Isolator Connections

Topic: Isolator Connections (Read 1567 times) previous topic - next topic

Isolator Connections

January 02, 2017, 02:21:41 pm

I have mentioned before that my alternator output and engine batteries are both on the center stud. Went to remove the nut to move the engine battery wire to the empty stud where it belongs. That way my Echo-Charger will keep it charged instead of periodically using my boost switch. The nut would not turn.

Put some Liquid Wrench on it; still tight. put some more on, waited a couple of minutes, tapped it with the wrench, added some more LQ and waited. Still will not move. Then I tried PB Blaster, still no joy.

I have several concerns:

I may be able to force it (especially with a cheater), but my concern is the stud itself. If I physically force it to turn, will it break the internal stud connection, and destroy my isolator?

I might be able to get a wrench on the back of the connecting wires, but I am afraid it might touch the heat sink fins. Is the heat sink grounded?

I thought of using a heat gun, but am concerned about the earlier penetrants catching fire. Obviously the heat shrunk cables are at the same location. But, would heat help loosen the nut?

I am very concerned about a second wrench, or a broken stud putting three fully charged red tops into play. Okay, since I have busbars, I can remove one cable, and avoid that; will do that when I go back out there.

What are my options? What is the recommended procedure?

What would y'all do to get past this step?

Thanks,

Trent

Re: Isolator Connections

Reply #1 – January 02, 2017, 02:34:05 pm

Trent,

Best advice is to use a good penetrating oil for a couple of more days. Then perhaps a little light, sharp "percussive persuasion". Breaking the stud would render the isolator recycle material.

I AM concerned about what that connection is doing to the battery. The "center stud" with the wire from the B+ terminal of the alternator, will have EXCESSIVELY high voltage (.7 VDC higher than either of the outer studs) and could easily damage the battery.

Wonder if the wire was moved because the isolator had already failed-- i.e. it was not passing power through the diode to the stud to the chassis battery. Easy to test.

With engine running, check voltage at center lug and at that outer lug. The outer lug should have about .7 VDC less than at the center stud and be in the range of 14.0-14.3.

Re: Isolator Connections

Reply #2 – January 02, 2017, 02:52:51 pm

Like Brett says, leave it for a couple of days. Applying heat with a micro torch and then more liquid wrench never hurts. Takes time for the stuff to penetrate and do it's thing. I like to replace all the washers/nuts with stainless. Get files ready to flatten the mating surfaces on the cables.

Isolators are not that expensive if you break yours. You just have to match the alternator output or a little more.

Pierce

Re: Isolator Connections

Reply #3 – January 02, 2017, 02:55:13 pm

One trick my dad showed me years ago was to put penetrating oil on the threads and then apply vibration ( I have used a palm sander body pressed against the bolt or threads)
Often fine vibrations will move material in ways that are just amazing. If you have ever seen high slump concrete turn to liquid with a concrete vibrator you will know what I mean.
Good luck!
Len

Re: Isolator Connections

Reply #4 – January 02, 2017, 03:00:35 pm

If you have access to acetone and transmission fluid; mix it 50/50 spray through spray bottle onto the nut and keep adding everytime you think of it.
Old farmer trick to unseize tractors bought at auction was to put the same mixture in the cylinders, places on trailer in gear and chained down for traveling home. Lots of time the tractors cylinders would be broke loose and able to start. Good luck.

Re: Isolator Connections

Reply #5 – January 02, 2017, 03:33:43 pm

Quote from: John/Pat – January 02, 2017, 03:00:35 pm

If you have access to acetone and transmission fluid; mix it 50/50 spray through spray bottle onto the nut and keep adding everytime you think of it.

Yup, one of the better penetrating oils.

Re: Isolator Connections

Reply #6 – January 02, 2017, 03:53:36 pm

Brett,

Thank you for the advice. Several people have suggested giving the penetrating oil several days to do its thing. I remember seeing a link somewhere (maybe here) to a comparison test of different penetrating formulas. My recollection is that (to my surprise) Liquid Wrench was one of the higher scoring. Although there was a "home brew" (maybe the acetone/transmission fluid?) mix that scored very high also.

Quote from: wolfe10 – January 02, 2017, 02:34:05 pm

With engine running, check voltage at center lug and at that outer lug. The outer lug should have about .7 VDC less than at the center stud and be in the range of 14.0-14.3.

This certainly sounds easy and straight forward, but I have a couple of concerns. We are often warned not to start our diesel engines if we cannot drive several miles before turning it off. I suspect that since it would only be on for a short time, it might not be a problem?

My other concern stems from the RV being up on eight 12" HF "safety stands". Would running the engine for a short time cause any problems from vibration? If it runs long enough to fill the air tanks, do I risk the air bags lifting the frame enough to allow one or more of the safety stands falling to the ground?

