batteries shot??
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From: airdrie canada
batteries shot??
I have a 2005 F350 supercab 6.0. Didn't plug it in a week ago, was -17c, couldn't get it started, seems batteries didn't turn it over fast enough, long enough( its started in the past, in colder weather no problem) I finally got it going, and thought I'd see if the batteries were charging, checked batteries next day 12.78 and 12.79 volts ( I had disconnected the cables night before to see if batteries drained overnight not hooked up)hooked up voltmeter, when engine started voltage dropped to 11.69 volts watched meter for a min or so the voltage slowly climed to 14.32 volts, did same test another day, same results except voltmeter jumped from 11.88 volts to 14.23 volts. Is it possible that the batteries are causing this or the alts?
More Turbo
Joined: Aug 2006
Posts: 548
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By "causing this" do you mean the voltage jump? If so, the answer is neither.
Your glow plugs continue to operate after start-up. The jump in voltage you observed is just the plugs cycling off.
Because your voltage recovers after start-up, it seems that you alternator is doing its job. But your batteries do not have sufficient CCA to reliably start cold, so it is probably time to change them.
Easy answer: Charge them fully, disconnect them from one another and give each one a load test. This will give you an accurate idea of the condition of the batteries. But make sure you disconnect them from each other before testing.
-mike
Your glow plugs continue to operate after start-up. The jump in voltage you observed is just the plugs cycling off.
Because your voltage recovers after start-up, it seems that you alternator is doing its job. But your batteries do not have sufficient CCA to reliably start cold, so it is probably time to change them.
Easy answer: Charge them fully, disconnect them from one another and give each one a load test. This will give you an accurate idea of the condition of the batteries. But make sure you disconnect them from each other before testing.
-mike
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From: airdrie canada
By "causing this" do you mean the voltage jump? If so, the answer is neither.
Your glow plugs continue to operate after start-up. The jump in voltage you observed is just the plugs cycling off.
Because your voltage recovers after start-up, it seems that you alternator is doing its job. But your batteries do not have sufficient CCA to reliably start cold, so it is probably time to change them.
Easy answer: Charge them fully, disconnect them from one another and give each one a load test. This will give you an accurate idea of the condition of the batteries. But make sure you disconnect them from each other before testing.
-mike
Your glow plugs continue to operate after start-up. The jump in voltage you observed is just the plugs cycling off.
Because your voltage recovers after start-up, it seems that you alternator is doing its job. But your batteries do not have sufficient CCA to reliably start cold, so it is probably time to change them.
Easy answer: Charge them fully, disconnect them from one another and give each one a load test. This will give you an accurate idea of the condition of the batteries. But make sure you disconnect them from each other before testing.
-mike
I had the batteries tested today, along with the charging system, and QUOTE UNQUOTE--- both checked out fine. of course hopefully the person testing them really knows what they are doing.
Thanks by the way!!
Senior User
Joined: Nov 2010
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From: wildwood, mo.
Ok. if the glow plugs are causing the "voltage jump" by cycling off, then why does the voltage "jump" on some occasions and slowly go up on others? Also if the alternator is turning(which it is) shouldn't voltage at battery (either one) be up to max ie. 13.45 volts or whatever this system can produce, as soon as the engine starts? As well on Monday( the truck had sat since friday about 11:00 am) I went to start it, it didn't turn over as fast as normal and for about (and I guessing here a little) 3-5 secs the tach needle bounced from 0- 250 or so rpm? To me that says somethings wrong?
I had the batteries tested today, along with the charging system, and QUOTE UNQUOTE--- both checked out fine. of course hopefully the person testing them really knows what they are doing.
Thanks by the way!!
I had the batteries tested today, along with the charging system, and QUOTE UNQUOTE--- both checked out fine. of course hopefully the person testing them really knows what they are doing.
Thanks by the way!!
Post Fiend
Joined: Oct 2009
Posts: 12,123
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From: N. Fort Worth, tx
By "causing this" do you mean the voltage jump? If so, the answer is neither.
Your glow plugs continue to operate after start-up. The jump in voltage you observed is just the plugs cycling off.
Because your voltage recovers after start-up, it seems that you alternator is doing its job. But your batteries do not have sufficient CCA to reliably start cold, so it is probably time to change them.
