chriswfoster
Posts: 4
Joined: Wed Mar 07, 2018 11:42 pm

What are you guys doing for long lasting battery power?

Tue Mar 20, 2018 12:07 am

I have a pi3.
I'm working on a ground drone. Weight isn't THAT much of an issue, I can probably make due with a large power wall or something.
The batteries that run the motors will be on a different circuit, I'm not worried about those. I just want my pi to be safe, and powered long enough for some good trial and error experimenting.

But I'm curious, if I wanted to make sure my pi had - 5+ish hours of play, maybe 10+ (or more), what would be the most cost effective way of doing so?

I currently have 6 UltraFire 3.7v batteries, HT14500, 1200maH. Are these a good option for this? I thought about getting a few more, and getting a an 8 AA holder for it.
I got this voltage down stepper from DROK:

Code: Select all

DROK LM2596 Analog Control Buck Converter DC-DC 4-32V to 1.25-30V Step-down Regulator Module 24V 12V to 5V 3A Power Inverter Volt Stabilizer with Red LED Display. 
But, I have a feeling that 8 3.7V batteries might be too much for the down stepper.

I found this on Adafruit: https://www.adafruit.com/product/1566
However, I was looking to spend even less if possible :D :geek: I have some laptop batteries but the batteries are worn, and I'd need to buy more Lipos to get them usable again. This isn't my final project, this is just to see if I can get a node.js bot/ground drone going. If so, I'll move onto an arm or so, video, automation, etc.
Any other recommendations? Anything new on the market?

Heater
Posts: 8856
Joined: Tue Jul 17, 2012 3:02 pm

Re: What are you guys doing for long lasting battery power?

Tue Mar 20, 2018 12:14 am

Before we start to think about this, what on Earth is a "ground drone" ?

W. H. Heydt
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Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: What are you guys doing for long lasting battery power?

Tue Mar 20, 2018 12:46 am

I use a 10.4Ah "powerbank" for a Pi2Bv1.1 attached to an RPF 7" display, with keyboard, mouse, a USB stick, and an RPF WiFi dongle. It will run for about 5 hours on a charge. You can get powerbanks with capacities up to at least 27Ah.

You need to specify your type of Pi and how much current you require (at 5v) in order to figure out how much battery capacity you need to meet your spec.

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Imperf3kt
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Location: Australia

Re: What are you guys doing for long lasting battery power?

Tue Mar 20, 2018 1:15 am

Heater wrote:
Tue Mar 20, 2018 12:14 am
Before we start to think about this, what on Earth is a "ground drone" ?
This is a wild guess pulled out of my tushie, but could it imply a robot on wheels with capabilities similar to the flying version?
Stephen Hawking, rest in peace.
8 January 1942 – 14 March 2018

Heater
Posts: 8856
Joined: Tue Jul 17, 2012 3:02 pm

Re: What are you guys doing for long lasting battery power?

Tue Mar 20, 2018 7:23 am

Yeah, "ground drone", turns out it's a thing that raises money: Ground Drone Ltd
https://angel.co/ground-drone

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bensimmo
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Location: East Yorkshire

Re: What are you guys doing for long lasting battery power?

Tue Mar 20, 2018 8:03 am

With the 18650 cells you want to wire them up in parallel lines of two series cells, then use the step down.
You'll get the voltage for the step down to 5/5.1V and have the greatest capacity.
That sort of setup is often used in bicycle lights. Many have now moved to 'usb' connectors for commuter setups, so also include the step down to 5V in the pack.
But you can buy slimline charger setups.

You could of course step up the voltage but you may be too close to the 5V and most i've seen step down from a higher voltage (on bikes they often go up to 8.4V(7.2V) to drop down to a stable voltage/current for LEDs)

Do a search to see how you should balance the wiring up for parallel cells. For Li-Ion cells, that is.
But you can buy premade packs.

Or for this setup, pop on to Amazon etc and buy a 10Ah USB battery pack that will give 2A+ output. They use LiPo packs inside them and all the gubbins and changing circuits.
Often with another 5V out to connect.other things to as well.

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Imperf3kt
Posts: 686
Joined: Tue Jun 20, 2017 12:16 am
Location: Australia

Re: What are you guys doing for long lasting battery power?

Tue Mar 20, 2018 8:07 am

bensimmo wrote:
Tue Mar 20, 2018 8:03 am
With the 18650 cells you want to wire them up in parallel lines of two series cells, then use the step down.
You'll get the voltage for the step down to 5/5.1V and have the greatest capacity.
That sort of setup is often used in bicycle lights. Many have now moved to 'usb' connectors for commuter setups, so also include the step down to 5V in the pack.
But you can buy slimline charger setups.

You could of course step up the voltage but you may be too close to the 5V and most i've seen step down from a higher voltage (on bikes they often go up to 8.4V(7.2V) to drop down to a stable voltage/current for LEDs)

Do a search to see how you should balance the wiring up for parallel cells. For Li-Ion cells, that is.
But you can buy premade packs.

Or for this setup, pop on to Amazon etc and buy a 10Ah USB battery pack that will give 2A+ output. They use LiPo packs inside them and all the gubbins and changing circuits.
Often with another 5V out to connect.other things to as well.
OP is using 14500 cells, somewhat smaller than 18650's
But in theory, the same practice can be observed.
Stephen Hawking, rest in peace.
8 January 1942 – 14 March 2018

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bensimmo
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Joined: Sun Dec 28, 2014 3:02 pm
Location: East Yorkshire

Re: What are you guys doing for long lasting battery power?

Tue Mar 20, 2018 9:05 am

Yep same difference, just the AA sized one
(I did miss that).

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