Guest felixlai Posted February 18, 2004 Report Posted February 18, 2004 Hello guys, I've made a prototype of a battery powered charger for MPX200, which will take any input voltage between 5 to 40 V and turn it into steady 5V. I'm using a 9V battery as an example but this unit works fine with 4 AA batteries (6V) and car batteries (12V) Check it out and any feedback or suggestions for improvement highly welcomed! :) :D
Guest awarner [MVP] Posted February 18, 2004 Report Posted February 18, 2004 Welcome to the site :) and nice first post :D/
Guest phonesmarts Posted February 19, 2004 Report Posted February 19, 2004 Welcome to the site :) battery powered charger? nice one. i know they have the emergency cell phone batts (it goes into the battery compartment and when all the juice is gone, just throw it away) for many phones, but does it work for the mpx? how long does the 9V last?
Guest awarner [MVP] Posted February 19, 2004 Report Posted February 19, 2004 there are chargers around that will do this but I've not seen one that will do various voltages before.
Guest equis Posted February 19, 2004 Report Posted February 19, 2004 Oh wow that is a great idea especially with the phone having a rather short battery life if used alot compared to other traditional phones.
Guest phonesmarts Posted February 19, 2004 Report Posted February 19, 2004 yeah, all you really have to do is to carry a bunch of AAs, 9Vs and your phone is virtually unstoppable...how long does 4 AAs last? 1 hour? 2?
Guest felixlai Posted February 20, 2004 Report Posted February 20, 2004 It's a clever cascade of a boost regulator creating an intermediate voltage of about 53V followed by a linear regulator, with a clean 5V coming out the end. The circuit controls the amount of current drawn from the batteries according to its voltage. I didn't invent it and the instructions for making it can be found here. How long it lasts depend on what batteries you put in. You can work that out by looking at the charge capacity multiplied by voltage of your batteries & the Motorola Li-ion batteries, and taking the efficiency chart in that instructions page into account. For example, my four Ni-MH rechargable AA batteries each having 1500mAh is good for two complete charges of the Motorola battery. In other words, it keeps my phone at 100% while watching two full length movie on a long haul flight. Using two AA batteries also work but the current doubles and hence it only last half as long. On the other hand, using a single 9V battery lasts longer than 4 AA despite having the same 1500mAh due to higher voltage (hence lower current) in the former. The use of regulation circuit makes this gadget (in theory) better than some of the commercial ones which simply feeds your battery to the phone without voltage and current control. Nonetheless, I've taken out full insurance before trying this, and I suggest you do the same before you venture!
Guest Will Posted February 20, 2004 Report Posted February 20, 2004 please can you post or PM me the circuit diagram, this is the precise thing i need.. Will
Guest Norky Posted February 20, 2004 Report Posted February 20, 2004 please can you post or PM me the circuit diagram, this is the precise thing i need.. He said, he got the instructions from http://www.maxim-ic.com/appnotes.cfm/appno...note_number/114 Looks a tad complicated though....
Guest Will Posted February 20, 2004 Report Posted February 20, 2004 damn that pesky link, thanks for pointing it out.. now time to play! Will
Guest ratcom Posted February 21, 2004 Report Posted February 21, 2004 I have a HP Ipac wall charger plug spare and it as a usb socket as the output anyway the lable on the plug says the output runs at 4 to 7 volts so would I be ok to simply plub a mini usb lead in and use it on my phone? (tried it for a minute and the phone does start to charge) Sorry I know its abit off subject but you guys seem to be in the know :wink:
Guest awarner [MVP] Posted February 21, 2004 Report Posted February 21, 2004 USB is a standard 5v so you should not have a problem. I have a wall adaptor and it's printed wrongly 12v :roll: checked the outputs and it's producing the standard 5v. Nice circuitry inside though.
Guest phonesmarts Posted May 12, 2004 Report Posted May 12, 2004 lets revive this topic and get more posts in
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