I have constructed a rechargeable battery-powered guitar amp using the following:
1. Anker Powercore 10000 powerbank,with a SINGLE usb output of 5 V / 2.4 A
2. A usb cable that steps up the output to 9v
3. A 'Spamp' 9v Jfet amplifier
4. A 4" 4ohm speaker
Unfortunately the Anker Powercore switches off after ~1m30s because the power draw is too low and it thinks it's not needed. Any ideas what the best work around might be for this? These are my ideas...
- A male-to-2 female usb splitter: one output feeding the 9v step-up cable and amp; the other feeding a dummy load - eg a small LED lamp - to convince the powerbank to stay on.
- patching in some sort of resistor either between the powerbank and the step-up usb cable or between the 9v supply and the amp.
Any ideas?
1. Anker Powercore 10000 powerbank,with a SINGLE usb output of 5 V / 2.4 A
2. A usb cable that steps up the output to 9v
3. A 'Spamp' 9v Jfet amplifier
4. A 4" 4ohm speaker
Unfortunately the Anker Powercore switches off after ~1m30s because the power draw is too low and it thinks it's not needed. Any ideas what the best work around might be for this? These are my ideas...
- A male-to-2 female usb splitter: one output feeding the 9v step-up cable and amp; the other feeding a dummy load - eg a small LED lamp - to convince the powerbank to stay on.
- patching in some sort of resistor either between the powerbank and the step-up usb cable or between the 9v supply and the amp.
Any ideas?
If you are using a step-up converter anyway, why not just use a single cell, LiPo or LiFePO4 - you'd loose the convenience of built-in charging circuit though.
Some circuit like this might serve the purpose (disclaimer haven't used it myself, I'd suggest substituting a CMOS 7555 timer and adding decoupling): Current Pulsing Keeps Power Bank Active - Instructables
Some circuit like this might serve the purpose (disclaimer haven't used it myself, I'd suggest substituting a CMOS 7555 timer and adding decoupling): Current Pulsing Keeps Power Bank Active - Instructables
This might help you.
PowerCore 10000 for low-power device and avoiding shutdown - General & Product Discussion - Anker Community
They mention 55mA as minimum drain to keepawake but also that there is a "trickle charge" version available.
The ghetto solution would be measuring actual 9V amplifier idle current and adding , say, a LED or something to keep power bank happy.
PowerCore 10000 for low-power device and avoiding shutdown - General & Product Discussion - Anker Community
They mention 55mA as minimum drain to keepawake but also that there is a "trickle charge" version available.
The ghetto solution would be measuring actual 9V amplifier idle current and adding , say, a LED or something to keep power bank happy.