Reply
 
Thread Tools Display Modes
 
Old 07-02-2020, 01:17 PM   #1
Bus Nut
 
Mountain Gnome's Avatar
 
Join Date: Oct 2017
Posts: 685
Year: 1999
Coachwork: BlueBird
Chassis: TC1000 HandyBus
Engine: 5.9L 24V-L6 Cummins ISB
Rated Cap: 26 foot
power distribution conundrum

I thought I was the smart guy, until this problem:


HISTORY:
Bought bus from school system, "commercial" size battery needed to be jumped.


Drove it 2 blocks, again needed to be jumped.


Bought a new "Wally World" #1 (starter) battery (for big pickup trucks, etc.), needed to be jumped the next day.


Disconnected #2 (wheelchair lift) battery at the ground (-) post. That solved my dead #1 starter battery problems. #2 battery (+) post looks "crooked" and there is a swell under it - like it melted internally for some reason, and must have been draining the #1 starter battery.

Weather got cold, had to add another "Wally-World" #1 starter battery in parallel with the first ... actually bought two more new matching ones, and put the first new one in storage.

All the above happened while on the road with a new vehicle. Never "dug deep" to find problems or understand the complete system. Noted some weeks/months later (still on the road) that the wheelchair lift "power" light was on. Traced the problem to the battery isolator - diode type by Sure Power, model 16023A (see pic). With the motor off, I had 12V at both battery-connector posts on the isolator, yet #2 was disconnected from the battery, so no isolation was occuring. This was double-verified by disconnecting battery #1. At that time, I disconnected the cable for battery #2 from the isolator, and directly connected the cable for battery #1 to the alternator cable stud, completely bypassing the isolator, and full-time isolating the circuit for battery #2.


Drove like that for a couple years...


Ironically for me, the COVID-19 shutdown freed up money that was propping up a failed business, so the big maintenance/repair projects found financing...



Started the project to get my A/C systems working this spring. Never really messed with it before then...maybe tried it once. Noted the fans came on, but the air was never cold. Pros vacuumed my systems (noting they were low on refrigerant), and then I replaced all the rubber refrigerant barrier hoses (another trip altogether down the rabbit hole - I can now custom make crimped-fitting hoses on-the-spot, so PM me if you're in need).



In the meantime, I also ordered a new battery isolator, so I can install a set of deep-cycle batteries for lights/computer/stereo/etc. that I will keep charged with my alternator (for now I will still be driving nearly every day, solar maybe in the future) in place of the #2 wheelchair battery. I got a Cole-Hersee 200-Amp isolator model #48162 made for "Delcotron" alternators; it says it works with all other alternators, also. This model has a 4th pole for the "IGN" (motor ignition) signal, as did the original isolator. The instructions say to connect a jumper wire from the #1 battery post back to the "S" terminal on the Delcotron alternators, and also to connect the IGN wire properly for those same alternators. It says not to connect the IGN wire or the jumper wire for other alternators.

I can't find anything on the alternator that says "Delcotron", and although there are 3 small screw terminals that are unused on the back, they are not labeled. It is a ProAmp alternator with the markings: TAE 1315 7613 520-622-7395. I emailed the ProAmp website, no response. I tried to cross-check the part numbers on NAPA's website, but nothing came up.


Back to the A/C, after getting all the new hoses installed, I took it back to the pros (who really did NOT want to work on my bus - "I've worked on buses before" the tech guy told me with a tone that said he didn't like them) to have the systems charged with refrigerant. All charged up, turned the system on, and ... nothing ... no fans ... nothing. Dude lent me a voltmeter (he really did not want to diag anything on a bus) and I found 0 volts at the power feed for the A/C systems. After a short belly-crawl under the bus, I found the power was being pulled directly from the alternator's (+) pole. HMMM.... ???????


So the new isolator was working with the motor off...so far so good. But with the motor back on, I only had 1-3 volts at the A/C power-feed. Took the bus back home, and verified everything....adding in battery #2. The reading that got me the most was this:
Motor on, voltmeter grounded to the (-) pole on the alternator, then again verified with voltmeter grounded directly to the (-) pole on battery #1:
3 volts at the alternator pole on the isolator.
13.3 volts at battery #1 pole on the isolator - connected to (2) starter batteries in parallel - both with a fresh charge.
14.5 volts at battery #2 pole on the isolator - connected to (1) starter battery - with a 2-3 month old charge.


