Replacing the isolator with a Sterling ProSplit R

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Replacing the isolator with a Sterling ProSplit R

February 24, 2017, 08:17:31 pm

Tomorrow I plan to replace my Isolator with a Sterling ProSplit R 180 Amp x 2 output. Everything looks pretty straight foward, my only concern is that it is recommend to disconnect all the positive and negative cables from the batteries.

Disconnecting the Start batteries is easy, I've done it several times.

The house batteries however is giant mess of heavy gauge wires. It's also very crammed into that compartment. I guess the batteries slide out?

So, what exactly do I need to disconnect? And in what order? Any particular steps I should take to make sure nothing goes awry.

And as long as we are discussing this, how is disconnecting and keeping seperated 6 different sets of wire safer than just removing the wires from one post on the old isolator and moving them to one post on the new isolator?

Any and all advice is appreciated. I would like this to go as smoothly as possible.

I've attached a few pictures, just because.
Thanks,

Re: Replacing the isolator with a Sterling ProSplit R

Reply #1 – February 24, 2017, 09:37:20 pm

Doug, a couple of years back I put on a new isolator and did not disconnect either the house or start batteries. I cut some small pieces of water hose and carefully slid them over the leads as I disconnected them to keep them from making contact with anything. Not that this is the way to do it, but it worked for me.

Re: Replacing the isolator with a Sterling ProSplit R

Reply #2 – February 24, 2017, 09:46:38 pm

Quote from: Forewheelers – February 24, 2017, 09:37:20 pm

I put on a new isolator and did not disconnect either the house or start batteries.

X2. I'm sure it's safer to take all your batteries off line before you mess with the isolator connections, but it is not mandatory. I've removed and replaced the battery bank cables on our isolator (when I was cleaning up the isolator panel), without disconnecting any of the batteries. I'm not recommending this - just saying I've done it without having any problem. No big sparks or any drama or anything...just need to be careful (like Lynn said) and don't ground the positive cables while they are disconnected. That would be exciting!

But, looking at your photos, I'd say it's past time to clean up those battery connections, so why not do the whole project in one sitting. After making a diagram and marking the cables, pull off all your old battery connections (negative cables first, then positive). Clean up (or replace with new ones) the military terminals, and while they are disconnected install the ProSplit. Clean up your batteries and battery posts. Reinstall your clean new battery connections (positive cables first, then negative), and you will have the whole setup back to trip-worthy condition.

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Re: Replacing the isolator with a Sterling ProSplit R

Reply #3 – February 24, 2017, 11:01:59 pm

Douglas, best practice to disconnect the coach from 110v power, disconnect the negative cables from the house and start batteries and protect the cable ends from contacting any frame parts.

Mark the cables as you remove them from the old isolator.
Connect the alternator cable to the Alt In post.
Connect cables from the start batteries to the Start Batt Post.
Connect the cables from the house batteries to the Batt 2 post.
Run a wire from the Sterling sense post to the sense post on the alternator.
Be sure to cover the end of the old sense wire or disconnect it at the other end.
Run a wire from the Ign post on the Sterling to the Ign post on the alternator.
Keep the original ignition wire (excite) connected to the alternator.
Run a wire from the Sterling Neg post to a ground point.

Make sure all of the connections are tight.

Reconnect the start battery negative cable.
Reconnect the house battery negative cable.

Start the engine. Set to high idle, 1000 rpms. Measure the voltage at the start battery between the positve post and a frame ground point. It should be somewhere around 13.8-14.6 volts. If it is any higher then you will probably have to adjust the voltage down on the LN alternator by turning the screw under the plastic screw on the flat plate on top of the alternator.

Re: Replacing the isolator with a Sterling ProSplit R

Reply #4 – February 25, 2017, 12:06:06 am

@Forewheelers That garden hose idea is great...thanks!

@Chuck & Jeannie Since I don't have new terminals I think I will hold off on pulling everything apart, but I will definately clean up that one negative terminal that has some corrosion. And thanks for clarifying the order for me!

Quote from: Roger & Susan in Home2 – February 24, 2017, 11:01:59 pm

Run a wire from the Sterling sense post to the sense post on the alternator.
Be sure to cover the end of the old sense wire or disconnect it at the other end.
Run a wire from the Ign post on the Sterling to the Ign post on the alternator.
Keep the original ignition wire (excite) connected to the alternator.
Run a wire from the Sterling Neg post to a ground point.

Start the engine. Set to high idle, 1000 rpms. Measure the voltage at the start battery between the positve post and a frame ground point. It should be somewhere around 13.8-14.6 volts. If it is any higher then you will probably have to adjust the voltage down on the LN alternator by turning the screw under the plastic screw on the flat plate on top of the alternator.

