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

[ipo]

A couple of days ago Darrel kindly to 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?

[Vanman]

Buy a multimeter to check electrical things. Could be as simple as a bad battery, won't take a full charge and or is self discharging.

A fully charged batt should read 12.5 to 12.6 volts. When charging from the motor running you should get 14.4 initally and as the truck batt gets charged up it will slowly drop down to 13.3 to 13.6 volts as a maintain voltage. Before checking the batt by disconnection, you should make sure it's fully charged or at least see what state of charge it's at to start with.

Short a meter you could make sure everything is turned off on the Toyota disconnect the hot side batt connection and flash it on and off to see if you get a spark. If the batt is good and going down that fast I would expect to see a small spark from a load that large.

Check it out,any more questions and we're here.

john

[Maineah]

Another trick is a cheap 12 volt test light connect it between the battery cable and the post. Remove the cable from the coach battery, clamp the test light to the battery post and the probe to the cable. Light on drain some where start pulling coach fuses until the light goes out then track down what that fuse powers.

[ipo]

Buy a multimeter to check electrical things. Could be as simple as a bad battery, won't take a full charge and or is self discharging.

A fully charged batt should read 12.5 to 12.6 volts. When charging from the motor running you should get 14.4 initally and as the truck batt gets charged up it will slowly drop down to 13.3 to 13.6 volts as a maintain voltage. Before checking the batt by disconnection, you should make sure it's fully charged or at least see what state of charge it's at to start with.

Short a meter you could make sure everything is turned off on the Toyota disconnect the hot side batt connection and flash it on and off to see if you get a spark. If the batt is good and going down that fast I would expect to see a small spark from a load that large.

Check it out,any more questions and we're here.

john

#1: So with the truck running and charging the battery, by the time it reads 13.3-13.6, if I shut the truck off the battery should read 12.5-12.6 volts. Did I get that right? Sorry for my denseness..my ol' brain is scrambled by all of this. lol

#2: when you say to make sure everything is turned off on the toy you're talking like headlights, radio, engine yes?

#3:By flash do you mean quickly touch and remove the hot battery cable connector to and from the hot post? And a spark would indicate a problem?

[ipo]

Another trick is a cheap 12 volt test light connect it between the battery cable and the the post. Remove the cable from the coach battery, clamp the test light to the battery post and the probe to the cable. Light on drain some where start pulling coach fuses until the light goes out then track down what that fuse powers.

OK I'm confused. Is this checking the coach battery or the truck battery?

When you say to remove the cable from the coach battery I assume you mean the hot cable, yes?

[grandview bill]

Maineah has the best idea, it looks like a there is slow drain on the engine battery, you probably wouldn't see the arcing of a small drain by the touching of a battery in daylight. Put the test light in series with the positive battery cable (it's a substitute for an ammeter) if it lights, (it might be dim) you know you have a drain.

[Vanman]

ipo

#1: So with the truck running and charging the battery, by the time it reads 13.3-13.6, if I shut the truck off the battery should read 12.5-12.6 volts. Did I get that right? Sorry for my denseness..my ol' brain is scrambled by all of this. lol

Except I forgot one important thing to mention: after charging any battery it will hold for several hours what's called a "surface charge" and any reading will be false, ie too high. So after charging let it sit for a few hours before checking the voltage.

#2: when you say to make sure everything is turned off on the toy you're talking like headlights, radio, engine yes?

yes

#3:By flash do you mean quickly touch and remove the hot battery cable connector to and from the hot post? And a spark would indicate a problem?

Yes BUT Maineah's post is probably a better method of tracing. I actually made a test light from my motorcycle days and use a 6 Volt lite bulb speedo lamp from an old Suzuki. The 6 V bulb makes it easier to see when Back in the day we had these things called "points" and used this test lamp to set the timing.

john

[fred heath]

OK I'm confused. Is this checking the coach battery or the truck battery?

When you say to remove the cable from the coach battery I assume you mean the hot cable, yes?

No, you remove the negative (-) post.

Be sure to use a test light and not a meter. The meter will give a false positive.

[Maineah]

The test light will work on either post but the general rule of thumb working with any battery is to remove the - cable first to avoid shorting the battery to ground with any tools. The test light looks at a load as a path if there is no load (some thing staying on) the light will not light. An ammeter will do the same thing but is harder to use where as a light is either lit or it's not there is no need to decipher how much draw there is if the light is lit it will eventually discharge the battery. This trick will work for either battery the truck or the coach. With the truck off there should be no connection to the coach.

[DanAatTheCape]

to check the start battery take to any chain auto parts store, or walmart etc they will test if for free,

or you can disconnect it (negative terminal is a good idea) and charge it fully . than let is set 24 hours unconected & see how much charge it needs to top it off. Before hooking up the charge measure the battery voltage - a dead cell will show up as about 10.4 volts.