That's what is really getting me!

(a) I thought that the voltage regulator in the alternator should keep the voltage above 12V
(b) I thought the isolator would limit the voltage to a fully charged battery while giving full charge to the more depleted battery, not step it up from 3V to 13.3V or 3V to 14.5V. I do remember it saying in the ad for the isolator that it automatically gives the right amount of charge for the battery without overcharging the others.


None of that would matter, as long as my batteries remain isolated, and get properly charged when I drive...
Except for the A/C system getting its power from the alternator's (+) post. It won't run on 3V.
SO HOW DID IT EVER WORK?
I thought the "shadetree mechanic" method of testing an alternator was to start the engine, turn on the headlights, and then disconnect the battery. It can ruin a good alternator, so don't try it, but if it is a valid test, then why won't this alternator produce 12V+ when it has the load from the A/C system on it? OK, when both battery banks are fully charged, maybe it won't...???



I bypassed the new isolator as I did with the original faulty one. I get 13.3 or something volts at the alternator (+) post with the motor running. The A/C systems both blow cold. AHHH. But for the life of me, how did it ever originally work?


The alternator looks relatively new. Maybe they installed one that was not the original type? Maybe then the A/C system failed to work, and they retired the bus? Maybe then also, it blew the old isolator and was killing the batteries? (both original "commercial" batteries were dead, but were only a year old and in warranty, yet I was not together enough to find a place to replace them for free)


So much still to learn.....


Anyway, assuming my newish alternator is actually good, the only way I see to get this system working is to disconnect the A/C system's power feed from the back of the alternator, and reconnect it to battery #1. A good place to reconnect it would be at the starter (+) post, as everything "comes together" there (see the diagram).


I can't see why this would be a bad idea, but I can't exactly see why they connected it to the back of the alternator; or how it ever worked unless (a) my newish alternator is bad, or (b) the "original" battery isolator was added later and was not original.


Any chimes to add to this symphonic mess?


(in pic 2 you can see the power feed come into the system in the upper right corner and then back out going to pic 3 where it feeds into the other system in the same corner)
Attached Images
File Type: jpg 0702201154a.jpg (123.4 KB, 37 views)
File Type: jpg 0507201539a[1].jpg (192.1 KB, 10 views)
File Type: jpg 0507201539b[1].jpg (169.4 KB, 9 views)
File Type: jpg 0702201235[1].jpg (137.1 KB, 13 views)
Mountain Gnome is offline   Reply With Quote
Old 07-02-2020, 03:00 PM   #2
Bus Crazy
 
Join Date: Nov 2016
Posts: 1,696
TL;DR

Try a short summary of only the relevant background data, then ask a concise questiin or two.

You'll get more, and better quality, answers.
john61ct is online now   Reply With Quote
Old 07-02-2020, 05:49 PM   #3
Bus Nut
 
Mountain Gnome's Avatar
 
Join Date: Oct 2017
Posts: 685
Year: 1999
Coachwork: BlueBird
Chassis: TC1000 HandyBus
Engine: 5.9L 24V-L6 Cummins ISB
Rated Cap: 26 foot
well, it seems I don't even know enough to ask a single (or two) pertinent question(s).



therefore, I think that the only IRrelevant info is a sentence or two about the A/C work.


How DID the system work originally? Or is the alternator acting weird? Or is the new isolator acting weird? Seems to me the alternator is producing the ADDITIONAL voltage needed to charge the batts (i.e. the three volts that the alternator is producing is split, and 2 volts are going to the lesser-charged battery bank (12.3+2.2=14.5), and 1 volt is going to the nearly charged battery bank (12.7+0.8=13.3) with the error factor being loss, or something like that....) ?????


