Join Early Retirement Today
Thread Tools Search this Thread Display Modes
All charged up? Charger question
Old 05-20-2010, 08:10 AM   #1
Moderator Emeritus
Rich_by_the_Bay's Avatar
Join Date: Feb 2006
Location: San Francisco
Posts: 8,827
All charged up? Charger question

My new cell phone AC power adapter puts out 5v/1 amp. My old wall charger from a different phone puts out 5v/ 0.7 amp and fits the connector.

Will using my old charger hurt the new cell phone (other than maybe charging a little slower)?
San Francisco Area
ESR'd March 2010. FIRE'd January 2011.

As if you didn't know..If the above message contains medical content, it's NOT intended as advice, and may not be accurate, applicable or sufficient. Don't rely on it for any purpose. Consult your own doctor for all medical advice.
Rich_by_the_Bay is offline   Reply With Quote
Join the #1 Early Retirement and Financial Independence Forum Today - It's Totally Free!

Are you planning to be financially independent as early as possible so you can live life on your own terms? Discuss successful investing strategies, asset allocation models, tax strategies and other related topics in our online forum community. Our members range from young folks just starting their journey to financial independence, military retirees and even multimillionaires. No matter where you fit in you'll find that is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with our members, see fewer ads, upload photographs, create a retirement blog, send private messages and so much, much more!

Old 05-20-2010, 08:14 AM   #2
Thinks s/he gets paid by the post
MasterBlaster's Avatar
Join Date: Jun 2005
Posts: 4,384
No the old charger won't hurt your new phone. It will just charge slower. The key here is the voltage being correct.

The reverse may not be true. Some batteries may not take to be charged too fast.
MasterBlaster is offline   Reply With Quote
Old 05-20-2010, 09:52 AM   #3
Give me a museum and I'll fill it. (Picasso)
Give me a forum ...
NW-Bound's Avatar
Join Date: Jul 2008
Posts: 29,150
The same 5V is paramount. But as you ask, what about the difference in the current ratings?

Charging these Li-Ion batteries requires an active circuit to monitor and regulate the charging current and voltage, else the battery may explode. It is not like the crude and cheap chargers for NiCad batteries that I have seen all the time on cordless tools.

A single Li-Ion cell has a nominal voltage of 3.6V and the charging circuit has to regulate the voltage down from the 5V. The current also has to be throttled according to the battery state. In the old days, I have often seen this regulator circuit being inside the charger. Nowadays, this regulator circuit is inside the phone itself.

Plugging a 1A adapter into a phone that uses only 0.7A wouldn't hurt. It is not likely to charge any faster either, because the regulator won't let it.

The other way of using a 0.7A adapter with a phone needing 1A most likely results in a slower charge. It shouldn't hurt the phone but may hurt the charger, depending on its design. If the designer does it right, the adapter should shut itself down for self-protection if the current demand is too high, or simply limits itself to 0.7A. After all, its cord may be shorted out accidentally by damage, or it may get plugged into a broken phone with a short. In most likelihood, it is OK (but don't sue me please).
"Those Who Can Make You Believe Absurdities Can Make You Commit Atrocities" - Voltaire (1694-1778)
NW-Bound is offline   Reply With Quote
Old 05-20-2010, 10:20 PM   #4
Recycles dryer sheets
Join Date: Apr 2007
Posts: 202
This type of question comes up all the time on cell phone forums. The overwhelming consensus is that it'll just result in a slower charge (if you charge a 1A phone w/ a .5A charger), or no difference (the other way around).

I think damage is highly unlikely (I don't ever recall anyone having an issue with this), but as always, your mileage may vary...
skyline is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Macbook Question/Printer Question kaneohe Other topics 5 10-15-2009 07:35 AM
1 Of 2 93-Year-Olds Charged In Manatee County Sex Sting Wags Other topics 18 03-28-2008 06:23 PM
15 minute battery charger for C and D size? Sam Other topics 17 01-24-2007 02:07 PM

» Quick Links

All times are GMT -6. The time now is 05:56 AM.
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.