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Old 07-15-2017, 08:31 PM   #1
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Isolators versus continuous duty solenoids

I always wondered why we see Solenoids instead of Isolators in some of the classics.
So I did a little digging and became to realize that a "continuous" duty solenoid seems to be the better way to go, since it only connects the batteries for charging with the terminal S activated by ignition on. So no voltage loss when dormant.
The important thing to note is that not any starter solenoid will work and probably burn out in short order, it has to be a a continuous duty solenoid like this one:
http://www.auto-parts-world.com/bwd-...s603-18970418/
Probably not news for most of you. Am i missing anything?
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Old 07-16-2017, 06:44 AM   #2
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Quote:
Originally Posted by PeterH-Airstreamer View Post
I always wondered why we see Solenoids instead of Isolators in some of the classics.
So I did a little digging and became to realize that a "continuous" duty solenoid seems to be the better way to go, since it only connects the batteries for charging with the terminal S activated by ignition on. So no voltage loss when dormant.
The important thing to note is that not any starter solenoid will work and probably burn out in short order, it has to be a a continuous duty solenoid like this one:
http://www.auto-parts-world.com/bwd-...s603-18970418/
Probably not news for most of you. Am i missing anything?
Peter, I came to the same conclusion a while back and decided not to use one of those "blue" solid state battery isolators. Instead I'm going to be installing a
Blue Sea 7622 ACR (Automatic Charging Relay).

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Every review I read about it was good so I figured I'd give it a try.

Brad
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Old 07-16-2017, 10:30 AM   #3
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Holy MSRP Batman!
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Old 07-16-2017, 10:52 AM   #4
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Holy MSRP Batman!
Well, I didn't pay quite MSRP
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Old 07-16-2017, 11:03 AM   #5
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Brad, I like what I read about it, but I don't think it solves one problem I had with the 310 and EFI:
If I would start the generator after starting the 454, the drag on the entire 12V system was sometimes so much that it would kill the more sensitive power requirement of the EFI module and its sensors to the point of the engine stalling. The only way around it was to start the generator first and then the fuel injected engine. I don't see a way around this with any of the systems mentioned above, do you?
Edit: It does the below, can that be applied to the reverse situation, like cranking a generator?
Start Isolation (SI): can be configured for temporary isolation of House loads from Engine circuit during engine cranking to protect sensitive electronics
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Old 07-16-2017, 11:21 AM   #6
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Brad, I like what I read about it, but I don't think it solves one problem I had with the 310 and EFI:
If I would start the generator after starting the 454, the drag on the entire 12V system was sometimes so much that it would kill the more sensitive power requirement of the EFI module and its sensors to the point of the engine stalling. The only way around it was to start the generator first and then the fuel injected engine. I don't see a way around this with any of the systems mentioned above, do you?
Which battery are you starting the generator from, coach or starting? I always have the generator powered from the coach battery.

What size battery cable is running from the battery compartment to the generator? Same for the ground, where is it grounded and what size is the ground, it should be the same size as the +12 feed and preferably #2 gauge or larger.

Since your's is an aftermarket EFI I'm wondering if the EFI is grounded properly. Mine insisted that the ground for the EFI system be made at the back of the head.

Also, the engine ground needs to run from the back of the head to the frame AND from the back of the head to the body. In other words the engine has two ground cables.

Where are you feeding the +12 to the EFI system and how large are the wires? You're obviously experiencing a voltage drop of some kind that is affecting the EFI components.

What it really sounds like to me is either undersized wiring for the EFI or poor grounding.

Brad
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Old 07-16-2017, 11:52 AM   #7
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Holy MSRP Batman!

The price answers your question in the first post.
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Old 07-16-2017, 11:57 AM   #8
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Originally Posted by bkahler View Post
Which battery are you starting the generator from, coach or starting? I always have the generator powered from the coach battery.

What size battery cable is running from the battery compartment to the generator? Same for the ground, where is it grounded and what size is the ground, it should be the same size as the +12 feed and preferably #2 gauge or larger.

Since your's is an aftermarket EFI I'm wondering if the EFI is grounded properly. Mine insisted that the ground for the EFI system be made at the back of the head.

Also, the engine ground needs to run from the back of the head to the frame AND from the back of the head to the body. In other words the engine has two ground cables.

