for Ni-Cd, which are well known to be the cheapest battery chemistry in terms of lifetime charge. At a conservative 1000 cycles, you get 600mAh * 1000 / ($20 [4 cells] + $10 [charger]) = 20 Ah / $ compared to 2000mAh* 1 / $2 = 1Ah/$. We could even do financial linear programming to find out when the break even point would be for rechargeables but essentially, the longer you use them OR the more power you need, the more it makes sense to use rechargeable batteries.

Gahhhrrrlic: I wasn't going to get into it but Jiggy kind of touched on it already. Alkalines SUCK... a lot, and they're expensive, being single use.

My point wasn't about alkalines, but about PP3s. A six cell battery is wasteful when a 3.3V variant can run directly off of 3 cells, and with some more advanced tweaking can run off of only 2 cells down to 1.8V.

adwsystems: I know the project I have in mind will run from a Arduino Uno, I'm hoping to be able to use a Mini or Pro Mini to reduce size (would a 5V version as one of the components requires 4-7VDC power input).

In the meantime, I'm trying to decide on how to power the unit. It will be portable so it will be battery powered.

I know I could use 9V batteries, but (a) I don't know yet how long it would run and (b) I don't want to keep buying batteries.

I was thinking of using one of the external cell phone power packs. As I recall most are 5VDC out at 1amp-hour or more. Has anyone tried this plan? How were the results?

How are you powering your portable battery powered Arduino projects?

Can you live with 8MHz or slower operation? Most things can. Then you can use a 3.7V pack or 3 cells with less draw on the duino. At 3.3 to 3.7V you can connect directly to 3V devices too.

9V battery through a 5V regulator has failed a lot of projects. They come here to find out why. A cheap buck converter will get more out of the thing but how many mAh does your 9V battery get?

The 9V form factor is all about convenience and space efficiency. It is inherently design-limited. The cells don't have the best aspect ratio and have too much internal resistance without enough electrode surface area. Good for a clock or smoke alarm as alluded to earlier but not much else. Since power banks are already regulated and rechargeable, they seem like a decent and affordable option, so long as the internal circuitry isn't too "smart" for the normal operation of the Arduino. If you don't go that route and your current demands are in the 10s of mA or higher, then custom rechargeable packs are the way to go and as far as they are concerned you are likely going to need some sort of regulating circuitry unless you happen to luck out on the pack voltage matching your needs within +/- 10%. That's my professional opinion.

The 3 cell/3.7V options are not going to work. Thank you for the thoughts. There is not enough juice for the 5V sensor with a Vin min of 4V.

What's the 5V sensor specifically?