wow!! thats is fantastic info thank you so much, i think i will look into that as a solution, especially if i can get a momentary switch (which is what i am using now on the test hardware)…that is of course assuming i can use my onoffshim in-between to control the power…hmmmm
You want a latching switch, not momentary, for the Powerboost Enable function. Grounded its off, not grounded its on.
righto gotcha, i will go read up on that now!
If you go here, https://learn.adafruit.com/adafruit-powerboost-1000c-load-share-usb-charge-boost/pinouts
It will tell you what all those contacts are for and do.
ok, I did a little more research this weekend. I have been looking at UPS type solutions and I wondered if a UPS device would be useful? I saw the PICO ups devices, and I would need to add the 4000mAh battery. This works out more expensive that a powerbank, but would have the correct OUTPUT i need and it would fit in my case. What I dont know is if it would work along side my onoffshim - which calls the clean shutdown script when the button is pressed…
actually…i think I just found my own answer. Looks like the UPS solution wont work exactly how i want because you cant cut power completely - so for example USB ports will stay active etc…
oh well, back to the drawing board…
Keep in mind that the MAH rating of the battery is basically its endurance. It’s how many ma it can deliver per hour.
To calculate what battery you need, you take your current consumption and multiply it by how long you want your device to run.
As a simple example, lets assume your Powerboost is outputting 1A, and you want at least two hours of use. 1A is 1000ma so that 1000 x 2 is 2000 MAH. Its actually more than that as you have to account for the 3.2V to 5V conversion. If I post that math it may just confuse things. What you would do is get a 2500 or 3000 MAH battery to be sure you could get at least 2 hours run time.
To see the actual current rating of the battery, the max it can supply, you have to read its specs.
I hope I’m not just confusing things more, just wanted to point out that the MAH rating of the battery may not be what you think it is? And you might want to read up on it for a better explanation than what I posted.
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No no this is really helpful stuff and I am following you. The most time I want is around 2 hours. It’s just a handheld retro gaming console, I don’t really game for hours on end so a few hours is enough…
I’ve been told a UPS type device will work, but I’ve just purchased a mini power bank which is 4000mAh but has 3 amp output…if that doesn’t work I’ll go down the ups route
Battery “packs” will give you more current than a single cell. I have a 6600 MAH battery that is three 2200 MAH batteries all wired in parallel. It can supply 3 times the current 1 2200 cell can deliver.
https://www.adafruit.com/product/353 Its what I’m going to use to feed my MP2636.
I have room for it so why not. I bought it more for how much current it supply to the load than run time. I should get both though. I’m at about the same run time, about 2 hours is the max I run it on battery. Unless we get a power failure or something. When its home its plugged in and running on a power supply.
The Powerboost 1000c and the MP2636 are essentially an UPS. With a power supply plugged in the battery is kept charged and the Pi is driver from the up converter. Unplug the power supply and the Pi is still being driven from the up converter. It shouldn’t know the difference. And will keep running until the battery runs down. If the power supply goes back on the battery gets recharged and the Pi is still powered. Again, it doesn’t know the difference. Its getting the same 5V source the whole time.
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