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.

HARBOR TEST 2015

A few weeks ago I did another of the annual harbor tests I have been doing on BIANKA's electric propulsion system. Here is a graph of the results:

Results are similar to least years tests with no real significant differences. Here is a graph of this years data compared with the 2014 test:

Some of the other data comparisons of the tests:

 The % battery at the end of the test was 89.7% compared to 90.6% last year.

The Amp Hours used for the test was 16.5 compared to 15.2 for the 2014 test.

NOTE: Some of the increase may be due to the distance traveled for the the test. This year the distance traveled for the test was 2.2 nm while in 2014 it was 1.8 nm. The difference might be explained by the location of the buoys which are removed and replaced each year in the harbor.

The tests show that the Thoosa electric propulsion system is still preforming well. It has been eight years after I installed it.  Along with  the reduction in maintenance and cost savings it continues to reinforce the notion  that it was a good decision to convert to electric propulsion back in 2007.


PREVIOUS HARBOR TESTS
2013
2014

HOT FUN IN THE SUMMER TIME: EMERGENCY FLARES

Looking through my emergency signalling canister this spring I found four handheld Handheld Signal Flares. Since it was the Fourth of July I thought it might be a good time to dispose of them by lighting them off on the shore. Seems to me learning and lighting about emergency signal flares is best tried with out being under an emergency situation. So soon after sunset I took the dingy to shore along with a large metal can that I would use to hold the flares after I set them off. It was an eye opening experience. While these flares are meant to be handheld the flame is extremely hot. They can also sputter dropping hot flaming particles about. How hot are these flares? Hot enough to melt through the metal can that I put them in:

That's pretty hot! If a handheld emergency flare can melt the metal can. Imagine what it will do to a fiberglass deck or the pontoon of an inflatable!
LESSON LEARNED: If you need to light an emergency handheld flare make sure you hold it far enough over the side so that it won't cause a fire on deck or damage your life raft.

BOTTOMS UP!

It's getting busier in the boatyard and roomier too as the boats begin to get launched. The smell of bottom paint starts filling the air. My boatyard's contract has a stipulation that only they can paint the bottom which as I get older seems like a better idea anyway. Though when thinking about bottom painting I get reminded of something I saw in Oyster Bay last fall. It was the test station for one of the manufacturers of marine bottom paints:

ELECTRIC PROPULSION HARBOR TEST 2014

I'm a little behind in posting blog  posts after being a month away from the boat working. I hope to be posting more frequently and catching up on things now that I'm back on board.  Here are the results of the 2014 harbor test of my Thoosa 9000 electric propulsion system. I did the test earlier in the season soon after launch showing the speed vs power required to move my 30 foot 16,000 lb sailboat using electric propulsion:

NOTE: Speed is in knots

Below is the 2014 test data compared with the 2013 test at the 10 to 50 amp throttle settings:

Note: To see the averaged power settings for the 2013 tests click here. The graphs show very little change in performance in me electric propulsion system from last year.

HARBOR TEST 2013 Part Two: Watts Up With The Data!

Someone expressed an interest in what the battery voltage was doing during the 2013 harbor tests so here is the raw data and the averaged results that were shown in the plotted results in the previous post.

HARBOR TEST WITHOUT MAST 6/18/13

TIME START 9:32
TIME FINISH 10:05

BATTERY VOLTAGE START 52.45
BATTERY VOLTAGE END   50.55

% FINISH 90.8%
AH FINISHED-14.7 AH
                                                          AVERAGED WATTS AND SPEED
AMPS VOLTS SPEED AMPS WATTS AVG    SPEED AVG
10E         49.75        2.0                      10                 497.5                  2.35
10W       49.75 2.7                       20                 977.0                3.35
20E   48.8         3.0                       30                1459.5                3.95
20W       48.9          3.7                       40                1937.0               4.40
30E        48.65 3.7                       50                2407.5               4.75
30W       48.65 4.2
40E        48.45 4.1
40W       48.40 4.7
50E        48.15 4.5
50W       48.15 5.0


