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The Raven
Samba Member
Joined: July 31, 2011
Posts: 303
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 Posted: Mon Oct 10, 2011 2:42 pm Post subject: Quick charging, battery question |
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I have a voltage question for you folks. Today I took the van out.
-When I left the voltage was 100% as I had it hooked up to a tender.
-I started it 6 times while out and doing things. All start ups were done within 15-20 minutes of each other, and the driving was at 3500+ rpm.
- At each start up the van had a harder time starting.
-The Green light on the fridge was on the entire time.
-The voltage upon getting home was about 12.6
-The alternator is putting out 13.9 at the terminal, 13.8 at the battery.
-Once home I hooked up the battery tender and the battery was below 80%.
-The starter is not new, the battery was new in 2007 and has dropped to below 30% at least twice that I know of.
I have my thoughts, but want to read yours. What do I need, what is the issue? |
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Timwhy
Samba Member
Joined: January 01, 2009
Posts: 4102
Location: Maine
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| Posted: Mon Oct 10, 2011 2:56 pm Post subject: Re: Quick charging, battery question |
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| The Raven wrote: |
I have a voltage question for you folks. Today I took the van out.
-When I left the voltage was 100% as I had it hooked up to a tender.
-I started it 6 times while out and doing things. All start ups were done within 15-20 minutes of each other, and the driving was at 3500+ rpm.
- At each start up the van had a harder time starting.
-The Green light on the fridge was on the entire time.
-The voltage upon getting home was about 12.6
-The alternator is putting out 13.9 at the terminal, 13.8 at the battery.
-Once home I hooked up the battery tender and the battery was below 80%.
-The starter is not new, the battery was new in 2007 and has dropped to below 30% at least twice that I know of.
I have my thoughts, but want to read yours. What do I need, what is the issue? |
You didn't mention how your wire/cables are? Also your grounding points? The ground
from the tranny to the frame as well as the alternator. Alot of folks have put another cable from
alt to block for extra added grounding. I'd check each cable and their grounds first.
_________________
'15 Audi A3 Quattro
'09 VW Tiguan (dead)
'87 VW Westy
'91 Tin Top
'90 Cabby
What the Westy wants the Westy GETS
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The Raven
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Joined: July 31, 2011
Posts: 303
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| Posted: Mon Oct 10, 2011 3:08 pm Post subject: |
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Tim,
I can't say that the ones I have seen have been perfect. They are candidates for a marine, waterproof connection treatment, but they do serve the purpose. I do know they have been disturbed and cleaned up in the past year. The battery terminals are clean. Though, in a search I found that corroded terminals do lead to hard starting....but a quickly depleted battery and .1v loss?
Do tell about this additional ground from alternator to block? |
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Timwhy
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Joined: January 01, 2009
Posts: 4102
Location: Maine
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Timwhy
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Location: Maine
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The Raven
Samba Member
Joined: July 31, 2011
Posts: 303
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| Posted: Mon Oct 10, 2011 3:40 pm Post subject: |
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Just crawled under there tonight. It seems the trans-frame strap has not been touched for a while. I will clean it up tomorrow. I'll also add an additional ground strap from the alternator as I have some extra wire hanging around.
One additional note; Although the ground strap has not been touched, when testing voltage I do the typical cross terminal test, and then the grounding test where you touch the seatbelt bolt instead of the neg terminal. No loss noticed.
But like I said before, I'm getting 13.9 at the battery when running so I believe the alternator is working fine, and the battery is not taking the charge. |
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crazyvwvanman
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Joined: January 28, 2008
Posts: 10487
Location: Orbiting San Diego
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| Posted: Mon Oct 10, 2011 3:45 pm Post subject: |
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Maybe, but you must put the voltmeter probes onto the center of the battery posts to know for sure. The actual posts, not any clamps, not any other ground point, BOTH posts. That is the only way to know what voltage the battery is seeing.
