battery not charging 87' GrandVilla

Topic: battery not charging 87' GrandVilla (Read 1584 times) previous topic - next topic

battery not charging 87' GrandVilla

January 21, 2021, 09:49:32 pm

Hi there!

looking at the starter battery system.

New key cylinder, new ignition switch, new starter.
Battery tested fine and so did the alternator.

However, the alternator only produces a tiny amount of juice.

anyone??

Re: battery not charging 87' GrandVilla

Reply #1 – January 21, 2021, 11:29:46 pm

Quote from: Firewhirrrl – January 21, 2021, 09:49:32 pm

However, the alternator only produces a tiny amount of juice.

Simple things first. Make sure all battery charging cable connections are clean and tight, including the ground cables.

Do you have the 12 volt (automotive) wiring schematic for your coach?

Where are you measuring the "tiny amount of juice"?

Try checking voltage output (engine running) at the alternator B (+) output terminal, AND at the battery isolator alternator post and start battery post, AND at the POS post on the start battery. If you can give us the readings from all 4 places, it will help to diagnose your problem.

It is possible for your alternator to work fine on a test machine, but then not work on your coach. When the alternator is connected to a diode based battery isolator instead of directly to the start battery, the charging output cable does not "see" battery voltage. Your alternator may require a small gauge "excite" wire which is HOT when the ignition switch is ON. If so, and if this wire is missing or broken, then the alternator will not put out juice. We need good clear closeup photos of the back side of your alternator, and of the I.D. label. We need to know the alternator brand and model, what the terminals look like, and how many wires are connected.

See the thread linked below for a somewhat clear explanation of a DUVAC alternator charging system.

What is DUVAC?

Re: battery not charging 87' GrandVilla

Reply #2 – January 22, 2021, 12:32:11 am

In the morning, I will get the data for you.

the connections are clear and solid.

the battery reading looks to be at 12.2, the alternator was about 1.3. at idle.

I have the service manual, and a great parts store.
I will get you all the readings sometime tomorrow, hopefully in the morning.

Re: battery not charging 87' GrandVilla

Reply #3 – January 22, 2021, 08:52:37 am

Battery voltage of 12.2 is not good...

Re: battery not charging 87' GrandVilla

Reply #4 – January 22, 2021, 09:42:16 am

Do you mean 1.3 or 13

Re: battery not charging 87' GrandVilla

Reply #5 – January 22, 2021, 04:30:49 pm

Yes, it read 1.3. Not 13.

Seems hubby is not so good with some things, so I will go back and double check all the readings. I work all day, so it might be hard to get them till Sunday morning...

Re: battery not charging 87' GrandVilla

Reply #6 – January 22, 2021, 04:46:26 pm

Post a pic of the alternator wires. I had one break that is the field/ exciter wire. Mine ran to the fuel injector solenoid , about 8 inches.

Re: battery not charging 87' GrandVilla

Reply #7 – January 22, 2021, 05:08:03 pm

Being 1.3 the alternator is not putting out so you need to find out why. First let us know what coach you have. Did this happen after you did all the work.

Re: battery not charging 87' GrandVilla

Reply #8 – January 22, 2021, 06:45:25 pm

1.3 VDC is a COMPLETELY DEAD BATTERY.

Before troubleshooting, fully charge it and have it load tested.

THEN do the tests.

Re: battery not charging 87' GrandVilla

Reply #9 – January 22, 2021, 08:48:51 pm

I think that this is a Oskosh rear engine gas which has a 460 Ford engine. They came with a Ford alternator with an external regulator.

Re: battery not charging 87' GrandVilla

Reply #10 – January 22, 2021, 08:57:36 pm

Yup, we REALLY need to know what coach/chassis/engine you have to be able to give you sage advice.

Re: battery not charging 87' GrandVilla

Reply #11 – January 22, 2021, 09:02:29 pm

Quote from: wolfe10 – January 22, 2021, 06:45:25 pm

1.3 VDC is a COMPLETELY DEAD BATTERY.

See Reply #2.

