Notices
Marine Electronics Forum

VHF Turning off on engine start

Old 08-24-2011, 12:06 PM
  #1  
Senior Member
Thread Starter
 
Join Date: Jun 2009
Posts: 833
Likes: 0
Received 0 Likes on 0 Posts
Default VHF Turning off on engine start

New battery, fully charged.. VHF turns off when I crank.. I understand the current being drawn causes an issue.. But my other electronics don't have the problem..

Thoughts on adding a cap in line to help hold the VHF through the initial current surge?

VHF is a Standard Horrizon unit, new...
Old 08-24-2011, 03:45 PM
  #2  
Senior MemberCaptains Club Member
 
Join Date: Nov 2002
Location: Pensacola, Fl
Posts: 12,287
Received 610 Likes on 447 Posts
Default

This is an illustration of why it is a good idea to either have the electronics on a separate battery, have a battery in line (as Newmar has in their "start guard" or "Nav Pac" ) or keep the electronics off when starting the engine.

If you were to measure the voltage at the radio (or other console points) it may be well below the threshold of shut off to protect the radio (such as 8 to 10 volts). There can also be spikes as the engine starts and the alternator first comes on line--years ago I blew a diode or two on some expensive instruments because of this. Most electronics have far better protection now. But I like to keep my electronics on a separate battery and use a VSR to isolate that battery during engine start.

I doubt that a single simple capacity would do the job--as you would use for the boost start circuit in an air conditioner etc.
Old 08-25-2011, 03:18 AM
  #3  
Admirals Club Admiral's Club Member
 
Join Date: Feb 2010
Location: Melbourne, FL
Posts: 57
Likes: 0
Received 1 Like on 1 Post
Default

I had same problem but was my A-series Raymarine that would turn off while my radio was okay. Just depends on which of your electronics is most sensitive to the power fluctuation. I put in the Newmar Startguard which kicks in when it detects the power drop and problem solved. But I do want to add a second battery when I get a chance.
Old 08-25-2011, 04:15 AM
  #4  
Senior MemberCaptains Club Member
 
Join Date: Feb 2002
Location: North Charleston, SC USA
Posts: 22,073
Likes: 0
Received 28 Likes on 28 Posts
Default

Originally Posted by cjldad View Post
New battery, fully charged.. VHF turns off when I crank.. I understand the current being drawn causes an issue.. But my other electronics don't have the problem..

Thoughts on adding a cap in line to help hold the VHF through the initial current surge?

VHF is a Standard Horrizon unit, new...
A "cap"? ;? Capacitor?

I assume you are talking about the large value capacitors car audio people sometimes use to regulate the voltage to their stereo systems?

It won't help. When you crank the engine, the capacitor will just be seen as a another small battery by the starter and its voltage will drop along with the battery voltage. You would need to install a diode in the circuit between the battery and the capacitor to prevent this.

Any of that would be nothing more than a Band-Aid to treat a symptom rather than correcting the problem. You may have a voltage drop caused by the cables or connections that are common to both the starter and the VFH or your battery may just not be able to supply the required current at a high enough voltage to keep the radio from shutting down. Have you always had this problem or is it a new problem and if new, when did it start? Is the new battery the same capacity as the one it replaced?

The best solution is to add a house battery to operate everything but the starter and gauges and a VSR to keep both banks charged.

The second best is to add one of the products marketed to solve this problem, but in the end, you will spend as much and not have the flexibility you would have with two battery banks.
Old 08-25-2011, 04:55 AM
  #5  
Senior Member
 
Join Date: Apr 2006
Location: Tidewater, VA
Posts: 1,166
Likes: 0
Received 0 Likes on 0 Posts
Default

If you REALLY insist on having your VHF up and running when you crank your engine, you could get a Lewmar Startguard. It will keep the radio up for about $155.

Or you could either turn the radio off, or live with it for $0.

Joe
Old 08-25-2011, 05:14 AM
  #6  
Senior MemberCaptains Club MemberPLEDGER
 
Join Date: Feb 2003
Location: Thornton's Ferry,NH,USA
Posts: 10,755
Likes: 0
Received 81 Likes on 47 Posts
Default

I suggest taking the VHF off the circuit that has your starter. Wire it back to the battery, or battery switch. Before you do "major surgery" you can run a temperary power supply from those points to see if it solves the problem.

Let us know what works.