After you have a good battery hookup the battery & measure voltage while running & than let it sit for 24 hours and again disconnect & charge. If it needs a lot of charge I would suspect something is draining the battery - when it should not be,

As for charging the house battery the solenoid on my 93 warrior gets its activation from a hot wire that is connected to the windsheild wiper circuit - a wire that is only hot when the ignition switch is "on". Note that the wires leading from the start battery going to the house battery creates a situation where the start battery can get over charged repeatedly - when the house battery runs down the engine alternator sense low voltage so output is raised - the starter battery is getting too much charge as the house battery is slowly charged.

On mine, a wire goes from the start battery + terminal thru a CB then thru the solenoid (which looks a lot like a ford starter solenoid but it is different, the ford is a momentary load use & these campers use a continual load use) then to a cb by the house battery then to the + terminal on the house battery. I lose about .1 volt at each step so that exacerbates the situation for both batteries.

[ipo]

OK I finally got to the store for a test light. There are some different kinds. Basically my choices are

• alligator clamp on 1 side and test probe on the other.

1 kind is for "power on" and another kind is for "power off."

• some come with batteries
• one has a red and a black large clamp plus a test probe and a connection that can be powered by the cig. lighter.

#1: So the 1st question is, which one?

#2: Are there any fuses, like under the dash, on the inside of the truck? I can only find the ones under the hood.

OK let me start there. I have more questions but I'll start with these.

[Vanman]

Test lites are just that, a lite bulb with wires and / or alligator clips on one or both ends. When you put it across the 12V it lights up.

As you go up the food chain of test equipment cost and complexity go up also. The auto parts shop should be able to explain how their testers work. It's up to you how complex you want to go with the tester, maybe start simple.

[ipo]

Simple is more my speed. The guy at the auto zone wasn't overly helpful probably because he didn't know.

Since I don't know what it means....does it matter if the test light is designed for power off or power on?

[Maineah]

Just a simple test light one clip and a point on the other end. Get that going and see what happens there are fuses under the hood and in a small panel by your left foot.

[ipo]

OK. I initially touched the point end on the (-) post (with the clip on the cable terminal/connector. ) It lit up, so if I understand it there's a draw from some place. I pulled all the fuses basic fuses under the hood and in the cab and they all lit up. Which I think means none of those are the draw culprit.

I went back under the hood and pulled the bigger fuses and was trying to get the 80 a one to the alternator out and it's stuck in there. I tried everything to get it out and of course in the process the top/cover piece of plastic where it says the 80 amp broke off.

Any suggestions on how to get it out of there? If not just to test it but to replace it since the top cover is missing?

[ipo]

Addendum: The broken fuse housing was only small piece off the side of the housing. The cover snapped back into place. Still can' get the fuse out.

[Derek up North]

I'd give it a spritz of WD40 and let it sit a while. Try rocking it back and forth while GENTLY prying with a flat blade screwdriver.

[Maineah]

It probably would be easier to remove the wire to the alternator the big fuse is bolted in.

[ipo]

It probably would be easier to remove the wire to the alternator the big fuse is bolted in.

Well no wonder! I'd say the bolt is doing it's job.

I'm afraid to ask where the wire is and how to remove it?

Isn't there any other way to see if the fuse is good or bad?

[grandview bill]

its getting complicated now, the issue is not whether the fuse is good, but if the alternator is drawing current, if a diode is shorted or leaking this can happen (it did in my 65 mustang) I cant say the charging circuit is the same, but you need to use your test light in series with the lead in the 80 amp fuse to verify current draw, in my mustang the alternator would 'motor' when the battery was connected, the alternator would move slightly so would the belt and fan.

[Maineah]

There is a large white wire bolted to the alternator remove it as long as your test light is in line it will not cause any problems if it touches any thing. Yes the alternator can cause a discharge but usually if there is a problem the charge rate will be degraded. If the fuse was bad it would not charge at all.

[ipo]

I looked pretty carefully and couldn't find a white wire connected to the alternator. I see 2 wires, one looks like a spark plug wire with the hood like cap on the end. And the other I can't get a very good look at, tho it's not white. Is there another wire I'm not seeing? It's pretty cramped quarters in there. What's at the other end of the white wire? Maybe I can follow it back to the alternator.

[ipo]

its getting complicated now, the issue is not whether the fuse is good, but if the alternator is drawing current, if a diode is shorted or leaking this can happen (it did in my 65 mustang) I cant say the charging circuit is the same, but you need to use your test light in series with the lead in the 80 amp fuse to verify current draw, in my mustang the alternator would 'motor' when the battery was connected, the alternator would move slightly so would the belt and fan.

When you say in series, where exactly does the alligator clip go and what do I touch the test probe to? I may be getting ahead of myself here since I can't seem to find the correct wire.

Of course it dawns on me now, am I really looking at the alternator? It's the round ball like thing with slits in the housing and copper wires wrapped on the inside isn't it? I really am very much the novice with all this.

[Derek up North]

It's the round ball like thing with slits in the housing and copper wires wrapped on the inside ...

