Truck Battery Not Holding Charge - Coach Battery charging problem identified.

[ipo]

A quick question. What type of batteries are used as the truck battery and the coach battery? I'm seeing mentions of #27 deep cell in the coach. Is the truck battery just a regular car battery?

[Vanman]

ipo

A quick question. What type of batteries are used as the truck battery and the coach battery? I'm seeing mentions of #27 deep cell in the coach. Is the truck battery just a regular car battery?

Yes, mine is a group 24 Truck and 27 deep in the coach. Check to see if you can fit a larger in coach, I think mine will fit a group 29. I guess it would be nice to see if you have room for a larger battery in the truck too. Back in the day I had a 1971 Dodge B-200 Tradesman and I put the largest batt I could fit in there it was huge, do not remember the size, but worked great. Larger will cost more but no too much. john

[waiter]

I checked mine, it draws about 15 milliamps , The only phantom loads I have is the radio and a remote starter. a 70 amphour battery should last several months.

John Mc

88 Dolphin 4 Auto (For Sale)

[Maineah]

The truck battery is just a starting battery nothing special same type of battery as any car or truck..

[grandview bill]

IPO youre' contradicting yourself if the test light lit up when the light was in series with the alternator then its drawing current, also you have too many people ,myself included,spoon feeding you advice,when you start buying multi meters and batteries that might be a useless expense

[ipo]

Thanks for the info on the batteries.

A guy who has done some metal fabrication among other things for me, came by for an entirely different reason. He has experience with auto and RV work.

He took a look at the battery and said it was starting to bulge. He recommended that if the RV was going to sit for another 2 years to just leave it.

I made the decision to replace it based on the current condition, the idea that I plan to use it more once the problem areas get fixed, it's age and the number of times it's been completely dead and recharged. It may have been the wrong decision, in part, since I didn't know if the 1st one was really a problem. But it's done now. Ok, and it didn't hurt that I got it at cost.

[ipo]

If the battery is dying after sitting for a few weeks, then there is one of three problems (or a combination). You need to purchase an inexpensive Volt/Ohm meter (get one that you can read AMPS also, if it doesn't cost to much)

1) The battery is not capable of holding a charge, or the battery has built up a lowered internal resistance. Unless you know specifically that the battery has been replaced, then this would be my first stop, replace the battery.

2) The Battery is not being charged properly (alternator/charging system) . With the truck running, you should see about 14.5 - 14.8 volts on the battery.

3) Phantom loads are drawing down the battery. I suspect this is your problem. These would be items that draw power from the battery, even when the ignition is turned off.

If you have an ammeter, this will be easy to isolate. Remove the keys from the ignition. Remove either cable (+ or -) from the battery, and connect the ammeter in series between the post and the battery cable. Do not turn on the ignition and do not try and start as you'll blow the fuse in the ammeter.

Take a reading as to what the current draw (When I get home, I'll do this on mine and report back) You should see something less than .25 amps (I'm guessing) A 1/4 amp draw will run your #27 battery down in about 2 weeks (70 amp battery drawing 1/4 amp per hour)

Heres a list of some items that could stay turned on and continue to draw a small amount of current, even when the ignition is turned off.

Alternator ( defective internal regulator or shorted diode )

Remote Starter (always watching for the signal)

Radio AM/FM or DVD player (remembers channels and runs clock)

Clock

Alarm system

110 Volt Inverter ( These draw a small amount, even when turned OFF, if wired to Truck battery)

Solid State Isolator ( leaky isolation diodes)

I would suspect ANY aftermarket device that has been added to the trucks power circuit could be causing your problem. If you have the ammeter hooked up, start pulling fuses until you see the current draw drop, that's your culprit.

I have a remote starter and a modern Toyota AM/FM radio. Mine will sit for a month, and will still crank.

John Mc

88 Dolphin 4 Auto (For Sale)

Thanks for this organized version of possible problem areas.

I did some of the testing already with a test light; pulling each fuse one by one. The only ones under the hood I didn't check are the ones that say "head" and "EFI" on them; there isn't a fuse or anything in the spot that says "CMH".

