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ELECTRICAL ISSUES!

Feb 26, 2004
21,003
Catalina 34 224 Maple Bay, BC, Canada
can't figure out why it blew. May never know.
Sometimes a loose connection can create that. When you replaced it, did it work? I've heard of fuses being in for years, "looked good" but didn't work; replace the fuse things worked again. Go figure...

As long as things work as they should when you replace the fuse, if you can't figure out why it blew to begin with. That's what Mike needs to know.
 
Oct 22, 2014
12,122
CAL 35 Cruiser Portland OR, moored EVERETT WA
JV I think sometimes fuses blow just to screw with the boat owner. No reason other than they have been there for years... Have had a couple of hot and cold cycles and then say... "If I burn out it will really mess with the owners head. He has no idea I' was placed here in the 80's and thinks all is well. So here I go in a blazing fury..."
 

tgrady

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Nov 22, 2013
53
Hunter 33.5 North Vancouver
Wasn't that the charger that almost put the company out of business? I had one and got a recommendation to change it out ASAP because it won't charge. Poor design I was told.
 
Oct 22, 2014
12,122
CAL 35 Cruiser Portland OR, moored EVERETT WA
Mike, here is thought on your charger... The manual indicates that it needs to be connected to a battery to properly function. It appears the Xantrex draws on the batteries to power the system dc circuits for battery charging performance. You need to disconnect from AC power and DC power to assure that the unit is safe to work around.
As Stu said the refrig is a battery killer. It draws till it cannot. If the charger failed or the fuse blew, then the batteries were drawn to zero. They will need to be removed and recharged/equalized and load tested to be sure they are still able to provide service on your boat.
I had that happen 2 years ago. Charger failed. 8 month old batteries zero'd. They were replaced when I installed the new charger. Here is a pitch for the Sterling Charger. When you remove the batteries for service the Sterling charger still can power your DC circuits. Something to consider if you have to replace the Xantrex.
 

jviss

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Feb 5, 2004
3,935
Tartan 3800 Westport, MA
It worked - so far, so good - when I replaced the fuse. Could have been an intermittent fault, who knows? Or maybe the fuse just gave up, from old age.
 
May 20, 2016
2,909
Catalina 36 MK1 94 Everett, WA
I had the same charger on my boat till this spring. Came back to the boat to find house dead twice. Power on to charger and no fault lights. Cycling power brought it back both times. After the second time it happened I got a 40A Sterling charger from Maine Sail and have been a happy camper since. I have a slightly used true charge 20 for cheap if you need one

Les
 
Feb 6, 1998
11,191
Canadian Sailcraft 36T Casco Bay, ME
I should be able to leave equipment like the refrigerator on during the week as long as shore power is plugged in, shouldn't I?
Mike
Mike,

Couple of thoughts.

While convenient to have the fridge always on there is always risk in doing so.

Risks:

* Marina power is anything but reliable. Muffy & Skippy unplug your cord when heading out on the Sea Ray and forget to plug it back in. A breaker trips because the pedestal was over loaded etc.. Darrell & Darrell are working on the dock system and forget to re-power your finger pier..Your own boat develops a fault and AC is interrupted etc.. A transient boater comes in and trips the docks ELCI or GF circuit taking your finger pier out. These are not at all rare incidents especially when you do this sort of work for a living. While folks can & do get lucky, sometimes for many years, this still represents and n=1 data set and is not something to rely on. Running dockside DC loads, that relay on the battery charger, are simply risky.

* Not all chargers are actually smart. A fridge compressor load can kick many chargers back into absorption mode and wind up actually over charging the batteries. One would think that boats plugged into shore power would see longer battery life but due to loads rebooting absorption I frequently see batteries that get abused, and have short life, even when tied to shore power. In a perfect world the charger would stay in float but they don't all do this. With no DC loads the charger can easily stay in float and you run a much lower risk of over-charging the batteries.

* When plugged in, and the batteries are full, the charger is supplying 100% of the fridge load, but during start up the battery usually kicks in some because the power supply in the battery charger is a bit too slow to keep up with the in-rush. In theory the batteries should just sit there and float but the reality is far too many chargers are not smart enough to know the batteries are full and they can get triggered back into a higher absorption voltage when the fridge compressor kicks on. Some will drop back to float quickly others may start a two plus hour timer once absorption has been re-triggered.

* If you do lose AC power, not uncommon and becoming more & more common everyday with the new NEC/NFPA requirements for GF interrupters in marinas, your batteries can be sucked below the chargers safe "turn on" voltage. Even though AC power was restored the charger may not resume charging the batteries because the charger assumes there is a "fault" because the battery voltage is so low.. This is a built in safety feature to prevent chargers from charging into a shorted battery.

*Chargers can and do fail.. The failure rate for marine battery chargers is routinely on the higher side of the failure spectrum for marine electrical items...


Options:


* Add a low voltage cut off to the fridge circuit. Set it at 12.1V and this will prevent your batteries ever being sucked below about 50% SOC regardless of whether or not you lose shore power. It will also ensure your batteries will have enough voltage to allow the battery charger to re-boot when the fault or power has been restored. The Blue Sea m-LVD is a good choice in a low voltage cut off. IMHO, as a marine electrician, every single boat owner who leaves DC loads on dockside should install a low voltage disconnect at a bare minimum. Battery banks can get very, very, very expensive and I replace thousands of dollars of batteries destroyed each year to to leaving DC loads running on shore power.

* Use a good quality charger that has a power supply setting or force to float feature or custom programming ability where you can manually set it at your float voltage when you leave the vessel. Often times a custom setting can be configured so the bank won't go above 13.XX volts no matter what. This prevents overcharging due to fridges rebooting absorption.