I just don't know what is really going on...
I only seem to know that I could rewire the A/C system to pull power from the circuitry of battery bank #1, and my problem should be solved. But why should I need to do that?
Mountain Gnome is offline   Reply With Quote
Old 07-03-2020, 10:10 AM   #4
Bus Nut
 
Mountain Gnome's Avatar
 
Join Date: Oct 2017
Posts: 685
Year: 1999
Coachwork: BlueBird
Chassis: TC1000 HandyBus
Engine: 5.9L 24V-L6 Cummins ISB
Rated Cap: 26 foot
just bumping this back on the list.


doesn't anyone understand battery isolators or alternators at a fundamental level? I thought y'all were smarter than me!
Mountain Gnome is offline   Reply With Quote
Old 07-03-2020, 11:37 AM   #5
Bus Crazy
 
Join Date: Jun 2013
Location: Picton,Ont, Can.
Posts: 1,956
Year: 1997
Coachwork: Bluebird
Chassis: GMC
Engine: Cat 3116
Rated Cap: 72
There is a lot here I don,t get from your diagram.


What is the "E" terminal intended for on the isolator?


Your connections off the isolator to both battery banks are shown on the neg battery terminals. Why not the pos terminals?


I have other questions but try and answer these 2 first?


John
__________________
Question everything!
BlackJohn is offline   Reply With Quote
Old 07-03-2020, 03:07 PM   #6
Bus Crazy
 
somewhereinusa's Avatar
 
Join Date: Nov 2010
Location: Andrews,Indiana
Posts: 2,192
Year: 1991
Coachwork: Bluebird
Chassis: AARE
Engine: 3116 Cat 250hp
Rated Cap: Just the two of us.
Quote:
Originally Posted by Mountain Gnome View Post

doesn't anyone understand battery isolators or alternators at a fundamental level? I thought y'all were smarter than me!
There are a lot of us who understand isolators, your explanation doesn't mean much.

I downloaded the Surepower installation instructions. Looks pretty straight forward to me. You have to know what alternator you have, they give instructions on how to do that. Post a picture of the back side of your alternator. And the plug.

Quote:
Or is the new isolator acting weird? Seems to me the alternator is producing the ADDITIONAL voltage needed to charge the batts (i.e. the three volts that the alternator is producing is split, and 2 volts are going to the lesser-charged battery bank (12.3+2.2=14.5), and 1 volt is going to the nearly charged battery bank (12.7+0.8=13.3) with the error factor being loss, or something like that....) ?????
I doesn't work like that.

It sounds to me like you have a bad connection/wire somewhere may be at one of the many grounds shown in your diagram.

John

Quote:
Your connections off the isolator to both battery banks are shown on the neg battery terminals. Why not the pos terminals?
What am I missing? It looks like they are on the pos terminals.
somewhereinusa is offline   Reply With Quote
Old 07-03-2020, 04:20 PM   #7
Bus Crazy
 
banman's Avatar
 
Join Date: Aug 2019
Location: Ohio
Posts: 1,456
Year: 2002
Coachwork: Thomas
Chassis: Freightliner FS-65
Engine: 7.2L Cat 3126 turbo diesel
Rated Cap: 71 passenger 30,000 gvwr
Caveat -- I didn't read your entire post -- I had trouble following it all...
BUT this statement jumped out at me.

SO HOW DID IT EVER WORK?
I thought the "shadetree mechanic" method of testing an alternator was to start the engine, turn on the headlights, and then disconnect the battery. It can ruin a good alternator, so don't try it, but if it is a valid test, then why won't this alternator produce 12V+ when it has the load from the A/C system on it? OK, when both battery banks are fully charged, maybe it won't...???


I don't know where the myth of this ever being a valid test of anything ever came from but it's not.
However breaking the load on a circuit this way can very easily fry your rectifier/voltage regulator in your alternator...

A good "in the field" test of an alternator is to turn on the lights, heater fans, stereo, etc -- create a good load on the alternator -- run the engine a little above idle speed and measure the voltage being produced -- it should be at/over 13.5v for a well working alternator. If the alternator can only put out 12.x volts then the voltage reg is fried...

