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What should the Galvanic meter readings range between?

Posted: Thu Sep 13, 2018 12:39 pm
by oef0102
I recently purchased a 1975 28' Marinette that has a galvanic meter installed on the dashboard.
Asking what the reading should be to be considered in a safe zone? Trying to find out specifically when I need to replace the anodes.
Thank you

Re: What should the Galvanic meter readings range between?

Posted: Thu Sep 13, 2018 1:05 pm
by bill
BigM
Your meter should tell the acceptable ranges. Look at the fine print for aluminum. ;)

Table 1. Galvanic Series Of Metals In Sea Water With Reference To Silver/Silver Chloride Reference Cell [Sea water flowing at 8 to 13 ft./sec. temperature range 50 degree F (10 degree C) to 80 degree F (26.7 degree C)]

Anodic or Least Noble Corrosion Potential Range in Millivolts
*The range shown does not include sacrificial aluminum anodes. Aluminum alloy sacrificial anodes are available that have a maximum corrosion potential of -1100 mV.
Magnesium and Magnesium Alloys -1600 to -1630
Zinc -980 to -1030
Aluminum Alloys -760 to -1000
Cadmium -700 to -730
Mild Steel -600 to -710

bill
Please use a signature when you post. :D

Re: What should the Galvanic meter readings range between?

Posted: Fri Sep 14, 2018 9:14 am
by barkleydave
Ideal range:
.95-1.05

numbers will vary depending on water clarity and wether fresh or salt water.

safe boating,
Dave

Re: What should the Galvanic meter readings range between?

Posted: Fri Sep 14, 2018 10:29 am
by shade2u2
Mine reads .85 - .92 most of the time now. How much of a concern is this?
I added a cabled anode but it doesn't seem to change the readings. I may not have a good connection with the clip.

Re: What should the Galvanic meter readings range between?

Posted: Fri Sep 14, 2018 10:16 pm
by jralbert
shade2u2 wrote:Mine reads .85 - .92 most of the time now. How much of a concern is this? I added a cabled anode but it doesn't seem to change the readings.
If you haven't done so already, clean the wire connections on the meter and see if that makes a difference. It may since the current amounts are so small to begin with. Meanwhile, imho, your readings seem pretty close to the listed range