Sudden change in shore power use

RussRuss

My shore power use is by the kWhr, read with a meter at each boat.  I have always been below the minimum charge ($15 a month).  For July I got a bill for $130!!! Double checked the meter and the reading is correct.  Any idea of what could cause the sudden surge - I used the boat even less in July due to some travel. I checked what I could and everything seems normal:  heater off, ac working fine (only use when on boat), water heater off, I felt shore power cord connections and they are not hot or anything.  They are having an electrician check the meter and hookup, but I am nervous that if I really used that power it went somewhere as heat or into the water eating my drive.  Anyone have any ideas?  Thanks. 

Stodge

I have 2 fridges, one is DC only (from the factory).  Last boat only had a DC powered fridge.  If it's iced up or otherwise working harder than normal it might put added load on the battery charger to keep up.

I've also heard Mercathod units can be power pigs.  Perhaps it's having an issue that is making it work harder than normal.

Happy hunting.  Curious to hear the cause.

RussRuss

I do have some frost in the freezer section, if that is what you mean (broke my plastic door opening it :-(   

Interesting about the battery charger.  I felt it and it was warm, almost hot on top. Is that normal for a charger?  Mercathode is also a good one to check out.  I have a Fluke ammeter I am taking to the boat tonight to snoop around.

Thanks for the comments

Black_Diamond

Check your batteries that they are not low on water or are hot (impending failure..explosion).  Also check the voltage at them.  Chargers do get warm as they convert 120VAC to 12VDC, but the power has to go somewhere..like the batteries.

The Mercathode does consume power and it would up current usage if stray electrical current was in the water, but it can only put out so much too based on the model installed..I would doubt $100 worth though.

A little frost is normal in the freezer/frig, but if it got 'stuck' running that would be a cause.  More ice = harder working as noted.

RussRuss

Batteries looked good, added a little water while I was in there.  I checked around the DC circuits with an ammeter and nothing exciting.  Mercathode power cord read 0, but the ammeter only reads to the nearest amp.  Too hard to check any AC without pulling things apart to isolate each leg.

The power consumption numbers per day appear back to normal too.  

Does anyone have a feel for how much power a bad shore power cord connection could use?  My cord is about 10 years old, and seems a little shakey.  But it is not hot and there is no evidence of melting or anything.  I am wondering if it pulled and sat with a bad connection for a while.

I feel like I am chasing a ghost - but the $130 electric bill is real! 

Black_Diamond

Even with a bad connection, the power has to go somewhere. Maybe someone borrowed your connection. lol

wm61356

Unless you can identify something external to your boat that would cause a major increase in electricity usage (like hot weather that caused your A/C and fridge to run a lot more) I would challenge the meter reading with the marina. Either they have been under-estimating the usage all season and finally took an actual meter reading and charged you for the difference between their previous low estimates of the past months, and your actual usage, or, the meter reading is flawed. Regardless, I can't imagine anything that would spike the electricity usage that much in one month other than high consumption devices like the A/C system, Hot water heaters, stoves, Ice Makers, and fridges.

Cableguy Greg

My guess would be the A/C was left on and working overtime.

mvn

Here's an idea if this ever happens again....

If you are somewhat technically inclined, electrically speaking, put in a permanent ammeter on the AC side and log the data using a cheap data logger.  Collect some data and make your own consumption graphs.

There are also plenty of portable current data loggers available as well.  Here's an example.....

http://www.omega.com/pptst/OM-PL.html

 

Mark

RussRuss

MYSTERY SOLVED.  There is a third outlet on the dock power box that is apparently tied to my meter.  I have never connected to it, or seen anyone connected to it, but my neighbor was using it sometimes and he keeps his air on 24/7.  Nothing mischievous - he is a good dude (with lots of $) and just didn't know.

Michael T

Yeah. MT