Does anyone know of a USB battery bank that does not shut off when the current draw is too low?
I have a project that requires 5V and right now I am power it via my computer but I want to make it portable. I know I have lots of options (boost converters with batteries, lipo batteries with switcher to 5V, etc.) but since I already have a cut USB cable my hope was to use a simple usb battery bank but the problem is it shuts off after like 30 seconds since my load is too small. I could from reading online put a load resistor (of appropriate power rating) but that would burn through the usb bank like candy and would only last a day at most. My projects dictates that I want to be able to set my unit outside for several days so a load resistor that kills the battery in a day is not a viable solution. So that brings me back to my original question of does anyone know of a particular brand that doesn't have the protection circuitry? And if not then does anyone have any other advice or idea, all help is welcome!
I would just use a pack of NiMH or even lead acid rechargeable batteries. They aren't very finicky about how they are charged, in contrast to Li-based cells. In all cases, you need a low voltage cutoff of some sort.
Ok, I may have to look into that. I wasn't too worried about the charging aspect as the USB battery banks are very easy to charge. It was mostly the discharging aspect.
I may have to just get a large capacity SLA and a 5V regulator and throw something like that together.
wes000000:
Does anyone know of a USB battery bank that does not shut off when the current draw is too low?
...
So that brings me back to my original question of does anyone know of a particular brand that doesn't have the protection circuitry?
Unfortunately, the other thread didn't answer the question either!
It in fact muddies the waters further, implying that there exist "always on" USB power banks, but not citing any such devices (and "always on" is too generic to get useful results, in my brief googling just now). The OP is asking for specific suggestions, and looking at some of the other things he's considering, he's pretty desperate.
The other question, probably even more useful, is whether there is a generic way to lobotomize a power bank such that it doesn't do that anymore. How do they detect the current? Probably with a shunt, I mean, how else...? That suggests that one should be able to find that shunt, cut the sense trace, and then use a voltage divider to get an appropriate voltage on the sense pin so it thinks it's under an appropriate voltage.
OK, maybe the thread itself wasn't helpful, I was specifically pointing to my previous answer - to avoid having to re-write or cut-and-paste it - explaining why they are simply not going to be "always on".
This thread of Nick Gammon has me thinking about capacitors, specifically supercaps although the one in his example is a normal one I think.
A 1F supercap like this is less than 20mm diameter.
Could that play a part in your solution?
Boy, things have changed, the line printers we worked on we're 1F in a 36"x36"x36" package, they were 36 volts however. Some melted screw drivers on it.
I don't know when it was released, but now googling for ' "always on" USB battery ' led me to the Voltaic Systems V15 and V44 -
What is Always On Mode?
Always On means that the output of the battery or power bank does not shut off after a set amount of time. It stays on.
When shipped, most of our batteries are in Auto Off Mode.
[...]
However, there are times when you want to prevent the battery or power bank from shutting off when there is little to no power draw. With an Always On battery, you could power GPS tracking devices, perform time-lapse photography with GoPro and other cameras, or run Arduinos and Raspberry Pis. Essentially, if you want to power a device over several days, weeks, or months without human intervention, then the Always-On Mode is a good fit.
As of posting, the V15 177 is 35 dollars on Amazon
I haven't tried it out, but it sounds promising....
I also see that several Amazon reviewers of various RAVPower power bank chargers have mentioned using those for Arduino and/or RPi.
Old thread I know, but I finally found a power pack that doesn't turn off automatically. All the ones made by TalentCell. This one for example:
I should mention that I've only tested the one in that link, but I believe they all stay on permanently. Very refereshing after fighting auto power off for so long.
