Re: SM Batteries

Martin Birkhoff

Hello Bill, 

sorry for my late response but I would like to add a different aspect to the discussion.

I'm sorry, but I have to disagree about your opinion concerning household batteries. If the batteries you name last 2 bi 3 years, they are not a convincing choice. According to my research they have a capacity of 225 Ah at 12 V for 107 USD. Currently an AGM Varta 115 Ah / 12 V costs about 280 € at SVB, Germany.
Looking at a battery bank of 600 - 700 Ah at 12 V, you can buy 3 Deka (675 Ah) or 6 Varta (690 Ah). The price difference is 321 USD to 1,580 €. But: the AGMs will last at least 6 to 7 years. So, arithmetically, this comes out to approximately the same amount of money. Against this background, there is no reason to buy classic lead-acid batteries. Another thing to consider: Such batteries are not designed for the characteristics on board a sailing boat, even if they are heavy-duty or deep-cycle batteries or whatever they may be called. 

From our personal experience: We started our circumnavigation 2004 to 2009 with gel batteries. After 7 years (!) of use, we had to replace them in Chile in early 2008 if my memory is correct. Since we couldn't get adequate batteries, we bought heavy-duty lead-acid batteries (maintenance-free). It soon became apparent that they were not suitable for the consumption or discharge characteristics on board a sailing boat on a long voyage and broke down after a few months. About nine months later (still in 2008) we bought AGM batteries of comparable capacity in Peru. These were on board our boat until 2020!  

To be honest, I never understood the reason why Amel still provided lead-acid batteries for the 54. This was not state of the art even 15 years ago. In addition, from my personal point of view as an environmental engineer, it is not a good idea to use batteries that have to be disposed of every two to three years. The goal should rather be to strive for the most sustainable use possible. In addition, there is what happens to the disposed lead-acid batteries in many countries. We have had extremely questionable experiences with this.

I ask for your understanding, but I simply have to put this up for discussion.
Best regards 

SY Mago del Sur - 54#40
currently Marina di Ragusa

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