Am I understanding this about charging car batteries correctly? - Page 3 - Fuelly Forums

Android Users - Coming Soon! - Migrating from aCar 4.8 to 5.0

Go Back   Fuelly Forums > Fuel Talk > General Fuel Topics
Search Today's Posts Mark Forums Read Click Here to Login
Reply
 
Thread Tools Display Modes
 
Old 06-10-2011, 09:32 AM   #21
Registered Member
 
kamesama980's Avatar
 
Join Date: Nov 2007
Posts: 742
Country: United States
Location: Columbus, IN, USA
Send a message via AIM to kamesama980 Send a message via Yahoo to kamesama980
Re: Am I understanding this about charging car batteries correctly?

you don't need a fully charged battery to start the car. period. barebones 500 cca batteries are twice what even the biggest engines need (well maybe not some of the diesels and 8l+ ones) most starters, once the engine is spinning, draw well under 200 amps. the other how-many-hundred CA the battery has is extra for when you leave your lights on at the supermarket or 5 years down the line when the battery's only working at 60% of it's original capacity so it can still start the car.

Academically speaking, no the alternator won't push the 15+ volts to shove every last milliwatt into the battery but practically speaking who gives a hoot.

as far as not charging at idle, I haven't seen a car made in the last 25 years that couldn't maintain 13.5v at idle (unless something was broken). In all actuality it's been longer since they converted to alternators but I haven't worked on much older than mid-80s. The reason city-drivers replace more batteries is more starts and shorter trips.
__________________

__________________
-Russell
1991 Toyota Pickup 22R-E 2.4 I4/5 speed
1990 Toyota Cressida 7M-GE 3.0 I6/5-speed manual
mechanic, carpenter, stagehand, rigger, and know-it-all smartass
"You don't get to judge me for how I fix what you break"
kamesama980 is offline   Reply With Quote
Old 06-10-2011, 11:06 AM   #22
Registered Member
 
imzjustplayin's Avatar
 
Join Date: Dec 2011
Posts: 720
Country: United States
Re: Am I understanding this about charging car batteries correctly?

Well part of the reason you want to keep a battery fully charged is because they get sulfated if you don't do that.. Also because of the electronics and alarm systems cars now have, I'm starting to see people replace their batteries every 4 years instead of something like every 10 years+. Batteries can easily last a decade or more if they're taken care of but by the looks of things, that's not happening and I feel the cars are to blame.
__________________

imzjustplayin is offline   Reply With Quote
Old 06-10-2011, 11:43 PM   #23
Registered Member
 
add|ct's Avatar
 
Join Date: Jun 2010
Posts: 534
Country: United States
Re: Am I understanding this about charging car batteries correctly?

Quote:
Originally Posted by ************* View Post
Sounds like you need that buzzer to remind you to turn off your headlights like the civics come with.. Also just because you can start the car just fine, doesn't mean the battery isn't discharged. 10.5V is the minimum voltage needed to crank most cars but 11.7v is generally considered a fully discharged battery and to charge a battery from 11.7v to 12.7v (full charge) requires quite a few amps, something you can't normally do with your car since it would take several hours of highway driving. What your car was likely doing was charging the battery just enough so that you could drive around with it but that doesn't mean the battery wasn't discharged.
My civic needs one added!
__________________
'92 Civic VX, Canadian model
add|ct is offline   Reply With Quote
Old 06-11-2011, 04:36 AM   #24
Registered Member
 
theholycow's Avatar
 
Join Date: Apr 2008
Posts: 6,624
Country: United States
Send a message via ICQ to theholycow Send a message via AIM to theholycow Send a message via MSN to theholycow Send a message via Yahoo to theholycow
Re: Am I understanding this about charging car batteries correctly?

I too would like a headlight buzzer.

I searched the12volt.com thinking I'd find it in their DIY relay projects, but then I found this:
Quote:
They sell tiny headlight warning buzzers at local autoparts stores. I've bought one before and it came with little clips to plug it right up to the fuse box. You hook the hot to the headlight fuse, and the ground to any ignition fuse. Simple 5 minute installation! And it only cost like 2 or 3 bucks. That less than the price of one relay!
I can't find one for sale, so from that same thread:
Quote:
Your headlight wire should have +12v on it and your Ignition line from steering column should be at Ground when the car is off, so those would be the wires to hook up to the coil of the relay. Then get yourself a little buzzer, Ground the black lead and use the relay to switch +12v to it. 30=+12V, 87=to buzzer red wire, 85=Headlight wire, 86=Ingnition wire.
__________________
This sig may return, some day.
theholycow is offline   Reply With Quote
Old 06-11-2011, 06:29 AM   #25
Site Team
 
Join Date: Dec 2006
Posts: 656
Country: United States
Re: Am I understanding this about charging car batteries correctly?