I figured I would have to run a wire for the Neg post.
Are you recommending running a new sense wire? Any particular reason? I had planned to reuse both the sense and the excite wires.

And thanks for the alternator procedures.

Re: Replacing the isolator with a Sterling ProSplit R

Reply #5 – February 25, 2017, 12:41:18 am

Your original sense wire might come from somewhere nearby, not sure where on your coach but if it is you can reuse it. You want the wire to go from the Sterling sense post to the alternator sense post. This lets the Sterling manage what the alternator sees as battery voltage to adjust its output. This helps make charging the house batteries more efficient.

When you have time and material it is a good idea to replace both the excite wire and the sense wires with #12 or #10 wire with new heat shrink, adhesive lined connectors at each end. It is not uncommon for the original connectors to corrode and weaken or fail.

A once a year cleaning of battery connections and more frequent checking to ensure that they are tight is a good thing to add to the service list.

Re: Replacing the isolator with a Sterling ProSplit R

Reply #6 – February 25, 2017, 08:03:11 pm

If you have solar disconnect the ground of that too

Re: Replacing the isolator with a Sterling ProSplit R

Reply #7 – February 25, 2017, 08:53:45 pm

Well today went pretty well.

Pulled the cables from the start batteries. Disconnected shore power/inverter off.

Probed everything with my volt meter.

Took pictures of everything.

Pulled all wires from the isolator, sleved the hot wire to the house system.

Removed the old isolator.

Marked and drilled new holes, installed the new isolator.

Ran new ground.

Pulled new 10 gauge wires from the alternator (sense and ignite) to the new isolator.

Tomorrow, weather permitting, I'll finish up and test everything.

Terminate old sense and ignite wires.

Replace terminals on the start batteries.

Test alternator voltage.

Re: Replacing the isolator with a Sterling ProSplit R

Reply #8 – February 25, 2017, 08:57:57 pm

Doug and Amanda, I see the splitter is outside the coach so I would definitly protect it with some form of removable cover. It would be nice to keep it clean and dry.
JohnH

Re: Replacing the isolator with a Sterling ProSplit R

Reply #9 – February 25, 2017, 09:12:10 pm

There is one wire, I'm just not completely sure about.

Under the isolator there are two solenoids. I assume one is ignition and one is boost.

There was one wire probably 8 - 10 gauge going from the right lug of the solenoid on the left (closer to the driver), to the start battery post on the isolator.

I can't figure out what that wire would do. Anyone have any thoughts?

Re: Replacing the isolator with a Sterling ProSplit R

Reply #10 – February 25, 2017, 09:42:24 pm

This is the 12v supply to one side of the starter solenoid, the other big post of the starter solenoid would go to the big solenoid on the engine starter.

So, you turn the key, the starter solenoid contacts, powering the big solenoid on the starter, the big solenoid engages the starter gear with the flywheel and connects the high amp 12v battery current to the starter motor and the engine cranks and starts.

Just for fun I looked up what current a truck starter solenoid draws. There are 2 windings, a "pull in" winding that draws approx 30 amps for a second for the heavy lifting, then once engaged that winding disconnects and the "hold in" winding continues to draw approx 5-7 amps. The first winding can only by on for a few seconds without overheating, the second winding can hold during cranking without overheating.

Re: Replacing the isolator with a Sterling ProSplit R

Reply #11 – February 26, 2017, 12:48:07 am

The Sterling isolator has an IP66 waterproof rating.
iP
6 Dust Tight No ingress of dust; complete protection against contact.
6 Powerful water jets Water projected in powerful jets (12.5mm nozzle) against the enclosure from any direction shall have no harmful effects.

Profecting the cable connections might be a good idea.

Re: Replacing the isolator with a Sterling ProSplit R

Reply #12 – February 26, 2017, 10:23:52 am

Quote from: John Haygarth – February 25, 2017, 08:57:57 pm

Doug and Amanda, I see the splitter is outside the coach so I would definitly protect it with some form of removable cover. It would be nice to keep it clean and dry.
JohnH

I totally agree. See if you have room for that under the foot of the bed (the "electric area").

Re: Replacing the isolator with a Sterling ProSplit R

Reply #13 – February 26, 2017, 12:41:13 pm

Brett, I think they do but cable lengths are different. I told Douglas that when they come to our house this summer 🌲 I would make them new cables and we could move it.

Re: Replacing the isolator with a Sterling ProSplit R

Reply #14 – February 26, 2017, 02:46:19 pm

Be sure you make them (actually Amanda) "Sing for their cables"!

Re: Replacing the isolator with a Sterling ProSplit R

Reply #15 – February 26, 2017, 04:33:25 pm

She might if they show up. This is a very busy year for them but we have seen them three times so far anyway. There is always room at Camp Hastings for friends.

