MORE BATTERY ISSUES: The 12 volt House bank

After installing and testing of the new 8A4D battery for the electric propulsion bank I noticed the 12 volt house bank was experiencing some issues too. What tipped me off was the Morningstar Solar controller was cutting off voltage to it's output lugs. I had wired my Engel refrigerators, AIS, and Fan to this output. The controller cuts the output when the battery voltage drops below 11.4 volts. It looks like one or both of the 8G27 Gel Cell batteries BIANKA uses for the house 12 volts had reached the end of their useful life.   As I opened the compartment that held the batteries I could feel some heat rising from the space.

I took out my infrared temperature probe and took some measurements. One of the batteries measured 141 degrees fahrenheit.

 Way too warm for comfort. The temperature of the second battery had a much better reading of 107 degrees fahrenheit. Much cooler but, still warmer than normal.

Since both of these house batteries are operated in parallel it said to me that the hotter battery was the major problem. As the cooler battery was trying to continually charge the defective warmer battery. I turned the battery switch from "BOTH" to the individual settings and took some voltage readings. The warm battery was around 10.5 volts and the other was over 12 volts. So one battery was truly defective but, I replaced both since ten years providing the house 12 volts was a good run and best practice is to have both batteries the same age when installing them.

After I installed the new 8G27 batteries I used the Centech Battery analyzer  to get a baseline reading of each.

They appear to be pretty closely matched though their cold cranking amps was slightly lower than the  spec but, I am not too concerned. I will recheck them after they have been in operation for a bit. All in all I can not complain about these MK 8G27 Gel batteries.  They were installed when I converted BIANKA to Electric Propulsion in 2008. So ten years was a god run. I hope the new ones last as long.

TESTING AN ELECTRIC PROPULSION BATTERY BANK

It came time to test the batteries of BIANKA’s electric propulsion bank to make sure  
the suspect battery 1 was indeed bad and the others we're still good. To test the
batteries I first needed to empty out the locker so I could squeeze myself down into
the space.

Once that was done I gathered my tools and tester hoping I didn't forget anything
because working down below is a tight space for big guy like me and getting out of it
is much harder than going into it.
So I try to minimize going in and out of the space. The nice thing about down below
since I took out the diesel and put in electric propulsion is my clothes will remain pretty
clean and I won'tsmell of diesel and oil.

I use the Centech Battery Analyzer tester for quick checks on the batteries.
It tests the internal resistance of the battery and also the cold cranking amps
available.  It's not a load tester but can give you a quick look at the condition of
the battery. I'm particularly interested in battery 1 which seemed to have very
limited capacity when I used it last season.
Time to head down below and begin the testing:

As I suspected battery number one had tested numbers were way out of line
compared to the other three batteries in a 48 volt string.

While the voltage reading  on the battery Look good at 13.11 volts.  The internal
resistance of the battery was very high reading 35.8 milliohms.

Compared this to the next battery in the string which had an internal resistance
of 1.95 milliohms.
Also note at the top of the display screen. The one above has only one pixel
and says NG. While the one picture below pixels all the way across and says
good.

This confirmed my suspicion that there was definitely something wrong with
battery 1. Likewise batteries 3 and 4 had similar internal resistance specs to
those of battery 2 with regards to the internal resistance of the batteries.

Moving on to the  cold cranking amp tests  once again showed that battery
one was a indeed defective. The tester showed that there were only 85 cold
cranking amps available.

The  spec for the 8A4D battery is 1100 cold cranking amps. Tests of the
other three batteries showed  they were all over the 1100 spec for cold
cranking amps.

I tabulated the results and  and entered them into BIANKA’s logbook.

Now I also have a data on the three good batteries and can keep an eye
on them as they age. Only thing left to do is order a new 8A4D battery to
replace the defective battery 1.

WHEN SHIP HAPPENS

I have one critical item on my Spring Outfitting list before bottom painting and  launching BIANKA for

the season. It is to replace one of the four batteries in the 48 volt electric propulsion  
battery bank. Even though the batteries are only two years old it looks like one of them
failed and needs to be replaced due to an error in judgment on my part but, caused by
the freight company that did not secure the batteries in shipping. Herein lies the cautionary
tale for others to not make the same mistake I made.  I converted Bianka to Electric
propulsion in 2008. At that time I installed four 8A4D batteries in series to make up the
48 volt propulsion Bank. They did quite well and lasted for eight years. In year eight one
of them showed signs of failure.

Since it is good practice to try and keep all the batteries used in the same bank the same age. I decided to replace all of the batteries instead of the one that was beginning to fail.  The Battery was drop shipped from a warehouse in Florida and took a week to make it up to Long Island. The four batteries were supposed to be delivered to my house.  However I got a call from the shipping company that I needed to come by and pick them up at the warehouse. I thought this was a little strange but I was too excited and wanted to have the batteries installed on board as soon as possible.   So I made no complaint. I drove to the warehouse on a hot summer day to pick up the four batteries. A couple of the warehouse workers were acting a little strange as I asked about my order and they seemed to take their time bringing out the  batteries with the forklift.

There were a few things I noticed that seem strange but I did not question them at the time.
 First was the batteries were not secured to the pallet, the plastic they were wrapped in was
ripped off of them and the cardboard that covered them  was kind of ripped up too. I lifted up
the cardboard from two of the batteries they seemed okay so I accepted the order and and
I had the workers load the batteries into my car.

It was only after I drove to the boatyard to install the batteries on the boat that I discovered
to my horror that two of the batteries were physically damaged. Unfortunately, these were
the two that I didn't look at at the warehouse. Their lugs were bent over like they had been
dropped on them.

The other two batteries looked physically okay.  Here is where I made my error. I called the company where I bought the batteries and told them of the damage to the batteries and I
would need two replacements. I should have rejected the entire shipment because even
though the other two did not look physically damaged one of them was damaged internally
which I discovered while on one of my cruises last year. It’s voltage would start dropping
rapidly when under a heavy current draw compared to the other three batteries in the bank.
Which is why I plan on replacing it this year. But, just to make sure the suspected bad battery is indeed bad. I’ll do a quick check of all the batteries to confirm my suspicions.