Easy answer: Charge them fully, disconnect them from one another and give each one a load test. This will give you an accurate idea of the condition of the batteries. But make sure you disconnect them from each other before testing.
-mike
Your glow plugs continue to operate after start-up. The jump in voltage you observed is just the plugs cycling off.
Because your voltage recovers after start-up, it seems that you alternator is doing its job. But your batteries do not have sufficient CCA to reliably start cold, so it is probably time to change them.
Easy answer: Charge them fully, disconnect them from one another and give each one a load test. This will give you an accurate idea of the condition of the batteries. But make sure you disconnect them from each other before testing.
-mike
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Post Fiend
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Not so fast... new batteries with a weak alternator / bad cables mean the same merry go around..
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The Voltage drop is normal, you read low voltage for a short time after engine start because the glow plugs draw a lot of voltage and get it from the aternator AND batteries. once the glow plugs cycle off there is more than enough Alternator output to run everything AND recharge the Batteries. It can also take a few minutes at idle for the alternator to ramp up to full output sometimes.
The slower cranking speed at extremely low temps is probably related to oil weight.... To save time, trouble and wear I would change to a full synthetic oil for the temps. and/or Plug it in at night
The slower cranking speed at extremely low temps is probably related to oil weight.... To save time, trouble and wear I would change to a full synthetic oil for the temps. and/or Plug it in at night
Got Diesel?
Joined: Jan 2004
Posts: 4,345
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When testing batteries on a diesel (due to two batteries)... they must be disconnected!!!
If not, then the load test will not be accurate for each battery. If you have one battery that is weak, then the other battery is working extra hard to make up for it... especially when cold.
1) Load test each battery seperately - go to different parts store and watch.
2) Check alternator output (It sounds like yours is doing fine... unless it is slowly going out?)
3) Do you use synthetic oil? Makes big difference in very cold temps for easier starting... not mandated... but makes it easier on cold mornings?
4) Do you use anti-gel in your fuel? Wax forming on/in your fuel filters will restrict fuel flow through out the entire fuel system... making for slow starting and rough running.
5) How old are your batteries... if 5 years or older.. then your due for new ones. Depending on where you live, some people don't even get 5 years out of their set!!!
If not, then the load test will not be accurate for each battery. If you have one battery that is weak, then the other battery is working extra hard to make up for it... especially when cold.
1) Load test each battery seperately - go to different parts store and watch.
2) Check alternator output (It sounds like yours is doing fine... unless it is slowly going out?)
3) Do you use synthetic oil? Makes big difference in very cold temps for easier starting... not mandated... but makes it easier on cold mornings?
4) Do you use anti-gel in your fuel? Wax forming on/in your fuel filters will restrict fuel flow through out the entire fuel system... making for slow starting and rough running.
5) How old are your batteries... if 5 years or older.. then your due for new ones. Depending on where you live, some people don't even get 5 years out of their set!!!
Cargo Master
Joined: Feb 2002
Posts: 2,414
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From: Tucson USA
Just put new batts in mine, sears has 100 mo batteries with 3 year free replacement, maint free for $110 each. They also have a 4 year battery (also 100 months I think, it is AGM techknowledgy) $200 each . The first are 770CCA the 2d are 900 CCA.
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From: airdrie canada
Ok, I started the truck today( it was warm, had used it already) heater on full, headlights on, radio, etc on, voltage was 12.81 sitting, while cranking with all the above on dropped to about 10.46, started and after 30-40 sec ramped up to 13.38. I'll try to have someone else test the batteries tomorrow. and I'll let you know.
Thanks
Thanks
Post Fiend
Joined: Jul 2005
Posts: 6,127
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You need the voltage reading after 10 min of running, at idle, and at 2000 rpm.
Plus, temperature outside.
And what accessories are on.
Off hand, if you are doing 10:46 cranking with glow plugs on, in a temperate climate, you are alright.
What is temp in airdire? If it is really cold... it is excellent.
I was getting 9.7v cranking last year in the cold.
Plus, temperature outside.
And what accessories are on.
Off hand, if you are doing 10:46 cranking with glow plugs on, in a temperate climate, you are alright.
What is temp in airdire? If it is really cold... it is excellent.
I was getting 9.7v cranking last year in the cold.
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