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solar3000
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Re: UPS for Pi?

Thu Mar 26, 2015 2:12 pm

henryhanselscott wrote:My solution uses 2 100 farad supercaps in series charged by a 5 volt supply through a diode and a 1 ohm power resistor. The supercaps actually charge to about 4.4 volts because of the diode drop. The supercaps charge feeds a DC boost convertor.

Boost convertor:
http://www.ebay.com/itm/3-pcs-XL6009-St ... 43c840c37f

supercaps:
http://www.ebay.com/itm/2pcs-New-Origin ... 3cedeb76ad

This combination has made the power to my Rpi brownout proof and is very stable. I am actually using a pic on the setup to signal the pi to start a shutdown procedure in the event that power goes out for more than 10 seconds, I know that that is beyond the scope of what you want.
I'm interested in what the endpoint of all those discussions is.
This solution is most certainly not that.

Henry

those supercaps seem a bit tiny to be 100F even at 2.7v. Not sure I would trust those guys.
You know, you can put three of them together to get a max of 8v. Then charge it to perhaps 5.5 volts.
I'm not sure if you already know that 2.7v means maximum. you can safely use it at 0.5v or 1v or 2v but not above.
Antikythera

Joe Schmoe
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Re: UPS for Pi?

Thu Mar 26, 2015 2:13 pm

So far, the best thing I've seen is the "Limefuel" at $26.
And some folks need to stop being fanboys and see the forest behind the trees.

(One of the best lines I've seen on this board lately)

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blachanc
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Re: UPS for Pi?

Thu Mar 26, 2015 2:55 pm

Hi Joe,

Not sure if it would meet your requirements, but If you can wait, I just backed the PIJuice this morning.

PIJuice: Portable PI /UPS on kickstarter

Ben

Edited: but it is more expensive ($30-40 USD)
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djole94hns
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Re: UPS for Pi?

Thu Mar 26, 2015 7:02 pm

The cheapest possible solution I've found was using these Chinese-made USB battery packs:

Image

It can send power while being charged at the same time.
It even has LED power indicators, heh ;)

It's not the best, but it works.

Got this one for around 20$ + free shipping from China.
Take a look around aliexpress.com or something of the sort!

rpiswag
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Re: UPS for Pi?

Fri Mar 27, 2015 1:25 am

Go buy a pi juice it is about 20 Euros on kickstarter.
A computer's power can't be just measured Gigahertz. It is the same thing with us humans.

Joe Schmoe
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Re: UPS for Pi?

Mon Mar 30, 2015 2:37 pm

Joe Schmoe wrote:So far, the best thing I've seen is the "Limefuel" at $26.
Unfortunately, just got my LimeFuel - looks nice and seemed like it would work, but, alas, no-go.

Lots of things to like about it, but unfortunately, when I detach the power supply (from the input side of the LimeFuel), to simulate a power drop, the Pi reboots. Not only that, but when I re-attach the input side of the LimeFuel, the Pi reboots again. My guess is that both/either of these events are enough to jostle the voltage level seen by the Pi just enough to cause it to go non-linear.

So, the LimeFuel that I bought is going to get re-purposed...

P.S. It occurs to me that it might be possible to fix this problem by putting a few (say, 3) supercaps (in series) across the output side of the LimeFuel (i.e., between the LimeFuel and the Pi). That might be enough to stabilize the voltage in the event of a power drop. What do you think?
And some folks need to stop being fanboys and see the forest behind the trees.

(One of the best lines I've seen on this board lately)

Joe Schmoe
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Re: UPS for Pi?

Mon Mar 30, 2015 2:38 pm

rpiswag wrote:Go buy a pi juice it is about 20 Euros on kickstarter.
BTW, if it is on kickstarter, that means it is still in the vapor state, right?
And some folks need to stop being fanboys and see the forest behind the trees.

(One of the best lines I've seen on this board lately)

KeithSloan
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Re: UPS for Pi?

Mon Mar 30, 2015 3:47 pm

Joe Schmoe wrote:
rpiswag wrote:Go buy a pi juice it is about 20 Euros on kickstarter.
BTW, if it is on kickstarter, that means it is still in the vapor state, right?
Its fully funded with stretch goals.
They have working prototypes so its a bit unfair to call them vapour ware

See https://www.kickstarter.com/projects/18 ... every-rasp

henryhanselscott
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Re: UPS for Pi?

Mon Mar 30, 2015 4:31 pm

Supercaps might not be the right solution, but normal electrolytic caps in the range of 1000uf might be worth a shot just to keep the power stable for a few milliseconds of transition.

Henry

Joe Schmoe
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Re: UPS for Pi?

Mon Mar 30, 2015 4:40 pm

henryhanselscott wrote:Supercaps might not be the right solution, but normal electrolytic caps in the range of 1000uf might be worth a shot just to keep the power stable for a few milliseconds of transition.