Mark
| The Raven wrote: |
.......
But like I said before, I'm getting 13.9 at the battery when running so I believe the alternator is working fine, and the battery is not taking the charge. |
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The Raven
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Joined: July 31, 2011
Posts: 303
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| Posted: Mon Oct 10, 2011 3:49 pm Post subject: |
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| crazyvwvanman wrote: |
Maybe, but you must put the voltmeter probes onto the center of the battery posts to know for sure. The actual posts, not any clamps, not any other ground point, BOTH posts. That is the only way to know what voltage the battery is seeing.
Mark
| The Raven wrote: |
.......
But like I said before, I'm getting 13.9 at the battery when running so I believe the alternator is working fine, and the battery is not taking the charge. |
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Did it, dug right into the lead. Even if I wasn't, the indicated voltage was indicating a charge so the only result would be a higher voltage. |
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crazyvwvanman
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Joined: January 28, 2008
Posts: 10487
Location: Orbiting San Diego
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| Posted: Mon Oct 10, 2011 3:54 pm Post subject: |
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Not accurate. You missed the whole point.
Mark
| The Raven wrote: |
Did it, dug right into the lead. Even if I wasn't, the indicated voltage was indicating a charge so the only result would be a higher voltage. |
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The Raven
Samba Member
Joined: July 31, 2011
Posts: 303
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| Posted: Mon Oct 10, 2011 4:19 pm Post subject: |
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| crazyvwvanman wrote: |
Not accurate. You missed the whole point.
Mark
| The Raven wrote: |
Did it, dug right into the lead. Even if I wasn't, the indicated voltage was indicating a charge so the only result would be a higher voltage. |
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Ok....so I pushed both leads into the lead of the terminals and got 13.9 when running? How did I miss the point? I only later tested voltage on the seatbelt bolt to ensure I actually had a clean, no loss ground.
What point were you trying to make? |
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Timwhy
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Joined: January 01, 2009
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Location: Maine
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The Raven
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Joined: July 31, 2011
Posts: 303
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| Posted: Mon Oct 10, 2011 4:28 pm Post subject: |
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Ah, yeah I got 12.6 when I was home with the probes in the lead terminals.
I'm beginning to think that my battery is fine, but I have a ground loss somewhere that won't allow for a full 14.5 charge?
That and I have a crappy starter connection. I think I need to crawl under there tomorrow and do some cleaning. |
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Timwhy
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Location: Maine
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kamzcab86
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Joined: July 26, 2008
Posts: 8607
Location: Arizona
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| Posted: Mon Oct 10, 2011 5:27 pm Post subject: Re: Quick charging, battery question |
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| The Raven wrote: |
-Once home I hooked up the battery tender and the battery was below 80%.
-The starter is not new, the battery was new in 2007 and has dropped to below 30% at least twice that I know of. |
Sulfation begins at 75% state of charge, or 12.4 volts. It's highly likely that one or more cells is shot. According to one source, "Only 30% of batteries sold today reach the 48-month mark" (what I went through last year with batteries, I can believe it). Allowing a discharge of 50% or more usually shortens the lifespan.
I'd have the battery load tested; if it fails the load test, a new battery is in order.
_________________
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 1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子 |
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The Raven
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Joined: July 31, 2011
Posts: 303
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| Posted: Tue Oct 11, 2011 1:04 pm Post subject: |
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Well,
Cleaned the body to trans ground, installed the alt to block ground and started the van up. 14.01 volts at first startup. Then shut it off, restarted it, 13.9v. Hooked up the tender and it said the battery dropped below 80% charge. Although the battery volts do not plummet at startup, I am beginning to think it is the battery. I was thinking it is the starter, but when the battery is 100% it works every time. It just seems that when it gets low, it gets touchy. |
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presslab
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Joined: September 29, 2008
Posts: 1730
Location: Sonoma County
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| Posted: Tue Oct 11, 2011 1:42 pm Post subject: |
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I doubt the tender really knows the SOC (state-of-charge) of the battery. What criteria does it use to state 80%? Did you disconnect the battery from the van before attaching the tender?
