Reply
 
Thread Tools Search this Thread Display Modes
 
Old 12-13-2010, 02:09 PM   #15
Rivet Master
 
Dave Park's Avatar
 
2005 22' Safari
Hyde Park Place , Ohio
Join Date: Jul 2010
Posts: 972
The Apple power adaptor comes in only two variants: a 65W version for Macbooks and an 85W variant for larger screened Macbook Pros. Apparently, they're all 16.5V (the writing is very small).

The PSU does receive signaling for charge and float modes, as indicated by the green/orange LED in the MagSafe connector. The power management/control is handled by a PCU power control unit in the laptop. Battery charge is monitored by a battery CPU in the battery pack, or in the laptop for newer unibody models.

Hope this helps.
__________________

__________________
TX-16
Dave Park is offline   Reply With Quote
Old 12-13-2010, 02:34 PM   #16
A 7th year newby
 
IndyAnne's Avatar
 
1968 24' Tradewind
Indianapolis , Indiana
Join Date: Sep 2006
Posts: 466
Images: 8
Send a message via Yahoo to IndyAnne
Laptop power supply; TV?

Jammer and Dave, -- and Chris, and 2air --

Thanks very much for the conversation.

I'm trying to take all of this in.

The power management of a laptop, in this case, a MacBook1,1, is built into the interior power supply, the brick, and even the "plug" on the power cord.

So, the best approach to using the MacBook in the Airstream is to use 110v when possible, and let the electronics do what they are supposed to do. When 110v is not possible, or preferred, or whatever, use an inverter to raise the Airstream's or the tow vehicle's 12v to 110v, so the electronics can adjust the power accordingly.

Have I restated accurately?

Ready to go on to the TV questions? Is the brick on the power cord, and the built-in power supply inside an LED LCD HDTV, generally, doing the same kind of power conditioning that a laptop's brick and power supply circuitry is doing?

Power fluctuations are managed by the laptop [and possibly the TV] built-in systems. Both use between 12 and 16.5 volts, less power, by design, and will not drain the batteries as much as I imagined, if I am without 110v for a short while (not sure how long).

I would imagine a voltage regulator, generally, would be a good thing to add to the Airstream's power system, for the incoming 110v and also the 12v produced by the converter (Univolt, at present).

Adding to my list now:
Higher capacity 12v system, perhaps the 2 - 6v systems I have read about here
Battery charging monitor
Battery conditioning electronics
110v regulator
12v regulator

Anne
__________________

__________________
Anne
Indianapolis, IN
TAC IN-7
1968 Airstream Trade Wind
2005 Chevy K1500 crew, reg. bed, 4WD, gas
IndyAnne is offline   Reply With Quote
Old 12-13-2010, 08:10 PM   #17
Wise Elder
 
Jammer's Avatar
 
2010 30' Classic
Vintage Kin Owner
South of the river , Minnesota
Join Date: Dec 2009
Posts: 4,119
Quote:
Originally Posted by IndyAnne View Post
Jammer and Dave, -- and Chris, and 2air --

Thanks very much for the conversation.

I'm trying to take all of this in.

The power management of a laptop, in this case, a MacBook1,1, is built into the interior power supply, the brick, and even the "plug" on the power cord.

So, the best approach to using the MacBook in the Airstream is to use 110v when possible, and let the electronics do what they are supposed to do. When 110v is not possible, or preferred, or whatever, use an inverter to raise the Airstream's or the tow vehicle's 12v to 110v, so the electronics can adjust the power accordingly.

Have I restated accurately?
Mostly. The thing you've left out is that there are 12v power supplies, available from Apple and other sources, that do all the same tricks as the 110v power supply. The choice is yours.

Quote:

Ready to go on to the TV questions? Is the brick on the power cord, and the built-in power supply inside an LED LCD HDTV, generally, doing the same kind of power conditioning that a laptop's brick and power supply circuitry is doing?
It depends on the TV but generally not. Some TVs have a 120v power cord, and all the power supply components are internal. In general, this is considered to be the "right way" to do it. (As an aside, it used to be that way with laptops, but we ended up where we are now mainly because it reduces the weight of the laptop itself, which is what people compare, never mind that most people carry the power supply too)

Smaller TVs sometimes run on 12 volts either specifically to improve sales to RV and marine markets, and sometimes to streamline regulatory compliance. But in general the sort of tight integration between the power supply and the device that we see in the computer industry has never quite taken place with other electronics.

Quote:
Power fluctuations are managed by the laptop [and possibly the TV] built-in systems. Both use between 12 and 16.5 volts, less power, by design, and will not drain the batteries as much as I imagined, if I am without 110v for a short while (not sure how long).
The role of power fluctuations is greatly overestimated by most lay people.

Typical laptop AC power supplies are designed for international markets and will run on anywhere between 90 and 265 volts and are not picky about input frequency or waveform. They are typically equipped with MOVs that will clamp transient surges from reasonably distant lightning hits. Laptop power supplies designed for 12 volts (the auto/air adapter it's usually called, with the cigarette lighter plug on one end), similarly, are usually designed to run on a fairly wide range of input voltages, and are not especially picky about how clean the DC is.

Higher end laptops generally have better power supplies, because although the parts aren't especially expensive, they do cost a few bucks.

TVs are similar but since the market is more price sensitive the quality isn't always as good.

Quote:

I would imagine a voltage regulator, generally, would be a good thing to add to the Airstream's power system, for the incoming 110v and also the 12v produced by the converter (Univolt, at present).

Adding to my list now:
Higher capacity 12v system, perhaps the 2 - 6v systems I have read about here
Battery charging monitor
Battery conditioning electronics
110v regulator
12v regulator

Anne
It should be clear by now that I eat and breathe this stuff from time to time at least at my day job.

My Airstream electrical system is bone stock although I will probably add more batteries and a battery monitor this winter. I don't have any kind of regulator or surge suppressor devices and don't plan to get them. The thing to remember is that these devices (autoformer etc) are heavy and expensive and while there is a narrow range of situations where they will actually help, the stock electrical system is in fact quite capable of handling most surges and on the other side a direct hit of whatever (lightning, somebody at the utility dropping a 13.6 kv line by accident) is going to cook the autoformer and keep on going to cook everything else. So a cost-benefit analysis puts me in the red.

I am really happy with the Lenovo auto/air adapater, which as an added bonus has a little connector on it for charging my phone at the same time. Other laptop vendors have similar products, and as a result even though I carry a little inverter around with me I've never actually needed it for anything.
__________________

__________________
Jammer is offline   Reply With Quote
Reply

Tags
12 volt


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
12 Volts for Fridge? 85Sovereign Refrigerators 23 12-07-2010 11:36 PM
6.5 volts instead of twelve photoguy Batteries, Univolts, Converters & Inverters 4 05-28-2010 04:10 PM
New 6 volts draining too fast ! Phantom Batteries, Univolts, Converters & Inverters 4 09-19-2009 01:54 PM
12 volts shutoff then come back on??? dnrtheil Electrical - Systems, Generators, Batteries & Solar 9 05-01-2007 11:54 AM
need to chance to 240 volts remcolent Electrical - Systems, Generators, Batteries & Solar 1 12-16-2003 07:49 AM


Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 09:06 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.