HARBOR TEST WITH MAST 6/20/13

TIME START 8.28
TIME END   9:01

BATTERY VOLTAGE START 56.40
BATTERY VOLTAGE END   50.10

BATTERY % FINISH 90.4%
AH FINISHED -15.4%
                                                           AVERAGED WATTS AND SPEED
AMPS  VOLTS SPEED AMPS WATTS AVG     SPEED AVG
10E       49.40            2.2                    10              495                      2.00
10W      49.60            2.3                    20              985                      3.30
20E       49.25            3.4                    30            1467                      3.90
20W      49.25            3.2                    40            1936                     4.30
30E       48.95            4.0                    50            2396                     4.55
30W      48.85            3.8
40E       48.45            4.3
40W      48.35            4.3
50E       48.00             4.5
50W      47.85            4.6

NOTES OF AN ELECTRIC SAILOR: Harbor Test 2013 Part One

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Back in early June I had just splashed BIANKA but, had to wait for the boatyard to step the mast. Since I had nothing else pressing on board I thought I would take the opportunity to do some testing of the electric propulsion system both without and with the mast installed. So that's what I did. I made several runs between two buoys in the harbor that were 450 yards apart. I did a similar test back in the fall of 2011. Though I conducted these tests with a cleaner bottom since the boat had recently been splashed.

The mast on my 30 foot Nonsuch weighs about 300 lbs which is pretty heavy compared to a lot of other boats the same size. So I was curious to see what effect the mast weight might have on the boats performance. Like the test I did in 2011 I made two passes between the buoys. One going east and then turning around and making another pass going west. They were made at various current draws from the 48 volt battery bank of 10, 20, 30, 40 and 50 amps. The two passes were averaged to take into account any tidal current pluses and minus to the speed.
Here is the graph comparing the speed both with and without the mast on board:

As you can see there is a slight difference at the low end and upper end of the speed data. But, only about a  quarter of a knot or so. The sweet spot seems to be right around 3 to 4 knot range where both graphs are pretty close. Out of curosity I took the data from the Harbor Test of fall 2011 and added it to the above graph's data:

What's interesting to note is that the 2011 test data was taken at the end of the season just before I pulled the boat for the winter. The hull and prop had not been cleaned for probably a month or more:

So that growth seemed to have had some effect on that test data. 

CHECKING THE MAST LIGHTS

I pull the mast on BIANKA every year. I do this because having the mast up while the boat is on land puts stresses on the boat that are not as large when it is in the water because the hull does not move as on a mooring. It also allows me to have easy access to the chain locker and the windlass motor. It also allows me to inspect the mast and checkout the wiring and lights since the mast is on ground level.  I've mentioned how much I like to use Anderson Powerpole Connectors on board for connections. It also allows me to make various  adapters that help in testing various items around the boat.

 Using a small 12 battery and adapters made using Anderson Powerpole Connectors  and matching connectors for the mast fittings makes checking the mast light wiring an easy task.

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.

PREVIOUS BATTERY INVESTIGATION POST

NEXT BATTERY INVESTIGATION POST

BATTERY INVESTIGATION PART THREE: Overnight Charge & Battery Analyzer Test

So a few days later I came back on board to see what was going on with the problem battery in the 48 volt string. Here is a video of what happens when I plug in the Dual Pro Quad charger. It first goes through a quick self test then measures the battery voltage and checks the charge and then displays the results on an LED bar on front of the charger for each battery in the string:




I decided to leave the charger on overnight and see if that last battery bank would come up to a full charge. Below is a video of what I saw when I came back on board the next day:




