Hello! I've been thinking about this problem for some time now, but I've not been able to figure out a proper solution.
I have an Arduino that has to be powered via lead acid batteries. I have a choice: using a 12V 7ah lead acid battery like this or using a 5V battery. Which one should I pick? 12V batteries are cheaper, and I'd use a stepdown buck converter to lower the voltage to 5V. Also, they are much easier to find, so I'd prefer to use them if it's possible.
But, what I'm concerned of is power efficiency of that. My project needs to run for the longest time possible. Is 12V battery with a stepdown buck converter going to last as long as a 5V one?
Thanks!
Where have you found a 5V lead-acid battery? Sounds a bit unlikely since lead-acid naturally produces 2V per cell. A link would be interesting.
Anyway a DC-DC converter can easily be 90% efficient so you're not losing much.
Steve
A 5V battery is most likely a battery of (any) voltage with a buck or boost converter. Like a 5V power bank with a single 3.7V LiPo cell. Whatever the battery produces (3.2-4.2V depending on charge level) is converted into 5V.
Keep in mind: a 6s lead/acid 12V battery is indeed pretty close to 12V. A 3s LiPo 12V battery is a little less at 11.1V. And a 4s 12V LiFePO4 battery is a bit more, at 13.1V...
To run an Arduino for the longest time, I prefer 2s or 3s Alkaline. Nominal 3 resp. 4.5V. The first for projects where clock speed doesn't matter much (can do up to 12 MHz), the second for where I want to run at 16 or 20 MHz. No converter, as those waste quite some power as quiescent current and an Arduino in power-down sleep zeroes out my multimeter (so <1µA).
I run my weather station off a 12V LiFePo4 8Ah battery.
I use a step down thingy. Works great lasts a long time.
Post a link to the 5V batteries. I've been looking for 5V batteries for a long time now. I'm sure the supplier will sellout of their stock in no time.
slipstick
yeah, I was wrong, there's no 5V battery. I remember finding it, but it was probably a mislabeling as I can't find it anymore.
wvmarle
thanks!
Idahowalker
thanks! read what I wrote above, I can't find it anymore, it was probably a mistake.
Thanks everyone!
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