Archive for March, 2010

VSR Grounding Concerns

March 10th, 2010 by Kevin Hannula and Nick Kroes

Hi,

I have read the page on installing a VSR but am still unclear about the issue of grounding.

Following the VSR instructions I have added a second marine battery (in a fiberglass boat) and made the following connections:

  • Positive lead from VSR to positive terminal of primary battery.
  • Positive lead from VSR to positive terminal of secondary battery.

Now the instructions say to connect a lead from the negative terminal of the secondary battery to the ground.

I have two questions:EzAcDc offers smart battery switches for your boat wiring project.

  1. Can I connect the negative terminal of the secondary battery to the negative terminal of the primary battery? -> i.e. it seems logical to assume the primary battery negative terminal has been earthed correctly already (I have not channged anything on the primary battery and everything was working).
  2. The VSR also has a very thin (and short) negative cable which the manual says must also be grounded – should this go to the negative battery terminal or somewhere else?

Thanks for your help

Mark

Mark,

  1. “Can I connect the negative terminal of the secondary battery to the negative terminal of the primary battery? -> i.e. it seems logical to assume the primary battery negative terminal has been eartherd correctly already (I have not channged anything on the primary battery and everything was working).”

    • YES.  Connect the two battery negative terminals together. Connect them with a wire that is at least as large as the engine start cables.
  2. “The VSR also has a very thin (and short) negative cable which the manual says must also be grounded – should this go to the negative battery terminal or somewhere else?”

    • The ground wire needs to go to either battery negative terminal or a ground buss.  The VSR is like a voltmeter that is connected to a battery switch.  It needs to have a wire connected to the positive and the negative of each battery to look at this voltage.  The batteries have a common ground so only one ground wire is needed.

I hope that this is helpful. Please let me know if you have any other questions.

Kevin

Posted in Uncategorized | Comments Off

Marine Grade or Regular Wire?

March 7th, 2010 by Kevin Hannula and Nick Kroes

“Can I use ‘regular wire’ for my boat wiring?” The answer to this common question is a qualified “yes,” if the wire is SAE (Society of Automotive Engineering) J378, J1127 or J1128. These wires are designed for “surface vehicles,” not for the special requirements of the marine electrical industry, but meet the minimum standards for boats in limited circumstances. Even if tinned copper, they should not be run in bilge spaces or other areas subject to moisture from spray or dripping. They should not be run in engines spaces, unless marked “oil resistant” and “75°C”. They should not be used in applications where subjected to vibration or frequent flexing and must never be used for 110 volt applications. For safety, use only wire which is marked with size and type.

Most importantly, SAE wire is up to 12% smaller than AWG Boat Cable which means that, in many applications, larger gauge wire must be used to stay within the voltage drop limits recommended by experts (see Tables C & D). The wire charts found in “Chapman’s Piloting” and other publications are all for “AWG” wire like ANCOR, not “SAE” type wire.

Using the wrong type of boat wiring can cost you more in the long run. Insist on Marine Grade™ Boat Cable by ANCOR. It is UL approved for the corrosive marine environment and charter boat service. Marine Grade™ Boat Cable is specially designed to exceed all test standards for cold bend, moisture and oil resistance, heat shock and flammability. This ensures the safest, easiest to install, longest lasting and ultimately the least expensive electrical system you can buy. Only ANCOR offers a complete line of Marine Grade™ Boat Cable for every need.

Posted in Boat Wiring, Corrosion, Harnesses | Comments Off