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blachanc
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PIJuice: Portable PI /UPS on kickstarter

Thu Mar 26, 2015 2:29 pm

PIJuice: Battery/UPS on kickstarter

I am in no way linked to this kickstarter (aside from being a backer),
but I find it a very nice idea at a very nice price bracket.

I was surprised to see so few mentions of that addon on the forums.

PIJuice Kickstarter main page

I saw it mentioned on the main blog, but I have to admit that I follow the forum much more closely than the blog:

Helen Lynn blog about PIjuice on raspberrypi.org

And of course, my main motivations for posting this is to bring more backers & get extra stretch goals unlocked. ;) :oops:

Ben

PS: edited 10 times because I somehow lost my already very limited English skills this morning
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beans
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Re: PIJuice: Portable PI /UPS on kickstarter

Mon Mar 30, 2015 3:32 am

It looks like a great project. I've been looking at making something similar, but it will be so much easier with something pre-made.

I have one concern with the details they are advertising. The run-time figure of 24 hours. I'm going to back it either way as it's still a great idea.

They state the 1400mAh battery will "last up to 24 hrs + in constant use". I wonder how they come up with this figure? By my calculations the only way you could get 24h from that battery is if the Pi draws < 40mA.

battery capacity (Wh) = 3.7V*1.4Ah = 5.18Wh
max average power for 24h operation = 5.18Wh/24h = 0.22W
max average current = 0.22W/5V = 44mA

From what I've seen, the pi (B+) rarely draws less than 200mA (with no accessories). Using this figure and assuming 100% efficiency (probably closer to 80-90%) the 1400mA battery would last just over 5 hours.

I'll back it and put the question directly to the creators. Will be interesting to see where they got the 24 hour figure from!.

KeithSloan
Posts: 321
Joined: Tue Dec 27, 2011 9:09 pm

Re: PIJuice: Portable PI /UPS on kickstarter

Mon Mar 30, 2015 4:38 pm

beans wrote:It looks like a great project. I've been looking at making something similar, but it will be so much easier with something pre-made.

I have one concern with the details they are advertising. The run-time figure of 24 hours. I'm going to back it either way as it's still a great idea.

They state the 1400mAh battery will "last up to 24 hrs + in constant use". I wonder how they come up with this figure? By my calculations the only way you could get 24h from that battery is if the Pi draws < 40mA.

battery capacity (Wh) = 3.7V*1.4Ah = 5.18Wh
max average power for 24h operation = 5.18Wh/24h = 0.22W
max average current = 0.22W/5V = 44mA

From what I've seen, the pi (B+) rarely draws less than 200mA (with no accessories). Using this figure and assuming 100% efficiency (probably closer to 80-90%) the 1400mA battery would last just over 5 hours.

I'll back it and put the question directly to the creators. Will be interesting to see where they got the 24 hour figure from!.
Are you sure it is a 3.7v battery? Given the Pi runs with a 5v supply 7.5v with a regulator makes more sense to me

KeithSloan
Posts: 321
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Re: PIJuice: Portable PI /UPS on kickstarter

Mon Mar 30, 2015 5:15 pm

KeithSloan wrote:
beans wrote:It looks like a great project. I've been looking at making something similar, but it will be so much easier with something pre-made.

I have one concern with the details they are advertising. The run-time figure of 24 hours. I'm going to back it either way as it's still a great idea.

They state the 1400mAh battery will "last up to 24 hrs + in constant use". I wonder how they come up with this figure? By my calculations the only way you could get 24h from that battery is if the Pi draws < 40mA.

battery capacity (Wh) = 3.7V*1.4Ah = 5.18Wh
max average power for 24h operation = 5.18Wh/24h = 0.22W
max average current = 0.22W/5V = 44mA

From what I've seen, the pi (B+) rarely draws less than 200mA (with no accessories). Using this figure and assuming 100% efficiency (probably closer to 80-90%) the 1400mA battery would last just over 5 hours.

I'll back it and put the question directly to the creators. Will be interesting to see where they got the 24 hour figure from!.
Are you sure it is a 3.7v battery? Given the Pi runs with a 5v supply 7.5v with a regulator makes more sense to me
The kickstart page says it is a Motorola BP6X battery which indeed it a 3.7v.
I assume they must use some form of switched power circuitry to get the 5v

beans
Posts: 6
Joined: Mon Mar 30, 2015 3:21 am

Re: PIJuice: Portable PI /UPS on kickstarter

Tue Mar 31, 2015 12:49 am

The creators clarified that the 1400mAh battery will last 6 hours. We will need to upgrade the battery to 5,000 or 10,000mAh for the longer run time. They also updated the main page description to reflect this. This make more sense to me. Laws of physics are no longer being bent.