In case it needs saying -- start the engine before creating the electrical load.
with a diesel I guess the "a little above idle speed" for testing should be ~1000 rpm
__________________
David

The Murder Bus
banman is offline   Reply With Quote
Old 07-03-2020, 05:31 PM   #8
Bus Nut
 
TJones's Avatar
 
Join Date: Jul 2017
Location: Rapid City, SD
Posts: 557
Year: 2001
Coachwork: Blue Bird
Chassis: CS RE
Engine: ISC 8.3 L 260 hp
Rated Cap: 36
I would leave the air conditioning power connected to the (+) terminal on the alternator if that is how it was from the factory. What this does is keeps the the currant needed to run the AC off the cable that runs from the alternator to the battery.

Your problem likely lies in how the isolater is wired in. I would check the installation instructions again and pay particular attention to the wire from the ignition. This wire should have power whenever the ignition is turned on and the engine is cranked not just when the engine is cranking. Also check that the wire from the batery #1 (+) to the "S" terminal on the alternator is wired correctly. Also check for proper grounding of everything.

Ted

EDIT: You do not show a connection from battery #1 (+) to the "S" terminal of your alternator. If your alternator is a 4 wire alternator it will need this connection to function.
TJones is offline   Reply With Quote
Old 07-03-2020, 06:42 PM   #9
Bus Crazy
 
Join Date: Jun 2013
Location: Picton,Ont, Can.
Posts: 1,956
Year: 1997
Coachwork: Bluebird
Chassis: GMC
Engine: Cat 3116
Rated Cap: 72
John

Quote:
Your connections off the isolator to both battery banks are shown on the neg battery terminals. Why not the pos terminals?
What am I missing? It looks like they are on the pos terminals?


I just had another look and see if his connections from the isolator to battery terminals going to the neg on both battery banks. You are totally right.

I didn't look close enough I guess.

Off the #1 terminal he goes to the starter pos, why not to the battery only? Would this not add more resistance to the isolator's path to that battery bank?

Terminal #2 looks connected fine.



Still don't know what the "E" connection means, exciter, Earth or..E is used to specify voltage in electrical equations. My isolator has no E at all.
So I don't know how to explain this part.


John
__________________
Question everything!
BlackJohn is offline   Reply With Quote
Old 07-03-2020, 09:55 PM   #10
Bus Nut
 
Mountain Gnome's Avatar
 
Join Date: Oct 2017
Posts: 685
Year: 1999
Coachwork: BlueBird
Chassis: TC1000 HandyBus
Engine: 5.9L 24V-L6 Cummins ISB
Rated Cap: 26 foot
Quote:
Originally Posted by BlackJohn View Post
There is a lot here I don,t get from your diagram.


What is the "E" terminal intended for on the isolator?


Your connections off the isolator to both battery banks are shown on the neg battery terminals. Why not the pos terminals?


I have other questions but try and answer these 2 first?


John
The "E" terminal (on the old Sure Power isolator that I removed, shown in the picture) had the wire from the IGN relay connected to it. When the Ignition switch is "ON", that wire has 12V+ power. I bought the new isolator model based on the fact that the old one had this terminal; so the new one has it also, but it is for "Delcotron" alternators according to the installation instructions on the new Cole Hersee isolator. Again, I can't even figure out if I have a "Delcotron" that was rebuilt by ProAmp or something else. "Delcotron" is originally made by "Delco"


The cables from the isolators to the battery banks are connected to the (+) battery posts in the diagram. You seem to be mistaken.



More questions?
Mountain Gnome is offline   Reply With Quote
Old 07-03-2020, 10:08 PM   #11
Bus Nut
 
Mountain Gnome's Avatar
 
Join Date: Oct 2017
Posts: 685
Year: 1999
Coachwork: BlueBird
Chassis: TC1000 HandyBus
Engine: 5.9L 24V-L6 Cummins ISB
Rated Cap: 26 foot
Quote:
Originally Posted by somewhereinusa View Post
There are a lot of us who understand isolators, your explanation doesn't mean much.
My explanation is hopeless, because I seem to be clueless as to WHY I get the results I get.


Quote:
Originally Posted by somewhereinusa View Post
I downloaded the Surepower installation instructions. Looks pretty straight forward to me. You have to know what alternator you have, they give instructions on how to do that. Post a picture of the back side of your alternator. And the plug.
The new isolator is a Cole Hersee. I read the instructions with that one. Pics of alternator below...