Battery 1 (most negative battery in the string) definitely still has a problem. At the suggestion a fellow named Arby over on the electric boats group I bought a Centech battery-analyzer. It seemed like a good idea to buy one. This device measures the voltage, internal resistance of the battery and the capacity including the Cold Cranking Amps. I tested the suspect battery and the next one up in the string and also the highest (most positive) battery in the 48 volt string. Here are the results:

                                                VOLTS  mOHMS  CC AMPS

BATTERY 1 (SUSPECT)       13.03     2.34         1273

BATTERY 2                           13.62    2.42          1437

BATTERY 4*                         14.45    2.43          1724

* Reading taken soon after shutting down charger which may explain the higher numbers in volt & CCA readings. Also note I did not take any readings off of battery 3 for this test. 

The voltage of the suspect battery 1 is a little low but, not overly so. The internal resistance seems OK compared to the other two batteries in the string tested. The Cold Cranking Amps available is certainly lower but, it's not a completely dead battery. I've once again disconnected the Paktrakr as this problem did not show up until I added the optional data recording cable to it. I'm sure it added an additional load to the battery beyond the Paktrakr's 25 milliamps but, I doubt it was that great. Still I'm trying to eliminate what might have caused the sudden change in this battery. Next warm day I'll be doing a load test on the suspect battery.

                                        

TO BE CONTINUED

NOTES OF AN ELECTRIC SAILOR: Tests from the harbor 2011

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When I started this blog back in 2006 I thought it might just be a little online scrap book of travels with some photos. An easy place to put those memories and share it with anyone who happened by. It has since morphed into something a little bigger. In between my thoughts, photos, cruises and travels I also post things about products here and there. Those that work and those that don't work for me. I also use the blog as the name implies as somewhat of a log book of maintenance and boat projects on board BIANKA. This is one of those posts.

I had wanted to do some propulsion tests of BIANKA's electric propulsion system as soon as I splashed her for the 2011 season. But, that did not happen. But one morning a few weeks later I was having my usual 6 AM coffee in the cockpit. The air was still in the harbor, the water like glass and it was quiet and empty of any boat traffic. I thought well why not do some testing. Even though it would was not perfect conditions. It was midway to low tide so there would be some currents running and they do run oddly in this harbor. Probably would have been better to do it at the peak of the high or at low tide when currents would have been minimal. The boat had also been on the mooring for two weeks so I did not know how clean the bottom and prop were which could affect things somewhat. Anyway, I turned on the system slipped the mooring and headed out to the channel.  I made several passes between channel markers that were about 450 yards apart. One pass was made in each direction drawing 10, 20, 30, 40 and 50 amps from the battery bank.  I then averaged the speed of each pass and calculated the watts used. Here are the results:

PASS #      AMPS   KNOTS   WATTS

1                  10            1.9           495

2                  20           2.8            984

3                  30           3.3          1458

4                  40           3.7          1933

5                  50           4.1          2417

Again these are the average of the two passes. One against and one with the current. I also did one additional test where I just throttled up to 5 knots and the power used there was 4346 watts. The test data pretty much confirms what I have noticed on board. Especially on pass number two. I can move my 8 ton 30 foot sailboat at about three knots just using power from my Honda 2000 eu generator and the Zivan NG-1 battery charger which is rated at 900 watts. The numbers show I could add an additional 48 volt 500 watt power supply into the mix.  I should then obtain the results of pass number three and still be within the power limits of the Honda 2000 generator. Which is good to know if I ever feel the need to add one. But, since BIANKA is a primarily a sailboat I have never felt the need for it.  I'm also using the same three bladed prop that BIANKA used with the diesel. It has a few dings here and there. I might be able to improve things a bit with a prop optimized for my electric propulsion system. But, I tend to be if it ain't broke don't fix it type of sailor. Anyway I'll try and do another test at the beginning of next season and see how they compare. Also it is good to have this data to compare if I do decide at some point to change the prop at some point. But, I'm very happy with things the way they are and have been for the past four years. So I really don't expect to be making any changes soon.

