Batterys interesting/confuseing

[jjrbus]

I have had some starter/ battery issues and found something confuseing but interesting. It seemed to start with the death of a 7 year old starter battery, 2 group 31 batterys @ 24 volts.
One battery died, the one connected to my disconnect switch, battery #1. I purchased 2 new batterys and noticed they would not hold a charge, battrey #1 being the worse. I took them back, batterys test good.   Batterys will still not hold a charge, I spend much time looking for drain, can find nothing!!  These batteries are draining with the positive cable unhooked!!!! It seems Ace is the only other person to experience this. I take batteys back and #1 will not pass load test and is replaced.   They still will not hold a charge. I decide new batterys are junk and start useing maintainer.
Next I have starter problem and couple other issues. I am convinced now that I will never buy cheap batterys again and am ready to junk the ones I have.
Several things happen here, I take batterys back and they replace #1 again. I have starter rebuilt. Replace lug on battery cable. All terminals have been unhooked and cleaned 27 times now.
Since putting everything back together the batterys are holding thier charge with no maintainer. I checked them everyday for 10 days and the voltage varies by 1 or 2 tenths. Befor this in 10 days they would be down 2 volts!!
  When the starter was rebuilt they told me the fields were grounding to the case. I am electrically challenged and this may be a stupid question but could the starter fields grounding have been draining the batterys??  This drain was occuring with isolator switch off and at one time with positive cable unhooked from battery. The only thing hooked up was the ground cable.
Gremlins, ya gotta love em!  Jim

[makemineatwostroke]

JR: the problem most of you guys have is caused by not enough amps a starter should last 20 years or more .The starter is a 12hp electric motor and a 24 volt starter will draw from 1000 amps min and with 2 group 31 batteries that is iffy use 4 and your troubles will go away.I read here where people are replacing the starter every 2 or 3 years unheard of if you have have the right CC amps and plus the low amp are going to shorten the life of your batteries.   
  Have a great and wonderful day

[JackConrad]

Electricity has to have a complete circuit for the little electrons to travel.  If you disconnect the positive cable, the electrons can no longer travel since there is not a complete circuit from them to use.  I have no idea how the electrons got out of your battery.  Jack

[makemineatwostroke]

Flooded lead batteries will usually lose 1 volt about every 2 days till they reach about 11 volts depending on the manufacture a natural process AGM batteries have a less drop over the same time frame fwiw   

Sorry guys but I forgot it is not always the case in other parts of the USA I live in AZ and TX and the voltage drops like a rock in a few days

[jjrbus]

Mike after reading your post I thought I had a problem. However I cannot find a 1000 amp figure anywhere for a starter.
I tried the ampacity charts to see what size wire should be used for 1000 amps at 24V @ 5 feet it appears that it would take 2 4/0 and 1 2/0 ?
Again I am not electrical, so this is a question.

[makemineatwostroke]

JR; when my grandson comes home I will get him to scan the page from the Delco book and email it to you showing the HP and amps for the 50,42 and 37 Delco starter always the minimum amp draw shown for 32 and above 32 degrees there is a page in the DD  manual that shows the minimum amp for the 50 starter  have a great day

[Blacksheep]

Wow JR that's hard to understand. I know that ever since I installed my on-board marine battery charger/tender, I have never never ever had a start problem or issue of any kind! I found that I can leave the charger disconnected for 2-3 days and my batteries will be down enough that they won't start the coach but when I plug the charger up and let it do its thing, the next morning, the coach is good to go! While the coach is parked in my driveway I leave the charger connected until I am ready to leave!
It made a believer out of me!
Like you, I exhausted every effort to find out why I was experiencing what it was! It wasn't until I talked to the guyds at Marathon coach and another busnut that persuaded me to install a charger. The guys said that our coaches sit more as a motorhome than they do when they are seated coaches and that goes even for the million dollar coaches so that is why they have the on-board charger/tenders. The best money I have ever spent and I REALLY mean that!

Ace

[Nick Badame Refrig/ACC]

Hi Jim,

I think it's time to get your Hydrometer out and test each cell. They should be consistant..

If one cell is shorted, it will bring the whole bank down very quickly. The batteries will still take a charge and seem normal with

proper voltage and all but, that one shorted cell will drain your bank even with the batt cables removed.

Good Luck
Nick-

[Lin]

Nick,
     I had that exact thing happen with a 3 battery bank.  I thought that they were all bad, finally tested them and found one bad cell.  When I got rid of that one battery, the others popped back like new.

[gumpy]

Flooded lead batteries will usually lose 1 volt about every 2 days till they reach about 11 volts depending on the manufacture

I have to disagree with this statement. Flooded lead acid batteries do not lose 1/2 a volt a day if they are maintained properly.
It's true that a fully charged battery will naturally lose voltage over time, but it's more like hundredths of volts per month.
A good battery with no load on it in normal climatic conditions will retain a starting charge for up to a year or more.

[JackConrad]

Flooded lead batteries will usually lose 1 volt about every 2 days till they reach about 11 volts depending on the manufacture a natural process AGM batteries have a less drop over the same time frame fwiw

The 2 batteries in our Ford Dually with 7.3 liter diesel engine sometimes sit for 12 weeks (84 days) while we are traveling. When we get home, I can get in it and it spins right over.  These batteries are about 2 years old and although I have not checked them with a voltmeter, I am sure thay are higher than 11 volts, based on how the engine spins and starts.  We do not keep any kind of trickle charger or manitainer on them.  Jack

[makemineatwostroke]

Take 1 12 volt battery charge it 13.5 and see how fast it will drop to 11.5 to 11 volts the cheaper and light weight batteries will discharge faster

[Blacksheep]

I'm a firm believer that all batteries will drop in voltage over a period of time some sooner than others and some longer but as long as they are connected to source/s the time usually accelerates this is if nothing at all is done to replenish them!

Prevost regional tech told me that ALL electronic buses have voltage drain in the start batteries as a result of many possible different items and that is when the batteries are in the disconnect mode better known as phantom drain! Could be a simple digital clock or a light in a radio, speaker, or the radio itself.
With the looks of some bus wiring, it could lead to almost anything shorting out on the frame to cause a drain! It doesn't end there! It can even result from a LOOSE terminal!

Ace

[kyle4501]

A fully-charged 12-volt battery, allowed to "rest" for a few hours (or days) with no load being drawn from it (or charge going to it), will balance out its charge and measure about 12.6 volts between terminals.
(from Phred's Poop Sheets -   http://www.phrannie.org/battery.html  )

I have an 8D that has been sitting since February & it reads 12.5V on a digital multimeter.
I must have gotten a 'good one' 

The battery is CLEAN & DRY & stored inside my shop.

[jjrbus]

 A new curve, I did not check my voltage this morning becuse it was raining! The voltage has been  measureing over 25.5 volts everyday for the past week.
This afternoon it measures 24.6 volts, that is a 1 volt drop in one day!  So now I am thinking rain = wet + electricity, I wonder    Yes there is water on the batterys.  Jim