It is amazing how many alligators we can find when we just wanted to drain the swamp.

Thanks,

Trent

Re: Isolator Connections

Reply #7 – January 02, 2017, 04:17:21 pm

With the engine battery cable located on center post you don't need to start the engine. If there is any voltage on the other terminal at all the isolator is probably working. Usually when they fail there is not conduction between the posts. Like Brett said the expected voltage drop would be .7 volts going from the center terminal to outer ones.

Re: Isolator Connections

Reply #8 – January 02, 2017, 04:19:56 pm

Agree. That is close enough to "real world" that you should be able to tell if the isolator is good/bad.

Re: Isolator Connections

Reply #9 – January 02, 2017, 05:49:15 pm

While not a good practice to just start them to warm up, modern oils have a lot of anti rust/corrosion additives built in. No problem to start to move, check voltage, etc. Just not good to get in to the habit on a regular basis.

Once oil temp goes over about 185 degrees, the condensation starts to evaporate. Need about 20 miles to do that.

Pierce

Re: Isolator Connections

Reply #10 – January 02, 2017, 05:56:08 pm

Quote from: TulsaTrent – January 02, 2017, 03:53:36 pm

My other concern stems from the RV being up on eight 12" HF "safety stands". Would running the engine for a short time cause any problems from vibration? If it runs long enough to fill the air tanks, do I risk the air bags lifting the frame enough to allow one or more of the safety stands falling to the ground?

Sounds like you don't really need to start the engine to check the isolator, following the advice above.

However, if you ever DO want to run the engine when you have the coach up on safety blocks, don't worry about it. It won't hurt a thing - I have done it many times. The vibration won't be a problem, assuming the coach is actually sitting down on the blocks. With 30,000+ pounds of coach holding them in place, they aren't going anywhere.

As for the air suspension, it is also not a concern. When you start the engine, the HWH system will try to go to travel height - i.e. it will attempt to let air out of the bags (if there is any pressure still in them). The only way you are getting the coach up off the stands is by using the manual "RAISE" button on the control pad.

Re: Isolator Connections

Reply #11 – January 02, 2017, 06:04:56 pm

There is a product that is similar to pb blaster but better. Its called Kroll and its hard to find but I found it to be able to loosen anything. Above suggestions about letting it soak and also tapping on the socket or wrench is like vibration might also work.

Re: Isolator Connections

Reply #12 – January 02, 2017, 06:06:02 pm

Quote from: Chuck & Jeannie – January 02, 2017, 05:56:08 pm

The only way you are getting the coach up off the stands is by using the manual "RAISE" button on the control pad.

Chuck,

That reminds me of something. When I raised it up, I initially used the "raise all" button. Went back to start installing them, and it was only up about 11". I went back inside and used the front raise button and it went up to 13.5"set the stands and lowered the front to the stands. Raised the back the rest of the way, and it also went up to 13.5".

Did I just not let the raise all button work long enough, or did the raise front and raise rear actually have additional lift?

Trent

Re: Isolator Connections

Reply #13 – January 02, 2017, 06:07:28 pm

Quote from: joeszeidel – January 02, 2017, 06:04:56 pm

There is a product that is similar to pb blaster but better. Its called Kroll and its hard to find but I found it to be able to loosen anything.

Yup, used it on the bolts on the exhaust manifold bolts of a Cummins ISL a month ago. Good (expensive) stuff.

For most stuff I use the acetone/ATF as it is a fraction of the price. But, a broken bolt in an ISL head.........

Re: Isolator Connections

Reply #14 – January 02, 2017, 06:15:04 pm

Quote from: TulsaTrent – January 02, 2017, 06:06:02 pm

Did I just not let the raise all button work long enough...

Yes.

Sometimes it takes a while to achieve full erection, especially in the rear.

(There are several wrong ways to read that sentence, but I trust our Forum members are above such crass thoughts)

Re: Isolator Connections

Reply #15 – January 02, 2017, 06:45:47 pm

Be nice! It could be your sentence.

Re: Isolator Connections

Reply #16 – January 02, 2017, 09:02:21 pm

Quote from: wolfe10 – January 02, 2017, 06:07:28 pm

For most stuff I use the acetone/ATF as it is a fraction of the price.

Ignoring the health problems associated with acetone, I see another possible problem.

Acetone is extremely volatile. When mixed with a non volatile substance like transmission fluid, is there not the possibility that the acetone in the mixture will evaporate, leaving only transmission fluid?

Just curious,

Trent

Re: Isolator Connections

Reply #17 – January 02, 2017, 09:07:37 pm

here are the results

Penetrating Oil Showdown!!! | The H.A.M.B.

