Adjustable power banks with DC output - Page 1
Forum section: electronics / general

author: MrMobodies
author_rank: Super Contributor
timestamp: November 26, 2018, 02:40:51 am
content: I was looking small power bank that would, give me:USB portsDC OUTVoltage adjustment.A display to show battery voltage, output voltage and current.To be able to change the batteries.I had difficulty finding one but on some Russian boards I discovered one they were using.It is called a QD188-ALTThey reported issues with it:DC output voltage being a bit higher than the one set when they measured it.When charging the batteries they don't charge all the way and can become unbalanced.I don't use the built in charger.I charge them on a Sky RC MC3000 charger so it isn't a problem for me.I wouldn't trust the percent counter on it but it tells you the actual voltage of the batteries so that is good and it does auto cut off if the voltage is too low.I brought some Sanyo batteries from a supplier I use and of course I cycled and tested them for a while and no problems and so far they seem fine. I am paranoid about fakes. It has an advertisted voltage of 0.1 to 24 in 0.1v increments but I only need 12v 1 to 3 amp load and it seems to handle that fine without heating up too much.I see most of them sealed shut and then you have to desolder the batteries to replace them.It is very handy for powering up things like 12v hard drive enclosures and the portable network switches in places with no power.There is another one called Tomo for USB.The voltages are displayed.The batteries are charged and discharged individually which is a lot better than AD-188 where they are in series and parallel.You can use any 18650 battery in it.No DC out.I see the big powerbanks for cars on Amazon selling with a DC out and voltage adjustment but they are sealed shut and/or batteries are soldered together.Have you seen power banks like this before?Edit:Oops, accidentally posted it in "Dodgy technology"

author: Raj
author_rank: Frequent Contributor
timestamp: November 26, 2018, 03:45:51 am
content: What do you mean by DC out... The USB port is the DC out... If you need a barrel jack female, wire one into a USB plugIf you want both, take a USB plug and wire a USB socket and barrel jack,both pararrel to it...If you just wanna experiment with power banks....the Chinese have a huge variety of 'diy power bank'Eg-https://www.ebay.com/itm/Portable-300000mAh-20-LED-Solar-Power-Bank-Dual-USB-Battery-Charger-For-Phone/332734225796?hash=item4d78815d84:m:mP_w9F-E9WeFpUAYix-N7PAAnd you do have a change topic board, in this forum

author: MrMobodies
author_rank: Super Contributor
timestamp: November 26, 2018, 03:52:05 am
content: Quote from: Raj on November 26, 2018, 03:45:51 amMaybe I didn't explain well enough.I mean it has a separate output just for the dc socket that you can manually set the voltage using the up/down buttons under the display between 0.1v to 24v.It is made in China.I did attach some pictures of it connected up to a Surface 1 12v car charger drawing 12v 2.4aIt does have two usb ports.A regular and a QC2 port.I noticed after I posted that it was the wrong board/section.I don't know whether to delete this thread and re-post or ask a mod to move it.

author: Raj
author_rank: Frequent Contributor
timestamp: November 27, 2018, 12:57:01 pm
content: oh,ok, so you want something that can give you stable,safe,variable power.sorry, i've got nothing but Chinese & diy options,but you can get an 18650 bms for whatever voltage you need mainly, and use a buck boost converter for other voltages.You can make it inside of a pvc pipe with end caps to close it, put your charging port and output sockets through the end caps. Fill it up with flame retardant material and be done with it.Bonus: take it to an airport, you can cause a huge panic among security guys.(just a joke...I had a crt tube in a similar pipe, but with lens at one end and video and power input at the other....They didn't even bat an eye while looking at it through Xray.)

author: Raj
author_rank: Frequent Contributor
timestamp: November 28, 2018, 12:44:59 pm
content: ok,if you really wanna stay away from chinese, get some texas instruments ic that do the sameyou'll need--charge controller-battery protection-buck/boost

author: MrMobodies
author_rank: Super Contributor
timestamp: November 30, 2018, 10:26:18 pm
content: Yes they will look at the batteries and get suspicious on their arrangement.Really I should build my own if I want reliable and safety and Texas instruments components looks nice.I got to design a good case for it to go in.