Which LiIon battery pack will power my project? HELP PLS!

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Daz007
 
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Which LiIon battery pack will power my project? HELP PLS!

Post by Daz007 »

Hi folks,

I am looking to power a XY-P15W mini-amp (photos attached + links below... I also bought the 30W version) with the smallest possible 2 or 3 battery Li-Ion pack that includes a power management board. Which Adafruit battery pack and Power Management board can I buy that will be powerful enough to get this going?

The amp will be powering a single Dayton Audio TT25-8 transducer puck. I would also be happy to do this all in the Adafuit ecosystem if there is a powerful enough amp + batteries + PM board to make it happen. In fact, I'd prefer this, but also happy to work with what I have. Please help a noob out!! Many thanks

Amp v1: Stereo Bluetooth Power Amplifier Board PEMENOL 12V 24V 30W 40W Mini Amp Receiver
https://www.ebay.com/itm/194047439379

Amp v2: XY-P15W Stereo Bluetooth Power Digital Amplifier Board 12V/24V 10W/15W/20W USA
https://www.ebay.com/itm/324232175498

Transducer puck: https://www.parts-express.com/Dayton-Au ... ke-300-386
Attachments
Back of XY-P15W mini-amp
Back of XY-P15W mini-amp
4.jpg (728.21 KiB) Viewed 176 times
XY-P15W mini-amp
XY-P15W mini-amp
3.jpg (873.15 KiB) Viewed 176 times
30W version of same amp
30W version of same amp
1.jpg (869.2 KiB) Viewed 176 times

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adafruit_support_mike
 
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Re: Which LiIon battery pack will power my project? HELP PLS

Post by adafruit_support_mike »

We don’t know any of those boards, so I can’t say anything specific about them. I can offer a couple of general points though:

First, it looks like those are 12V boards, so look for 12V battery packs. If you want LiPo batteries, buy an assembled 12V pack instead of trying to build one from individual cells. LiPos are much less forgiving than alkaline cells, and mismatched cells can catch fire. The energy density of lithium polymer is a bit lower than gunpowder, and a failed cell can cook off about the same way as a loose pile of black powder.

One good source of multi-cell LiPo batteries is power packs for rechargeable drills. Places like Harbor Freight often have inexpensive packs on sale.

Another good option are Sealed Lead-Acid (SLA) batteries. Those are popular for thing like remote solar stations and game cameras, and come in 12V packages about the size of a soup can.


Second, the size of your battery will limit the amount of runtime you get from the speakers.. that’s the central tradeoff of all battery powered design. You can use any size 12V battery you want, but choosing a really small one will be like using a 500ml soda bottle as the fuel tank for a semi tractor. Technically it will work, just not for long.

Battery storage capacity is measured in milliamp-hours, which makes it easy to calculate how long a discharge cycle will last. A 2000mAh battery can put out 2000mA (2A) for 1 hour, 1A for 2 hours, 500mA for 4 hours, etc.

LiPos measure their maximum discharge rate using a value called C, which is the amount of current necessart to drain the battery in 1 hour. For a 2000mAh battery, C=2A, and for 100mAh battery C=100mA. A 2000mAh cell rated for 0.5C output doesn’t want to put out more than 1A, meaning its lifespan with a 1C load would be 2 hours. A 100mAh battery rated for 40C would be able to deliver 4A for about 1-1/2 minutes (mini quadcopter batteries, for instance).

A small battery’s C value will probably be lower than a large one’s, so you’d have to look for a higher multiple of C for its discharge rating to get the same amount of current.. 0.5C for a 2000mAh battery equals 5C for a 200mAh battery.

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