Portable battery bank  - Page 1
Forum section: electronics / projects

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: May 22, 2014, 10:33:36 pm
content: hey guys i was thinking of building a power back for the summer but i got stuck!! can't figure out what battery shall i use or what voltage I need it be.... i want to power a USB device of it like my phone (that means 5 volts and at least one amp) but i don't know1)what battery shall i use lion, lipo or maybe something else2)the voltage of it 3.7 or 4.2and 3)the capacity of it...i have been messing with this matter about a week now and i can't understand why it's so difficult to just pick a battery and the proper protection module as well as the suitable step up and charging board to power my phone and charge using some cheapo solar panel modules from ebay......it would be nice to get everything ordered soon so it arrives by the time i finish my finals....also I apologize because i read about these things a bit but not enough to understand them and build the thing my own..Sent from my C5303 using Tapatalk

author: hamdi.tn
author_rank: Frequent Contributor
timestamp: May 22, 2014, 11:14:12 pm
content: hi, well i build something similar with TPS61222 5V step-up converter powered from a 3.7V 1.1Ah battery. The battery it self recharged via USB or a solar panel with BQ24210, the circuit is too simple with good results

author: Legit-Design
author_rank: Frequent Contributor
timestamp: May 23, 2014, 12:44:12 am
content: Try looking what is around?http://www.ebay.com/sch/i.html?_sacat=0&_from=R40&_nkw=18650%20power%20bank&_fscr=1take a case from something like this:http://www.ebay.com/itm/UP-to-10000mAh-Power-Bank-USB-Battery-Charger-18650-DIY-Box-for-Cellphones-MP3-4-/370980485160?pt=US_Cell_Phone_PDA_Chargers&var=&hash=item566028f828I think I saw somewere only those cases sold.Do a whole redesign of the electronics based on your needs. Good thing about 18650 cells is you can get them cheap anywhere with all kinds of capacity and price. Typically old laptop batteries might have few cells which have died, or all the cells are fine and protection circuitry has gone.

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: May 23, 2014, 11:19:07 am
content: hmmmm i have not thought of a case... in your first link i found thishttp://m.ebay.com/itm/390730077885?nav=SEARCH&varId=660193172900but do i power the thing with this onehttp://m.ebay.com/itm?itemId=161300583260&varId=460334107913or the 3.7 volt one?(http://m.ebay.com/itm/351057803214?nav=WATCHING_ACTIVE)can't figure the voltage thing out (i must sound like a retard)Sent from my C5303 using Tapatalk

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: May 23, 2014, 11:24:00 am
content: Quote from: hamdi.tn on May 22, 2014, 11:14:12 pmwhat about a protection circuit? do i need one?Sent from my C5303 using Tapatalk

author: HKJ
author_rank: Super Contributor
timestamp: May 23, 2014, 01:26:33 pm
content: You can easily and cheaply buy that kind of box, I have looked at a couple here:http://www.lygte-info.dk/info/indexUSB%20UK.htmlIf you are interested in how they are build, there are high resolution photos of the circuit board.To make you own it would probably be easiest to use LiPo batteries, they are rectangular and comes with wires attached.

author: hamdi.tn
author_rank: Frequent Contributor
timestamp: May 23, 2014, 02:13:39 pm
content: i used a battery already contain a protection circuit for over charge / over discharge , the BQ24210 feature short circuit protection, Thermal Regulation Protection and over voltage protection ... i didn't take lot of time thinking about protection since i made this charging circuit for experiment not as a product for long term use. Texas instrument give sample of BQ24210 and the step-up circuit, few external component used with both and i salvage all of them from PCB laying around, so i didn't spend a single $ for this circuit.

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: May 23, 2014, 10:51:48 pm
content: Cool thank you guysI think ill just buy a cheapo case that takes care charging and voltage step up for now and ill design my own portable bank after it arrives so i can take my time designing and building itI also found the excact same one in ebayhttp://www.ebay.com/itm/5V-9v-12v-Dual-USB-Power-Bank-6x18650-Battery-Charger-Box-for-iPhone-5S-4-Note-3-/370972718284?pt=Battery_Chargers&hash=item565fb274cchttp://lygte-info.dk/review/Review%20USB%20battery%20box%206x18650%20Qidian%20UK.htmlAnd a cheaper but still functional (for me ) duplicateWhat would you suggest of these 2 ?The one is a lot more expensive and it outputs multiple voltages (Useless for me since i need only a 5 V output)Also i think ill hack it by hooking up 2 of these http://www.ebay.com/itm/6V-0-6W-Solar-Panel-Poly-Module-DIY-Small-Cell-Charger-/301018398863?pt=LH_DefaultDomain_0&hash=item461618408f]http://www.ebay.com/itm/Black-Plastic-6x18650-USB-Power-Bank-Battery-Charger-DIY-Box-Case-Shell-/191171001970?pt=UK_MobilePhones_MobilePhoneAccessories_MobilePhoneChargers&hash=item2c82adfe72/url]What would you suggest of these 2 ?The one is a lot more expensive and it outputs multiple voltages (Useless for me since i need only a 5 V output)Also i think ill hack it by hooking up 2 of these http://www.ebay.com/itm/6V-0-6W-Solar-Panel-Poly-Module-DIY-Small-Cell-Charger-/301018398863?pt=LH_DefaultDomain_0&hash=item461618408fparallel to the usb input and using an LM7805 to output a "clean" 5 v signalAlso while searching for the panels i stumbled across thishttp://www.ebay.com/itm/30000mAh-Dual-USB-Solar-Panel-Power-Bank-External-Battery-Charger-for-iPhone-HTC-/201054235387?pt=UK_MobilePhones_MobilePhonesCasesPouches&var=&hash=item2ecfc42afbwhat do you think about it ?