Henry
Yeah, I could try that. Thanks for the suggestion.

Just out of curiosity, why not supercaps? Would that cause a problem?
And some folks need to stop being fanboys and see the forest behind the trees.

(One of the best lines I've seen on this board lately)

henryhanselscott
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Re: UPS for Pi?

Mon Mar 30, 2015 4:59 pm

Technically they could work, but would not be the preferred solution to your goal. You need something that can carry the pi and stabilize the voltage for a few milliseconds. You could string up a bank of supercaps, but they are better suited for supplying large current loads over time than short burst of power like an electrolytic type. Electrolytics will be less cost and you can buy them rated for the voltage, that will negate the need to use them in series.

Henry

Joe Schmoe
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Re: UPS for Pi?

Mon Mar 30, 2015 5:13 pm

Good points. Thanks.
And some folks need to stop being fanboys and see the forest behind the trees.

(One of the best lines I've seen on this board lately)

henryhanselscott
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Re: UPS for Pi?

Mon Mar 30, 2015 5:30 pm

Attached is the solution that I am using. I am NOT an EE, just an experimenter. So if anyone uses the information contained USE AT YOUR OWN RISK. I share it with the intent of education and no guarantee exist that says it is the correct way to do this. This is and has been working on my Rpi2 for several weeks and it works perfectly to ride over brownouts and power outages of less than 10 seconds. When power is interrupted for more than 10 seconds the PIC signals the Rpi to begin the shutdown procedure. The PIC monitors the supercap bank charge status through the analog channel and when the charge status is ample (on startup) then and only then it supplies power to the Rpi. The cap bank has sufficient reserves to fully boot up and shutdown the pi.

The circuit has been edited to fit within the file size limit so I think that what is left is correctly shows the charging circuit. I had to take out the bulk of the diagram to shrink the file size so I may have removed some of the charging parts. You should be able to study the diagram and get the idea of what and how it works.
Attachments
Rpi2 Power supply - Schematic.zip
(49.11 KiB) Downloaded 257 times

Joe Schmoe
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Re: UPS for Pi?

Mon Mar 30, 2015 5:46 pm

Keep in mind that principle among OP's requirements was that this *not* be a DIY.

OP needs something that can just be bought off the shelf and work.

Which means that my idea of throwing a capacitor over the output of the LimeFuel might also be a non-starter, but I have hopes that that could be made "almost off the shelf". What I imagine is cutting off the Micro USB end of a standard Pi power cable, putting the cap in there and then connecting to the pi via GPIO.

Or maybe just splicing the cap into the cable itself...
And some folks need to stop being fanboys and see the forest behind the trees.

(One of the best lines I've seen on this board lately)

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davidcoton
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Re: UPS for Pi?

Mon Mar 30, 2015 10:31 pm

Joe Schmoe wrote:
Or maybe just splicing the cap into the cable itself...
Or it might work (and be easier to implement) to leave the microUSB well alone and connect the electrolytic to the 5V and Gnd pins of the GPIO header. I haven't tried it.
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ame
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Re: UPS for Pi?

Mon Mar 30, 2015 11:32 pm

Joe Schmoe wrote:
Joe Schmoe wrote:So far, the best thing I've seen is the "Limefuel" at $26.
Unfortunately, just got my LimeFuel - looks nice and seemed like it would work, but, alas, no-go.

Lots of things to like about it, but unfortunately, when I detach the power supply (from the input side of the LimeFuel), to simulate a power drop, the Pi reboots. Not only that, but when I re-attach the input side of the LimeFuel, the Pi reboots again. My guess is that both/either of these events are enough to jostle the voltage level seen by the Pi just enough to cause it to go non-linear.

So, the LimeFuel that I bought is going to get re-purposed...

P.S. It occurs to me that it might be possible to fix this problem by putting a few (say, 3) supercaps (in series) across the output side of the LimeFuel (i.e., between the LimeFuel and the Pi). That might be enough to stabilize the voltage in the event of a power drop. What do you think?
Interestingly, this device:
http://www.adafruit.com/products/1565

which is $24.95 will also run its output whilst charging. But the description says "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". A big cap on the output might get around this.

I expect all of these devices (including the LimeFuel) are based on the same reference design, probably the same control chip, built by the thousands all in slightly differently shaped housings, colours and materials. You'll just have to scour reviews and odd blogs to find the one that works in the way you want.

Steve Drain
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Re: UPS for Pi?

Tue Mar 31, 2015 9:04 am

Here is one battery pack I know works as you require: http://uk.rs-online.com/web/p/power-ban ... 451834|alt. Unfortunately it is £32, but I bought mine when they were on offer at half price. Perhaps that will happen again. There is a smaller and cheaper one in the same series which I expect has the same circuit, but I have not used it.