1.3 VDC is what the OP was reading at the alternator - not the battery voltage. Battery was 12.2 VDC.

Re: battery not charging 87' GrandVilla

Reply #12 – January 23, 2021, 12:34:31 am

Mine is an Oshkosh with a reap push gas Ford 460 ( and I rather like how she takes hills...

I will proceed with checking the excite wire ( which I had thought was the ground...)
This will tell me about the juice going into the system.

From there, maybe the belt is not tensioned perfectly. I will only check the belt after I determine that there is enough excite juice.
I do have a new volt regulator if I need it.

Re: battery not charging 87' GrandVilla

Reply #13 – January 23, 2021, 08:34:58 am

Quote from: red tractor – January 22, 2021, 08:48:51 pm

I think that this is a Oskosh rear engine gas which has a 460 Ford engine. They came with a Ford alternator with an external regulator.

Our front gas 454 86 GV had a FORD alternator with external regulator from factory. We had a failure on a TX trip and replaced with a new FORD alternator with ONE wire

Re: battery not charging 87' GrandVilla

Reply #14 – January 23, 2021, 02:25:54 pm

I had a similar problem, turned out it was a $5 relay, runs from the alternator rear over to the bay wall under the bed.

Re: battery not charging 87' GrandVilla

Reply #15 – January 27, 2021, 06:49:48 pm

Hello again!

Ok. So volt regulator has been replaced.
We have 12 volts coming from the alternator

But not enough to be considered good.

What should I check next?

Re: battery not charging 87' GrandVilla

Reply #16 – January 27, 2021, 07:32:18 pm

Quote from: Subsilked – January 23, 2021, 08:34:58 am

Our front gas 454 86 GV had a FORD alternator with external regulator from factory. We had a failure on a TX trip and replaced with a new FORD alternator with ONE wire

I had a Lucas alternator on my Perkins boat engine. It failed fairly quickly on our trip so when I came back to the States, I ordered 3 single wire alternators from JC Whitney. Easy to wire from the big alternator terminal to anywhere you want. They were only $16 back in the early '80s. Not that hard to find one that matches the pivot and mounting points.

Pierce

Re: battery not charging 87' GrandVilla

Reply #17 – January 27, 2021, 07:46:19 pm

Quote from: Pierce & Gaylie Stewart – January 27, 2021, 07:32:18 pm

I had a Lucas alternator on my Perkins boat engine. It failed fairly quickly on our trip so when I came back to the States, I ordered 3 single wire alternators from JC Whitney. Easy to wire from the big alternator terminal to anywhere you want. They were only $16 back in the early '80s. Not that hard to find one that matches the pivot and mounting points.

Pierce

ok, sounds really attractive...
but this would mean by passing the isolator? or pugging into the isolator and regaining the system from there?
what size alternator, and how would it know if it was ovwecharging? what about the house battery?

Re: battery not charging 87' GrandVilla

Reply #18 – January 27, 2021, 07:55:39 pm

It wouldn't work with the isolator as the voltage has to be turned up .7 volts to allow for the voltage drop in the isolator. If you had bought a combiner instead of and isolator form Blue Sea it would work with an off the shelf alternator.

Re: battery not charging 87' GrandVilla

Reply #19 – January 27, 2021, 08:05:09 pm

On our 7.3 diesel conversion on the old SOB, I just plugged the single wire into the isolator and it worked OK. You can pay a voltage penalty connecting an alternator straight to a solid state isolator. But there are a couple of ways around it. Read here: Tech Tips - Battery Isolators in Three Flavors - RV LIFE

If you have a DUVAC alternator, read here.
How to Wire a Battery Isolator in a Camper | It Still Runs

Pierce

Re: battery not charging 87' GrandVilla

Reply #20 – January 30, 2021, 10:50:44 am

Quote from: Chuck & Jeannie – January 21, 2021, 11:29:46 pm

Simple things first. Make sure all battery charging cable connections are clean and tight, including the ground cables.