Good luck!
Old 08-25-2011, 07:23 AM
  #7  
Senior Member
Thread Starter
 
Join Date: Jun 2009
Posts: 833
Likes: 0
Received 0 Likes on 0 Posts
Default

I do have two batteries on a selector switch.. I don't like VSR's for many reasons.. I'd rather use something like the Minn Kota MK1 alternator charger... I'll try it without extra components first...

I'm going to clean up connections for the terminals at the battery and on the engine to make sure they are getting everything they need, and then move the connection from the VHF direct to the crank battery and go from there.. If it still cuts out, there isn't much more I could do..(short of adding some component) If that works, I'll start by upgrading the wire to the panel and make the VHF and other electronics first in line on the panel..
Old 08-25-2011, 08:21 AM
  #8  
Senior MemberCaptains Club Member
 
Join Date: Feb 2002
Location: North Charleston, SC USA
Posts: 22,073
Likes: 0
Received 28 Likes on 28 Posts
Default

Originally Posted by cjldad View Post
I do have two batteries on a selector switch.. I don't like VSR's for many reasons.. I'd rather use something like the Minn Kota MK1 alternator charger... I'll try it without extra components first...

I'm going to clean up connections for the terminals at the battery and on the engine to make sure they are getting everything they need, and then move the connection from the VHF direct to the crank battery and go from there.. If it still cuts out, there isn't much more I could do..(short of adding some component) If that works, I'll start by upgrading the wire to the panel and make the VHF and other electronics first in line on the panel..
Well, your electronics should not be connected to the battery that's used to start the engine.

From reading your post and your "plans", I don't think you really understand electricity. You might do well to get some qualified local help on this.
Old 08-25-2011, 08:31 AM
  #9  
Senior Member
Thread Starter
 
Join Date: Jun 2009
Posts: 833
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by rwidman View Post
Well, your electronics should not be connected to the battery that's used to start the engine.

From reading your post and your "plans", I don't think you really understand electricity. You might do well to get some qualified local help on this.

I don't need to qualify myself here.. But I'll keep it in mind the next time I'm working on a 100kw transmitter at work...

Thanks to the other folks suggestions..

Last edited by cjldad; 08-25-2011 at 08:43 AM.
Old 08-25-2011, 08:42 AM
  #10  
Senior Member
 
Join Date: Aug 2010
Posts: 235
Likes: 0
Received 21 Likes on 8 Posts
Default

I keep my electronics wired to a house battery, and the starter to a starting battery. It avoids screwing up my electronics when I start and avoids draining my starting battery when using my electronics while the engine is off.
Old 08-25-2011, 09:02 AM
  #11  
Senior Member
Thread Starter
 
Join Date: Jun 2009
Posts: 833
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Madhavok View Post
I keep my electronics wired to a house battery, and the starter to a starting battery. It avoids screwing up my electronics when I start and avoids draining my starting battery when using my electronics while the engine is off.
Yeah, that all makes sense.. What happens if your start battery goes for whatever reason? Or if your house battery goes? Do you have means to use either as a backup for one another at that point?
Old 08-25-2011, 09:16 AM
  #12  
Senior Member
 
Join Date: Feb 2009
Posts: 556
Likes: 0
Received 0 Likes on 0 Posts
Default

I would advise that you not have your electronics connected to the battery you use for starting. Very large voltage spikes are produced during starting from the collapsing magnetic field of the starter and/or solenoid when dis-engaging the starter. They can degrade your equipment without showing any initial signs of it by being repeatedly hit with them during starting. You are reducing the MTBF (mean time between failure) of your equipment.

Eric
Old 08-25-2011, 09:31 AM
  #13  
Senior Member
Thread Starter
 
Join Date: Jun 2009
Posts: 833
Likes: 0
Received 0 Likes on 0 Posts
Default

How is that accomplished in this situation with two batteries, one selector switch?

Just use battery 1 as my main starting and battery 2 as backup starting/sensitive electronics?
Old 08-25-2011, 10:47 AM
  #14  
Edd
Senior Member
 
Join Date: Aug 2008
Location: Inland Waters of California
Posts: 1,944
Received 13 Likes on 11 Posts
Default

You really should listen to rwidman and get someone who understands marine 12v systems. You ask for help, then shun or question all the suggestions. My suggestion would be for you to have fun with it then seek a qualified Physician.

