BetaTest

Klaynos, I haven't done much research on this topic either, but what I have done led me to believe that there are two types of usb wire: 1) Data cable - which is similar to the diagram above with the D+ and D- there. 2) Charging cables - where the D+ and D- are shorted which lets the device know that it can charge at full speed. I'm not sure if my cable is shorted or not. ============================================================================= Back on topic. Since the phone can no longer charge effectively with this setup, it has led me to believe that there is some power loss or connection loss between the wire / probe connection. I'm looking to try different methods of connection to endure a consistent connection! -Frozen

Four wires (sometimes 5) Vcc +5V (Red) D+ (White) D- (Green) Ground (Black) +Shielding in some wires

First, thanks for the informative reply Sensei. I should have been more clear. The second part of my post about "having loss in my circuit" was not about normal charging that I do. It refers specifically to the experiment with the modified usb wire and the multimeter in series. Simply put, when I use the wire with my setup the phone receives some current but not enough to charge. During all of my testing there are no games or apps running, just the OS. I have one charging base that works really well, and even using that base with this modified wire the phone is still losing charge slowly. -Beta

Hi Everyone! Thanks for the replys. The phone I'm using in my testing is a Samsung Galaxy S3 with a 3.8V 2100mAh battery. Mordred I'll be reading that pdf as soon asI get a chance! Sensei I never did the calculation of the charge time but I agree it makes sense. However consider this evidence: 1) The phone charges faster with a 2.1A charger compared to a 1.0A charger 2) When I play certain games, a 1.0A charger will not be able to keep us and the battery slowly discharges. Even some cheaper 2.1A chargers won't keep up. This was the reason I decided to conduct this experiment! I think that there is some loss in my circuit; because of your input I decided to measure the charge time. It was at this point I realized the phone was not charging and was actually very slowly losing charge. So I have to find the point at which this is happening! -Beta

I made this diagram in the hopes of more clearly demonstrating my setup.

Is there anything I can put in the circuit to make it draw the maximum current from the base?

Hi Every! Thanks for reading. I'll start off by saying I'm not sure if this is the right sub forum for this question and I apologize in advance if I have posted in error. I wanted to do a simple experiment to compare the current output of 4 different usb charging bases. I used a multimeter and modified usb wire. If you're not familiar with this item here is a quick intro: To charge many devices at home a "wall charger" is usually included. It consists of a base that plugs into the wall outlet and has a usb port. A usb cable is used to connect the base to the device (phone / tablet / etc...). Most bases are typically 5 Volts and have a current between 1.0 amps to 2.1 amps. What I did: I dissected a spare usb wire to find the "hot" or current carrying wire. I cut that wire and put my multimeter in series with the phone. Then I set up the multimeter and plugged in the base, the phone, turned on the multimeter and observed the current. The Problem: The currents I observed on all four charging bases was well below what was expected. I observed currents in the range of 200-400 mAmps. I was expecting to see between 1.0-2.1 Amps. The test phone I was using showed the charging icon when the multimeter was activated but it was only getting enough current to maintain its current level of charge but not to actually charge up. What I'm trying to understand: Basically I'm trying to understand why I didn't observe the currents I was expecting. The multimeter I was using should measure currents all the way up to 10 Amps! Did I add too much resistance to the circuit? Was the voltage drop changed by the multimeter? Any insight would be much appreciated! -BetaCase

Hi everyone! I'm trying to make an at home tooth whitening gel that needs a final concentration of 6% hydrogen peroxide, when means I need a stock of 12%(1:2 dilution). My local drug store only sells 3% hydrogen peroxide. Now I know that I can buy 30-35% online very easily but the problem for me is it costs a lot. So I was reading another topic on this forum about people getting h2o2 to like 90% (not sure why) but they mentioned that you can get h2o2 to 62% by freezing. My question is how can I get 12-20% by freezing? I don't want it to get all the way up to 60% and I'm also not clear on the method (just place it in the freezer and take out the ice cubes?). Also after I'm done with the freezing concentration, how do I estimate the final concentration? thanks to everyone who read this, any advice would be appreciated!