Re: Isolator Connections

Reply #18 – January 03, 2017, 12:35:57 am

Trent,

(as others have mentioned), any penetrant needs to "set", in order for it to work.

From my experience, Mouse Milk penetrant works better and is not as flammable.

An isolator case is usually grounded to the frame - easy to verify with a DVM/VOM.

Remove (+) cables from your isolator at the other end (your Battery bus bars).

Each isolator post should have an inner nut, then a round wire lug, then an outer nut sequence landed on the stud. At least that is the way it is on mine.

Toolsmanship: To confine torque to the stud (and prevent damage to the isolator), use two slightly offset wrenches and then squeeze them together with one hand. That way there is no torque applied to anything except the stud between the two nuts. If you have no inner nut, use a pair of vise grips set onto the round wire lug and then a slightly offset closed end wrench, squeeze them together to free the nut slightly, work in more penetrant, work the nut off slowly using more penetrant.

[/list]
High heat and flammable solvents may not be the best things to use around the somewhat soluble potting compound (that black stuff that is molded into the face of the Isolator cooling fins).
HTH,
Neal

Re: Isolator Connections

Reply #19 – January 03, 2017, 02:32:10 am

My small motorcycle motor builds routinely have badly stuck filter retaining fasteners.

My routine removal method is to use an air impact wrench and remove the offending fastener with the tools percussive persuasion quickly.

Obviously a corroded shaft may have enough friction to slow the removal and failure is a possibility.

A double nut on the exposed shaft tensioned against each other and a wrench applied would allow more force to be applied to the stuck fastener.

This presupposes that some sufficient shaft is exposed

Re: Isolator Connections

Reply #20 – January 03, 2017, 11:57:58 am

As a heads up, Kroll is running a Google Deal of 2 cans of Kroll for $14 + shipping.

Google Deal

Re: Isolator Connections

Reply #21 – January 09, 2017, 01:05:35 am

Quote from: JohnFitz – January 02, 2017, 04:17:21 pm

With the engine battery cable located on center post you don't need to start the engine. If there is any voltage on the other terminal at all the isolator is probably working. Usually when they fail there is not conduction between the posts. Like Brett said the expected voltage drop would be .7 volts going from the center terminal to outer ones.

Here are the results of my voltage measurements at the isolator studs (three), with the engine and boost switch off, and plugged into 50 amp shore power:

Left Stud (House battery) Center Stud (Alt + Engine batt) Right Stud (No Connection)

14.3 VDC 13.1 VDC 12.6 VDC

Using the cheap digital voltmeters plugged into the two 12VDC outlets on the dash:

Upper Outlet (house battery): 13.8 VDC

Lower Outlet (engine battery): 12.7 VDC

Would someone who understands what these readings mean, please let me know what, if anything, information this data reveals about my battery systems and the isolator?

Thank you,

Trent

Re: Isolator Connections

Reply #22 – January 09, 2017, 01:06:58 am

Alan,

Thanks, I ordered mine.

Trent

Re: Isolator Connections

Reply #23 – January 09, 2017, 01:31:04 am

Quote from: TulsaTrent – January 09, 2017, 01:05:35 am

Here are the results of my voltage measurements at the isolator studs (three), with the engine and boost switch off, and plugged into 50 amp shore power:

Left Stud (House battery) Center Stud (Alt + Engine batt) Right Stud (No Connection)

14.3 VDC 13.1 VDC 12.6 VDC

Using the cheap digital voltmeters plugged into the two 12VDC outlets on the dash:

Upper Outlet (house battery): 13.8 VDC

Lower Outlet (engine battery): 12.7 VDC

Would someone who understands what these readings mean, please let me know what, if anything, information this data reveals about my battery systems and the isolator?

Thank you,

Trent

It appears your isolator is good, and voltages about normal. While on shore power the engine batteries are not charged. By your engine battery being on the center stud when running you would be putting too muck voltage to the start batteries. Center stud is .4 volts higher than the left and right studs.

Re: Isolator Connections

Reply #24 – January 09, 2017, 04:50:22 am

I agree with Craneman. Your isolator appears to be working. Next step would be to check the voltage with the engine running.

One possibility that hasn't been mentioned yet is whoever put the engine battery on the center post might have also turned the voltage output down on the alternator (or moved the sense wire with it). This would make it such that while driving the engine battery would get a full charge and the house batteries would get a mild "float" like charge that would take much longer to reach 100%. Not necessarily bad and might be a good way to prevent over taxing the alternator if you started your days drive with depleted house battery from boon-docking. You could always turn on the boost solenoid if you want to bring up fully right away along with the engine battery.

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