Quote:
Originally Posted by somewhereinusa View Post
I doesn't work like that.
Then how does 3 volts at the alternator terminal on the isolator charge both battery banks, when both batteries are 12+V when disconnected? I always thought the alternator was in parallel with the batts, but now I am wondering if it is in series?


Quote:
Originally Posted by somewhereinusa View Post
It sounds to me like you have a bad connection/wire somewhere may be at one of the many grounds shown in your diagram.
The grounds look pretty solid and clean. Perhaps I should take them apart and clean them.


But can you explain how the grounds are keeping the voltage at the alternator 3V when the isolator is installed?
Attached Images
File Type: jpg 0703202259[1].jpg (143.3 KB, 12 views)
File Type: jpg 0703202259a[1].jpg (131.7 KB, 6 views)
Mountain Gnome is offline   Reply With Quote
Old 07-03-2020, 10:12 PM   #12
Bus Geek
 
ol trunt's Avatar
 
Join Date: Apr 2012
Location: So Cal
Posts: 2,763
Year: 1935
Coachwork: Superior
Chassis: Chevy
Engine: 317 ci/tid / Isuzu
Does the ac work if the isolator isn't hooked up? I may have missed that.

On my Isuzu powered multiplexed wiring system it is not possible to use the type of battery isolator you have at all. I tried it and in my case the alternator fails to put out any power at all. I went to a battery to battery charger (Sterling Power BB1230) and solved all my problems. I don't know if your bus has multiplex wiring but if it does this may be your answer.
Jack
ol trunt is offline   Reply With Quote
Old 07-03-2020, 10:19 PM   #13
Bus Nut
 
Mountain Gnome's Avatar
 
Join Date: Oct 2017
Posts: 685
Year: 1999
Coachwork: BlueBird
Chassis: TC1000 HandyBus
Engine: 5.9L 24V-L6 Cummins ISB
Rated Cap: 26 foot
Quote:
Originally Posted by banman View Post
Caveat -- I didn't read your entire post -- I had trouble following it all...
BUT this statement jumped out at me.

SO HOW DID IT EVER WORK?
I thought the "shadetree mechanic" method of testing an alternator was to start the engine, turn on the headlights, and then disconnect the battery. It can ruin a good alternator, so don't try it, but if it is a valid test, then why won't this alternator produce 12V+ when it has the load from the A/C system on it? OK, when both battery banks are fully charged, maybe it won't...???


I don't know where the myth of this ever being a valid test of anything ever came from but it's not.
However breaking the load on a circuit this way can very easily fry your rectifier/voltage regulator in your alternator...

A good "in the field" test of an alternator is to turn on the lights, heater fans, stereo, etc -- create a good load on the alternator -- run the engine a little above idle speed and measure the voltage being produced -- it should be at/over 13.5v for a well working alternator. If the alternator can only put out 12.x volts then the voltage reg is fried...

In case it needs saying -- start the engine before creating the electrical load.
with a diesel I guess the "a little above idle speed" for testing should be ~1000 rpm

Like I said, yea, don't pull the cable off the battery with the motor running and/or with other electrical loads. But I HAVE seen it done (I don't do it!). You do that when you don't have a voltmeter in hand. And the headlights stay bright when the alternator works well.



OK, well according to the GOOD test as you describe above, I have a "well working" alternator. I am assuming in your test, there is no battery isolator. Why do I only get 3V at the alternator stud on the isolator? I forgot to mention it will drop to 1V once the batts are fully charged.


And if 1-3V is normal when the isolator is installed, how did my A/C ever work. When you look at all the wiring, it seems all original from the factory. The cables that are connected to the isolator to the batts won't even reach the alternator. They disappear behind bundles of air-brake tubing, like they were there from the start....
Mountain Gnome is offline   Reply With Quote
Old 07-03-2020, 10:28 PM   #14
Bus Nut
 
Mountain Gnome's Avatar
 
Join Date: Oct 2017
Posts: 685
Year: 1999
Coachwork: BlueBird
Chassis: TC1000 HandyBus
Engine: 5.9L 24V-L6 Cummins ISB
Rated Cap: 26 foot
Quote:
Originally Posted by TJones View Post
I would leave the air conditioning power connected to the (+) terminal on the alternator if that is how it was from the factory. What this does is keeps the the currant needed to run the AC off the cable that runs from the alternator to the battery.

