Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 27-04-2016, 16:15   #16
Registered User

Join Date: Dec 2012
Location: Mannum, Australia
Boat: Houseboat, 45ft.
Posts: 84
Re: Generator starter allowable voltage drop

Started & died?
Most Gennies will die within a short time if any number of things aren't satisfied.
Oil pressure.
Exhaust temp high. (no water)
Genny output.
Short circuit in output.
Output too high.
Output too low.
Look up "watchdog".
I'd check the oil pressure sending unit first. (or jump it)
__________________

__________________
BruceS is offline   Reply With Quote
Old 27-04-2016, 16:20   #17
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,062
Re: Generator starter allowable voltage drop

Quote:
Originally Posted by Cadence View Post
I can not imagine that type of draw on a starter for a gen. of that size. As fare as load, you don't start a gen. under load. JMHO

No, but since there is no clutch or other way to disengage the generator head, it is sort of like starting an automobile in gear as the starter has to overcome the inertia of both the engine and generator and accelerate both. Just like I'd bet Lunch that my single cylinder always stops right at the beginning of the compression stroke, so the starter has to deal with compression right as its beginning to accelerate the engine.


Sent from my iPad Pro using Cruisers Sailing Forum
__________________

__________________
a64pilot is offline   Reply With Quote
Old 27-04-2016, 17:07   #18
Registered User

Join Date: Apr 2015
Location: West Coast FLA
Boat: 1978 Pearson 424 Ketch
Posts: 451
Re: Generator starter allowable voltage drop

When troubleshoot a starting problem the test in order are: battery voltage 12.5, battery voltage whilst cranking 11.5 - 12, voltage at starter 12.5. voltage at starter whilst cranking 11 - 11.5...all systems acceptable. So voltage at starter whilst cranking should not be less than 11 volts 11.75 is best. If the voltage drop is more than one volt betwixt the battery and the starter the cable is insufficient. either too small or too old. It'll probably work fine....for a while...with 1.5 volt drop, but you'll take life out of the starter.

this is all assuming that the battery has sufficient cranking amps (CCA) 650 CCA would work with pristine conditions. 800 CCA would give the most versatility...ie...old connectors, high humidity, cold temperatures, low charge..... if the CCA of the battery are too low, the tests above will be wrong. if you had a 24 volt system the voltage drop test would be the same .5 to 1.5

a 15 foot run one way? 1/0 would be about right, measuring round trip...ie...positive and negative runs from and to the battery. usually I try to mount the cranking battery as close to the starter as possible. Less load and aging on the circuit. the wires in a circuit are part of the load, not just the motor. Hence the voltage drop. 15 foot oneway is a long ways for a cranking battery. My cranking Battery is only 7 feet oneway - Pearson 424.
__________________
tinkrman69 is offline   Reply With Quote
Old 28-04-2016, 01:29   #19
Registered User

Join Date: Jun 2013
Location: canada
Posts: 1,700
Re: Generator starter allowable voltage drop

nobody does a starter at 3%.

I'd say 1-2v is pretty normal. which is like 10-20%. but of course not ideal.

I would aim for 10%

2awg is pretty common for smaller gens.

I fuse them at 200-300a with MRBF's

should have own battery and battery switch. going off an engine starter post is just silly.
__________________
smac999 is offline   Reply With Quote
Old 28-04-2016, 04:47   #20
Don't ask if you can't handle it
 
sailorboy1's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: On the boat somewhere
Boat: Hunter 410
Posts: 12,320
Re: Generator starter allowable voltage drop

color me silly
__________________
jobless, houseless, clueless, living on a boat and cruising around somewhere
sailorboy1 is online now   Reply With Quote
Old 28-04-2016, 05:58   #21
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,062
Re: Generator starter allowable voltage drop

Quote:
Originally Posted by smac999 View Post
should have own battery and battery switch. going off an engine starter post is just silly.

Why? If your going to say you need a third bank just in case your first two die, then of course you should have an independent fuel supply too
__________________
a64pilot is offline   Reply With Quote
Old 28-04-2016, 06:20   #22
Don't ask if you can't handle it
 
sailorboy1's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: On the boat somewhere
Boat: Hunter 410
Posts: 12,320
Re: Generator starter allowable voltage drop

Quote:
Originally Posted by smac999 View Post
nobody does a starter at 3%.

I'd say 1-2v is pretty normal. which is like 10-20%. but of course not ideal.
I consider this thread dead really as far as helping me. But, my original wiring worked out to 15% and the generator wouldn't spin.
__________________
jobless, houseless, clueless, living on a boat and cruising around somewhere
sailorboy1 is online now   Reply With Quote
Old 28-04-2016, 06:43   #23
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,062
Re: Generator starter allowable voltage drop

Quote:
Originally Posted by sailorboy1 View Post
I consider this thread dead really as far as helping me. But, my original wiring worked out to 15% and the generator wouldn't spin.