* You could use an AC to DC power supply but you'll still want/need a battery in the circuit, as a buffer for start up loads. Ones that can handle motor in-rush, without a battery can get a bit expensive.

Safest Option:

*When you leave your boat, turn all DC loads off. This is the lowest risk for ruining a battery bank.
 

jviss

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Feb 5, 2004
3,935
Tartan 3800 Westport, MA
I have had success with a simple, inexpensive, waterproof shore power charger, a Guest 2611A Charge "Pro Series Marine Battery Charger", 12/24-Volt, 10-Amps 5/5, Double Output. It's only 5A per channel, but tied up to a dock this shouldn't matter, since your 'fridge, if it's like all the rest, draws about 4.8A, and likely at a 50% duty cycle. It only cost $100. This replace my 10 year old Xantrex TruCharge 20+, which bit the dust.
 

jviss

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Feb 5, 2004
3,935
Tartan 3800 Westport, MA
MaineSail makes excellent points. My solar charger has a low voltage disconnect load output, and the plan was to isolate my fridge breaker from the plus bus, and feed it with this. It's very true that a charger that restarts an absorption timer when the battery voltage dips below the float voltage is not very smart, indeed.
 

Bob S

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Sep 27, 2007
1,520
Beneteau 393 New Bedford, MA
The Blue Sea m-LVD is a good choice in a low voltage cut off. IMHO, as a marine electrician, every single boat owner who leaves DC loads on dockside should install a low voltage disconnect at a bare minimum
Maine,
I looked this up on the Blue Sea's site. Am I correct this is wired between the battery and the frig.

It's funny, this is the first season with my new to me boat and I have been leaving the frig on (nice to have a freezer). I went to the boat to replace a pump assembly in the head only to find my house bank at 31%. Either I forgot to turn on the circuit breaker or someone inadvertently shut it off. Not only did I replace the pump assembly but I installed the Sterling Battery charger I had that was part of my off season rewiring project.
 
Jan 23, 2020
2
Beneteau Oceanis 400 Brisbane
Mike,
No. The reason is that the fridge is DC powered. It NEEDS DC from the batteries. The power it uses is replaced by the charger. If the charger is not working, your batteries will go flat if the fridge is running. Until you have this ifgured out, turn the fridge off when you're not there. Want a cold brew when you get to the boat? Stop at a 7-11 on the way!

You really need to do some research on your charger based on John's link to the manual. You need to tell us what the voltage at the batteries is. What is the output voltage of the charger?

And follow all the cautions folks have been explaining. If the fuse on the charger blew, it is important to find out why, too.

I also suggest you get a boat electrical book and start reading. Charlie Wing's is excellent.

Good luck.
After reading all of these posts I have just ordered 2 Charlie Wing books! Thanks guys.
 
May 20, 2016
2,909
Catalina 36 MK1 94 Everett, WA
Maine,
I looked this up on the Blue Sea's site. Am I correct this is wired between the battery and the frig.

It's funny, this is the first season with my new to me boat and I have been leaving the frig on (nice to have a freezer). I went to the boat to replace a pump assembly in the head only to find my house bank at 31%. Either I forgot to turn on the circuit breaker or someone inadvertently shut it off. Not only did I replace the pump assembly but I installed the Sterling Battery charger I had that was part of my off season rewiring project.
Bob

I installed the BS LVD putting it between the Circuit Breaker and the fridge. I had two occurrences wher I lost shore power and came back to completely flat batteries. Not good for fridge or batteries. It’s fairly easy to install but lots lo wires to run. In addition to the disconnect you need to pickup a piezo alarm.
 
Jan 23, 2020
2
Beneteau Oceanis 400 Brisbane
Bob

I installed the BS LVD putting it between the Circuit Breaker and the fridge. I had two occurrences wher I lost shore power and came back to completely flat batteries. Not good for fridge or batteries. It’s fairly easy to install but lots lo wires to run. In addition to the disconnect you need to pickup a piezo alarm.
Wouldn't it be great if it could send a message to your phone if you leave the boat for a period of time!
 
Apr 5, 2009
1,076
Catalina '88 C30 tr/bs Oak Harbor, WA
With an LVD your batteries will be fine if the dock looses power but any perishable food in your fridge could be unsafe to use. I always keep a baggy of ice cubes in the freezer compartment. if they "change their shape" I know that the box has been warm.
 
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May 20, 2016
2,909
Catalina 36 MK1 94 Everett, WA
With an LVD your batteries will be fine if the dock looses power but any perishable food in your fridge could be unsafe to use. I always keep a baggy of ice cubes in the freezer compartment. if they "change their shape" I know that the box has been warm.
I have a dual thermometer with max and min to tell me about problems.
 
May 20, 2016
2,909
Catalina 36 MK1 94 Everett, WA
Even with the anemic 35A alternator or a 20A shore charger you can run the fridge and charge batteries. The fridge only takes ~3-5A when running and only runs part time.

I don’t know what you consider slow but my FLA’s can accept 60+ amps in bulk. AGM’s and newer battery chemistries will charge even faster.

In sailboats the majority of us have DC only fridges. AC/DC compressors are much harder to find.
 
Feb 26, 2004
21,003
Catalina 34 224 Maple Bay, BC, Canada
The battery charging system is only capable of slowly charging the system at a moderate level.
Even if the battery charging system is on 24/7, the fridge will out-pace that charging system because it uses more than can be replenished by the charging system.
Les responded more tactfully, and he's right.
Your post is wrong.
I know because I've had a battery monitor on my boat for almost 20 years.
Any charger in excess of the consumption of the fridge (which most of us have, anybody here with a 3 amp shorepower charger?????) will provide current to make up for the "use,", i.e., the fridge draw.
I see this on my coulomb counter all the time.
 
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