A non LiPo power-supply


I want to use a Nano 33 outside - standalone - with batteries (in fact: with NiMh eneloops for example).

All I find when I search, is a LiPo shield/battery. But LiPo can burn and are not as safe as NiMh batteries.

I did not find any NiMh power solution to my project.

I want a battery life for at least 1 week (I still have to measure the actual current used by my project). I would charge the batteries in an external charger and put them back in to a battery case for the nano.

All I need is a battery case with enough mAh (3+ batteries) which are controlled by it (undervoltage detection etc). Is there no solution for this requirement yet? Exists other, “safe” ways to power a ardunio outside?

I hope someone can shed a light on this, I did not found any informations so far :frowning:

Thanks in advance!

A low voltage cutoff with NiMh is usually not used and it should be easy enough to put the project to sleep when the batteries are low, someone notices it has stopped working, and its time to chnage the batteries.

But I see little point in speculating further until you actually measure how much power your project needs.

I use NiMh eneloops all the time and they work fine BUT I don't need the run times that you are looking for.

But as noted above you need to measure your current draw first, then the approximate run time can be calculated.

Add a small solar panel to your "outside project". NiMH batteries can be safely trickle charged for years.

Considered using a Lithium Iron Phosphate Battery, Rechargeable LiFePo4?

Thanks for your answers!

Okay, so NiMH should work. It is enough to stick them together in a battery case? I still need somethibg like a step up/down converter to achieve stable 5V?

@saildude: How do you use your eneloops?

I would use a case like :

@Idahowalker: No, not yet. But after some reading LFP batteries should be ok as well since they are safer as LiPos.

Do you use LFPs?

I have 2 projects where I use these https://smile.amazon.com/gp/product/B07Q7FY8CC/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1 as part of a homemade UPS.

How do you step down to constant 5V?

Higher voltage to 5V stepdown regulator

I use a DC 12v 24v to 5v Step Down Converter Regulator 5A 25W Power Adapter Reducer for Car Electronics Truck Vehicle Boat Solar System (Accept DC 8-40V Inputs) https://smile.amazon.com/gp/product/B07Q5W1BG3/ref=ppx_yo_dt_b_asin_title_o01_s01?ie=UTF8&psc=1

Thanks for your answers!

@saildude: How do you use your eneloops?

The most used project is Building an Aids to Navigation Demonstration Display | Boating Safety Tips, Tricks & Thoughts from Captnmike
I am in the process of doing larger versions with more lights and using an Arduino.

Power has been up graded to 6 x AA eneloops - I went to the 6 cell holder because it has a cover over the batteries, before I used a 5 cell holder, I also use a 5 cell holder for testing. The display runs around 8 to 10 hours on a charge which works for a public display.

I put fresh batteries at the start of the day.