Pi USB Batter UPS Setups

Pimoroni and

sell Pi UPSes but, after you add a battery, they may be more expensive than you're expecting.

But, there's always DIY:

Using an in-line 6 or 12 v SLA (Sealed Lead-Acid battery) together with an off-the-shelf battery charger plus something that outputs constant 5v when driven by the battery is probably the easiest DIY approach.

Notes:

1) Size the SLA to match your measured load and the length of time the system must run if there's a mains outage.

2) The SLA charger must be able to output more power than the RPi plus connected devices needs or the battery will slowly drain.

3) The SLA charger should be a 2 or 3 stage unit that goes into float mode when the SLA is full and can go back to charge mode as the RPi pulls the battery down below its float level. Not all can go back into float mode, so ask the vendor specifically about that (in writing?).

4) This is probably not much cheaper than buying one from the two suppliers mentioned above: if you want something with more than toy capacity its going to cost more than the RPi by the time you add sensible sized batteries.

5) An SLA of a given capacity is cheaper than an equivalent rechargeable lithium battery and MUCH less likely to catch file than a Li Ion battery.

--
martin@   | Martin Gregorie 
gregorie. | Essex, UK 
org       |

Can't resist asking what you're doing. In most cases a few minutes outage isn't a big deal, just wait for the Pi to reboot. I've depowered mine many times with no ill effect, except maybe a prolonged fsck on restart.

Martin's answer seems to be as close to "no building" as is practical.

You could use something like Amazon's Jelly Comb car charger with a regular 12 volt battery and a separate charger. You'd still have to buy cables, wire the USB charger to the battery and hook up the battery charger. By the time you're all in I'd expect the cost to exceed $100. This approach avoids custom USB cables but certainly isn't plug and pray.

hth,

bob prohaska

========================================

Rick,

If the capacity is sufficient, I can confirm that this device charges and supplies power at the same time:

Perhaps the same in the US?

--
Cheers, 
David 
Web: http://www.satsignal.eu

A car USB charger is quite a good option for the "something", easily available and cheap - either open up the case and wire it in, fix wires to the plug or even get a socket for it.

--
Steve O'Hara-Smith                          |   Directable Mirror Arrays 
C:>WIN                                      | A better way to focus the sun 
The computer obeys and wins.                |    licences available see 
You lose and Bill collects.                 |    http://www.sohara.org/

I'd go for opening the case and wiring it in every time.

Put it in a small, preferably metal, box from Maplins (or your local electronic parts retailer) looks neat. Some of these have LEDs, letting you mount it by gluing the LED into a hole in the box lid, or just hold it down with a Pritt adhesive foam pad or two.

The 'cigar lighter' sockets are far too prone to act as a randomly triggered USB-charger launcher, IME anyway. Strapping the charger into the socket with insulation or duct tape just looks disgusting.

--
martin@   | Martin Gregorie 
gregorie. | Essex, UK 
org       |

Add a 120V relay to switch the Pi's power from its regular PSU to the USB power pack, and a capacitor across the Pi's 5v to sustain it during switching. Equally applicable to any other source of backup power such as a 6V alarm battery on a trickle charger. Of course you could get the Pi to manage its own sensing/switching, and indeed charging, but a relay is simple and self-contained.

Rick, they seem to have ignored your comment it has to be plug and play.

.

Not necessarily. Readers here are no elderly houswives. Cutting off two plugs and soldering the two cables is no less plug and play than securing a plug with tape. "Plug and play" implies it's allowed to have to connect up ("plug") several components. Time consuming modification, setting up and calibration would be another thing.

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Hello Martin!

26 Jun 17 21:22, you wrote to me: MG> Pimoroni and sell Pi UPSes but, after you add a MG> battery, they may be more expensive than you're expecting.

Thanks, but, NOT *US* based distribution.I am just not fiddling with outside US shipping delays, or possibly never getting here... Second, it hooks into the GPIO pins, which it potentially intereferes with certain setups, I am one of the few and I guess only who ever used the THE EXCELLENT Wolfson Audio board , it truly is a GEM.. Too bad Cirrus fubar'd it.I guess its dead as all the source are OOS and no on wants to discuss it at Newark/14 etc.... URRGGGHH.

MG> But, there's always DIY:

Lastly, I don't really have time for that..

I need something I can plug AC adaptor into charge port, put plug into Pi, forget about it.

I have about 30 projects in my lab in progress right now for various things...

Using AC UPS's is OVERKILL for this IMO, and right now my current AC UPS are maxed on either power or outlets right now. Even adding in the Pi's charger would trigger shutdown before the generator started... I've actually had to shed some things right now that are not critical.

