Glow Plug Heater Circuit Issue M18 Diesel

jviss

jviss

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Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
Head Sail said:
It sounds like the OP doesn't have a start battery which could be part of the problem. That long wire run from the house bank and up to the cockpit may be part of the problem. Put in a start battery with short cables to the starter and you will substantially reduce voltage drop not just for the starter but for the glow plugs as well.
Click to expand
Typically, if you have one bank, i.e., no dedicated start battery, you would have a heavy wire from the alternator B+ to the starter lug, and a heavy cable to the battery bank positive. The wire that runs to the cockpit is the wire to energize the starter solenoid, and in some cases, the wires to energize the glow plugs, if no glow plug solenoid is installed.
 
L

Loose Ends

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Feb 9, 2011
70
Catalina 27 Forked River NJ
I do have 2 batteries, A/B All Switch. The instrument panel has operated fine for 30+ years.
 
B

brazenarticle

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Jul 8, 2012
126
Catalina 28 North East
Loose Ends said:
......I ran a new wire from my electrical panel through a spare switch directly to my glow plug. 10 seconds of juice to the plug and the engine happily starts. I WILL find the actual problem and get it corrected. just may take some more time in the lazarette.
Click to expand
Several replies have described the actual problem, and the actual answer.
 
Maine Sail

Maine Sail

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Feb 6, 1998
11,672
Canadian Sailcraft 36T Casco Bay, ME
brazenarticle said:
Several replies have described the actual problem, and the actual answer.
Click to expand
Some folks won't recognize or address a problem until the boat or marina burns. I had a guy today (a favor for a friend) who was trying to run a 1500W commercial microwave on his vessels 15A AC circuit. The circuit quit working. I found the outlets the production boat builder used were "stab-in" style and so cheap they did not even have screw terminals. The outlets were daisy chained and the first outlet smoked itself under the load on the hot wire creating high resistance and the owner claimed he smelled "burning electrical" just before the microwave shut off. I also found a fractured 120V hot solid conductor "jumper wire behind the AC panel that was causing "intermittent" charging issues unrelated to the outlets....

I explained that if I touched the electrical system, beyond a diagnosis, what ever I worked on had be brought up to current safety standards. There were numerous other safety violations, no less than at least 15 on the AC system alone. Some extremely dangerous such as a neutral ground bond on-board the vessel and a 30A service using 14GA solid conductor wire to feed the 30A single pole main breaker.. He decided to do none of that and grumbled that wire nuts are cheap.

Why builders went to this level of cheap is simply amazing. "Stab-in" only...
 
LeslieTroyer

LeslieTroyer

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May 20, 2016
3,014
Catalina 36 MK1 94 Everett, WA
That circuit from seaward is marginal in so many ways. It only gets worse as the wiring ages. When I replaced my whole harness I cut crack the old one till I hit good bright wire and it was several feet worth. Remember the current is mostly carried on the outside of the wire, corrosion there forces a non optimal path. It also doesn’t look like seaward used tinned wire.

I have relays on both the glowplugs and starter selonoid. The biggest draw I have at the panel is the fan at 5 amps. For me glowplugs=36A starter 32/12A. Way too much to run 20+ feet and expect good performance from aged wires
 
Mark Maulden

Mark Maulden

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Jan 25, 2011
2,401
S2 11.0A Anacortes, WA
Les, I have to disagree that DC current (normally) runs on the outside of the wire. That doesn’t happen until you’re in the RF frequencies. The higher the freq, the more it happens. Ultimately, you have a waveguide.
 
jviss

jviss

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Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
LeslieTroyer said:
Remember the current is mostly carried on the outside of the wire
Click to expand
Not so with DC. Skin effect only occurs with AC.

I agree completely with the glow plug solenoid. I measured 20A, as I recall on the C36 with universal M25 on the glowplug circuit. I never thought to install a solenoid for the start wire, but never had difficulty with it. I did install a terminal block at the engine and eliminate the trailer plug. That was huge!
 
Mark Maulden

Mark Maulden

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Jan 25, 2011
2,401
S2 11.0A Anacortes, WA
Well, Touche!! Practically speaking! However, this is caused by opposiong eddy currents in a conductor with changing magnetic fields. You won’t see this in a DC circuit..
 
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LeslieTroyer

LeslieTroyer

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May 20, 2016
3,014
Catalina 36 MK1 94 Everett, WA
Sorry my bad. I’ve only had two micro brews and 500ml of Champaign so not thinking clearly. But isn’t it interesting that our DC boat wire has at least an order of magnitude more SA than the Romex we stuff in our houses.

Les
 
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LeslieTroyer

LeslieTroyer

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May 20, 2016
3,014
Catalina 36 MK1 94 Everett, WA
The newish Costco cab box is wonderful. Only $13 and equivelant of 4-750ml bottles. I’ve got one stored for the next cruise
 
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jssailem

jssailem

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Oct 22, 2014
21,102
CAL 35 Cruiser #21 moored EVERETT WA
LeslieTroyer said:
equivelant of 4-750ml bottles. I’ve got one stored for the next cruise
Click to expand
Oh boy. I am so excited that I may find your boat during your next cruise. Keep your AIS on. It will help to join up and offer a testing service.
 
L

Loose Ends

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Feb 9, 2011
70
Catalina 27 Forked River NJ
If I install a Voltmeter in place of the Ammeter, what brand and model are you all using?
What minimum gauge wire should be used between the Starter and Alternator, what length, and what are the stud sizes for the terminal lugs? (I believe I have some #6 laying around) Boat is 60 miles away so info appreciated.
Thanks
 
jviss

jviss

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Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
Voltmeter: I used Teleflex when I redid my C36 panel in 2001, but they didn't last. I'm not sure it makes a difference.

Starter to alternator: I would shoot for a less than 1% drop at maximum alternator output. I would never use anything less than 4 AWG. You should also check what you have from the starter lug to the batteries - length and gauge.

Stud size is probably 5/16", could be 3/8", don't bet on what I say! It's been a while.

Do you have an internally regulated alternator, or do you have an external regulator installed?
 
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