Electrical Question (Alternator/Starter)

[mherrcat]

Can I do this? If not, why?
Trying to update the wiring a little on E30+ to eliminate the ammeter, add a glow plug solenoid, and basically clean up the rats nest, without adding multiple connections to the starter post.

 

[Kenneth K]

Yeah, I think that’s fine. It’s pretty similar to what I have but differs from mine, and the original setup, in one main way.

In the factory setup, everything on the engine panel (glow plugs included) is protected by the single 30A fuse in the red wire connecting the starter post to the engine panel.
Thus, with any problems (shorts) on the engine panel, everything, including the glow plugs, is de-powered.

With your setup, you could have a short on the engine panel, but still have power available to the glow plug relay. Depending on where the short on the engine panel is, this might be a problem.

You could mimic the factory setup more closely, if you wanted to, like this:

 

[Loren Beach]

When I installed a Blue Seas 5023 for a few lower-voltage circuits, many years ago, I thought it was a concept right up there with 'sliced bread'. Still Do!

 

[mherrcat]

Yeah, I think that’s fine. It’s pretty similar to what I have but differs from mine, and the original setup, in one main way.

In the factory setup, everything on the engine panel (glow plugs included) is protected by the single 30A fuse in the red wire connecting the starter post to the engine panel.
Thus, with any problems (shorts) on the engine panel, everything, including the glow plugs, is de-powered.

With your setup, you could have a short on the engine panel, but still have power available to the glow plug relay. Depending on where the short on the engine panel is, this might be a problem.

You could mimic the factory setup more closely, if you wanted to, like this:
View attachment 53151

Thanks. I figured that electrically its the same whether the alternator and fuse block are connected individually to the starter or as shown in the drawing.

Since I hate stacking ring connectors on terminals if I don't have to, what if I removed the first fuse and jumpered that terminal to the one with the 30A fuse? Same as stacking the two ring terminals on one fuse terminal, right? (And I get to use more of the fuse block connections that I paid for!)

Regarding your third paragraph above, if I keep the two separate fuses, and the engine panel shorts and blows the 30A fuse, wouldn't it have no effect on the power to the glow plug solenoid/relay since the glow plug switch wire would not be able to deliver power to the solenoid/relay to close the circuit?

Plus, I was thinking of lowering the fuse value to the engine panel since the high current for the glow plugs is no longer going through the engine panel, only lower current for the gauges and momentary switches.

 

[Kenneth K]

Thanks. I figured that electrically its the same whether the alternator and fuse block are connected individually to the starter or as shown in the drawing.

Since I hate stacking ring connectors on terminals if I don't have to, what if I removed the first fuse and jumpered that terminal to the one with the 30A fuse? Same as stacking the two ring terminals on one fuse terminal, right? (And I get to use more of the fuse block connections that I paid for!)

Yes, I used a jumper on mine rather than stacking terminals.

Regarding your third paragraph above, if I keep the two separate fuses, and the engine panel shorts and blows the 30A fuse, wouldn't it have no effect on the power to the glow plug solenoid/relay since the glow plug switch wire would not be able to deliver power to the solenoid/relay to close the circuit?

Yes, that’s correct. I suppose the other malfunction to consider is that of the solenoid sticking closed (on), regardless of the solenoid activation circuit. It’s difficult to say whether either configuration (one vs two fuses) is more or less likely provide protection in that situation.

Plus, I was thinking of lowering the fuse value to the engine panel since the high current for the glow plugs is no longer going through the engine panel, only lower current for the gauges and momentary switches.

Yeah, that sounds like a good idea, and may be the strongest argument in favor of keeping two separate fuses.

 

[mherrcat]

Thanks for your help!

 

[kloebereng]

Can I do this? If not, why?
Trying to update the wiring a little on E30+ to eliminate the ammeter, add a glow plug solenoid, and basically clean up the rats nest, without adding multiple connections to the starter post.

The only two concerns would be
1) It’s not ABYC compliant unless the fuse block is within 7” if the starter.
2) For best charging it is very unusual NOT to have the AO cable directly on the starter B+ terminal.

The panel feed being a #10, that light a lug (I use lugs there on my harnesses, not a ring) is no issue to stack.

What ga is your AO cable?

An ALT negative cable unless you have already.

The battery Neg should by on the starter bolt, nowhere else.
See my sketches at the bottom
https://groups.io/g/Catalina30/wiki/11336

Are you aware that the glow plugs are rated 10v and adding an unnecessary preheat solenoid can shorten their life?