Where are you feeding the +12 to the EFI system and how large are the wires? You're obviously experiencing a voltage drop of some kind that is affecting the EFI components.

What it really sounds like to me is either undersized wiring for the EFI or poor grounding.

Brad
Generator is started by the coach batteries, but I see voltage drops in the engine 12V system when cranking the generator.
I would definitely put some fault of this to the factory undersize wire running all the way from the front left (batt compartment) to the rear right (generator).
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Old 07-16-2017, 12:08 PM   #9
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Originally Posted by PeterH-Airstreamer View Post
Generator is started by the coach batteries, but I see voltage drops in the engine 12V system when cranking the generator.
I would definitely put some fault of this to the factory undersize wire running all the way from the front left (batt compartment) to the rear right (generator).
If the coach and starting batteries are not connected together then the only point in common is the grounding system.

This is the cable I'm using for the generator feed on my Argosy. Obviously the distance is abut 10 feet less than your 310!

You might consider using 1/0 to run that distance with a 1/0 ground cable as well.
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Old 07-16-2017, 01:48 PM   #10
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Quote:
Originally Posted by bkahler View Post
...
What it really sounds like to me is either undersized wiring for the EFI or poor grounding.

Brad
Brad, I really think you are on to something with the poor grounding. The only time the batteries are connected momentarily is during starting of the engine via a relay at the battery box. After that they separated at the Isolator. I wrongly assumed that starting the generator would draw more current via the Isolator to the point of voltage drop on the engine side. My bad. Thanks for your input.
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Old 07-16-2017, 02:07 PM   #11
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So I'm reading along here. My generator starts off my chassis battery. I thought the theory behind that set up is that you don't want the charging mechanism for a battery to also start off that same battery, or you're outa luck should you run that battery down to a point where it won't start the genny. So say you're boondocking and you accidently run your coach batteries down, the only way to charge them is running your genny...but it won't start cause it's starts off the coach batteries (that have been run down).

I have disconnect switches on both sides. So if we are stopped for several days in one spot I try to make a habit of switching the chassis battery off so I know I'll have juice to start the genny should I need it.

So I'm just wondering why both you fellers have your genny start off the coach side? How did they come wired from the factory? What's the theory behind having the genny start off the coach side......you two know wayyyyyyyyyyyyy more than I about this stuff

Mike
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Old 07-16-2017, 02:48 PM   #12
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So I'm just wondering why both you fellers have your genny start off the coach side? How did they come wired from the factory? What's the theory behind having the genny start off the coach side......you two know wayyyyyyyyyyyyy more than I about this stuff

Mike
One guess from the vehicle warranty side, not responsible for any other wiring/systems added by the RV side.

In a word, for any issues required to "do it right"


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Old 07-16-2017, 02:51 PM   #13
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....you two know wayyyyyyyyyyyyy more than I about this stuff

Mike
Mike, you are the one with all the On-The-Job training, so we have to rely on your first hand field experience.
BTW, i just figured out that my 310 generator was connected to the Motor Battery, which is causing all the voltage drop issues during firing up the generator
Besides the above voltage drop issue, which is a problem if your EFI wants a min of 9Volts to operate, the idea is to always reserve the chassis battery to start your Motor.
Ok, like you said, you are out boon docking and your coach batteries are getting low, so you want to start the generator. Damn thing cranks but doesn't start all the way to running down the engine battery. Bam, you are stuck.
If your generator would have been connected to the coach batteries, which are dead now, you can always start your engine and charge the coach batteries via the isolator, until you can start the generator.
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Old 07-16-2017, 03:42 PM   #14
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Originally Posted by PeterH-Airstreamer View Post
Mike, you are the one with all the On-The-Job training, so we have to rely on your first hand field experience.
BTW, i just figured out that my 310 generator was connected to the Motor Battery, which is causing all the voltage drop issues during firing up the generator
Besides the above voltage drop issue, which is a problem if your EFI wants a min of 9Volts to operate, the idea is to always reserve the chassis battery to start your Motor.
Ok, like you said, you are out boon docking and your coach batteries are getting low, so you want to start the generator. Damn thing cranks but doesn't start all the way to running down the engine battery. Bam, you are stuck.
If your generator would have been connected to the coach batteries, which are dead now, you can always start your engine and charge the coach batteries via the isolator, until you can start the generator.
What Peter said

Primary concern is being able to get home, secondary concern is being comfortabe
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