Edd
Old 08-25-2011, 10:47 AM
  #15  
Senior Member
 
Join Date: Apr 2006
Location: Tidewater, VA
Posts: 1,166
Likes: 0
Received 0 Likes on 0 Posts
Default

How about wiring selector switches (two 3-way switches, one per battery) where position one is engine, position two is house, and position three is both (feeds both house and engine). That way you have maximum flexibility, and can alternate which battery does what (odd days house, even days engine).
Old 08-25-2011, 12:48 PM
  #16  
Senior Member
Thread Starter
 
Join Date: Jun 2009
Posts: 833
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Edd View Post
You really should listen to rwidman and get someone who understands marine 12v systems. You ask for help, then shun or question all the suggestions. My suggestion would be for you to have fun with it then seek a qualified Physician.

Edd
Thanks for your suggestion too. I fully respect rwidman's first post as it was thorough and detailed. It certainly got me thinking. The follow up post questioning my competence felt unnecessary but whatever.

Perhaps it was my fault for not fully explaining my setup correctly in the first place.

I said no to the VSR because I don't like the idea of the house battery possibly being at a different state of charge then being put in parallel with the start battery. I would like a more controlled setup other than shunting the two batteries together. In my world of working on stand-by systems ideally you want the two batteries to be equal when you parallel them..

Either way, there were some good suggestions here to get me going..
Thanks!
Old 08-25-2011, 01:26 PM
  #17  
Edd
Senior Member
 
Join Date: Aug 2008
Location: Inland Waters of California
Posts: 1,944
Received 13 Likes on 11 Posts
Default

Originally Posted by cjldad View Post
Thanks for your suggestion too. I fully respect rwidman's first post as it was thorough and detailed. It certainly got me thinking. The follow up post questioning my competence felt unnecessary but whatever.

Perhaps it was my fault for not fully explaining my setup correctly in the first place.

I said no to the VSR because I don't like the idea of the house battery possibly being at a different state of charge then being put in parallel with the start battery. I would like a more controlled setup other than shunting the two batteries together. In my world of working on stand-by systems ideally you want the two batteries to be equal when you parallel them..

Either way, there were some good suggestions here to get me going..
Thanks!
You speak as though you plan on paralleling the 2 batteries on a daily basis. You will do that only in an emergency, so I ask; Do you plan on having an emergency every day?.

Edd
Old 08-25-2011, 01:30 PM
  #18  
Senior MemberCaptains Club Member
 
Join Date: Feb 2002
Location: North Charleston, SC USA
Posts: 22,073
Likes: 0
Received 28 Likes on 28 Posts
Default

VSRs are an accepted standard for charging batteries on boats. They have proven themselves for many years. If they work for other people, they will work on your boat.

A "starting" battery, a "house" battery, a VSR, and a means to use the house battery as a starting battery in an emergency is all you need. This can be a switch, a series of switches, or just a jumper cable.


Here is what makes me think you do not understand electricity, at least power distribution on a boat: "If that works, I'll start by upgrading the wire to the panel and make the VHF and other electronics first in line on the panel.. "

1. If the voltage is dropping when you operate the starter, the drop is before the wire to the panel. It's the battery or the cables from the battery to the battery switch or the negative battery cable. It's something that is common to the starter circuit and the feed to your electrical panel. If the voltage is dropping where the wire to the panel receives power, no "upgrade" of that wire will change anything.

2. "first in line on the panel.. " All the circuits on the panel receive the same voltage and can receive the same current. If there is a voltage drop from the "first" circuit to the "last" circuit, there is a wiring problem on the panel. You might be able to measure a drop in millivolts on a functional panel if there is a large load on the last circuit. Nothing to even consider.

If you don't want to take everyone's advice and put your electronics, lighting, etc. on a house battery, you need to get out your meter and find where the voltage drop is and repair it. Remember, the drop can be in the negative side of the circuit as well as the positive. Or both if you have undersized cables.
Old 08-25-2011, 01:38 PM
  #19  
Senior Member
Thread Starter
 
Join Date: Jun 2009
Posts: 833
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Edd View Post
You speak as though you plan on paralleling the 2 batteries on a daily basis. You will do that only in an emergency, so I ask; Do you plan on having an emergency every day?.

Edd
When the VSR is closed/charging the two batteries are paralleled..
Old 08-25-2011, 01:48 PM
  #20  
Senior MemberCaptains Club Member
 
Join Date: Feb 2002
Location: North Charleston, SC USA
Posts: 22,073
Likes: 0
Received 28 Likes on 28 Posts
Default

Originally Posted by cjldad View Post
When the VSR is closed/charging the two batteries are paralleled..
And the voltage will be the same at each set of terminals, but the one that needs the charge the most will get more of the charging current. Eventually, they will have an equal charge.

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.