Rick

... Ding Dong the Witch is DEAD! I Made America Great Again! President Trump!

Hello bob!

27 Jun 17 03:00, you wrote to me: bp> Can't resist asking what you're doing. In most cases a few minutes bp> outage isn't a big deal, just wait for the Pi to reboot. I've bp> depowered mine many times with no ill effect, except maybe a prolonged bp> fsck on restart.

I live in an area prone to power issues during storms, that may be extended...as well as the stray idiot with car and pole. I've already had to run for about 10 hours due to idiot verus pole.... amazingly some how the fiber was not cut for the ISP's and their power supplies for the line gear were far away enough to keep power... No they both suck in that they drudge out the idiots with generators on trucks if it goes too long... but till then you are SOL.

Contiuning my life outside of those situations is critical. I am to the point I am looking to have a VSAT for hot standby on internet.

Since the ding dongs here can't get the concept to bury stuff, and the paths for the various power, and two ISP's all runs the same poles.

Then there is the stray power glitches which the Pi's just don't like...

bp> Martin's answer seems to be as close to "no building" as is practical.

Afraid, I just don't have the time to spare for that... other projects in the work, I need to be able to order a battery, plug in charger/power, plug in Pi, move on in life.

Rick

... Ding Dong the Witch is DEAD! I Made America Great Again! President Trump!

Hello Rob!

27 Jun 17 13:40, you wrote to me:

RM> Add a 120V relay to switch the Pi's power from its regular PSU to the RM> USB power pack, and a capacitor across the Pi's 5v to sustain it

Thanks, but I am not in a situation for any DIY on this.

Rick

... Ding Dong the Witch is DEAD! I Made America Great Again! President Trump!

Hello David!

27 Jun 17 09:02, you wrote to me: DT> If the capacity is sufficient, I can confirm that this device charges DT> and supplies power at the same time:

DT>

That would be great, if you knew who the OEM was and and there was a source in the US... Shipping batteries is costly, and now a days an issue since they can't fly mostly.

And that is the key, finding the ones that power and charge... sort of like finding those Oriental HDMI splitters that some how forget to eneable the HDCP on the outputs. :)

Even the Adafruit one which would be perfect, has a glitch:

"Also, when you start and stop charging the pack, it will flicker the output, this can cause a 'power sensitive' device like the Pi or an iPhone to reset on the power supply"

Its one of the reasons you can salvaget the AC UPS minus the batteroes frm Ebay, and the get extorted on getting them locally, on averarge they run $35/EACH for 12VDC 8AH commonly used in UPS ...unless of course you can purhcase a bunch in bulk. Then sometimes it can work out..

Rick

... Ding Dong the Witch is DEAD! I Made America Great Again! President Trump!

And from the OP: "I don't really have time to build something."

That was just my point, which you seem to have missed. For the right people with the right equipment at hand, some things are less, not more time consuming to do than the "easy" ways aimed at the masses. Trying to make a dodgy "simple and straightforward" connection reliable is one of the latter.

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You're not reading the OP's comments elsewhere in this thread are you?

Rick Christian wrote on 6/27/2017 9:51 PM:

I have a rather old UPS for keeping my Internet modem and router running when the power goes down. When I have a Pi running, I just add it to the UPS. The real killer is the monitor though, as it uses more than the 2 or 3 watts the other devices use. Well, actually, the real killer is my WISP. If I lose power for 1 minute, they seem to lose power for hours or their equipment is whacked and has to be replaced again taking hours. So I have better up time ratings than they do.

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Rick C

I used a dollar store USB power-bank as a pi UPS. Like you say it doesn't have pass-through while it's charging so, I added pass-through by wiring the regular PSU and the power-bank output in parallel but with a Schottky diode in series with +ve of the power-bank output A separate PSU was used to charge the powerbank, I didn't investigate if one PSU could do both tasks. The project consisted of a Pi Zero wifi dongle and 1602 LCD display. Failover and power restoration was seamless and it ran for about an hour on the single 18650 in the powerbank.

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Graham. 
%Profound_observation%

Graham. wrote on 6/28/2017 8:08 PM:

Seems amazingly simple. So the makers of the power bank could make their device into a rPi UPS by simply adding a couple of Schottkey diodes. I can't imagine a single PSU wouldn't work unless there are separate grounds on input and output for some reason.

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Rick C

On 28/06/2017 02:51, Rick Christian wrote: []> That would be great, if you knew who the OEM was and and there was a source in

=========================

Rick,

This one (or similar) on Amazon US claims to be a UPS, and just needs 6

18650 batteries.

but also mentions a 1-second gap. Sigh!

--
Cheers, 
David 
Web: http://www.satsignal.eu