Mysterious electrical issue - SailNet Community
Reply
 
LinkBack Thread Tools
post #1 of 13 Old 09-22-2008 Thread Starter
Senior Member
 
garymcg's Avatar
 
Join Date: Jun 2006
Location: Ann Arbor, MI
Posts: 110
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 10
 
Mysterious electrical issue

Greetings

I have a plain old 12 volt cigarette lighter plug at my nav station. When I plug my 12 volt laptop power supply and laptop into it, the cabin lights instantly become noticeably brighter. Any ideas as to what could be causing this? I disconnected the 12 volt socket thinking there was something wrong with it, but it made no difference.

Thanks in advance

Gary
garymcg is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 13 Old 09-22-2008
Anything-Sailing Founder
 
ckgreenman's Avatar
 
Join Date: Aug 2008
Posts: 2,239
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
 
Send a message via AIM to ckgreenman Send a message via MSN to ckgreenman Send a message via Yahoo to ckgreenman
Do you have a single or dual battery system? also are you running any auxiliary charging system (solar, wind, shore power etc)?

Chris

S/V "The Jade Dragon"
1975 O'Day 25
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Meet me at
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Ignore Power = Currently Rebuilding
--
ckgreenman is offline  
Quote Quick Reply Share with Facebook
post #3 of 13 Old 09-22-2008
Junior Member
 
Join Date: Sep 2008
Posts: 14
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Sounds like your laptop battery is charging the boat battery- can you remove the laptop battery and run direct from the external supply and see if the lights are affected now?
NorthUp is offline  
Quote Quick Reply Share with Facebook
post #4 of 13 Old 09-22-2008
Anything-Sailing Founder
 
ckgreenman's Avatar
 
Join Date: Aug 2008
Posts: 2,239
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
 
Send a message via AIM to ckgreenman Send a message via MSN to ckgreenman Send a message via Yahoo to ckgreenman
Quote:
Originally Posted by NorthUp View Post
Sounds like your laptop battery is charging the boat battery- can you remove the laptop battery and run direct from the external supply and see if the lights are affected now?
Duh. I missed the obvious I think.

Try taking a volt meter and measuring the voltage at the socket. Then plug your 12V charger into your laptop and test the voltage at the cigarette lighter plug of the laptop charger (do not plug it into the boat's receptacle). if the voltage at the plug is higher than the voltage at the receptacle then you most likely ARE charging your boat battery with your laptop battery.

Also try plugging something else into the 12V receptacle that does not also have a battery (i.e. a fan or something with a heating element. These should make the lights dim as expected

Chris

S/V "The Jade Dragon"
1975 O'Day 25
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Meet me at
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Ignore Power = Currently Rebuilding
--
ckgreenman is offline  
Quote Quick Reply Share with Facebook
post #5 of 13 Old 09-22-2008
Telstar 28
 
sailingdog's Avatar
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 15 Times in 12 Posts
Rep Power: 14
         
Of course, if the laptop is discharging into the boat's 12 VDC system, I'd expect the laptop to have a much shorter run time. If that isn't the case, something else is going on

Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
sailingdog is offline  
Quote Quick Reply Share with Facebook
post #6 of 13 Old 09-22-2008 Thread Starter
Senior Member
 
garymcg's Avatar
 
Join Date: Jun 2006
Location: Ann Arbor, MI
Posts: 110
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 10
 
Additional info

OK, I haven't been out to the dock to test what happens with the laptop battery removed, but that's a good suggestion. That said, I can't see how the laptop battery would be discharging as I use it to run chartplotting software and it ran for about 6 hours without the engine running on Sunday, so it must be drawing power.
garymcg is offline  
Quote Quick Reply Share with Facebook
post #7 of 13 Old 09-23-2008
Once known as Hartley18
 
Classic30's Avatar
 
Join Date: Aug 2007
Location: Melbourne, Australia
Posts: 4,856
Thanks: 46
Thanked 65 Times in 65 Posts
Rep Power: 10
   
Dock
Gary, if it's discharging into your 12V system, how long the laptop will run for will depend entirely on the state of charge of both sets of batteries.

It's extremely unusual for this to happen (the power supply should have reverse polarity protection diodes in it which would stop this), but from the information you've given, to my finite mind, it can't be anything else..

-
"Honestly, I don't know why seamen persist in getting wrecked in some of the outlandish places they do, when they can do it in a nice place like Fiji." -- John Caldwell, "Desperate Voyage"
Classic30 is offline  
Quote Quick Reply Share with Facebook
post #8 of 13 Old 09-23-2008
Telstar 28
 
sailingdog's Avatar
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 15 Times in 12 Posts
Rep Power: 14
         
If the laptop is running for six hours, it ain't discharging into the 12VDC system, since NO LAPTOP I'VE HEARD OF can run for six hours while discharging the battery externally.

Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
sailingdog is offline  
Quote Quick Reply Share with Facebook
post #9 of 13 Old 09-23-2008
Anything-Sailing Founder
 
ckgreenman's Avatar
 
Join Date: Aug 2008
Posts: 2,239
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
 
Send a message via AIM to ckgreenman Send a message via MSN to ckgreenman Send a message via Yahoo to ckgreenman
Off the internal battery alone, no it wouldn't run for 6 hours. I'm guessing it starts charging from the internals at some point. However I doubt after 6 hours the laptop is still causing a voltage rise at the lights.

Then again, maybe gary has managed to come up with a self sustaining power source

Chris

S/V "The Jade Dragon"
1975 O'Day 25
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Meet me at
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Ignore Power = Currently Rebuilding
--
ckgreenman is offline  
Quote Quick Reply Share with Facebook
post #10 of 13 Old 09-23-2008
Senior Mumble
 
jbondy's Avatar
 
Join Date: Mar 2001
Posts: 320
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 15
 
I don't know how many amp hours a laptop battery has, but it doesn't seem likely to me that one would contribute enough to a typical boat's electrical system to make a noticeable impact on what voltage the lights are seeing. And I'd think the two batteries, if connected that way, would equalize very quickly.
jbondy is offline  
Quote Quick Reply Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now



In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.


User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Calculating Your Electrical Load Kevin Jeffrey Gear and Maintenance Articles 0 03-03-2003 07:00 PM
Electrical Power on Board Kevin Jeffrey Gear and Maintenance Articles 0 02-11-2003 07:00 PM
Electrical Power on Board Kevin Jeffrey Her Sailnet Articles 0 02-11-2003 07:00 PM

Posting Rules  
You may post new threads
You may 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 On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome