Batterys interesting/confuseing

[gumpy]

If your battery tops are not clean, the crud can actually conduct energy out of the batteries. It's unuaual, and typically doesn't discharge a high current, but it can have an effect.

Still normal batteries do not discharge at a significant rate when not connected.

I had a problem with mine when I first got the bus. One battery was draining. It turned out to be a phantom load on the 12v side. I never found it, but I installed a cutoff switch and the problem stopped. Now, I just leave the inverter plugged in on float, and the crossover switch activated, so I'm floating my coach batteries along with my house bank.

craig

[Sojourner]

Hi Jim
As long you had turn the main power off (master switch), no other tapping connected and batteries are free of acid coating around the battery case. There is no reason to cause a run down. However, old battery will normally build up deposit under plates to cause shorts after many heavy discharges and recharge. This is not the case because it brand new.

In the mean time, keep the batteries acid free on outside of case & hold down. Watch your voltage at least once a week for several times and without a floater charger on. Then tell us the results.

Remember your pass problem with corride wire end and fuel pressure switch has a lot to do with the confusion for blaming battery & starter condition.

BTW...purchase 2 new group31 at wally world 3 years ago and it still over 12v from sitting....even jump start a car 2 month ago and never charge since 3 years ago. Would it be the cause for been locate in Elloree, Sc.? ? ?...LOL

BTW...try never to purchase starter battery with refill capable...more prone to parasite drainage from acid coated case and weaken electrolyte by adding water at the wrong time.  Deep cycle must be refillable due to heavy discharge & recharge.

About Gremlin...I am not afraid of them because I chase them out after the step by step diagnostic check points to repair the problem. LOL

FWIW

Sojourn for Christ, Gerald

[jjrbus]

JERRY DO NOT MOCK THE GREMLINS, they will get you!!!!!

I've considered useing the selector switch to hook the bus batterys to the inverter, but I use12V and 24V from the house batterys daily and am concerned that it would be detremental to the bus batterys. Also this is a new problem and should be solveable, something is different, something had to change??
I would like to check the batterys with a  hydrometer, but these are sealed, I know I can open them but that will void the warrenty, so will be the last thing done.
  Here are one week results, I knew Jerry would ask this!!
                                                Positive battery       Negative battery
charged to 26.3 volts                  Bat # 1 12.8            bat #2 13.2 
Removed surface charge 25V                   12.5                      12.5
                                  25.6                   12.8                      12.8
                                  25.7                   12.8                      12.9
                                  25.7                   12.8                      12.9
                                  25.7                   12.8                      12.9
                                  25.6                   12.7                      12.8
                                  25.6                   12.7                      12.8
                                  25.5                   12.6                      12.8
  Today                        24.2                   11.7                      11.9                   

[Sojourner]

JERRY DO NOT MOCK THE GREMLINS, they will get you!!!!!

I've considered useing the selector switch to hook the bus batterys to the inverter, but I use12V and 24V from the house batterys daily and am concerned that it would be detremental to the bus batterys. Also this is a new problem and should be solveable, something is different, something had to change??
I would like to check the batterys with a  hydrometer, but these are sealed, I know I can open them but that will void the warrenty, so will be the last thing done.
  Here are one week results, I knew Jerry would ask this!!
                                                Positive battery       Negative battery
charged to 26.3 volts                  Bat # 1 12.8            bat #2 13.2 
Removed surface charge 25V                   12.5                      12.5
                                  25.6                   12.8                      12.8
                                  25.7                   12.8                      12.9
                                  25.7                   12.8                      12.9
                                  25.7                   12.8                      12.9
                                  25.6                   12.7                      12.8
                                  25.6                   12.7                      12.8
                                  25.5                   12.6                      12.8
  Today                        24.2                   11.7                      11.9                   

Thanks Jim for your report. There is either an error in the last day reading or was the weather change to freezing temp Buffalo, NY's winter in southwest Florida? ? ?

The last report should be at least half of 24.2v.

And from 25.5v to next day 24.2v is some reason that needs to be explain? Is it an error or actual?

Otherwise at given temperature of 77°F, it should level out at 12.6v per battery.

You need Excel viewer to open temperature & voltage chart: http://jgdarden.com/batteryfaq/SoC.xls

The higher the battery temperature while in storage, the quicker it will self-discharge.

Waiting for your answers?

Take Care, Gerald

[jjrbus]

Thanks Jerry, there is no error is last days reading, I checked it two times!! The battery switch was off, there was no use of any bus power!!

Todays numbers I checked three times

   24.7 volts          12.1V          12.3     

I know it does not add up, but I checked three times!!

[gumpy]

Are you sure your meter is correct?  Maybe need a new battery in it?

[jjrbus]

I am not sure is mutimeter is correct. I have checked it on different voltages and it seems to be ok.
I got out new battery, checked voltage 9.3 volts replaced old battery and checked it 8.1V
Rechecked batteries  This morning reading was 24.7V  now shows 25.2V  changed back to old meter  battery and got 25.2V. Wish I would have checked befor changeing battery!

