3.02.2008

Battered by Batteries












We have been having some issues with our batteries lately and we determined that it was time to replace them. We were adding up to one and one half gallons of distilled water every two or three weeks. The batteries dedicated to the radar were consuming even more and we hardly ever used them. It was obvious that they were on the last leg. For those of you that have been following the blog from the beginning, you will remember the instance with the malfunction of the voltage regulator within the first few days after leaving Fernandina Beach. It appears that the loose ground wire on the regulator caused the engine alternator to over charge the batteries and shorten their life. The batteries we were replacing were 6 volt golf cart batteries hooked in series to create 12 volts. We had six of these for a total of three battery banks. One of the banks was dedicated to the radar system.

We spoke with other long distance cruisers and did some research and made the decision to replace the old batteries with Absorbed Glass Mat Batteries (AGM). Here is a brief AGM 101 primer gleaned from this web site. http://www.wind-sun.com/Batteries/Battery_FAQ.htm


A newer type of sealed battery uses "Absorbed Glass Mats", or AGM between the plates. This is a very fine fiber Boron-Silicate glass mat. These type of batteries have all the advantages of gelled, but can take much more abuse. We sell the Concorde (and Lifeline, made by Concorde) AGM batteries. These are also called "starved electrolyte", as the mat is about 95% saturated rather than fully soaked. That also means that they will not leak acid even if broken.


AGM batteries have several advantages over both gelled and flooded, at about the same cost as gelled:


Since all the electrolyte (acid) is contained in the glass mats, they cannot spill, even if broken. This also means that since they are non-hazardous, the shipping costs are lower. In addition, since there is no liquid to freeze and expand, they are practically immune from freezing damage.


Nearly all AGM batteries are "recombinant" - what that means is that the Oxygen and Hydrogen recombine INSIDE the battery. These use gas phase transfer of oxygen to the negative plates to recombine them back into water while charging and prevent the loss of water through electrolysis. The recombining is typically 99+% efficient, so almost no water is lost.


The charging voltages are about the same as for any standard battery - no need for any special adjustments or problems with incompatible chargers or charge controls. And, since the internal resistance is extremely low, there is almost no heating of the battery even under heavy charge and discharge currents. The Concorde batteries have no charge or discharge current limits for all practical purposes - you would exceed the wire amperage capacity long before you reach the danger point. Note that we do not recommend "super charging" them, but it can be done if you really need to.


AGM's have a very low self-discharge - from 1% to 3% per month is usual. This means that they can sit in storage for much longer periods without charging than standard batteries. The Concorde batteries can be almost fully recharged (95% or better) even after 30 days of being totally discharged.

AGM's do not have any liquid to spill, and even under severe overcharge conditions hydrogen emission is far below the 4% max specified for aircraft and enclosed spaces. The plates in

AGM's are tightly packed and rigidly mounted, and will withstand shock and vibration better than any standard battery.


Even with all the advantages listed above, there is still a place for the standard flooded deep cycle battery. AGM's will cost 2 to 3 times as much as flooded batteries of the same capacity. In many installations, where the batteries are set in an area where you don't have to worry about fumes or leakage, a standard or industrial deep cycle is a better economic choice. AGM batteries main advantages are no maintenance, completely sealed against fumes, Hydrogen, or leakage, non-spilling even if they are broken, and can survive most freezes. Not everyone needs these features.
OK, so now you have an idea of the type of battery that we installed. While cruising we plan to spend a almost 100% of our time at anchor or under way. We will not have access to 110 volt shore power for the battery charger. We will have three other methods of charging the batteries. 1. We can run the engine and charge them with the alternator. 2. We will have a wind generator. 3. we will also have solar. We do not want to run the engine just to charge the batteries so we will rely on the wind and solar for 100% of our energy requirements.

Now about the installation. I had to build a rather crude but effective scaffolding system around the engine to protect the engine from the weight of the batteries and to aide with ease of removal and installation. It took about one day to build an effective scaffolding system and prep the batteries for removal. The second day I removed the batteries and began the work of preparing new beds for the 8D AGM batteries to rest on in the new configuration. Removal consisted of sliding the old batteries up wooden ramps and then hoisting them up the companionway stairs and on to the dock. I saved the two best batteries for a temporary power supply. There was very little clearance and some of the shelf bracing had to be removed from the bulkhead. The new beds made from high grade plywood had to fit securely with support as the 8D AGM batteries weigh 156 pounds each. Each of the six 6 Volt batteries weighed about 75 pounds. I temporarily removed some of the hoses and piping to facilitate ease of installation. I also took the opportunity to trace wiring to assist with the upcoming installation of a new energy management/breaker panel and system. The third day arrived and my back was just about done in from all of the contortions from the previous two days. Ron from Everafter Marine showed up and we installed the batteries. Two 8D and one Group 27 AGM batteries. The Group 27 will be dedicated to engine start up and the two 8D will be for the house bank.

The photos will show all of the various items discussed to this point as well as show you the way I had to back into the engine compartment feet first on my belly and do a slight roll and twist to make room for the battery to slide in on the scaffolding and then help Ron guide the batteries into place. I really don't want to ever have to do this again. Great motivation to find a new place for the next ones to be installed or get a good job and hire someone to do it. The rest of the third day was spent hooking up the new batteries so we had power and to allow them to charge off of our 110 volt charger. I also started the blocking of the batteries. The blocking I used were web straps and then wood blocks securely placed and fastened to prevent any movement of the batteries. They are blocked well enough to stay in place in the event of a roll over. We do not want to ever experience a roll over but if we do we will want to make sure our power supply survives to assist in recovery and communications. The fourth day was spent pulling excess wire from the battery bank that was eliminated and then securing all pipes, hoses and checking to make sure nothing was kicked loose during the crab crawl through the engine compartment. Fortunately this inspection revealed a broken hose clamp on the fuel system. Oh, I also replaced the emergency bilge pump hose on the port side while I was fully encapsulated by the engine compartment. Now the temporary scaffolding could be dismantled and the engine started and systems all checked out fine. We will start the new energy management panel install next month and it should take two to three weeks.

I have to say that the Admiral handled all of the MESS very well. She worked some very long hours and came home to quite a mess. It looked like we were living in a tool/storage shed.
I was literrally battered by batteries and the Admiral and I took the day off today.
I hope you enjoy the photos!

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