Opinion needed on lm2956 based portable power supply  - Page 1
Forum section: electronics / projects

author: Asim
author_rank: Regular Contributor
timestamp: July 15, 2014, 06:40:05 am
content: Hi guys,i am planning on making a portable power supply ( I move a lot) and I decided not to bother building one?, so I want to use this onehttp://m.ebay.com/itm/400561586157?nav=SEARCHAs the power supply. I will have 18650 batteries as the input ( they will be connected to a charging module so i can charge them without taking them off)Here is a review of the productMy input will be 14.8v , it will not be used for high currents ( not more than 1.5A)Do you think there is/ are reason/s for me not to go ahead ?

author: Zepnat
author_rank: Regular Contributor
timestamp: July 15, 2014, 07:20:58 am
content: Sounds great, I would love to a have portable power supply so I've been using a Heath Robinson lash up with a lm2596 and two lithium 18v cordless drill batteries in series and it works great. If you used protected cells there wouldn't be any worries about over discharging and subsequently killing the battery. Please don't use any of those garbage 18650 on ebay with ***fire on the label but you probably know that already.

author: Asim
author_rank: Regular Contributor
timestamp: July 15, 2014, 07:31:47 am
content: For proteceting the batteries from over discharge or charge. I will use thishttp://m.ebay.com/itm/261191600278?nav=SEARCH( never tried it before or seen anyone using it) I will test it and hopefully it is good enough.Btw, what is wrong with ultrafire batteries ? I have used them before

author: tom66
author_rank: Super Contributor
timestamp: July 15, 2014, 09:27:27 am
content: They usually won't meet anywhere near the printed rating.eBay sellers are selling 5000mAh and even 6000mAh 18650s. Completely nonsense. Panasonic (an actual battery manufacturer) recently announced they had achieved 3900mAh in an 18650 with new silicon electrode design. So it's laughable for an ultrafire to even come close. Most of them are only in the 500mAh range, sometimes even less.

author: Zepnat
author_rank: Regular Contributor
timestamp: July 15, 2014, 10:12:36 am
content: Just watched that review video and I must say I'm very temped to get one of those power supply boards..A few years ago my first torch batteries were ultra fire but they were just too inconsistent with missing safety features and wildly varying capacities any name brands are much better.http://budgetlightforum.com/node/27603why do they go to so much trouble to fake something that's only worth a couple of dollarsHow about posting some photos when you get it up and running?

author: Asim
author_rank: Regular Contributor
timestamp: July 15, 2014, 01:45:27 pm
content: I will put some photos when I finish it( waiting for the components atm )

author: mij59
author_rank: Frequent Contributor
timestamp: July 15, 2014, 03:11:55 pm
content: Quote from: Asim on July 15, 2014, 06:40:05 amWhat output voltage range do you have in mind ?

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: July 15, 2014, 03:14:19 pm
content: Quote from: tom66 on July 15, 2014, 09:27:27 amYeah I've had mixed results with batteries on eBay, perhaps the rating refers to total lifetime capacity as you can only charge them 10 times...

author: Zepnat
author_rank: Regular Contributor
timestamp: July 15, 2014, 08:24:14 pm
content: Quote from: Alex Eisenhut on July 15, 2014, 03:14:19 pmHa Ha very good