BLOG UPDATE:  After doing this test I pulled the boat for the season. I found the prop was not as pristine as it could have been as this photo shows just after the boat was pulled:

Usually I would have dived and cleaned it but, it being late in the season the water was too cold. I expect to have even better results in the spring doing the tests with a much cleaner prop.
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WINTERIZING AND TESTING THE ANTIFREEZE ON BOARD

I've mentioned one of the nice things about converting BIANKA to electric propulsion is those recurring pleasant reminders of cost savings of going electric. This shows up most dramatically at the end of the season when it comes time to winterize the boat. Not having to change oil, filters and buy gallons of antifreeze to winterize the engine certainly something that I do not miss doing nor does my wallet. The only thing I really need to do is winterize the fresh water system and as I pointed out in this post on winterizing BIANKA I only need to use a small amount of propylene glycol antifreeze to do that. Though if you still have a diesel to winterize you might want to take a look at Maine Sails sage advice on that issue. I'm only dealing with the on board water system here.

While I have not had a problem with winterizing using this method I did have an online discussions with some other sailors about checking to make sure that the after winterizing that the antifreeze was not diluted to the point of being ineffective at the temperatures in my location. Not a bad idea I thought. Some use chemically treated slips of paper that change color to match the level of protection the antifreeze solution is providing. Others use the floating ball gauges and others use an optical hand refractometer.

So I began researching the testing methods. The antifreeze test strips were reasonably cheap around ten bucks for 50 strips. But, then I read they were only reliable for about two years. This might make sense for a boatyard that winterizes a lot of boats but, not for me. They could also give erroneous readings if contaminated. The next device was the floating ball antifreeze testers. Reasonable in price perhaps only ballpark in accuracy.

The third option was the hand refractometer. The most accurate in my opinion but, also the most expensive. In my initial research I saw prices of $120 to $220. Way to expensive to make sense for my wallet.
 But, found other antifreeze refractometers for around fifty bucks. Now that's more like it. Even better it has scales for propylene glycol, ethylene glycol and one for checking the charge on flooded lead acid batteries. That's a win, win, win situation in my book so I bought it.

The above photo shows the unit I bought. It comes with two eyedroppers. The one shown here has the blue tape around it to remind me that I only use it to sample distilled water. The little black cap covers the alignment screw should one need to realign the gauge. It also includes the screwdriver in the case. The photo below shows the plastic cover in the open position.

To use this device you open the cover and put a a drop or two of the solution you are testing onto the blueish glass and close the plastic cover to spread the solution onto the glass. You then hold the refractometer up to a lighted area and take a reading by looking into the eyepiece. Here is what you see when you look into the refractometer with no liquid on the glass.
You have a completely blue field. You can see the three different scales for the propylene glycol antifreeze, battery fluid and ethylene glycol antifreeze. When you open the unit up and drop a few drops of distilled water onto the reading glass this is similar to what you will see when you do a reading:


Notice how it is clear at around 32 degrees F scale. This is how you check the alignment of the device. Note: The photo shows a slightly lower freezing point which may be due to some slight contamination from an earlier test. Cleaning the glass or adjust the alignment screw would correct his offset. But you get the idea. Next the cover was opened the glass cleaned and dried and a drop or two of propylene glycol antifreeze taken from BIANKA's winterized water system was analyzed as shown below:

This shows a freezing point of about 15 degrees Fahrenheit on the propelyne gycol scale. Only 3 degrees "warmer" than the pure antifreeze used to winterize the system. The bursting point for pvc piping according to the manufacturer of the antifreeze should be about - 7 degrees Fahrenheit. Which is "comfortably" below the normal lowest winter temperatures in my area. As they say your mileage may vary or location temperatures may be different. But, using a refractometer to test the antifreeze used to winterize the on board water system will give you peace of mind as you wait for spring to return. Just remember:

"How sad would be November if we had no knowledge of the spring!"- Edwin Way Teale