It may help others, and the information that at 15%, it won't start is I believe good info, it sort of tells me that 10% while it works may be marginal, and I believe the less loss there is, the longer a starter will last, cost a little extra money, but kind of hard to go too big with battery cables
__________________
a64pilot is offline   Reply With Quote
Old 01-05-2016, 17:29   #24
Don't ask if you can't handle it
 
sailorboy1's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: On the boat somewhere
Boat: Hunter 410
Posts: 12,320
Re: Generator starter allowable voltage drop

It started right up this weekend and I didn't do anything. I ran it an hour plus and it powered the reverse cycle air conditioner and warmed the boat. But it would occasionally slow and then come back to speed. So I'm going to run a separate fuel line for it which will reduce the fuel hose length. Of course that means a separate fuel/water filter unit and more $$$ into this project.

Good thing my labor rate is just beer.
__________________
jobless, houseless, clueless, living on a boat and cruising around somewhere
sailorboy1 is online now   Reply With Quote
Old 01-05-2016, 17:37   #25
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,062
Re: Generator starter allowable voltage drop

First indication I get of a clogging fuel filter on mine is it will bog down under load, I fist ran just a 2 micron filter and after clogging two, decided to plumb in after the 30 micron Racor for the main engine.
Maybe you have a fuel restriction, not enough flow?


Sent from my iPad Pro using Cruisers Sailing Forum
__________________
a64pilot is offline   Reply With Quote
Old 01-05-2016, 17:55   #26
Don't ask if you can't handle it
 
sailorboy1's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: On the boat somewhere
Boat: Hunter 410
Posts: 12,320
Re: Generator starter allowable voltage drop

Quote:
Originally Posted by a64pilot View Post
First indication I get of a clogging fuel filter on mine is it will bog down under load, I fist ran just a 2 micron filter and after clogging two, decided to plumb in after the 30 micron Racor for the main engine.
Maybe you have a fuel restriction, not enough flow?


Sent from my iPad Pro using Cruisers Sailing Forum
I'm already coming off the main engine Racor line. That makes the loop about 30' from the tank to the filter and then to the generator. I'm going to install a new Racor filter and run it right off the tank which will shorten the line to about 10' each way. I never really liked the idea of having the generator fuel connected to the main engine supply line anyway and was probaby a stupid thing to save $80.
__________________
jobless, houseless, clueless, living on a boat and cruising around somewhere
sailorboy1 is online now   Reply With Quote
Old 02-05-2016, 09:14   #27
Registered User
 
Cadence's Avatar

Join Date: Dec 2008
Location: SC
Boat: None,build the one shown of glass, had many from 6' to 48'.
Posts: 6,063
Re: Generator starter allowable voltage drop

Quote:
Originally Posted by sailorboy1 View Post
It started right up this weekend and I didn't do anything. I ran it an hour plus and it powered the reverse cycle air conditioner and warmed the boat. But it would occasionally slow and then come back to speed. So I'm going to run a separate fuel line for it which will reduce the fuel hose length. Of course that means a separate fuel/water filter unit and more $$$ into this project.

Good thing my labor rate is just beer.
Are you sure it isn't slowing down when the heat pump compressor kicks in?

Could be compressor start up load slowing it periodically.
__________________
Cadence is offline   Reply With Quote
Old 02-05-2016, 09:20   #28
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,062
Re: Generator starter allowable voltage drop

Run two filters, one 30 and one 2 or you may be like me and get only about 10 hours or so out of a filter before it clogs.
I ran a little Racor 120 filter, I even put on on my outboard as it's the same parts of course.
Check with Hopkins Carter, he may can give you a deal on two of them as I believe you have to filter to 2 microns, and to do that you need maybe a 30 micron first or the 2 micron clogs early.

Or maybe stay with what you have and install an electric boost pump, that should fix the issue too.
__________________
a64pilot is offline   Reply With Quote
Old 02-05-2016, 15:53   #29
Don't ask if you can't handle it
 
sailorboy1's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: On the boat somewhere
Boat: Hunter 410
Posts: 12,320
Re: Generator starter allowable voltage drop

Quote:
Originally Posted by Cadence View Post
Are you sure it isn't slowing down when the heat pump compressor kicks in?
Yes as it did it even unloaded
__________________
jobless, houseless, clueless, living on a boat and cruising around somewhere
sailorboy1 is online now   Reply With Quote
Old 02-05-2016, 15:56   #30
Don't ask if you can't handle it
 
sailorboy1's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: On the boat somewhere
Boat: Hunter 410
Posts: 12,320
Re: Generator starter allowable voltage drop

Quote:
Originally Posted by a64pilot View Post
Run two filters, one 30 and one 2 or you may be like me and get only about 10 hours or so out of a filter before it clogs.
If you were clogging it so fast why isn't your main engine fuel also clogging?
__________________

__________________
jobless, houseless, clueless, living on a boat and cruising around somewhere
sailorboy1 is online now   Reply With Quote
Reply

Tags
generator

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Allowable Ship Stores while in CUBA Nomad 1 Atlantic & the Caribbean 15 17-12-2015 14:30
78 pearson 30 maximum allowable prop size simplynick912 Propellers & Drive Systems 8 26-02-2013 17:11
Cutlass bearing shot, what is max shaft wear allowable ? Jd1 Engines and Propulsion Systems 7 23-07-2012 20:20
Allowable Chart Folder / Subfolder Structure paul2 OpenCPN 6 27-12-2010 23:32
Windchargers and Voltage Drop Question 4 Experts. dkall Electrical: Batteries, Generators & Solar 6 25-03-2008 22:34



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 07:33.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.