Do you have the 12 volt (automotive) wiring schematic for your coach?

Where are you measuring the "tiny amount of juice"?

Try checking voltage output (engine running) at the alternator B (+) output terminal, AND at the battery isolator alternator post and start battery post, AND at the POS post on the start battery. If you can give us the readings from all 4 places, it will help to diagnose your problem.

It is possible for your alternator to work fine on a test machine, but then not work on your coach. When the alternator is connected to a diode based battery isolator instead of directly to the start battery, the charging output cable does not "see" battery voltage. Your alternator may require a small gauge "excite" wire which is HOT when the ignition switch is ON. If so, and if this wire is missing or broken, then the alternator will not put out juice. We need good clear closeup photos of the back side of your alternator, and of the I.D. label. We need to know the alternator brand and model, what the terminals look like, and how many wires are connected.

See the thread linked below for a somewhat clear explanation of a DUVAC alternator charging system.

What is DUVAC?

hi again,

After many days and learning so much, the following has been determined.
the alternator will read the battery charge amount.

I changed the volt regulator and tried to excite by giving power directly to the s wire on the volt regulator with a small wire and a grounded jumper pack, and to no avail.

I got a new alternator. I installed a new isolator.

Do you have any final thoughts?
I know there are fuselinks. Should I just replace the wire anyways and see? if so which one?

With all said and done, It appears the alternator is not getting the excite signal.

Re: battery not charging 87' GrandVilla

Reply #21 – January 30, 2021, 11:40:23 am

You seem to have thrown lots of parts at this problem. What are you using for a start battery and what is the current voltage?
Are the battery terminals clean and the cables tight?

Re: battery not charging 87' GrandVilla

Reply #22 – January 30, 2021, 11:48:40 am

Quote from: Firewhirrrl – January 30, 2021, 10:50:44 am

I changed volt regulator and tried to excite by giving power directly to the s wire on the volt regulator with a small wire and a grounded jumper pack, to no avail.

I know there are fuselinks. Should I just replace the wire anyways and see? if so which one?

With all said and done, It appears the alternator is not getting the excite signal.

Try to use a logical approach to finding a solution.

In typical alternator terminology "S" does NOT indicate the "Excite" terminal. "I" (for Ignition) would commonly indicate the "Excite" connection. This marking may also hold true for voltage regulators, although I'm not sure cuz it's been decades since I last saw one. See diagram below for a generic diagram of alternator + external voltage regulator. Notice the switched ignition signal goes to the "I" terminal on the regulator.

If you believe the alternator is not getting the excite signal, try to determine why.

Try to search the alternator brand/model number online. There are "installation instructions" available online for almost every common alternator. If you have a separate voltage regulator, you also need the instructions for that device.

The reason you want to see the installation instructions is to identify the correct connection of wires to the alternator/regulator. Does the alternator (or the regulator) have a terminal dedicated to a EXCITE wire connection? If so, do you have a wire connected to that terminal?

If you DO have a EXCITE wire connected to the alternator/regulator, is that wire HOT when the ignition switch is turned to ON position?

IF the wire is HOT with ignition, then it is good. If not, you must either replace the wire or find the break and repair the wire.

Any length of wire, or fusible link, can be easily tested for continuity with a multimeter or even a simple 12 volt test light.

Re: battery not charging 87' GrandVilla

Reply #23 – January 30, 2021, 07:50:02 pm

Look up for like a 84 Ford pickup with I think 100 amp alternator wiring and this should help sort this.

Re: battery not charging 87' GrandVilla

Reply #24 – January 30, 2021, 09:51:18 pm

Often the Ford voltage regulator has to be grounded, and grounded to the engine as well as the battery . Any period correct service book for Ford will show the diog tree for the alternator and tell how to full field the alternator.

Affiliate Notice