alternator kill switch - Automotive Wiring and Electrical


	Auto Repair Home	SEARCH POSTS	WHO'S ONLINE	LOG IN

Automotive Repair

Car Troubleshooting Topics
  Car Troubleshooting
  Engine Troubleshooting
  Engine Fault Codes
  Electrical and Wiring
  Transmission Problems

Car Repair Topics
  Car Making Noises
  Car Stereo Repair
  Heating or AC Issues
  Motorcycles and ATVs
  Tricks of the Trade
  Truck Repair Advice

Site Options:
  Login
  Sign up here!

Latest Forum Post

2006 Toyoto Camry XLE Driver Side Electric Window Trouble

Hello, Looking for a little brain help ...

Tierod end change caused some kind of leak

Hello so I just took my car to the nearb...

2011 Dodge Nitro OBD scanner seems to drain battery in 10-20 minutes

When I bought this car in summer 2023, a...

Grounding Cable, 2017 Jeep Renegade Trailhawk

The Cable that connects my negative batt...

Rough Idle (Found new thing)

Hi everyone. First of all sorry for bad ...

equipment

hey yall. im a first year engineering st...

HELP

I have a 1956 1/2 ton panel truck, 69 35...

Howdy

    Just wanted to s...

ABS/Tractiob/Brake Lights on But No DTCs

Hello all, Recently while driving m...

Chevy strut replacement

I'm trying to get a sensor of some kind ...

alternator kill switch

Sign up here!

Email This Post

Auto Repair Home>> Automotive Repair>> Automotive Wiring and Electrical

flaviobonzer
New User

Aug 12, 2013, 3:21 AM

Post #1 of 4 (1576 views)

alternator kill switch	Sign In

Hi everyone,
I am wanting to install a kill switch or something to enable me to control when the alternator charges the battery. This is actually for a diesel engine in a yacht and I need to cut the load that the alternator puts on the engine every now and again.
I have tried putting a switch in the field/ exciter wire. with this I can start the engine with the alternator off and then flick the switch and the alternator starts charging but then when I turn the switch off doesn't turn off the alternator as now the regulator is supplying voltage to the field circuit. Is there any way I can install a switch somewhere to achieve what I want? Was thinking maybe adding another batt in series to the sense wire so regulator thinks batt is full charged and cuts alternator output. Would this work?
Any suggestions greatly appreciated
cheers
Tim

Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Aug 12, 2013, 4:45 AM

Post #2 of 4 (1566 views)

Re: alternator kill switch	Sign In

Would help if we knew what kind of alternator you have.

Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

flaviobonzer
New User

Aug 12, 2013, 5:21 AM

Post #3 of 4 (1557 views)

Re: alternator kill switch	Sign In

Alternator is a Mitsubishi. not sure of amperage or model etc. Alternator only has field/sense/tach connections on back of alternator. Apart from main batt + of course.

cheers

Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 12, 2013, 5:57 AM

Post #4 of 4 (1550 views)

Re: alternator kill switch	Sign In

You won't save a thing - forget that idea completely. Did a ton of pretty large yacht misc stuff over many years.

OK - just because the engine may not need electricity for anything to run there are a zillion things still using some power all over a typical yacht unless it's an empty shell.

Alternator is almost just a nothing pulley for power loss if not powering something anyway. Even the best deep cycle battery(s) w starting amps enough for a diesel engine doesn't like going low just tolerates it lots better and when you do enable it it would just make up drag to recharge them later.

Do you really want to risk it not starting because you let it get too low?

Last yacht I did a lot on had power for water for 3 sinks, ice maker, six bilge pumps, TV, radios, gauge lighting and 100 more things I can't think of right now and guess you could do without blowers for heat and A/C if equipped underway.

Even sail boats of size need power for pumps. Yes - most charge battery(s) slowly with just a little wind generator usually at the top of the mast.

The other problem is when you ask an alternator to charge hard with low battery(s) is you are really stressing it out and can kill it. Much bigger bucks than automotive as it must be designed not to make sparks.

In short - you save nothing and risk a lot. Last one I deal with a lot had SIX deep cycle batteries and could choose 3 at a time, all or either set such that a failure still left you with at least starting power if one set failed in any way.

Enough crap is always going wrong in a real yacht all the time and you want to mess it up even worse?

T

Email This Post

Search for (options) Privacy Sitemap