[Sojourner]

Are you sure your meter is correct?  Maybe need a new battery in it?

Good point gumpy! Thank you!

Now about digital meter it self....replace its battery and recheck to see if it read the same. If it does or not, I would not be comfortable with that reading yet. I would try to barrow a another good digital meter within store such as Sears or Radio Stack or auto parts, to compare a new 9v battery reading. If it doesn't match within point 1(.1) volt, you may have an out of calibration meter.

Whatever you need to do if it is the meter error, than try to purchase one with a 10 + days return policy. Example 19.95 Sears http://www.sears.com/shc/s/p_10153_12605_03482345000P?mv=rr

Or check Radio Stack. Or call me anytime while in store or wherever you are...almost likes me being there with you. I promise to be very reasonable...LOL

Take care, Gerald

PS...I appreciate what anyone like Craig (gumpy) suggestion....Thanks...after all I am only human.

Oop....Jim already responded while I was typing this post.

[bigjohnkub]

Allright, I'm going to jump in on this.  I always test for battery drain, or short in wiring , after doing electrical system repairs on tractors. I have trained the four mechanics  I employ to remove battery negative cable and insert a test light between post on battery and battery cable end. If there is any draw (or short) the light will light up. It has worked for me for over 40 years.  
 Big John

[JackConrad]

Rechecked batteries  This morning reading was 24.7V  now shows 25.2V  changed back to old meter  battery and got 25.2V. Wish I would have checked befor changeing battery!

Jim,
  Are you sure you are getting a ggod contact between the meter test lead and the battery?  Jack

[jjrbus]

Jack I am not sure of anything at this point. I move the probes around on terminals to get several readings, I keep getting same numbers!!  I could find nobody to borrow a mutimeter from so bought a new one for comparision.
Even for the electrically challenged the rise in voltage from 24.7 to 25.2 makes no sense. Maybe in Barffalo Ny when it is 10 below in the morning and 60 in the afternoon.

[Fredward]

This is all getting pretty scientific here. I'll just report that on my MC-5 which is still 24 volt, I have two Group 31 Optima Deep Cycle batteries for coach. Basically engine start only. They are not connected to the house battery charger in any way. The batteries are at least three probably four years old; they were in the coach when I bought it. I know deep cycles are not ideal for engine start applications. But living in Minnesota, they will start the 8V71 down to 45 degrees without ether. They have sat for up to two months in the winter and they will still start the engine if I plug it in.

Point is, they certainly are not loosing one volt per day. FWIW - FRED

[luvrbus]

This whole battery deal confuses me, I have own heavy equipment for 30 years and have been told by many of battery manufactures that a battery will lose 4% to 5% of it charge every week and will lose more if the temperature is over 80 and yet people are saying that a battery will start your engine a year later and one has 2 batteries 3 years old that have over a 50% charge.   
This has never worked for me when we stored the equipment with fully charged batteries you were lucky if it would start in 2 months with the batteries disconnected.I did a job in Az 1 year and spent 1000's of dollars on batteries because they would drop so low in a week or 2 and I didn't buy cheap batteries most were from CAT. I am missing something here or all these years  have I been buying the wrong batteries.If you guys come to AZ it's a good place to test batteries they do not last long here a battery in 110 degree heat will be dead in 30 days if it is not charged daily. Friday I am going to SAM's and check the voltage on some of the batteries with different dates on them just to see were the voltage is after 2 months   good luck on your chase JR

[Sojourner]

luvrbus.....you are so right about temperature kill battery. Up in native lower Michigan area, we don't wear out batteries like in hot climate state but we some time have put battery in a warm room or light bulb next to battery over night for very cold morning start.

At work (General Motor Tech Center), one of my job is under hood heat study. Install 9 Chromel® Alumel thermocouple in 12v battery to record temperature as well with the other parts with thermocouple under the hood. Tested in Arizona room at GMTC. Amazing what the poor battery has to go through this cycle time after time. In just a few time of heat cycle...it is bulge shape and quit taking healthy charge.
Thanks for your report.
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I typing the following after 5pm but didn't finish it till now.
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Thanks Lee for bring up the reason why battery need to be free of acid coating. I was assuming most of here on board known about getting voltage by scanning around the battery. Good that you brought that out. This is what I do (clean battery) with my customer's car before computer equips to tune-up as well repair dead cars.

About "self-discharge" is another way to run it self down which normal due to nature of its electrolytic with lead dioxide. It about high temperature, idle too long with no charge, many cycle of discharge & charge will breakdown battery quicker than steady 77°F, very few cycle and fewer idle times with float charger.

http://www.mca-battery.com/Technology/sla-faq.htm

Jim...keep checking with meter and if you will IR (temp gun) to add temp in report. Temperature will cause to vary voltage too.

FWIW

Sojourn for Christ, Gerald