One of the other comments on the kickstarter page referred to the solar unit. I think they also need to crunch the numbers on this one (and clarify the product description). With the 1400mAh battery it won't run 24/7. I am also skeptical that the 5W solar panel will have enough juice to charge anything larger (while also running the pi).

Even with these little hiccups it's still a great idea/product. I'm happy to have pledged my amount and will probably buy more when they're commercially available.

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blachanc
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Re: PIJuice: Portable PI /UPS on kickstarter

Tue Mar 31, 2015 1:21 pm

5 hours to go and 8000 pounds from the 120000 pounds stretch goal ( Larger battery)

I unfortunately do not believe it will make it :(

Ben
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http://www.raspberrypi.org/forums/viewtopic.php?f=62&t=70191

DirkS
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Re: PIJuice: Portable PI /UPS on kickstarter

Tue Mar 31, 2015 4:41 pm

blachanc wrote:5 hours to go and 8000 pounds from the 120000 pounds stretch goal ( Larger battery)

I unfortunately do not believe it will make it :(
Just another 1.8k with more than 2 hours to go... It may just get there! :D

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blachanc
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Re: PIJuice: Portable PI /UPS on kickstarter

Tue Mar 31, 2015 6:28 pm

DirkS wrote: Just another 1.8k with more than 2 hours to go... It may just get there! :D
With 33 minutes to go, it made it: 122,909 pounds.

I guess you need to deduct a few % for the pledges that will not be recoverable (false pledges).
This could bring the total amount under 120K pounds...



IIRC Alex Ealmes said he lost 5% of the pledges for the HDMI PI kickstarter.


Ben
Autism/Asperger syndrome: what is your score on this quiz?
http://www.raspberrypi.org/forums/viewtopic.php?f=62&t=70191

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blachanc
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Re: PIJuice: Portable PI /UPS on kickstarter

Wed Oct 14, 2015 8:02 pm

Hum,

I am starting to have cold sweats.

I hope it is just a simple communication issue.
You know, theses @#$ computers geek are no got at communication ;) :lol:

Ben
Autism/Asperger syndrome: what is your score on this quiz?
http://www.raspberrypi.org/forums/viewtopic.php?f=62&t=70191

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alexeames
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Re: PIJuice: Portable PI /UPS on kickstarter

Fri Oct 16, 2015 12:02 pm

blachanc wrote:Hum,

I am starting to have cold sweats.

I hope it is just a simple communication issue.
You know, theses @#$ computers geek are no got at communication ;) :lol:

Ben
I think it's a question of trying to do too many things at once. I have no doubt that Aaron will deliver the goods - he's a decent bloke. I think he's found out the hard way (by running several at once) that large, complex KS projects can be 'a bit of a pig' to manage when things go wrong (as they surely do in complex projects). :o
Alex Eames RasPi.TV, RasP.iO

BMS Doug
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Re: PIJuice: Portable PI /UPS on kickstarter

Fri Oct 16, 2015 12:51 pm

alexeames wrote:
I think it's a question of trying to do too many things at once. I have no doubt that Aaron will deliver the goods - he's a decent bloke. I think he's found out the hard way (by running several at once) that large, complex KS projects can be 'a bit of a pig' to manage when things go wrong (as they surely do in complex projects). :o

We've had much the same problem with the PaPiRus (ePaper HAT), running late, very little communication. Aaron has started talking to us again, letting us know what the delays are but for awhile we were wondering if anything was actually happening with it.
Doug.
Building Management Systems Engineer.

shawaj
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Re: PIJuice: Portable PI /UPS on kickstarter

Fri Oct 16, 2015 2:35 pm

I don't come on the forum much anymore (as Alex says, I am pretty darn busy).

But I can absolutely guarantee that this is not a scam, and products will be delivered.

We still have all the money neatly tucked away ready to make the full order of units as soon as the design is finished...and we will not be touching it for anything other than PiJuice related activities until we have shipped every single reward. (We have a web shop as well, which is ticking over nicely, so we have no reason to touch the money other than for PiJuice related purposes).

PaPiRus and Pi PoE are both about to go into production. PiJuice is a little further off - although the hardware is done it is mostly firmware issues to fix/finish.

Thanks for your patience, and apologies for the delay.
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alexeames
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Re: PIJuice: Portable PI /UPS on kickstarter

Fri Oct 16, 2015 4:36 pm

blachanc wrote:
DirkS wrote:
IIRC Alex Ealmes said he lost 5% of the pledges for the HDMI PI kickstarter.


Ben
Just seen this. It was more like 1% actually. 22 from 2523 :D
Alex Eames RasPi.TV, RasP.iO

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