Need thoughts on battery draw

[Airslide]

Here's my dilemna...

My batteries only last about 2 weeks after starting off fully charged. Last year I was able to leave the trailer for months and the batteries were still hot. Each time I make sure the battery cutoff switch is off. Something has changed.

I charged the batteries up with my external charger to make sure they are good and measured 12.68 volts.

With both postive cables removed I used my fluke meter to measure the draw with the cutoff switch in the off position.

The meter read battery voltage and 16.38 miliamps.
Its typical for a modern car to sit between 30 and 50 miliamps after all the electronic have shut down so 16 ma is nothing. Just for fun I disconnected the sensor for carbon monoxide as I know its somehow wired direct. The reading was the same. So why is there any draw with the manual cutoff switch in the off position? Maybe that switch is bad?
Could it be that the batteries are just sulfated?
If I was thinking about isolating the draw, would I remove wire by wire in the electrical distribution box located under the front window?

I also verified that the batteries are charging when plugged in.

Thoughts? Just buy new batteries? They are about 2 years old.

Thanks Vinnie

[bukib]

i just went through a simlar situation with my land yacht. it turned out after hours of examination by high powered rv tech we might ought to look at the schematics. turned out that the ISOLATOR was the culprit. the coach batteries cud only charge through the house batteries which were 'isolated' by that bad boy. turn on your aux battery switch. be sure you're plugged into shore power. go to bed. tomorrow morning turn on what you want to. it shud spin like michael jackson in his prime. let me know. it wont cost you one red cent to try.

[bukib]

however, with a trailer none of what i said may be relevant. but i think it will. try.

[ROBERTSUNRUS]

Hi, my batteries seem to last only three years. [replaced twice now] I took mine out and to the Ford dealer and put them on the high dollar, magic battery charger/tester and they were both bad. I'm sure you have access to a magic battery charger/tester used by Mercedes or Volvo. This would be the first place to start.

[tpi]

I agree testing the batteries would be a good place to start.

Although on mine, I disconnect the cables when leaving it for a while. I was getting slow discharge thru the CO detector (I think).

[masseyfarm]

I don't believe the OEM Aux. battery switch is an on/off switch, but rather is a "hold on to activate".
If it is an on/off switch then someone has modified it to solve the problem of grid power not charging the chassis batteries.
Caution: If you leave this modified switch in the on position while boomdocking, there is a good chance you will be stranded with no power to start.
The only real solution to this ongoing problem is the SurePower SEPARATOR.
Sure Power 1315 Battery Separator
I have used this and the simplisity and results are unmatched.
Dave

Originally Posted by bukib

i just went through a simlar situation with my land yacht. it turned out after hours of examination by high powered rv tech we might ought to look at the schematics. turned out that the ISOLATOR was the culprit. the coach batteries cud only charge through the house batteries which were 'isolated' by that bad boy. turn on your aux battery switch. be sure you're plugged into shore power. go to bed. tomorrow morning turn on what you want to. it shud spin like michael jackson in his prime. let me know. it wont cost you one red cent to try.

[masseyfarm]

I assume you have not used the batteries over the winter.
Most cheap chargers will not rejuvenate a battery that has not been cycled for a extended periods even though it appears to be charged.
You may purchase an expensive charger that has a anti sulfating pulse charge or,
IF THEY ARE WET CELL WITH CAPS FOR INSPECTION, take batteries out of the unit, check each cell with hydrometer to determine battery condition. Then, try to source a manual charger that you can charge the battery at a high rate (less that 16V) for at least 6 hours. This will cause gassing that is explosive and possible acid spill. Top off with distilled water and you should find that the batteries will have increased life.
If you are not comfortable working with batteries and acid/explosive gasses, then trade the batteries for new and go camping.


Dave

Originally Posted by Airslide

Here's my dilemna...

My batteries only last about 2 weeks after starting off fully charged. Last year I was able to leave the trailer for months and the batteries were still hot. Each time I make sure the battery cutoff switch is off. Something has changed.

I charged the batteries up with my external charger to make sure they are good and measured 12.68 volts.

With both postive cables removed I used my fluke meter to measure the draw with the cutoff switch in the off position.

The meter read battery voltage and 16.38 miliamps.
Its typical for a modern car to sit between 30 and 50 miliamps after all the electronic have shut down so 16 ma is nothing. Just for fun I disconnected the sensor for carbon monoxide as I know its somehow wired direct. The reading was the same. So why is there any draw with the manual cutoff switch in the off position? Maybe that switch is bad?
Could it be that the batteries are just sulfated?
If I was thinking about isolating the draw, would I remove wire by wire in the electrical distribution box located under the front window?

I also verified that the batteries are charging when plugged in.

Thoughts? Just buy new batteries? They are about 2 years old.

Thanks Vinnie

[Airslide]

Thanks for the responses.

Maybe I dont understand the on/off battery switch. I know that even with the switch in the off position and the terminal is touched to the battery it arc's as there is a load. I agree that the life span of these batteries are about 3 years so I think i will go replace them but that wont solve the draw issue. If it wasnt so much work to get to the terminal side of that switch where i could test it when in the off or open position. For now I think I will just keep the batteries disconnected when not in use.

Vinnie

[masseyfarm]

Do you not have the 280 Classic anymore?

A solar panel would help the drawdown on the batteries on the trailer. The c/o detector is hard wired and will draw down the batteries over a short time.
Dave

Originally Posted by Airslide

Thanks for the responses.

Maybe I dont understand the on/off battery switch. I know that even with the switch in the off position and the terminal is touched to the battery it arc's as there is a load. I agree that the life span of these batteries are about 3 years so I think i will go replace them but that wont solve the draw issue. If it wasnt so much work to get to the terminal side of that switch where i could test it when in the off or open position. For now I think I will just keep the batteries disconnected when not in use.

Vinnie

[Airslide]

Hello Dave,

The 280 never belonged to me. I was just the guy making it road worthy for its trip to England.

Good thought on the solar panels. This unit did have the panels on the roof at one time from the PO. The wiring is still in place but disconnected. It would be easy to set it up that way again. I also thought about the CO detector. I have a switch wired in it allowing me to shut it off. So its still a mystery.

Thanks Vinnie

[Bill M.]

I have no idea what is causing a 16 milliamp draw. maybe your meter is just too good. But that is not what is discharging your batteries in 2 weeks as that would only be 5 Ah, Buy new ones. The batteries are probably shot, for whatever reason. At least that is what I did today. 2.5 years old. I do not think they last 5 years anymore unless you have very good ones. I do not think a new Die hard will start 250 cars in the cold in Green Bay stadium like Sears used to advertise either.

[Airslide]

Ok.. so I removed that batteries after being gone a few days. One of the batteries was completely discharged on its own. The other battery was sitting at 12.3 volts disconnected. I just bought two new interstate deep cycle batteries. They sure are purdy!

I bet the others were just junk and couldnt maintain. Questions still exists.. Why is there a draw with the switch in the off position and the CO meter disconnected? Maybe the power supply has something internally pulling down the battery when disconnected from shore power. I have a small solar panel that i think i will connect when not in use. That should get me through the summer and I will leave that question for a winter project.

Vinnie