Power Bank (backup phone charger) as battery - experiences?

Hi,

I’ve been looking for the best solution to power my spark robot which uses 3 servos, and got seduced by these portable “power banks” which are sold as backup power for cell phones. The one I bought offered 10000 mAh, 2.1A output, overcharging protection and protection from draining the battery, charging from any 5v usb connection, and it’s possible to leave the spark running while it is charging.

All this seemed great but when I start using the servos the power cuts and the spark core restarts.

I’m guessing that this has to do with it’s curcuits wanting a steady discharge and not sudden spikes in power demand which my servos are causing.

Does anyone here have experiences with using these kinds of batteries, also with servos or similar power demands?

It did seem a bit too good to be true, but if it would work with one of these it would be ideal for my project.

I always use a battery bank with the core and the servo might be drawing too much current for sure.

How are you powering the servo?

@kennethlimcp I’m powering the servos directly from the battery. Do you have any experiences with drawing much or sudden current from your battery? If so, which kind is it?

I use the Neopixel with the core and though it works fine, performing ADC conversion gives funny results due to a fluctuating powe4 supply.

Can you try to add a capacitor of… 100-200uF and test again? :slight_smile:

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@kennethlimcp Thanks for the tip, I will try to add a capacitor.

I was just reading through the reviews now of the battery I got and came across this:
When a(n) overcurrent/short circuit/overcharge/overdischarge happens,
PB10000C will cut off its energy output automatically and enter
Protection Mode to prevent damage to itself and your device(s).

I guess servos can cause “overcurrent”…

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Servos can draw a fair bit of current but I’m guessing the instantaneous spike might be casuing the power bank to kick in protection :smile:

The capacitor should help :slight_smile:

@kennethlimcp thanks, i’ll try this tomorrow, european time. Which brand/type battery are you using?

Just some really random portable battery bank. Nothing special :slight_smile:

Thank you Kenneth - a 200 uF capacitor and it all just works :smiley:

I put a 1000 uF there in the end just to be sure.

This makes for a great discovery to me since these power banks come cheap with great features for charging etc :smiley:

I’ll report back when I’ve had things running for a while.

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Hey Kenneth! :smile: Just want to ask a simple question. How do you keep the power bank on when the core goes into deep sleep for about 30 minutes or 1 hour. I notice that my power bank will turn off after like 30 seconds or a minute and the core also turns off with it.

Guess there’s no solution for now and I experienced this issue recently as well due to the battery bank thinking that no device is using power. Haha!

Aww hahaha guess we have no choice then. Was thinking of using a 10400 xiaomi portable charger. It’s like SGD14.

This is Jeff from Voltaic Systems. We have created an override function on two of our batteries for these types of applications when a device like the Electron or an Arduino goes into sleep mode. Our V15 and V44 batteries can be switched into Always On mode and don’t ever shut off. A high current spike can affect that setting, so the V44 is preferred if you are going over 1A. See https://www.voltaicsystems.com/always-on

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Has anyone tried monitoring the battery status and doing a System.reset() to reawaken the power bank when the normal battery is nearing depletion?

Tried this but doesn’t seem to work, at least not for my power bank. Neither calling System.reset() or pressing the reset button reawakens the battery. Unplugging and plugging back in or pressing one of the buttons on the power bank are only things that reawaken it.