Batteries discharge on INT DT466

[daveshoe]

My dump truck sees occasional use and can sit for a month without running. After replacing batteries, I decided enough was enough and had a mechanic ''test '' it . He put a test lite between battery and cable and detected no drain-- at least not enough to lite the lite. He also let it sit outside in case the heater on the air brake acumulator would draw it down. Cost was 20 bucks for his expertise.

Batteries still drain down completely dead . I even took the precaution of unhooking the positive cable to the starter. It STILL discharges completely dead. I ain't no EL genius so stupid question is should I unhook negative side instead. Also would a voltmeter be a better tool to detect a voltage leak? If so , what is proceedure? I guess if we cannot solve this , I will just buy a float charger and keep it charged.

Thanks in advance Daveshoe

 

[nickleinonen]

get yourself a digital multimeter with fused amp inputs. disconnect the positive cable, and place the multimeter inline between the battery + cable and the battery + terminal. with the multimeter set on ±10A scale, read the amperage that is being drawn while everything you think of is turned off. modern vehicles can have up to 1. 5A draw with the computers and sensors and such drawing power while everything is off... maybe you have a light in the glove box that is turned on draining the batteries while the cables are connected. are the batteries damaged internally? internal shorting or low water level can cause the batteries to discharge and die. or if the alternator is over charging while running, it can cause the water to boil out leaving the cells dry... many variables there...

 

[illflem]

My '63 Int dump did the same thing till I invested $25 in a dash top solar charger. Since it is a seldom used rig it was also getting hand me down batteries from other vehicles, that could have been part of the problem.

Fired right up recently after sitting for over a year with a 7 year old stock Dodge battery.

The light bulb in line with a disconnected battery cable method is very good, even with under a half amp draw the bulb filament will glow.

 

[daveshoe]

This is a 1978 truck. However the add ons wired in are certainly not done in a workmanlike manner. For example, radio will run with key off. Why would it discharge even with the + cable unhooked? Batteries are less than a year old . They charge up fine. I guess I could place a multimeter to jump between fuse clips [with fuse removed] and try to detect current draw on individual accessories. It seems like someone suggested the alternator [brushes?] could cause this. Still looking for answers. Thanks for input.

 

[Philip]

Clean the outside of the battery with baking soda mixed with water. If there is any acid on the outside of the battery it can discharge it.



Be carefull to not get any into a vent cap. It will launch the cap.



Also being a late 70's truck most likely it has a delco alt on it. If it is the internial regulator model. Check it for discharge back threw the battery terminal. I have seen many of them blow the diode pack and discharge back threw themselfs.

 

[daveshoe]

Originally posted by Philip

Clean the outside of the battery with baking soda mixed with water. If there is any acid on the outside of the battery it can discharge it.



Be carefull to not get any into a vent cap. It will launch the cap.



Also being a late 70's truck most likely it has a delco alt on it. If it is the internial regulator model. Check it for discharge back threw the battery terminal. I have seen many of them blow the diode pack and discharge back threw themselfs.

So what I would do is disconnect the wire from the alt. terminal that says Batt and place multimeter between terminal and wire looking for current draw. I will do this ASAP, But is what you are saying that this could still discharge with the positive battery cable disconnected from the battery? Please bear with me as I am not too swift on things electrical. Batteries are new condition , but I will clean them just the same. Truck is elsewhere ,so I will tell you what happens ASAP

 

[Philip]

The alt would not cause discharge with the batterys disconnected.



Most likely the battery acid on the outside of the case is doing it. Take a multi meter and put one lead against the neg terminal. Put the other on the top and sides of the battery. The tell us how much voltage is showing. Any is to much. Clean the battery if you see any voltage showing.

 

[daveshoe]

Thanks, phillip. now I understand. I'll do the test. then if no voltage is detected, I will separate the batteries, place them on rubber for a week and see if they put out full voltage. Keep you posted.