Your 13.9 V from the alternator should charge it up just fine, so I don't think that is a problem. This voltage will vary with engine temperature - colder being higher.
The certain way to measure SOC is to disconnect the battery for at least 4 hours and measure the terminal voltage. Even still this voltage will change with ambient temperature. 100% SOC is about 12.8 V at 20 C.
Even a worn out battery will usually reach 100% SOC. What you really need to do is load test the battery. I suspect you have a bad battery and / or bad starter.
Good luck.
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1988 Subaru GL-10 EJ20G --- 2000 Honda XR650L
2010 Titus El Guapo --- 2011 On-One 456 Ti |
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PDXWesty
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Joined: April 11, 2006
Posts: 6344
Location: Portland OR
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| Posted: Tue Oct 11, 2011 1:46 pm Post subject: |
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You really do need to take the battery somewhere that has the right equipment. I took a battery I suspected was weak in once for a test. They made me leave it overnight with them so they could make sure it had a full charge. Then they load tested on a machine that spit out a computerized report. Turns out the battery was within specs. I had to make a few changes to my system to get it to perform optimally.
The thing is, I don't think you can get the battery to a full charge by just driving short distances. It takes many hours to properly charge a battery then float charge it to a 100% state.
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Last edited by PDXWesty on Tue Oct 11, 2011 1:56 pm; edited 1 time in total |
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The Raven
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Joined: July 31, 2011
Posts: 303
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| Posted: Tue Oct 11, 2011 1:55 pm Post subject: |
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I will pull it and take it in. I don't think 6 start up should begin to weaken a battery. It was purchased in 07 and with two known discharges who knows what condition it's in.
The tender I'm usign is a battery tender Jr, typically used with motorcycles and charges at 750mv and floats it after that. |
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Timwhy
Samba Member
Joined: January 01, 2009
Posts: 4102
Location: Maine
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| Posted: Tue Oct 11, 2011 2:34 pm Post subject: |
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Wally world will check a battery, so will Batteries Plus. 2007 battery, may have already seen its better days?
I have Schumaker tenders for both my battery banks, one is a 2amp and the other is a 1 1/2amp
they work great once the batteries are fully charged. Takes a long time to charge a 1/2
capacity house battery bank. My charge controller will show when the batteries are at
half capacity, though the voltage is 12.7 and higher. I am speaking from the point of view
that when my house batteries were taxed. It was really cloudy for five days straight, my batteries
were not drawing a charge from the panel and it took awhile for them to recover.
Hope you figure it out!
_________________
'15 Audi A3 Quattro
'09 VW Tiguan (dead)
'87 VW Westy
'91 Tin Top
'90 Cabby
What the Westy wants the Westy GETS
http://www.thesamba.com/vw/forum/album_search.php?search_author=Timwhy&show_results=summary
http://www.youtube.com/user/TIMWHY2?feature=mhee |
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The Raven
Samba Member
Joined: July 31, 2011
Posts: 303
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| Posted: Tue Oct 11, 2011 3:14 pm Post subject: |
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| Timwhy wrote: |
Wally world will check a battery, so will Batteries Plus. 2007 battery, may have already seen its better days?
I have Schumaker tenders for both my battery banks, one is a 2amp and the other is a 1 1/2amp
they work great once the batteries are fully charged. Takes a long time to charge a 1/2
capacity house battery bank. My charge controller will show when the batteries are at
half capacity, though the voltage is 12.7 and higher. I am speaking from the point of view
that when my house batteries were taxed. It was really cloudy for five days straight, my batteries
were not drawing a charge from the panel and it took awhile for them to recover.
Hope you figure it out! |
You run off solar too?
I actually installed a wind turbine to take advantage of some of the wind that accompanies the cloudy days. |
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