2nd Gen Non-Engine/Transmission Is this a sign of weak batteries?

[CCiatteo]

My dodge has been in my possession for 18 months and the batteries are of unknown vintage and have performed flawlessly. In the last two days however, I have noticed that upon startup the volt gauge is slow to come up to the 14v mark (actually just a little past 14v). It takes maybe a minute or two, then proceeds to go to about the 15 volt mark (which is high compared to what I usually see).



The grid heaters cycle normally and the voltgage and lights dim like usual and this stops once I get heat in the motor or start off down the road. I feel confident in saying they are working correctly and not sticking on.



With winter approaching here in the northeast I don't want to get caught. So tonight I went out and threw a voltmeter across both batteries with the truck at operating temp and both read 14. 5 +/- volts (old analog meter), so it appears the alternator is doing its job and the guage in the truck is reading accurate. I cleaned all the terminals (cables are in good condition) and noticed that the driver side battery was low really low on water in one cell (end closest to the negative terminal). That terminal was really nasty too with a acidic paste all over it (normally its a dry crust?). I am thinking that maybe the battery is leaking at the post? I saw no obvious cracks in the case. I topped off the battery, cleaned everything and was hoping to solve the problem, but same thing. Upon initial startup, the volt guage hangs at the very bottom of the normal range and slowly works its way up to 14 (normal) then once going down the road (70mph @ 2000rpm) it will read 15+/-volts. So I went for 20 run down highway to see if maybe they need a quick charge, but same deal.



Could this be the alternator trying to recharge a weak battery? If so could this damage the alternator in the short term, one or two days until I can get the batteries?



Just for reference, up until this point, I would start the truck volts go to 14+/- right away and dip as the grid heaters cylce, but never was she slow to climb to 14+/-volts nor did she go past 14+/- like she is reading now.



If the batteries are the culprit I am leaning towards Optima Yellow tops, any specific part number?



Thanks

Chris

 

[JFaughn]

To test the alt , batteries , starter , you need to have a load tester [ reads amps & volts ] .
From what your post it would seem like the batteries , but testing is how to do it right the 1st time .

 

[Oasis-3]

Test

Chris Try unhooking the battery that you think is bad and see if your voltmeter reades normal.



Good luck

Cliff

 

[RBallard]

Take it to an Auozone or such and have them load test it. Both of my batteries read the correct voltage but under load, one dropped to 5 volts. I could tell something was wrong because it took longer for the engine engine to turn over.

 

[K5IP]

Cliff has a good suggestion, You need remove only the negative post connection. For a really good load/balance test, start the engine using one battery. Then switch to the other one and do the same test. Note/'compare the cranking speed for each individual battery, and the also the rate the voltmeter comes back up. Both batteries should act the same. Also, the higher readings you are seeing are probably due to the temperature compensation in the charging system. (about -25mv/degC)

So, cold winter weather will increase the alternator output to above 15Vdc.

Rog

 

[DPellegrin]

I agree with the posters that have recommended you load test your batteries. This is the best way to determine their state of health. Your charging system appears to working OK.



When two batteries are connected in parallel the charging system is going to see an average voltage of the two. Current will flow from the good battery (high voltage) to the not so good battery (low voltage), thus the average. I would not recommend cranking the engine using one battery, this is hard on the starter motor, especially if one of your batteries is low. While load testing is probably more work it is much safer and will yield a more certain diagnosis of your problem.



As you can see I live in Minnesota. When it is -20F here my charging voltage is 14. 4 to 14. 6 volts. I have never seen 15. 0 volts.



Good luck with your diagnosis.

 

[CCiatteo]

Update....

Thanks to everyone for the suggestions.



Tonight I did a quick test and simply disconnected (both terminals) one battery at a time, started the truck. Repeat with the other battery. Truck cranked slower with just one battery, but started quick enough. Both batteries behaved the same and were slow to come up to the 14v mark. Over the weekend I will take both batteries out and over to the autozone and have them load tested. I am starting to think that both are near the end of their life, originally I thought the driver side battery was wounded. Either way if one comes up as bad, both will get replaced.



Is the reason the volt guage is slow to come up to 14v because the grid heaters/starter are pulling them down so far and in their weakened state they aren't recovering as quickly? Just trying to understand.



Another question, is there any advantage to rotating the batteries? Does the driver side battery see more load than the passenger side battery and if so would the occasional rotation prolong life? I am thinking that as long as the cable and terminals are good, the benefits would be very minimal at best. Curious?



I will keep you guys posted, thanks again.

 

[DPellegrin]

The grid heaters certainly draw current from the batteries as the alternator can not supply all the current that is needed. This is why the voltage falls when the grid heaters are on. I would not be alarmed that the voltage does not recover quickly when the heater goes off, especially if you are observing the voltage from the dash gauge. If you like, use a good digital gauge and try the same thing only take the voltage reading right at the battery post. You will probably see a difference between what the dash gauge says and what is actually happening at the battery.



I see no benefit in swapping locations for the batteries. These batteries are connected in parallel and see the same charging voltage and current.

 

[CCiatteo]

The grid heaters certainly draw current from the batteries as the alternator can not supply all the current that is needed. This is why the voltage falls when the grid heaters are on. I would not be alarmed that the voltage does not recover quickly when the heater goes off, especially if you are observing the voltage from the dash gauge. If you like, use a good digital gauge and try the same thing only take the voltage reading right at the battery post. You will probably see a difference between what the dash gauge says and what is actually happening at the battery.



I see no benefit in swapping locations for the batteries. These batteries are connected in parallel and see the same charging voltage and current.

