Multi Battery Isolator

[Gregorys6601]

I am a newbie to the electrical components of my boat. For a fear of being called an idiot in so many different ways, I have want may be a very basic question.

My boat is a 1999 Maxum 4100 SCA.

I currently have a Shore Power Multi Battery Isolator Model 3202.
At the end of last years season I replaced all my batteries. Three banks of 2 batteries each.

I know enough, based on the photos I've shared, that this is bad. My questions to help me fix the issue.

1. How do I test the Isolator to determine if it needs to be replaced?
2. Should I replace all the positive battery cables going to the Isolator that appear to be burned?
3. What questions should I be asking that I don't know what to ask?

Thanks everyone for you advice!!
43 days before I can splash
Scott

[GordMay]

INSTRUCTIONS FOR TESTING A SURE POWER ISOLATOR WITH OHMMETER*:

1. Remove all wires from the isolator.

2. Using a needle movement ohmmeter RX-1 scale or a digital ohmmeter diode scale, hold the Red* probe on the terminal "A" and with the Black* probe touch terminal #1 and #2, and the "E" terminal for 3A isolators (group 2), and the "R" terminal for (group 3) isolators. A good isolator will show a current flow from "A" to #1, #2 and "R", and no current flow to "E".

3. Next, hold the Black* probe on the "A" and with the Red* probe touch terminal #1 and #2 (terminal "E" and "R", if used). A good isolator will allow no current flow from "A" to #1, #2 or "R" and will show current flow from "E" to "A".

4. Hold one probe on the aluminum heat sink, being sure there is contact by scratching through the protective coating. Then touch with the other probe, terminals "A", #1, #2 (the "E" terminal for 3A isolators [group 2] , the "R" terminal for group 3 isolators). A good isolator will show no current flow.

5. Colored terminal indicates "E" post on group 2 isolators and "R" terminal on most group 3 isolators.

The Sure Power #3202 is a Group 1 Isolator.
*On some import ohmmeters, the red and black probes are reversed for these tests.
**If using a digital ohmmeter, a diode scale MUST be used.

[Gregorys6601]

Gord May,
Thank you for the detailed testing instructions. I plan to do my testing of it on Saturday.
Scott

[CharlieJ]

Gordo is spot on with the testing procedure but the bigger picture is that that the isolators have been abused (rusting caused by water damage) and the wiring has failed...possibly by short circuit as the insulation appears to have overheated and melted and/or burned away.

This is a serious issue and because of your lack of experience and the fact that these cables carry very significant loads, I highly recommend that you have the corrective action performed by an ABYC Marine Electrician.

[smac999]

That boat should not be used untill that is all replaced!

The wire and isolator. Get a low loss isolator. Like an argofet. That diode one is obsolete.

[Gregorys6601]

Smac999 & CharlieJ,
Thank you. I am in contact with an ABYC guy I used for some upgrades to electronics a couple of years ago.



I don't plan on using the boat until I have it fixed/replaced. Currently in winter storage and not plugged in. From my research, so far, it appears Victron has good products and the prices seem reasonable. I think I will replace what I have with your suggested Victron Argo Fet.


Saturday I will determine the length of my cables and order them from Best Boat Wire to get a good marine wire.