From: Richard Prosser <rhprosser@gmail.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Fri, 14 Feb 2020 21:29:00 -0800
Subject: Re: [EE] large USB power banks
Thread-Topic: [EE] large USB power banks
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One trap of these is that they are usually (always?) advertised with the
cell capacity and 5V output.
So a 5V, 3000mAH pack will not actually do this. They have 3000mAhr (or
whatever) cells meaning about 10Whr capacity. This is only 2AHr at 5V -
less allowing for conversion efficiency.
The better known the manufacturer, the better chance of getting consistent
results. If possible, look for units using cells from one of the major
manufacturers. (Samsung, Panasonic etc). Even so, cell capacity is
generally stated as better than you will get - the advertised capacity is
under 'ideal' conditions. If you can, find out the cell type, a datasheet
should then give you a better idea.
RP


On Sat, 15 Feb 2020 at 08:52, Denny Esterline <desterline@gmail.com> wrote:

> I've had maybe a dozen of them over the years, can't say I've had good
> enough or bad enough experiences to make useful recommendations.
>
> Recently, I've been using adapters for name brand powertool batteries. Th=
is
> one got me started:
> https://www.amazon.com/Milwaukee-49-24-2371-M18-Power-Source/dp/B07WH43HX=
L
> Uses the standard M18 Milwaukee batteries and presents a USB port. Many
> options available, but Milwaukee has a 12.0 AH pack in the M18 line.
>
> Lots of other brands doing something similar, plus plenty of options for =
3D
> printed holder and a buck converter to roll your own.
>
> I believe I've also recently seen some brand that had the USB plug right =
on
> their batteries (Ryobi? B&D?)
>
> -Denny
>
>
>
> On Fri, Feb 14, 2020 at 10:03 AM David Van Horn <
> david.vanhorn@backcountryaccess.com> wrote:
>
> > I'm looking for a couple of large USB power banks, and hoping to get so=
me
> > recommendations.
> > I see mAh ratings that are starting to sound like stun gun voltages,
> which
> > is why I'm not just grabbing the biggest number on Amazon
> >
> > The application is astrophotography, running a bunch of peripherals
> > including a lens heater.
> >
> >
> > --
> > David VanHorn
> > Lead Hardware Engineer
> >
> > Backcountry Access, Inc.
> > 2820 Wilderness Pl, Unit H
> > Boulder, CO  80301 USA
> > phone: 303-417-1345  x110
> > email: david.vanhorn@backcountryaccess.com<mailto:
> > david.vanhorn@backcountryaccess.com>
> >
> > --
> > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> > View/change your membership options at
> > http://mailman.mit.edu/mailman/listinfo/piclist
> >
> --
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