With my Raspberry Pip attached to a Motorola Lapdock I use a pair of 2.7V 1F supercaps in series and connected in parallel with the 5V on the board. This provides sufficient current when the Lapdock lid is closed to cover the momentary loss of power. There are other supercaps with different voltage ratings that would also do the job, but I think you need at least 1F.

I think it is worth warning that there are two types of supercap. The disc type have a high internal resistance and only discharge at low rates, which makes them unsuitable. The cylinder type usually have a low internal resistance, but that does mean they can discharge extremely high currents if short-circuited. This can be dangerous. ;-(

Killertechno
Posts: 174
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Re: UPS for Pi?

Tue Apr 21, 2015 3:37 pm

I'm waiting for a LTC4089-1, to be used with a 1000 mAh li-ion battery.
So I can use AC wall adapter to power Pi, then if it fails I get power from battery.
Regulator outputs could be used to send to Pi an "emergency shutdown" signal.
If anyone interested I can share results when done.

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electronicsguy
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Re: UPS for Pi?

Sun Apr 10, 2016 6:21 am

I know this is an old thread, but as others have pointed out, a battery pack is the simplest solution for a RPi "UPS". The battery pack I've been using are the ones from Hootoo. TM-01 and TM-05 both work great. They maintain the voltage even when the powewr is disconnected so in effect, acting as a UPS.
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darkbibble
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Re: UPS for Pi?

Sun Apr 10, 2016 11:57 am

the product you are looking for is this;
http://www.modmypi.com/raspberry-pi/bre ... &limit=100
plus if you buy the upgrade battery you will get 8hour runtime without mains supply
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A; Whats a Linux problem

rbray89
Posts: 1
Joined: Thu May 18, 2017 3:00 am

Re: UPS for Pi?

Thu May 18, 2017 3:03 am

Found this, thought people should know: https://www.amazon.com/uxcell-Adapter-3 ... rds=5v+ups

cecodere
Posts: 1
Joined: Sun Jun 04, 2017 11:24 am

Re: UPS for Pi?

Sun Jun 04, 2017 11:35 am

Greetings,
Even though its not cheap at all, last year I bought the Slimline Solarmonkey adventurer solar battery pack by powertraveller (which can also be charged through USB) for another project, and I decided to try to see if it could be used as a UPS for my raspberry pi model B, since it does permit to charge and discharge at the same time.
  • Charge the Solarmonkey through USB
  • Connect the Solarmonkey to my raspberry pi (through Ethernet, no USB ports used) while the Solarmonkey is still charging.
  • Disconnect the USB power from the Solarmonkey
  • My rpi continued working as expected while connected with VNC to it without any power loss.


I did not do further tests, but this was an unexpected surprise for me :)
One note though, the Solarmonkey is rated at only 2500 mAh, and has a max output rating of 700 mA, so it might not work with all peripherals connected, which from my understanding can draw up to 850 mA of current.

p.s: The version I am talking about:
https://www.amazon.com/Powertraveller-S ... B008AZP0SE

There is a new version at 3500 mAh:
https://www.amazon.com/Powertraveller-S ... B007ZN9B9Q
Last edited by cecodere on Sun Jun 04, 2017 5:45 pm, edited 1 time in total.

W. H. Heydt
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Re: UPS for Pi?

Sun Jun 04, 2017 5:05 pm

cecodere wrote: One note though, the Solarmonkey is rated at only 2500 mAh, and has a max output rating of 700 mA, so it might not work with all peripherals connected, which from my understanding can draw up to 850 mA of current.
Depends on which model of Pi... The Pi2B and Pi3B can supply up to 1200mA to USB devices, plus minor amounts through GPIO. With a 700mA rating, I'd want to restrict it driving a Pi0/Pi0W.

Might be work researching to see if they make units that will supply more current...say on the order of 2A.

percykawas
Posts: 1
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Re: UPS for Pi?

Sun Aug 06, 2017 12:10 am

DISCLOSURE (/ BLATANT promotion...)

I designed the Pi-UpTime UPS board... And I sell that on eBay, Tindie, Amazon, MCM etc. etc.

Please check out www.alchemypower.com for a good UPS solution for a Pi-Zero and for a Pi-3 or a Pi-2. I would appreciate feedback on it.

Thanks.

shpe11
Posts: 1
Joined: Thu Sep 21, 2017 5:33 pm

Re: UPS for Pi?

Thu Sep 21, 2017 6:57 pm

it is possible to hook a standard battery pack (cheap that doesn't give output when charged) in parallel on the charger cable?

so we have the charger cable which go from wall-charger to the pi
take a standard battery pack charger form mobiles and hook the wires on the charger cable, the IN to the wall-charger, the OUT to the pi

so when we got current from wall the battery will charge, and the pi is powered and somehow the current is divised between the two... and when there is no power from wall the battery will charge the pi right?

so you can get a UPS with the golden $5 and some wiring!

right?

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