Re: Replacing the isolator with a Sterling ProSplit R

Reply #16 – February 26, 2017, 09:43:15 pm

Between the weather, a couple of other things I needed to focus on, and my cell phone deciding it's never going to boot up again

, nothing got done on the project today. Fingers crossed that tomorrow goes better.

@prfleming Thanks for the info, I figured that wire was important. I just couldn't figure out what it was supposed to do.

@John Haygarth I've been thinking of some sort of shield for it, but it would have to be clear so I can check the lights on the splitter. It is IP66 rated, and has "boots" for all the wires, which I coated in dielectric grease.

@wolfe10 Relocating it to the base of the bed looked doable but challenging. It would definitely require some new cables. I made the new sense and excite wires long enough to reach, if I do relocate the splitter. Putting this off also gives me an excuse to visit Minnesota and make Roger help me with it.

Alan at Bay Marine suggested there is an electronics spray I could coat it with that would add some protection. Anyone have any thoughts on that?

Re: Replacing the isolator with a Sterling ProSplit R

Reply #17 – February 26, 2017, 09:52:05 pm

yes clear is a good idea. What I was thinking of for someone that may not be as used to working around these kind of problems is go to your local Lowes/home depot/ home improvement store and see if they have any clear (correct size of course) of the shelf or draw containers for storing things in I am sure you can find something an inch or so bigger that will fit completely over it, and just cut slots in it for the cables and attach some 1"x 1" 90 deg angle brkts to it to be able to use screw to hold it to backing plate. POP rivet the angle brkts to the cover first than use self tapping scres to hold it to plate. Simple but effective.
JohnH

Re: Replacing the isolator with a Sterling ProSplit R

Reply #18 – February 27, 2017, 07:39:10 pm

I wouldn't want to impede cooling airflow to the inverter. Those fins are there for a reason.

Re: Replacing the isolator with a Sterling ProSplit R

Reply #19 – February 28, 2017, 12:55:16 am

The new isolator is in and working properly. I'll add my thoughts and some tips tomorrow.

Re: Replacing the isolator with a Sterling ProSplit R

Reply #20 – February 28, 2017, 01:08:28 am

The Sterling has no fins for cooling. It does not get hot.

Re: Replacing the isolator with a Sterling ProSplit R

Reply #21 – February 28, 2017, 10:50:19 am

I wouls also have put some drilled holes in the bottom side just for breathing etc but as Roger said it does not get hot.
JohnH

Re: Replacing the isolator with a Sterling ProSplit R

Reply #22 – March 01, 2017, 10:14:22 pm

This was a pretty easy swap. Swapping for an identical isolator would have been easier (and a little cheaper) but for the extra few bucks I like the alternator over voltage protection and "smart" charging.

On my coach the sense and excite don't go anywhere near the isolator, I didn't understand this until I got into the project.

So ultimately what I did:
Pulled the cables from the start batteries. Disconnected shore power/inverter off.
Probed everything with my volt meter.
Took pictures of everything.
Pulled all wires from the isolator, sleeved the hot wire to the house system.
Removed the old isolator.
Marked and drilled new holes, installed the new isolator.
Ran new ground.
Ran a new wire 6 gauge wire from the start battery post to the ignition solenoid (the old wire ring terminal was too small for the ProSplit's post)
Ran a new 10 gauge wire from the sense post on the ProSplit to the sense post on the alternator.
Leave original excite wire attached to alternator.
Covered old sense wire with two layers of heat shrink, re-routed back into the wiring harness. I originally covered both the sense and excite wires with heat shink, but that was a mistake.
Run a new wire (I used 10 gauge) from the Pos Ign post of the ProSplit to an ignition key switched 12V source.
Replace terminals on the start batteries.
Test voltage.
Start coach, test voltage and adjust alternator.

What I really didn't fully understand going in to this project is this:
1. The sense wire needs to send a signal from the ProSplit to the alternator, so that the ProSplit is in essence "controlling" the alternator.
2. The excite wire for the alternator does NOT need to go to the ProSplit.
3. Running a wire from the "excite" post on the alternator to the "Pos Ign" post on the ProSplit WILL NOT provide 12V to the ProSplit.

Last tip, by leaving the ring terminal on the sense wire, and double coating it in shrink wrap, I could bypass a dead ProSplit by:
1. Cut shrink wrap off old sense wire with any knife.
2. Remove new sense wire, re-install original sense wire.
3. Move the wire from the alternator in post to the start battery post of the ProSplit, with an 18mm socket.
4. Use the boost switch or generator to keep the house batteries charged.

For more info and a good guide on what to expect when testing visit Roger's thead here:
Delco 40si 240 Amp Alternator, Sterling ProSplitR Installation

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