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Forum section: electronics / projects

author: daywalkerdha
author_rank: Contributor
timestamp: October 19, 2012, 07:52:50 pm
content: no text

author: karlmag
author_rank: Contributor
timestamp: October 20, 2012, 10:03:57 am
content: Hi,That is a really nice project!I would certainly want a PCBDetails in PM.Thank you! :-)--Karl Magnus

author: peter.mitchell
author_rank: Super Contributor
timestamp: October 20, 2012, 06:11:12 pm
content: I thought i'd link this:http://www.tracopower.com/products/tsr1.pdfI was wondering if linear or smps so I had a quick look, nice product!

author: peter.mitchell
author_rank: Super Contributor
timestamp: October 21, 2012, 05:18:32 am
content: With a larger power supply you could use a 7805, yes, but you'd need a heatsink and get less than half the battery life from the UPS!

author: Psi
author_rank: Super Contributor
timestamp: October 21, 2012, 09:31:58 am
content: It occurred to me while reading this thread that two of those boost caps in series would work quite well for a raspberry pi ups battery.Two in series would be 5.2V max and 1300FarradThe pi draws around 300mA idle so 0.3A/1300F = 0.000230769V drop per second = 0.2V per 15minSo you'd get at least that out of it before the volts dropped a bit low.If you included a boost converter down to say 2V it would last 5.2 - 2 = 3.2V/0.2V = 16 lots of 15min.16*15min = 4 hours4 hours is probably more than most people need, so you could use smaller boost caps to reduce the size of it.And the best part is you'd never need to replace worn out SLA batteries. (i hate buying new ups bats every 2 years)

author: Psi
author_rank: Super Contributor
timestamp: October 21, 2012, 10:13:18 am
content: There are many sizes but this is the one you see most often.http://home.comcast.net/~hlandis0/photos/ucap2600f.pdfYou see them come up on electronic goldmine from time to time for ~$10-20 eachThey a bit expensive new, so 2ndhand is how most hobby people get them.I suspect they're used in massive banks of 1000 for high energy physics/research. Every so often they upgrade their cap bank to newer model boostcap. That's when you see lots of 2nd hand ones available.Because their ESR is so low they will draw lots of current if it's available, so you'd need a charger that is current limited and also voltage limited to their rated volts

author: peter.mitchell
author_rank: Super Contributor
timestamp: October 21, 2012, 10:29:33 am
content: I was going to mention the current draw thing and the price thing and the size thing.

author: SeanB
author_rank: Super Contributor
timestamp: October 21, 2012, 10:40:29 am
content: I want some of those caps...........Like the UPS you put together.

author: peter.mitchell
author_rank: Super Contributor
timestamp: October 21, 2012, 12:54:10 pm
content: There was a point in time where I worked for a company who installed security systems, even the cheapest, nastiest batteries would last 2 years with a full cycle every 3-6 months and a float charge. Powersonic was the cheapest brand we had used without troubles. 12v 7aH Were about $15 a pop in quantity, $20 single.

author: SeanB
author_rank: Super Contributor
timestamp: October 21, 2012, 01:02:47 pm
content: Security system manufacturers normally design in a proper power supply, not just a hope it works till warranty is over one. The battery can last over 5 years on one like that, as it is kept at float voltage which means it is always at 95% of capacity, so it does not generate much gas until the one cell decides to go short or open circuit from contaminants in the lead.

author: SeanB
author_rank: Super Contributor
timestamp: October 21, 2012, 01:06:53 pm
content: If you want to learn a lot more about battery system design, maintenance and operation you will find a lot of very good papers atwww.battcon.comwhere they have all the archived papers freely available for download. I learned a lot from browsing there, and have found it good to know how cells age, why they have the designs they do and how to use them properly.

author: ptricks
author_rank: Frequent Contributor
timestamp: October 21, 2012, 03:37:32 pm
content: Quote from: Psi on October 21, 2012, 10:13:18 amThey had a large amount of them about 2 months ago and someone made a large order and got nearly all of them, wonder what they built .

author: Psi
author_rank: Super Contributor
timestamp: October 25, 2012, 12:10:20 am
content: Quote from: ptricks on October 21, 2012, 03:37:32 pmIt wouldn't surprise me if the geekgroup bought them.

author: Monkeh
author_rank: Super Contributor
timestamp: October 25, 2012, 12:13:42 am
content: Quote from: Psi on October 25, 2012, 12:10:20 amDon't think so. I imagine I'd have heard of it by now.

author: adampielok
author_rank: Newbie
timestamp: June 03, 2013, 07:13:26 am
content: Is it possible to order some PCB's ?

author: manu
author_rank: Regular Contributor
timestamp: March 31, 2014, 09:06:03 am
content: Nice project!

author: Antoine.
author_rank: Newbie
timestamp: October 29, 2014, 06:01:23 pm
content: Hello,I drew the schematic with KiCad, but I have difficulty with the PCB.Can you give the PCB, or a more detailed picture of the card.Thank you.

author: magetoo
author_rank: Frequent Contributor
timestamp: October 30, 2014, 03:12:44 am
content: Antoine, this project was posted two years ago and the OP hasn't been active in the forum for six months. It seems unlikely you will get a response.That said, if it turns out he (or anyone else) wants to pick this up again and make PCBs, I'd be interested. I have a Pi that I've been meaning to do something with and I really like this idea.

author: stryker
author_rank: Regular Contributor
timestamp: October 30, 2014, 04:57:42 am
content: Hi guysI did buy a couple of these boards for a project that I'll some day get back to. Will see if I can dig them up this weekend and post a shot of both sides.Cheers! Geoff

author: stryker
author_rank: Regular Contributor
timestamp: November 12, 2014, 12:15:01 pm
content: Quote from: Antoine. on October 29, 2014, 06:01:23 pmHi AntoineI forgot this was a black PCB. Here's adropox linkto a PDF. I didn't scan the back since only the drills are on that side. Aside from the schematics and other links in this thread, I also have this dropbox link to the BoMhttps://dl.dropbox.com/u/678261/PiSupply_BOM.htmlI had asked for clarification on two points: In the BoM R18 is 15k but in the shopping cart it is a 5.1k; and in the BoM R15 is 130k, but in the shopping cart it's 120k. Daniel's response wasQuoteCheers! Geoff

author: Antoine.
author_rank: Newbie
timestamp: November 12, 2014, 08:39:44 pm
content: Hi stryker,thank you for all.I will open a topic on my realizationBye

author: Chris Jones
author_rank: Regular Contributor
timestamp: November 28, 2014, 03:02:35 pm
content: I guess you may have seen this RPi UPS already, if not it seems to be quite nicely designed:http://juice4halt.com/?p=6

author: GuitarZaan
author_rank: Newbie
timestamp: March 04, 2015, 04:02:57 am
content: Hi Daniel;I see that this thread is a little dated but your circuit is very nice and I'm interested in a backup for my RPI Sprinkler Controller.If you've made some boards I'd be interested in purchasing two from you. Any other information would be grand.Thanks;Wayne