When I checked with the test light and fuses, they all seemed OK, each time the light lit up when pulling each fuse. Sine the alternator wire connected to the alternator was close to impossible for me to get to I had help pulling the wire. Again with the test light in series (alligator clip to neg battery connector and test probe to the neg post) the test light lit up. I thought this meant it was OK as when it lit up when pulling the fuses.

[ipo]

IPO youre' contradicting yourself if the test light lit up when the light was in series with the alternator then its drawing current, also you have too many people ,myself included,spoon feeding you advice,when you start buying multi meters and batteries that might be a useless expense

OK. Do I I have it wrong about when the test light is lit? I guess I was thinking that if, when I pulled the fuses, one by one and the test light lit, then all was OK. I assumed it was the same with the alternator. Or am I not understanding this corrrectly :?

What would you recommend in terms of too many people 'spoon feeding' as you say? I know everyone is trying to help, which I really appreciate, and I've learned a lot, so I'm not sure how to address your thought on this. I do admit sometimes it gets a bit confusing and overwhelming.

I do have access to a multi-meter though I'm not confident in how to use one..which is in part why I was using the test light. As for the battery, as I said in another post I ended up buying.

[waiter]

IPO, Your test light isn't capable of measuring very low current draw. i.e 0.015 amps (15 milliamps) and quantifying it.

I believe you'll be doing yourself a service by learning to use the meter to measure voltage, resistance, and amps.

With that said, if the battery is showing signs of buldging, its bad. replace it. If your in cold weather country, consider removing the batteries and store them in a warm place. (make sure they are fully charged before storing.

JOhn MC

88 Dolphin 4 Auto (For Sale)

[Maineah]

The light must go out until it does you have a current draw. A radio will not kill your battery unless it's on, a dome light will not kill your battery unless it's on. If you find some thing that does then an amp meter to decide if it is enough to kill the battery over time. The test light is positive there is no guessing if it's on there is a current draw large enough to kill the battery. If a month or two down the road and you have a dead battery that is pretty much normal especially with newer car/trucks as the proliferation of gadgets that plug in continues.

[WME]

If you just can't find your ghost go the E bay and get a small solar panel that will plug into the cig lighter. Try a search for VW solar panel. VW uses these by the hundreds when cars sit in the off load storage lots.

[ipo]

A couple of days ago Darrel kindly took a look at my '92 Dolphin to determine areas that need fixing.

Among many other things, he did troubleshoot why my coach battery wasn't charging the way it should; i.e. when the truck was running. For one thing the cable that runs from the truck battery to the isolator (I think I've got that right) was completely disconnected, the wire terminal connector was wrapped in electrical tape and left hanging within the maze of other wires. The isolator and alternator worked as they should but the fuse between both sides of the isolator (I think that's right) was blown.

The reason I mention the disconnected cable is because I believe the previous owner was having trouble as I am with the truck battery not holding a charge and they must have thought the charge was being depleted by the coach battery...though I can only guess what their thinking was on this. At any rate they didn't tell me about it and it's probably the reason they were selling the mh.

Due to time and weather constraints Darrel didn't have time to look into the problem of the truck battery not holding a charge; it's been a problem from day one since we bought it. The battery dies within about 2 weeks if I don't run the mh every week for about 20 mins. Initially I noticed that the bathroom fan would suddenly start to run on it's own. Not knowing anything I thought this might be the drain on the battery so I disconnected the fan. I did replace the truck battery thinking that was the problem, but the issue continued. So after too many times of being dead (and the coach battery problem at the time) I ended up putting a separate float charger on each of the batteries. Which seemed to do the trick but it's only a temp solution.

In reading the forum I found a suggestion to disconnect the cables from the truck battery and let it sit to see if it's the battery or something else that's draining the charge. I will have to disconnect the battery for at least 3 weeks to see if it is the problem. Is there any reason not to do this?

Are there other things I can check in the meantime, perhaps for more quickly identifying the problem?

Just an update on all of this. 1st you were all most helpful especially spelling everything out for me. Being out of my depth a friend offered to pull the alternator to have it checked; it came back as good. Not sure if that answers the alternator leaking current question or not . Over the winter I "solved' the problem by putting battery tenders on the truck and coach batteries. Depending on time and ambition I may try to troubleshoot the problem further or just live with it for now.