Cheers
Ken

 

[mherrcat]

1) It’s not ABYC compliant unless the fuse block is within 7” if the starter.

The fuse block will be on the engine support stringer just under the starter.

2) For best charging it is very unusual NOT to have the AO cable directly on the starter B+ terminal.

Is my drawing not electrically equivalent to connecting the alternator directly to the starter?

What ga is your AO cable?

2 AWG (From alternator to fuse block and from fuse block to starter.)

An ALT negative cable unless you have already.

Will be adding an alternator negative/ground cable. (Where should this connect?)

The battery Neg should by on the starter bolt, nowhere else.

Please explain this. The main battery negative (looks like 1/0 or 2/0) connects to the engine block just aft of the glow plugs/injectors next to the secondary fuel filter, but there is another smaller (looks like 1 AWG or even 2 AWG) negative cable attached there, too. Not sure where that goes, but will be at the boat Saturday to explore this further. I am also trying to aggregate all the miscellaneous ground wires I see attached to that engine to a single ground bus if possible. (Can't swear to those sizes since not on the boat, but one is larger and one is smaller.)

Are you aware that the glow plugs are rated 10v and adding an unnecessary preheat solenoid can shorten their life?

Even if the solenoid allows the glow plugs to be activated for a shorter period of time as opposed to a longer period of time? The glow plugs are still going to get the same voltage and draw the same current, it just won't be going through as much wire anymore.

See my sketches at the bottom

I don't see any sketches at the link, only a few pics of a corroded wiring harness.

 

[Kenneth K]

Is my drawing not electrically equivalent to connecting the alternator directly to the starter?

As I see it, it is. Electrically, the alternator output, the starter, and the fuse block all share the same pole.

Unless, kloebereng is suggesting that the 2 ga wire, between the alternator and the starter, itself needs to be fused (which I have never heard of anyone doing) the 7" rule does not apply. The power pole for the fuse block is rigidly and immediately connected to the fuses for the branch circuits (engine panel and glow plug solenoid). There is no chance for chafing prior to the fuses (unlike there would be for inline fuses), thus no 7" restriction.

but there is another smaller (looks like 1 AWG or even 2 AWG) negative cable attached there, too. Not sure where that goes, but will be at the boat Saturday to explore this further.

That is likely the ground wire for the main DC electrical panel.

There is no ground bolt/lug on the starter. It grounds itself by its physical connection to the engine block (just like the glow plugs do). Usually, the same for the alternator, too, but not so for the alternator regulator.

 

[mherrcat]

That is likely the ground wire for the main DC electrical panel.

Any reason not to add a negative bus bar, connect that to the engine, and connect all other negatives/grounds to the bus bar?

There is no ground bolt/lug on the starter. It grounds itself by its physical connection to the engine block (just like the glow plugs do). Usually, the same for the alternator, too, but not so for the alternator regulator.

The replacement alternator I am installing (looks like it came off another Universal engine, but tests good) has an internal regulator. Does your statement apply to external regulators? My alternator has these connections: B (+), E (gnd - which looks like it's never been used), EXC (excite), S (batt sense), L2 (lamp?), and P (AC tap?).

Thanks again all for this good information! Very helpful!

 

[Kenneth K]

Any reason not to add a negative bus bar, connect that to the engine, and connect all other negatives/grounds to the bus bar?

No reason at all. A negative bus bar is a great idea. Connect it to any easy-to-access threaded hole on the engine block. Just make sure the connection point is free of paint/grease/thread-locker, etc, for a low-resistance connection. I found some unused threaded holes below and forward of the starter:

Does your statement apply to external regulators?

Yeah, mostly, but it's hard to make a blanket statement for all engines/alternators.

Here's my stock Motorola. The regulator's "neg ground" wire bolts to the alternator body, which is then grounded through metal-to-metal contact with the block. I have no external ground wire for the alternator or regulator.


FYI, here's my seutp. Yours sounds slightly different, but equally suitable:


[Alternator to Stater Post connection (the trailer plugs are long since gone--see below)]


[Terminal bar replacement for the trailer plug.]
Engine panel power and glow plug power are jumpered together on the terminal bar. Everything on the terminal bar is protected by the 30A inline fuse coming off the start post (though I have individual fusing for most circuits at the engine panel). Is the inline fuse within 7" of the starter? I don't know, I've never checked. But it's far enough away to protect it from the heat of the engine and close to be secured, chafe-free, and easy to access.

 

[mherrcat]

That Motorola alternator is the same one I’m replacing.

