Wednesday, October 05, 2016

I Screw Up

Charlotte Harbor Boat Storage, Placida FL

Long term readers of this blog know that I screw up often, and that I usually confess my mistakes on this blog.  This is yet another case.

I learned in the past that if I shut down the refrigeration system, that the R134A coolant leaks out and air leaks in.  If it stays cold, no leaks.  I think it was 6-7 years ago the last time I let it get warm and the last time I needed to add coolant.

So what about the summer?  In 2013, I left the solar panels in place and the refrigeration system turned on at normal temperatures for the whole summer as we tourned the USA by car.  It worked fine.  When we returned to Tarwathie in the fall, there was ice in the freezer and all was well.

I did the same this year, but the outcome was bad.  One of the wires from the panel connections was pulled loose, cutting solar capacity 50%.  The fridge plate was cool, but not cold.  Worse, the batteries were totally sulphated, and useless.

We had the boat yard put straps on Tarwathie while we were away.  The straps attached to augers in the ground to prevent tip over in case of hurricane.  It is possible that one of the techs tripped on the solar panel wire when working on the straps.   The water level in the battery cells was full.  That indicates that the problem happened very soon after we left Tarwathie last spring.

My mistake, risking $250 worth of batteries to avoid a $150 charge to have a tehnician suck the air out and put new R134A in.  Because it went wrong, I risked $150 plus $250 expenses. :-(  Bad strategy.

But I repaired the panel wires, and then set my smart charge controller to do an "equalize charge".   The batteries seem much better today.  I'm going to equalize a second time.  If I'm lucky, the batteries can be rescued 100%.


In case you don't know, sulphation is a condition that happens to lead-acid batteries when they sit long times with a low percent charge.  It can happen to flooded, sealed gel cell, or AGM batteries.

The symptom of sulphation is that the battery acts like there was a large resistance in series.  When drawing a load current, the voltage sinks to overly low values.  The other day, with the fridge drawing 4 amps, the voltage was 11.6 volts.   But when charging, the voltage goes to high values, even 14 V long before the battery is charged.

The cure for sulphation is the so-called equaliztion charge (I prefer to call it the desulphating charge).  For me, that means charging up to 15.2V for one hour.  I'll recheck the water levels afterward.  With gel or AGM batteries, one has to be very careful with equalizing charges because of the risk of overpressure.

Hurricane News, I don't expect much effect way over here, but:
One very ugly forecast scenario is for Hurricane Mathew to make a circle out in the Atlantic and return to Florida after a week with a direct hit on Miami and the Keys.  OH NO!
Also, the marine forecast from Jupiter Fl for Thurs:
IN THE GULF STREAM...BECOMING NORTH NORTHWEST 80 TO 100 KNOTS WITH
GUSTS TO AROUND 120 KNOTS...SEAS 9 TO 11 FEET WITH OCCASIONAL SEAS TO 14 FEET BUILDING TO OVER 20 FEET WITH OCCASIONAL SEAS TO 31 FEET. DOMINANT PERIOD 8 SECONDS.
I sure hope that nobody is out there in the Gulf Stream that day.   Remember that North winds are in the direction opposite the Gulf Stream.  That causes highly dangerous "square" waves.

1 comment:

  1. Ouch. Unfortunately that air getting in also has moisture which can cause it's own problems. I would have done the same thing and left it running. Maybe you'll get lucky and cheaply find and repair your leak.

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