I have no doubt the dash gauge is not a precise instrument, but the gauge did not behave this way previously, that is what initially tipped me off that there may be a problem. I'll borrow a good digitial gauge see what kind of readings I can get during starting and when the grid heaters are cycling.



Maybe the gauge is failing, certainly possible.

 

[tgordon]

My truck is starting to crank slower and I know my batteries are getting bad, along with the gauge starting to read high. The other thing that causes me to say batt is that you had to add to one of the batteries. I am guessing that water was added and that will slightly deminish tha capacity of the battery. I will also go to the Optimas, but am thinking about goin gto the blue tops because they have some with a higher CCA rating, if they will fit into the trays.

 

[JFaughn]

When there is a problem inside the battery , it does not matter much is current is going out or in , the battery is not going to react well in either direction .
If its slow to put out , its slow to take in .

 

[K5IP]

Chris,

It sounds like your batteries are OK.

But, if you live in a cold climate, perhaps changing them is good for piece of mind.

I am now in Arizona where my Costco batteries (group 27) are now eight years old and going strong.

 

[DPellegrin]

CCiatteo, In considereing your observations of your dash voltmeter please remember that in general, when colder temperatures set in, the battery gets smaller in terms of its ability to produce current while the charging sytem voltage is higher in order to charge the battery when compared to warmer temps. On the other hand the engine gets larger, i. e. it takes more current to crank a cold engine. Thus the volt meter probably behaves differently in the winter than it does in the summer.



Best regards,

 

[Skydiver]

This is about 30 minutes of reading about batteries.



Batteries -- and Other Electric Stuff by phred



I found it useful.

 

[Rattler]

My truck was acting just like yours. I even was worried that my VP was on the way out. I really did not think about the battery,s even though they were 6 years old this past august. My truck had to sit for a week before Thanksgiving and i had to jump it off to start it, so i went ahead and put 2 new batteries on and it made all the difference in the world. The truck starts as good now as it used to. I guess i had not notticed the crank speed slowing down as much as it had. Randy

 

[obert]

Take it to an Auozone or such and have them load test it. Both of my batteries read the correct voltage but under load, one dropped to 5 volts. I could tell something was wrong because it took longer for the engine engine to turn over.

I went there once to have them check for a key off voltage draw. I had to show the guy how to use the VAT machine! :-laf :-laf



Clean ALL the conections, not forgetting the cable between the the batt. 's that crosses the radiator. If the "cross" cable isnt well, the left battery does work harder. Even if connections look clean, oxidation could still be a problem. A digital volt meter lead on each side of the connection (ie, probe on batt post and another on cable end) shouldn't read more than 0. 1v drop thrugh the connection.



on the opimas... . the blue tops are 1000cca starting batteries. Yellow top are 1000cca RV/marine deep cycle. Red are 900 cca starting batteries. Last time I bought them was a couple years ago, there may be changes. I wouldn't recomend Yellow top for your truck, go with blue if you want the higher cca. I have had red tops in since Jan. '03, still work great even with the truck sitting alot. I have a yellow top in the camper.



Best thing about the gell cell batts is NO yellow/green fuzzy acid corrosion on the battery terminals-- all clean even after nearly 5 years. We've had great luck with them.

 

[CCiatteo]

Weekend update....

Chris,

It sounds like your batteries are OK.

But, if you live in a cold climate, perhaps changing them is good for piece of mind.

I am now in Arizona where my Costco batteries (group 27) are now eight years old and going strong.

Well today I had lots of running to do and I figured it'd be a good test to see if the batteries are indeed ok. First stop was to Autozone, and with the batteries still in the truck and connected they did the load test. I am unfamiliar with this test and the machine used, so I have to hope the pimply faced kid knew what he was doing. Both batteries looked to behave in similiar fashion and would read 11. 2 or 11. 1 when put under the load and this was done 3 or 4 times to each battery, and the machined flashed good for both batteries.



So now I am really confused or maybe just losing my mind. I continue on my way making all kinds of short trips, long trips, blasts down long high way strectches and all seems well. No sign of trouble at all. The last stop of the day is at Sears, where I pick up a new digitial multimeter on sale. I race home home and this is what I find.



(Results were the same for both batteries)



Truck off 13. 09 V



Immediately after start up (grid heaters cycling) 13. 80v cycling down to 12. 70v



At temp with all accessories off and truck idling in neutral 14. 02v.



Truck in neutral at 1500 rpm (roughly, I was by myself) 14. 10v.



These numbers seem reasonable to me, the last two I thought should be 14. 2 or above, but they aren't wildly off the mark are they?



Then my buddy stopped over with a 2001 CTD and he had 14. 20+/- at the batteries after warm up, but otherwise was very close.



So now I am thinking that maybe my brain is fried and I am just not remembering correctly.



I think the last check would be to have the alt. load tested, just to be sure. Connections all look good and terminals are all clean. Cables all look good, I should check the cross over cable for resistance just to be sure.



I don't know what else, maybe this has all been a false alarm?



Thanks for everyone's help and have a safe and happy holiday.

 

[DPellegrin]

Chris,



It appears that your charging system is working properly, including the alternator. I am encouraged by the voltage reading of 13. 09 volts with the engine off. This means that the batteries are taking a surface charge. After about a half hour I think you will find the open circuit voltage is 12. 6V. Finally the only way to accurately measure the the voltage drop (resistance) in the battery cables is with a carbon pile load tester. In order to test the cable you have to flow current through it. Cable suppliers typically publish specifications that specifiy the voltage drop per foot of cable at a specified current flow (amperage) for a given size of cable. However I really don't think you have a problem with the integrety of the system cables.



Have a great holiday