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.

CHOICES: Batteries

I was looking around for some specs for battery terminal torque specs and came upon this chart at the MK Battery site:

I'm about to start my seventh season with the four 8A4D AGM batteries that make up my 48 volt electric propulsion bank. Somehow I instinctively used them in a way that should provide over a thousand life cycle charges.  I typically revert to Hybrid mode using the Honda 2000i generator once the battery bank has dropped to 70 to 80% from 100% full charge.  Turns out that looks like a good point to have a good charge life cycle for the bank.  So far so god. I still think I made the right decision in going with AGM batteries over the Lithium Ion batteries that were still fairly new back in 2008 when I did the conversion. The cost and availability were factors I considered. Today I think I would still go with the AGM's as they seem to be holding up well. I'll do some more in depth battery testing in a few weeks to see how well.    The following video is and example of my modus operandi using electric propulsion and when I operate in hybrid mode on an unusually windless day heading down the Hudson River:

GOING ELECTRIC PART 16: BATTERY SNAFU

Well, I am finally seeing light at the end of the tunnel. Good thing too. As I have just three weeks to finish the electrification project, launch, check things out and head off on the two hundred mile cruise to Newport in early July. Now that I have seen how the layout for the batteries will work it's time to order the batteries. I choose MK 8A4D batteries for their capacity and size. After doing some online searches I found a reasonable source with free shipping. I placed my order and was told I would have my batteries in few days. Everything is looking good.
On the day the batteries arrived my heart sank. I looked a the pallet of batteries being off loaded off of the truck and was surprised at how big they looked compared to my cardboard models. A quick look at the truck driver manifest invoice showed the problem. The batteries being delivered were 8A8D AGM batteries not the 8A4D AGM batteries I expected. I asked the truck driver if he could take them back he said no that had to be arraigned separately. So I took the delivery which also contained two new 12 volt Gel batteries for the house bank which were the correct size.
When I looked at the confirmation invoice sent by the battery seller it did indeed show that the order was for four 8A8D batteries. Even though I must looked at this invoice at least three times I did not pick up on the error.
I tried to see if it might be possible to fit the larger 8A8D batteries in the same space. It might have worked but, would have been tight and since they were 30 lbs heavier each would have been harder for me to handle by myself. Not to mention adding another 120 pounds of weight to the boat.
So after ultimately realizing it was my mistake for not picking the error up sooner I arranged for the proper batteries to be sent. It would take another week for the right batteries to be delivered and would ultimately cost me another $220 to send the first batteries back. An expensive mistake to be sure.

MIKE'S GOING ELECTRIC TIP: Make really sure the batteries you want are the batteries you are going to get. Double and triple check all your invoices very carefully before hundreds of pounds of batteries are dropped on your doorstep.

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