Portable battery pack cuts out when using the 12 volt usb bo

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DaBo
 
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Portable battery pack cuts out when using the 12 volt usb bo

Post by DaBo »

I recently received a Digipower JS-PB1010 portable charger power bank as a birthday gift.

http://www.digipowersolutions.com/produ ... ts_id=1022

I am trying to use it to power a portable turntable (Numark PT01 Scratch). The turntable requires 12 VDC and 500mA. In order to obtain the 12 volts required by the turntable, I am using the 12 volt usb booster cable.

https://www.adafruit.com/product/2778


When I plug the booster cable into the JS-PB1010 the power bank "wakes up" and the green LED starts flashing. I also measure 12 vdc at the output of the booster cable. When I plug the barrel jack end of the booster cable into the turntable and switch it on, the JS-PB1010 cuts out. The LED stops flashing and no output power can be measured. I suspect that some sort of protection circuit within the JS-PB1010 gets triggered.


I can confirm that my setup works fine when using a standard 120 VAC usb phone charger instead of the JS-PB1010. Also, the power bank works fine when simply charging my phone or tablet. Trying the turntable in either output 1 or 2 of the power bank makes no difference.


Can I do anything to make the JS-PB1010 work the way I want it to in this setup? Is there a chance that the power bank is malfunctioning?

Dan

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adafruit_support_mike
 
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Re: Portable battery pack cuts out when using the 12 volt us

Post by adafruit_support_mike »

It looks like you might be running into the limits of the power brick's output protection circuit.

There's a table of efficiency values on the product page for the booster cable, and according to that, getting 500mA @ 12v of output requires 1500mA @ 5v of input. The booster cable works by converting the extra current into higher voltage.

If your power brick has a 1A output limit, trying to draw 1500mA would make it shut down.

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DaBo
 
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Re: Portable battery pack cuts out when using the 12 volt us

Post by DaBo »

Hi Mike, thanks for your response.

The power brick has 2 outputs. Output 1 limited to 1A, Output 2 limited to 2.1A or 10.5W

12 vdc pulling 500mA should be 6W, within output 2's spec. And, like you pointed out, getting 500mA at 12 vdc requires 1.5A input on the 5 vdc usb end. Output 2 on the power brick should be able to supply 2.1A.

Also, for added troubleshooting purposes, in my setup, the power brick cuts out immediately as I turn on the power switch of the turntable. There should be very little current draw at that time as the platter is not being called to spin, no volume output through the built in speaker, ect, simply "livening up" the turntable.

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adafruit_support_mike
 
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Re: Portable battery pack cuts out when using the 12 volt us

Post by adafruit_support_mike »

I'm afraid I'm out of ideas. I don't know anything about the power brick or turntable that are involved in the problem, and it sounds like the Booster Cable works im general.

Without more detailed information, like oscilloscope traces of the input and output power lines in the cable, I'm afraid the best I have is a guess that the turntable wants a lot of current right at the start.

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