That is my thinking. But it doesn't work!


Quote:
Originally Posted by TJones View Post
Your problem likely lies in how the isolater is wired in. I would check the installation instructions again and pay particular attention to the wire from the ignition. This wire should have power whenever the ignition is turned on and the engine is cranked not just when the engine is cranking. Also check that the wire from the batery #1 (+) to the "S" terminal on the alternator is wired correctly. Also check for proper grounding of everything.

Ted

EDIT: You do not show a connection from battery #1 (+) to the "S" terminal of your alternator. If your alternator is a 4 wire alternator it will need this connection to function.
The IGN wire is connected correctly, and has solid power, even when cranking. My instructions mentioned that, and I verified it.


There IS no LABELED "S" terminal on the alternator...
There are only 3 wires: heavy cable (+), heavy cable (-), and a small wire that according to BlueBird's wiring diagrams for a Cummins motor in this specific bus, should be a "tach" signal connection.


The engine wiring diagram is the PDF link
Attached Files
File Type: pdf wiring(obsolete).PDF (124.8 KB, 3 views)
Mountain Gnome is offline   Reply With Quote
Old 07-03-2020, 10:37 PM   #15
Bus Nut
 
Mountain Gnome's Avatar
 
Join Date: Oct 2017
Posts: 685
Year: 1999
Coachwork: BlueBird
Chassis: TC1000 HandyBus
Engine: 5.9L 24V-L6 Cummins ISB
Rated Cap: 26 foot
Quote:
Originally Posted by BlackJohn View Post

Off the #1 terminal he goes to the starter pos, why not to the battery only? Would this not add more resistance to the isolator's path to that battery bank?

Terminal #2 looks connected fine.



Still don't know what the "E" connection means, exciter, Earth or..E is used to specify voltage in electrical equations. My isolator has no E at all.
So I don't know how to explain this part.


John

I did not "create" the diagram specs. I just drew out what is already wired from the factory in the bus. As to "why", it seems that it is the shortest path, using the least cable. Since the body electrical pulls off this (+) spot on the starter (headlights, fans, etc), it is actually a shorter path from the alternator to supply power to those loads. I swear that the diagram for the body electrical for a 1999 BlueBird All American shows this exact same setup (can't get the diagram for my bus, but I assume they are very similar if not essentially the same). It's too big, but I included it for your enjoyment....


EDIT: the PDF file for the BBAA electrical diagram was too large and was rejected....
Mountain Gnome is offline   Reply With Quote
Old 07-03-2020, 10:41 PM   #16
Bus Nut
 
Mountain Gnome's Avatar
 
Join Date: Oct 2017
Posts: 685
Year: 1999
Coachwork: BlueBird
Chassis: TC1000 HandyBus
Engine: 5.9L 24V-L6 Cummins ISB
Rated Cap: 26 foot
Quote:
Originally Posted by ol trunt View Post
Does the ac work if the isolator isn't hooked up? I may have missed that.

On my Isuzu powered multiplexed wiring system it is not possible to use the type of battery isolator you have at all. I tried it and in my case the alternator fails to put out any power at all. I went to a battery to battery charger (Sterling Power BB1230) and solved all my problems. I don't know if your bus has multiplex wiring but if it does this may be your answer.
Jack
A real answer!
And, yes, the A/C works when the isolator is not connected.
But what is multiplex wiring?
Mountain Gnome is offline   Reply With Quote
Old 07-03-2020, 10:41 PM   #17
Bus Crazy
 
banman's Avatar
 
Join Date: Aug 2019
Location: Ohio
Posts: 1,456
Year: 2002
Coachwork: Thomas
Chassis: Freightliner FS-65
Engine: 7.2L Cat 3126 turbo diesel
Rated Cap: 71 passenger 30,000 gvwr
OK, well according to the GOOD test as you describe above, I have a "well working" alternator. I am assuming in your test, there is no battery isolator. Why do I only get 3V at the alternator stud on the isolator? I forgot to mention it will drop to 1V once the batts are fully charged.