A fair description, as long as it's got a pulley and belt to drive it too!

https://www.google.ca/search?q=1988+toyota+pickup+alternator&client=firefox-a&hs=gx9&rls=org.mozilla:en-US:official&source=lnms&tbm=isch&sa=X&ei=70SEUpGvFMjAyAHFxYDoDw&ved=0CAkQ_AUoAQ&biw=1366&bih=594#q=+toyota+pickup+alternator&rls=org.mozilla:en-US%3Aofficial&tbm=isch

[Maineah]

I looked pretty carefully and couldn't find a white wire connected to the alternator. I see 2 wires, one looks like a spark plug wire with the hood like cap on the end. And the other I can't get a very good look at, tho it's not white. Is there another wire I'm not seeing? It's pretty cramped quarters in there. What's at the other end of the white wire? Maybe I can follow it back to the alternator.

Yes it's the big one. I maybe wrong on the color I believe it's white with a red stripe but it is the big one with the little rubber cap.

[Maineah]

When you say in series, where exactly does the alligator clip go and what do I touch the test probe to? I may be getting ahead of myself here since I can't seem to find the correct wire.

Of course it dawns on me now, am I really looking at the alternator? It's the round ball like thing with slits in the housing and copper wires wrapped on the inside isn't it? I really am very much the novice with all this.

The test light goes between the post of the battery and the cable end that gets removed from the battery clip on one tip on the other. Either post will work but it's better to remove the - to avoid sparks, Yeah it's the aluminum round thing with all the copper windings.

[ipo]

The test light goes between the post of the battery and the cable end that gets removed from the battery clip on one tip on the other. Either post will work but it's better to remove the - to avoid sparks, Yeah it's the aluminum round thing with all the copper windings.

OK. I think this is finally beginning to sink in. It's the exact same test light setup as checking the fuses except instead of pulling fuses you're pulling the alternator wire.

When the wire is disconnected is there any issue I need to be aware of ,like don't touch the end of the wire to any metal part kind of thing? I'm thinking of something like getting zapped or blowing something up.

[ipo]

A fair description, as long as it's got a pulley and belt to drive it too!

https://www.google.ca/search?q=1988+toyota+pickup+alternator&client=firefox-a&hs=gx9&rls=org.mozilla:en-US:official&source=lnms&tbm=isch&sa=X&ei=70SEUpGvFMjAyAHFxYDoDw&ved=0CAkQ_AUoAQ&biw=1366&bih=594#q=+toyota+pickup+alternator&rls=org.mozilla:en-US%3Aofficial&tbm=isch

Thanks for the pic link. Verified what it looks like. I'm definitely a visual learner.

[Maineah]

OK. I think this is finally beginning to sink in. It's the exact same test light setup as checking the fuses except instead of pulling fuses you're pulling the alternator wire.

When the wire is disconnected is there any issue I need to be aware of ,like don't touch the end of the wire to any metal part kind of thing? I'm thinking of something like getting zapped or blowing something up.

No, as long as the test light is in line no sparks. But it kind of negates the test if it's touching some thing.

[ipo]

But it kind of negates the test if it's touching some thing.

That makes sense, thanks.

[ipo]

OK. The short version is the test for draw from the alternator was negative for draw i.e. there was no draw; the test light lit up. Actually I'm somewhat disappointed, lol, I was hoping it was the culprit so the search could stop there.

any other thoughts?

[ipo]

You did have the battery itself tested to see if it is still viable didn't you? Even new batteries can be defective.

No I haven't had it tested. It was having this problem (battery dying within a few of weeks of sitting) before I changed the battery and after. Though I just did look at the install date and was back in '09. The battery has been dead and recharged a number of times so, if I now understand it, that kind of ruins the battery. So maybe it is time for a new battery to start with a known good one; the battery I have now seems to charge ok....but

[Maineah]

OK. The short version is the test for draw from the alternator was negative for draw i.e. there was no draw; the test light lit up. Actually I'm somewhat disappointed, lol, I was hoping it was the culprit so the search could stop there.

any other thoughts?

Well no it's a search and destroy mission just a matter of time till you find it.. There are things that do stay on like it or not like the memory for the radio stations,clocks things like that but they should go away by pulling fuses.you may have to get to the point of removing them all and replacing them one at a time until it comes back.The parasitic draw (memory, clocks) is all way going to be there but it is minor and should take months to kill a battery. Finding gremlins can be a daunting task.

[ipo]

Well no it's a search and destroy mission just a matter of time till you find it.. There are things that do stay on like it or not like the memory for the radio stations,clocks things like that but they should go away by pulling fuses.you may have to get to the point of removing them all and replacing them one at a time until it comes back.The parasitic draw (memory, clocks) is all way going to be there but it is minor and should take months to kill a battery. Finding gremlins can be a daunting task.

Well I'd say the gremlins certainly are creating mischief and hiding well. Apparently no one before we got it was able to find the problem..though I don't know who tried or how hard they tried to find the problem.

So does starting with a new battery sound like a plan to begin with before proceeding on with something else?

[waiter]

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)