| Author |
Message |
davidw99
Samba Member
Joined: September 04, 2003
Posts: 696
Location: Boston, MA
|
 Posted: Thu May 12, 2016 5:20 am Post subject: Charging issues |
 |
|
Hello,
My car wouldn't start recently because of a dead battery. The car was turning over slower recently when starting so it seems that the battery has been slowly losing charge for a while. I charged it up and the car started right up. The battery checked out with 12.9 volts with the car off, 12.3 after trying to start it for twenty seconds with the coil wire off and 13.9 when running. The water was low in three cells so I added water. I then took the car for a twenty minute drive. After the drive the readings were 12.9 when running and 12.5 when not running.
My question. Is the 12.9 reading after the drive typical or is it and indication that the alternator is on the way out? The alternator (Bosch) is nine years old but only has 18,000 miles on it. Would an alternator belt that slips after the car warms up cause this? Is the 12.9 volt reading really a problem?
Any thoughts are welcome. Thanks.
_________________
Dave
'73 Saturn Yellow Sports Bug that has undergone a full pan off restoration. "Herbert IV."
'67 Sedan. "Bellamy." Currently being "refreshed" and recently repainted. |
|
| Back to top |
|
 |
TheStanfordWagen
Samba Member
Joined: October 06, 2013
Posts: 99
Location: Dresden, Ohio United States
|
| Posted: Thu May 12, 2016 6:41 am Post subject: Re: Charging issues |
|
|
Check your fan belt tension. If the belt tension is good, then I would take the alternator off of the housing and have it checked by someone. Anything is possible, even with an alternator that is fairly new.
_________________
1968 Type 1 - Royal Red --- Built: September, 1967
1600 Single Port Engine - F1950480 (VW Exchange) Made January 16th, 1970
113-905-205K
Solex 30 PICT-3
Fahrgest.-Nr. 118096544 |
|
| Back to top |
|
|
Cusser
Samba Member
Joined: October 02, 2006
Posts: 31379
Location: Hot Arizona
|
| Posted: Thu May 12, 2016 8:32 am Post subject: Re: Charging issues |
|
|
| davidw99 wrote: |
| My car wouldn't start recently because of a dead battery. The car was turning over slower recently when starting so it seems that the battery has been slowly losing charge for a while. ..... The water was low in three cells so I added water. Any thoughts are welcome. Thanks. |
Dead battery, low on electrolyte....how low was the electrolyte level?
My guess is that a new battery is in your near future !
_________________
1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297 |
|
| Back to top |
|
|
davidw99
Samba Member
Joined: September 04, 2003
Posts: 696
Location: Boston, MA
|
| Posted: Thu May 12, 2016 12:04 pm Post subject: Re: Charging issues |
|
|
The battery was new last fall but there is no telling how long it was sitting on the shelf at the FLAPS. I'm sure bug batteries don't sell real fast in New England. The electrolyte level was just touching the top of the plates on two cells and below the plates on the third. The other three cells looked OK.
_________________
Dave
'73 Saturn Yellow Sports Bug that has undergone a full pan off restoration. "Herbert IV."
'67 Sedan. "Bellamy." Currently being "refreshed" and recently repainted. |
|
| Back to top |
|
|
Cusser
Samba Member
Joined: October 02, 2006
Posts: 31379
Location: Hot Arizona
|
| Posted: Thu May 12, 2016 12:11 pm Post subject: Re: Charging issues |
|
|
| davidw99 wrote: |
| The battery was new last fall but there is no telling how long it was sitting on the shelf at the FLAPS. I'm sure bug batteries don't sell real fast in New England. The electrolyte level was just touching the top of the plates on two cells and below the plates on the third. The other three cells looked OK. |
Hmmm - I'd guess water wouldn't evaporate from the electrolyte so quickly in New England either .... maybe related to underpressure in New England footballs...
_________________
1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297 |
|
| Back to top |
|
|
Danwvw
Samba Member
Joined: July 31, 2012
Posts: 8892
Location: Oregon Coast
|
| Posted: Thu May 12, 2016 12:41 pm Post subject: Re: Charging issues |
|
|
Yeah, 12.9 Volts is not enough to charge your battery. 13.9 or 14 or even 14.2 would be good. So it sounds like it's not charging when it's hot. It could be the belt but it would have to be really loose. What is the charging voltage with the headlights on when it's cold? If that's good then the alternator is putting out good current when cold. Lots of things it could be though. Battery, Battery connections, Ground connections, Other B+ connections and for sure a cooked fan belt.
_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths! |
|
| Back to top |
|
|
davidw99
Samba Member
Joined: September 04, 2003
Posts: 696
Location: Boston, MA
|
| Posted: Thu May 12, 2016 5:05 pm Post subject: Re: Charging issues |
|
|
I changed the belt. It was very smooth but it probably wasn't the issue. Voltage not running: 12.54; running with headlights on: 13.11; running with headlights off: 13.68. I think I'm just going to monitor the issue for now. If the cranking gets slow again I'll run the tests again.
_________________
Dave
'73 Saturn Yellow Sports Bug that has undergone a full pan off restoration. "Herbert IV."
'67 Sedan. "Bellamy." Currently being "refreshed" and recently repainted. |
|
| Back to top |
|
|
Danwvw
Samba Member
Joined: July 31, 2012
Posts: 8892
Location: Oregon Coast
|
| Posted: Fri May 13, 2016 4:22 pm Post subject: Re: Charging issues |
|
|
Yeah if your measuring just 13 volts at the alternator with the head lights on but almost 14 with them off it means the alternator is not putting out much current for some reason. But if those voltage readings are at the battery then it's likely a bad cable connection somewhere probably where it was routed around the old voltage regulator under the back seat.
_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths! |
|
| Back to top |
|
|
|