Well it looks like at least I’m on the right track. Where I end up might be another story!

Also, I wish my engine was as clean as everyone else’s appears to be. It’s embarrassing!

 

[mherrcat]

Looked at the wiring again this weekend and have a couple more questions.

The old alternator has a wire connected from the terminal labeled “regulator” to a light on the DC breaker panel that lights up when the engine is running to warn of not switching the battery switch to “OFF” while the engine is running. Should that wire be connected on the “new” alternator to the L2 (light) terminal? Not sure how this works, usually an “alternator light” is a light that does not illuminate unless the alternator is failing to charge, not a light that shows the alternator is charging. (?)




And what is this?
It’s mounted on the side of the exhaust manifold, black wire grounded to the exhaust manifold, red wire spliced into the oil pressure sender wire. Some kind of terminal block? A resistor?

 

[Christian Williams]

Overheat alarm? Monitors exhaust temp, sounds warning?

 

[mherrcat]

Overheat alarm? Monitors exhaust temp, sounds warning?

That’s it!
Aqualarm bolt-on engine overheat detector.
Thanks!
Not sure why it’s bent up like that though. Pictures on Aqualarm site, online, and installation instructions say it should “lay flat” on the engine block.

 

[Kenneth K]

Yeah, strange that the overheat sensor is bent away from the manifold. Maybe he was getting false alarms with direct contact.

Also interesting how he spliced it to the oil pressure sensor. I think that was a way to use the single engine-panel idiot lamp for both oil pressure and overheat warnings. It looks like he used the overheat detector to provide an alternate ground path for the idiot light when it senses an overheat. Then, when the light triggers you'd have to look at the temp gauge to see whether high temp or low oil pressure set it off. However the waring switches are wired, it's always better (and very simple) to wire a 12V piezo buzzer in parallel with the lamp, to get your attention when the lamp comes on.

I had to look up "alternator L2 terminal:"

• L Terminal:
  The "L" terminal on an alternator is generally used to control the charge indicator light. When the alternator isn't producing power, this light will illuminate, alerting the driver to a charging system issue.
  
  
• L2 Terminal:
  On some alternators, particularly those with an "L2" terminal, this connection serves the same purpose as the standard "L" terminal. It provides a ground path for the charge indicator lamp when the alternator isn't functioning correctly.

So, I wouldn't hook up anything to either the L2 terminal or to the light added to the DC panel. Seems silly to have a light tell you when the alternator is running (i.e. any time the engine is running, as if you can't hear the engine). A voltmeter is the best way to tell whether your alternator is charging or not, and I'd strongly recommend a digital voltmeter. Almost everything that happens with the batteries and charging systems happens between about 11.5 and 14.0 V. The old analog meters with a 0-20V range, just don't give enough detail in that range. For example, 12.7 V means a lead-acid battery is fully charged, but not charging, while 13.0 V means a charge is being applied.

Also, if you're worried about the potential of frying your regulator by switching the batt switch to OFF (or, a bad batt switch that loses contact when switching between 1-ALL-2), you can buy an alternator protection module for $70-80. That's slightly more pricey than just buying a new batt switch, but it's much less work to install (and, it idiot-proofs your switch).

APM-12 - Balmar

Alternator Protection Module, 12V Balmar APM devices provide intelligent, robust, solid state protection in a small, easily mounted package at the rear of the alternator between the B+ and B- terminals. Balmar APM devices can be used to protect all alternator brands. Click on the attached...

balmar.net

Sterling Power Pro Protect 12v Alternator Protection Device

Sterling Power Pro Protect APD12Sacrificial Protection Device for 12v alternators

baymarinesupply.com

 

[Loren Beach]

One little quibble have I, about the reference to the worthiness of an analog VM. Our '88 factory panel had an expanded scale VM, 8 - 16 volts DC. When the meter finally died a few years ago, I replaced it with a new one from Newmar (same company that built out our DC/AC panel, for Ericson.
While it certainly is not as "modern" as my Balmar digital gauge, it is nice to have a basic information source that, due to the expanded scale, is pretty easy to read/interpret.

To me, it's like navigation; it's good to have more than one confirming source of information.

My meter is pictured in this page from Newmar, among others that they sell.

https://dcpoweronboard.com/wp-content/uploads/2015/12/meters-white-background.png

Edit: apologies for the thread drift!

 

[Kenneth K]

One little quibble have I, about the reference to the worthiness of an analog VM. Our '88 factory panel had an expanded scale VM, 8 - 16 volts DC.

Yeah, agree completely. Much better than this: