Powering FLORA with Camcorder Batteries

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dr_etm
 
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Powering FLORA with Camcorder Batteries

Post by dr_etm »

Hi,

I thought that I got the specs right in that FLORA can be powered by a small camcorder battery. In particular I am using this:
https://www.amazon.com/gp/product/B09KC ... UTF8&psc=1
which is supposed to be rated at 7-9 V output.

I am trying to use this barrel jack to JST adapter: https://www.amazon.com/gp/product/B00EF ... UTF8&psc=1

I've verified the JST power port is working as I can use the Adafruit-sold 3-AAA battery pack just fine. But for my application I was hoping to get the much larger batteries to work. According to the FLORA specs, it shoudl be able to take up to 16 V input. Any ideas? (Sorry I am *very* new to hobby electronics. I took like 1 class in it about 15 years ago and am not an engineer...)

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Franklin97355
 
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Re: Powering FLORA with Camcorder Batteries

Post by Franklin97355 »

According to the flora document, it should be OK with the 7.2 volt battery but how do you plan to connect them? They don't seem to accommodate barrel jacks.

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michaelmeissner
 
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Re: Powering FLORA with Camcorder Batteries

Post by michaelmeissner »

A couple of things that occur to me:

1) There are 2 different orientations for the wires in the JST plug. Some of the 3rd party batteries have the wires reversed compared to the Adafruit orientation. Perhaps your adapter has the wires reversed.

2) The first link that you showed is a battery charger. It doesn't have links for providing output power from the battery. You would need something like the Adafruit camcorder for the NP-F750 (https://www.adafruit.com/product/2089) to actually get the power. There are units out there that combine both a charger and voltage output (https://smallrig.com/smallrig-np-f-batt ... -3168.html).

3) In terms of using camera batteries for microprocessors, one problem is the battery might be configured that it is expecting camera type power usages (typically 7-12 watts). If you power something like a Flora, it may not draw enough power, and the battery will shut down. I once tried taking a LI92B clone battery for my Olympus TG-5 camera (which produces 3.7 volts) for use with one of my neopixel projects, and I couldn't get it to power the microprocessor more more than a brief period of time, since my microprocessor wasn't pulling that much power.

4) Using a power source that gives you 7-8 volts of power will mean you lose a lot of the power in converting the power down to what the flora wants (3.3 to 5 volts).

5) You might want to look at larger li-po batteries. For example, Adafruit sells a 3.7v 6600mAh battery (https://www.adafruit.com/product/353). This has a capacity of around 25 watt hours. You would need a good li-po charger to charge it as your flora doesn't have charging capabilities. And they also have a 3.7v 10050mAh battery (https://www.adafruit.com/product/5035), which has a 37 watt hour capacity.

6) Another possibility is to use a USB battery meant for charging cell phones. Many will work fine, but a lot are designed for cell phone charging and will turn off if you use it for microprocessor stuff (unless you have many neopixels). I have quite a few of these batteries, and some will work fine, and some won't. Generally you can get these in many different capacities and form factors. If you travel, you likely want to limit yourself to a battery under 100 watt hours if you want to take the batteries on your carry on bag in plane.

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dr_etm
 
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Re: Powering FLORA with Camcorder Batteries

Post by dr_etm »

Thank you for the helpful reply! I should have provided more details.

I used my multimeter to verify that the battery is providing a steady 8.3 V on the leads (accessible on the underside of the above adapter, for better or worse...)

Regarding point #2, I am using the Camcorder-barrel jack adapter that adafruit sells. I tested that it could power a standard Arduino Uno R3, which I used for an early prototype before switching to FLORA.

#4 is an interesting point, I hadn't really thought about it. The 3 AAA battery pack I've been using as a temporary solution I think provides 4.5 V which is closer to the 3.3 V of FLORA.

I've been avoiding LiPo batteries because the application is a wearable therapy glove, and my husband (who will wear it) is rather clumsy due to a health condition and liable to fall asleep wearing it. We also have a toddler. So I liked the robustness of the camcorder batteries.

I will investigate possibility #1 as most likely first. I hope it's not #3 - I suspect not only because it's not powering the FLORA at *all*, not even for a split second. If it is a reversed set of wires, I would imagine I could just swap the leads on the battery adapter? They are accessible to be moved around. (The first one I ordered arrived broken and I had to re-solder the spring-loaded tip to the wire, so I know!)

Thanks again for all the ideas and suggestions!!

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