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Old 05-29-2019, 12:09 AM   #14
dhays
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City: Gig Harbor
Country: United States
Vessel Name: Kinship
Vessel Model: North Pacific 43
Join Date: May 2015
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Quote:
Originally Posted by O C Diver View Post
I question the choice of start versus deep cycle batteries and maybe the charge rate. My thoughts:
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If I had to guess, the windlass batteries may have reached the end of their life or lost a cell. The charger kept charging at full output (never was able to bring the voltage up to reducie charging rate) until the fuse popped.

Ted, I know there is a lot of discussion of start vs deep cycle for thruster batteries. If someone had a remote batter in the bow next to the bow thruster, then a start battery(s) would make some sense. In my case, I have one bank that supplies both thrusters and the windlass. The PO chose Lifeline 8Ds. I am sure the reason he made that selection was that is what the yard that did the work recommended and supplied. My understanding is that those batteries are kind of a hybrid. Not a bad choice really. If the bank is sufficiently large, it can provide the high, short term demand of the thrusters even if made up of deep cycle batteries.

You may be right about the potential of a failed battery. I will to research how to figure out if that is the case.

Quote:
Originally Posted by Island Cessna View Post
Since it has run for years you should be looking for what changed causing it to quit, not looking at faults in the original installation.

The Duo Charge manual says the input and output wires are both 10 gauge with 30 amp fuses. All fuses blow after a duration of time at a particular amperage. If your Duo Charger has been running for extended periods at exactly 30 amps the fuse may not have blown, but the element is running at a temperature just below it’s melting point, and the clips in the fuse holder will be at the same temperature, oxidizing and loosing their tension. The result is increased resistance in the junction with the fuse terminals, causing additional heat and the 30 amp fuse overheats and blows at an amperage below 30. The fix would be to replace the fuse holder.

While it violates my “ look for why changed” advice, this may be worth a quick look. The Balmar manual says that the input wire should be short, no longer than the supplied pigtail and the output wire should be 10 gauge, and a minimum of 8 feet long beyond the supplied pigtail. From their description it appears they use the resistance of the output wire as part of their regulation scheme. Quote from the manual: “the reason for the extra wire length is to act like an electric spring which allows the Digital Duo Charge to produce a higher current.” Do you have this length of 10 gauge wire? Since it has run for years I assume so, but worth checking, and adding length if needed.

Your point about asking for what has changed is a good one, and goes along with Ted’s question about a possible failure of the battery. I also like the idea of just aging connections at the fuse holder that could have increased the heat. The fuse holder definitely looks like got overheated.

I don’t believe the installation has that 10 gage wire. The supplied wire is connected to a buss bar which connects to the battery via a 4/0 battery cable. That runs probably 8’ to the battery. So the original installation doesn’t seem to conform to the Balmar installations.

Even so, it has worked for a number of years with no APPARENT problems. I still think that in some ways, that the design which causes the Balmar to shut down if there is too large a voltage delta between the house and charged bank poses some potential problems in this application.

If the current batteries are sound, then I think reconfiguring to use an ACR would be my best option as I have the ACR. If the batteries are not sound, then I am very tempted to simply upsize my house bank and run the thrusters and windlass off the house bank. Since all my primary charge sources run to the house bank, the alternator is charging it while using the thrusters or windlass as well.

That gets back to how to determine if the batteries that are there are OK?
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Regards,

Dave
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