With regards to temperature, I know of at least one OEM whose voltage regulators will charge a higher voltage when cold than when hot. For example, when you first start the car you'll get about 14.6V, then about 13.7V when everything is hot. Obviously this recharges the battery faster, then drops the system voltage for improved efficiency.

By the way, you won't find any kind of temperature compensation circuit in the regulator, they just take advantage of the effect of temperature on resistance (generally hotter items have higher resistance) in their circuit design.

One time we were on a long trip in my brother's truck and the regulator failed (external regulator), we measured 18.5 volts while running. (We noticed because the turn signals were kinda blinding, and we'd burned out two light bulbs within an hour of each other)

-BC
__________________
Think you are saving gas? Prove it by starting a Gas Log, then conduct a proper experiment.
bobc455 is offline   Reply With Quote
Old 06-11-2011, 06:43 AM   #26
Site Team / Moderator
 
Jay2TheRescue's Avatar
 
Join Date: Sep 2008
Location: Northern Virginia
Posts: 4,657
Country: United States
Location: Northern Virginia
Re: Am I understanding this about charging car batteries correctly?

HC, your Buick doesn't already have a headlight buzzer? They were stock on the Century and Regal. It replaces the seat belt buzzer on the fuse block, and has a wire that you tap into the dash lights. I even took one out of a Junk 1980 Century and put it in Rusty years ago. Just plugged right in.

EDIT: The Buick headlight "buzzer" is actually a chime unit
__________________






Jay2TheRescue is offline   Reply With Quote
Old 06-11-2011, 06:58 AM   #27
Site Team / Moderator
 
Jay2TheRescue's Avatar
 
Join Date: Sep 2008
Location: Northern Virginia
Posts: 4,657
Country: United States
Location: Northern Virginia
Re: Am I understanding this about charging car batteries correctly?

HC, what you need is a chime unit similar to this one:

http://cgi.ebay.com/ebaymotors/1984-...Q5fAccessories

The chime plugs into the fuse block instead of the stock buzzer. You may need to break the connector off the pigtail harness attached to it. The gray wire is spliced into the dash lights, and the other 2 wires connect to the fuse block. I'm sure if you went to a u-pull-it yard you might get it for $1 or $2.
__________________






Jay2TheRescue is offline   Reply With Quote
Old 06-11-2011, 07:17 PM   #28
Registered Member
 
add|ct's Avatar
 
Join Date: Jun 2010
Posts: 534
Country: United States
Re: Am I understanding this about charging car batteries correctly?

Speaking of headlight buzzer/chime mods, I believe a fellow VX owner on the forums mentioned they did that as a 'mod'. I also liked the idea of a WORKING wiper switch, but that's another story. I'd like to get intermittent ones, but I'm not sure if it requires other work than just replacing the existing original switch.
__________________
'92 Civic VX, Canadian model
add|ct is offline   Reply With Quote
Old 06-13-2011, 04:06 AM   #29
Registered Member
 
JanGeo's Avatar
 
Join Date: Jan 2006
Posts: 2,442
Country: United States
Send a message via Yahoo to JanGeo
Re: Am I understanding this about charging car batteries correctly?

Charging a lead battery fully takes many more hours than you would normally drive the car. From overnight to a few days of time to as much as a week of properly applied charging voltage.
JanGeo is offline   Reply With Quote
Old 06-13-2011, 07:14 AM   #30
Registered Member
 
theholycow's Avatar
 
Join Date: Apr 2008
Posts: 6,624
Country: United States
Send a message via ICQ to theholycow Send a message via AIM to theholycow Send a message via MSN to theholycow Send a message via Yahoo to theholycow
Re: Am I understanding this about charging car batteries correctly?

Jay, I may have the chime/buzzer already, I'm not sure. I've been working with the repair manuals trying to identify all the stuff at my fuse block and make sure everything is plugged in correctly. I have good documentation on the headlight warning circuit, I just need to check for existence and functionality of all the wiring and see if I have the right unit.
__________________

__________________
This sig may return, some day.
theholycow is offline   Reply With Quote
Reply

Thread Tools
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
Fuelly Android App - eehokie Fuelly Web Support and Community News 2 07-14-2010 09:59 PM
Notes Request earwhiskers Fuelly Web Support and Community News 2 07-20-2009 04:38 AM
Fuelly for Maintenance? brandonrossl Fuelly Web Support and Community News 11 01-05-2009 04:09 AM
Feature Request: City vs Highway jethrographic Fuelly Web Support and Community News 1 08-08-2008 10:43 AM
Modifying exhaust to increase mileage? Matt Timion General Fuel Topics 15 01-07-2006 08:44 PM

Powered by vBadvanced CMPS v3.2.3


All times are GMT -8. The time now is 02:35 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.