Assume in this method that you are measuring alternator output -- that would be measured at the alternator.
If (for ex) you get 14v at the alt output stud, and then you measure only 13v at the far end of a cable going from the output stud to wherever, you've lost one volt due to resistance along the length of that cable...

So if you're measuring over 13v at your alt and only 3v at your isolater then the wiring or connections between the two are your problem.
__________________
David

The Murder Bus
banman is offline   Reply With Quote
Old 07-03-2020, 10:51 PM   #18
Bus Nut
 
Mountain Gnome's Avatar
 
Join Date: Oct 2017
Posts: 685
Year: 1999
Coachwork: BlueBird
Chassis: TC1000 HandyBus
Engine: 5.9L 24V-L6 Cummins ISB
Rated Cap: 26 foot
Quote:
Originally Posted by somewhereinusa View Post
I downloaded the Surepower installation instructions. Looks pretty straight forward to me. You have to know what alternator you have, they give instructions on how to do that. Post a picture of the back side of your alternator. And the plug.
Do you have a link to download those instructions? That may be a big help! I looked at their website, but I don't see it.


According to the Cole Hersee isolator instructions, the IGN wire is not needed for my apparently NON-Delcotron alternator, since there was no "S" terminal wire originally connected, nor a terminal labeled as such on the alternator.
Mountain Gnome is offline   Reply With Quote
Old 07-03-2020, 11:01 PM   #19
Bus Geek
 
ol trunt's Avatar
 
Join Date: Apr 2012
Location: So Cal
Posts: 2,763
Year: 1935
Coachwork: Superior
Chassis: Chevy
Engine: 317 ci/tid / Isuzu
MG, explaining multiplex wiring is above my pay grade but I'm sure Google can help. It seems to be a way to get fewer wires to do the same work as many wires. My first experience with it was when I tried to hook up driving lights to my bus's high beam circuit and failing due to blown fuses--over and over. Long story short it turned out that the ground and power wires for high beam reversed polarity from the low beam circuit. Exactly why I don't know but once I figured that out I got the driving lights working as intended. Someone else (or the dealer or mfg) will be able to give you answer as to whether or not your bus has multiplex wiring. I'd be interested to know.
Jack
ol trunt is offline   Reply With Quote
Old 07-03-2020, 11:02 PM   #20
Bus Nut
 
Mountain Gnome's Avatar
 
Join Date: Oct 2017
Posts: 685
Year: 1999
Coachwork: BlueBird
Chassis: TC1000 HandyBus
Engine: 5.9L 24V-L6 Cummins ISB
Rated Cap: 26 foot
Quote:
Originally Posted by banman View Post
OK, well according to the GOOD test as you describe above, I have a "well working" alternator. I am assuming in your test, there is no battery isolator. Why do I only get 3V at the alternator stud on the isolator? I forgot to mention it will drop to 1V once the batts are fully charged.

Assume in this method that you are measuring alternator output -- that would be measured at the alternator.
If (for ex) you get 14v at the alt output stud, and then you measure only 13v at the far end of a cable going from the output stud to wherever, you've lost one volt due to resistance along the length of that cable...

So if you're measuring over 13v at your alt and only 3v at your isolater then the wiring or connections between the two are your problem.
This is how I thought I understood things to be...as you describe them. Maybe I am mistaken, but I thought (maybe I'm mistaken) I also checked the voltage at the actual (+) stud on the back of the alternator where the cable connects, and it's voltage matched the voltage at the end of the cable at the isolator's alternator stud. And it's a short cable.....but maybe it became corroded internally.
That still blows my mind that the isolator takes the 3V and uses that to up the battery voltages to 13.3V and 14.5V. I never measured over 13V at the alternator, UNLESS the isolator was bypassed/disconnected. Since the isolator is a diode type, the battery voltage cannot flow "backwards" from the battery to the alternator (+) stud when the isolator is connected, which is keeping the A/C from working.
Anyway, I'll double check the voltage at the alternator (+) stud with the isolator connected, tomorrow.


Thanks for the hint of insight!
Mountain Gnome is offline   Reply With Quote
Reply

Tags
battery isolator, power distribution

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 03:08 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
×