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.

BATTERY ANOMALY: Part Three: Additional Testing

After another day of charging I did some more tests of the suspect battery using the Centech Meter. This time the battery resistance reading had dropped to 9 milliohms. A big improvement from the 194 reading but,  still three times what I had measured back in 2012. In addition the meter said I only had 335 Cold Cranking Amps available from the battery. Manufacturing spec says it should be 1100. So even though after several charging attempts the battery is really not up to snuff and will need to be replaced.

I then decided to some quick tests of the other batteries in the string using the CenTech meter. Starting with the first (most positive battery in the string:

As the above photo shows this battery had 1404 Cold Cranking Amps available. So at least with this test seems good. Next I checked Battery Two:

   

As the readings above show the results are not as good as the first battery. In fact it only shows 884 Cold Cranking Amps available. Not as bad as the suspect battery but, under the spec of 1100 CCA.
Battery three was tested next:

This tested better than battery two but, not as good as battery one. At 1150 Cold Cranking Amps it was just over the battery specifications but, not by much.

After doing these tests and thinking about the age of the batteries I came to the conclusion that it would be better to change out all of the batteries in the 48 volt string. In addition after doing these test in the confines of the under the cockpit space I decided I would position the batteries differently to make access for future testing easier. The next question is do I go for Lithium Ion batteries or stick with the AGM's?

TO BE CONTINUED

BATTERY ANOMALY: Part Three: Additional Testing

After another day of charging I did some more tests of the suspect battery using the Centech Meter. This time the battery resistance reading had dropped to 9 milliohms. A big improvement from the 194 reading but,  still three times what I had measured back in 2012. In addition the meter said I only had 335 Cold Cranking Amps available from the battery. Manufacturing spec says it should be 1100. So even though after several charging attempts the battery is really not up to snuff and will need to be replaced.

I then decided to some quick tests of the other batteries in the string using the CenTech meter. Starting with the first (most positive battery in the string:

As the above photo shows this battery had 1404 Cold Cranking Amps available. So at least with this test seems good. Next I checked Battery Two:

   

As the readings above show the results are not as good as the first battery. In fact it only shows 884 Cold Cranking Amps available. Not as bad as the suspect battery but, under the spec of 1100 CCA.
Battery three was tested next:

This tested better than battery two but, not as good as battery one. At 1150 Cold Cranking Amps it was just over the battery specifications but, not by much.

After doing these tests and thinking about the age of the batteries I came to the conclusion that it would be better to change out all of the batteries in the 48 volt string. In addition after doing these test in the confines of the under the cockpit space I decided I would position the batteries differently to make access for future testing easier. The next question is do I go for Lithium Ion batteries or stick with the AGM's?

TO BE CONTINUED

BATTERY ANOMALY PART TWO: Readings and observations

 I looked to the cause of why Battery 4 of my 48 volt Electric Propulsion bank was not charging properly. Since the terminals for this battery can best be accessed by the starboard  locker hatch I first had to empty out the locker and then squeeze my large frame down into it.

Taking off the protective caps on the negative terminal I had quite a bit of corrosion on it.

 This was because I had become somewhat  complacent in checking and cleaning the terminals. Mostly because up to now the battery charging had been operating normally.  The failure of battery four just happened a few days ago. After cleaning the terminals I used an battery tester to check it:

The readings above show a voltage of 10.87 volts and an internal battery resistance reading of 196.2 milli ohms. Which is a much higher resistance reading than when I last checked it on February 12, 2012.Which was 2.43 milli ohms. So obviously something had changed in this battery.  I will try a few more attempts at charging but, I don't think things will approve much. TO BE CONTINUED.

BATTERY INVESTIGATION PART 8: LOAD TESTING

After charging up the battery bank and then disconnecting the batteries I let them rest over night. I came back on board the next day and measured each battery's voltage and did two tests on each battery  using the Centech Battery Analyzer  and a 100 Amp Battery Load Tester.

Here's a quick video showing how to use the Centech Analyzer:




Here is the data I got from the Centech battery analyzer testing

                                      VOLTS   mOHM  CCA     BAT CAPACITY

BATTERY 1                   12.94      2.39      1235          100%

BATTERY 2                   12.45      2.33      1265          100%

BATTERY 3                   12.92      2.35      1241          100%

BATTERY 4 (suspect)   12.92      2.48      1179          100%

All batteries have passed the test from the analyzer. Though battery 4 (the lowest battery in the string) is certainly has a slightly diminished CCA (Cold Cranking Amps) reading compared to some of the others. But, it still passed the tests. The parasitic load from the Paktrakr that was on this battery for four years seems to have weakened it a little. It also has a slightly higher milliohm resistance reading compared to the other batteries not much more though. This might be due to some sulfation internal to the battery because of the parasitic load.

I followed the Centech battery analyzer test with the  100 Amp Battery Load Tester. All batteries passed that load test too:

Obviously, I will be keeping an eye on battery four which when I started this investigation would not even complete a charge on two separate battery chargers. After those results some might have just thrown the battery away and replaced it. But, as you can see it did manage to redeem it's self over time once the parasitic drain was removed. Why all of a sudden did I have this problem after four years? The only thing different this year is that I did not have my 48 volt Air X wind turbine also providing additional charging over the winter layup. This made the solar panels the only charging source and it may have not been enough considering the constant parascitic load on the fourth battery. I also added an additional device to monitor the charging of the battery bank. This additional load may have been enough to add additional sulfation to the suspect battery. So the lesson learned for this electric sailor is to keep parasitic loads off any one battery in the string. Another good thing from this investigation is I now have data to see how each individual battery the 48 volt propulsion bank ages from here on.

BATTERY INVESTIGATION PART FOUR: USING THE CENTECH BATTERY ANALYZER

So another unseasonably warm winters day has me back on board looking at the fourth battery in the electric propulsion system. I bought with me again the Centech Battery Analyzer.  It's really easy to use but, in the previous test I did not have the cold cranking amp spec for the 8A4D battery entered into the Centech tester. So I decide to redo the test since it's pretty easy to do. Here is the video:



As you can seen the results are pretty much the same that I experienced earlier which I noted in a previous post. The battery tested OK. I also bought along a load tester and hooked it up to the battery. It also confirmed that they battery had over 1100 cold cranking amps available.  I then hooked up an external 15 amp charger to the suspect battery and it too like the Dual Pro charger said the battery was bad and failed to charge it completely.  So it's a dilemma to me how bad the battery really is and what to believe as far as testing vs chargers. I am suspecting that having the Paktrakr battery monitor connected over the winter has sulfated the battery a bit. Then adding the optional data collecting cable added an additional load which sulfated it more. Enough so that it has a problem charging. In attempting to measure the additional current load with my digital volt meter I accidentally blew the internal fuse on it. So I'm not exactly sure how much the data cable additional draw is. So for now I have disconnected the Paktrakr from the battery and have the solar panels charging the the bank. I will see how things look the next time. I have an idea on how I may remove the sulfated material off the battery grids but, I will need to rearrange some of the battery cables and need to order some 2 AWG crimp connectors to make some jumper cables first.

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