[Maineah]

Over the winter you will have to put battery tenders on it even if there are no loads more so if you live in an area where it freezes. Likely as not there is no alternator drain particularly if it's charging fine.

[zero]

Just an update on all of this. 1st you were all most helpful especially spelling everything out for me. Being out of my depth a friend offered to pull the alternator to have it checked; it came back as good. Not sure if that answers the alternator leaking current question or not . Over the winter I "solved' the problem by putting battery tenders on the truck and coach batteries. Depending on time and ambition I may try to troubleshoot the problem further or just live with it for now.

I may of missed a few comments in all the posts so if I repeat something - it's not on purpose. There is one sure way to diagnose your problem. Buy yourself a $5 multimeter. Something with two amp scales. A $5 meter from Harbor Freight with have a 10 amp scale, and a milliamp scale. Disconnect one battery cable from the battery (positive or negative) and hook the two test leads between the cable end and battery post. Use the 10 amp scale first. Hopefully it will read nothing. Then switch to the milliamp scale. On an older vehicle - up to 50 milliamps is normal. Some newer cars and trucks draw over 200 milliamps and will drain a new battery in 4 weeks if not started. Things that draw power all the time are clocks, radios, alarm systems, on board computers, electronic rust preventers, and just about anything that works by remote control. 50 milliamps is 1/20th of an amp. A cranking battery under your hood can supply 50 milliamps 24 hours a day for several months.

Note also that all lead-acid batteries go dead all on their own - even if hooked to nothing. The "self discharge" rate is often 5% per month and higher with some. Some as high as 20% per month.

One other thing I guess worth mentioning. Take my 1988 Toyota RV. If I turn the engine off but do no remove the key - the battery will drain excessively. To stop the drain I must push the little button by the key and make sure it is all the way off. The owner before me kept having his battery go dead. He bought two new batteries and one new alternator and still had the problem. All it was - was the key not being turned all the way off when parked. Obviously not an issue if you remove your key. But if you tend to leave it there and just shut the engine off - even though there are no lights on in the dash - it will still draw current. Mine draws 600 milliamps when key "off" just far enough to shut the engine down and turn off the dash lights.

[ipo]

I may of missed a few comments in all the posts so if I repeat something - it's not on purpose. There is one sure way to diagnose your problem. Buy yourself a $5 multimeter. Something with two amp scales. A $5 meter from Harbor Freight with have a 10 amp scale, and a milliamp scale. Disconnect one battery cable from the battery (positive or negative) and hook the two test leads between the cable end and battery post. Use the 10 amp scale first. Hopefully it will read nothing. Then switch to the milliamp scale. On an older vehicle - up to 50 milliamps is normal. Some newer cars and trucks draw over 200 milliamps and will drain a new battery in 4 weeks if not started. Things that draw power all the time are clocks, radios, alarm systems, on board computers, electronic rust preventers, and just about anything that works by remote control. 50 milliamps is 1/20th of an amp. A cranking battery under your hood can supply 50 milliamps 24 hours a day for several months.

Note also that all lead-acid batteries go dead all on their own - even if hooked to nothing. The "self discharge" rate is often 5% per month and higher with some. Some as high as 20% per month.

One other thing I guess worth mentioning. Take my 1988 Toyota RV. If I turn the engine off but do no remove the key - the battery will drain excessively. To stop the drain I must push the little button by the key and make sure it is all the way off. The owner before me kept having his battery go dead. He bought two new batteries and one new alternator and still had the problem. All it was - was the key not being turned all the way off when parked. Obviously not an issue if you remove your key. But if you tend to leave it there and just shut the engine off - even though there are no lights on in the dash - it will still draw current. Mine draws 600 milliamps when key "off" just far enough to shut the engine down and turn off the dash lights.

Thanks for your input..I can use all help. Didn't know about the self discharge (or if I ever knew I didn't remember ) I think I've gotten a bit complacent with the battery tenders in place. Troubleshooting the problem is still on my project list however.