Hi all,

I won't get into the six volt vs twelve volt debate. It is to my mind, foolish, because what matters is the number of available amp hours. In an ideal world I'd use an LI battery pack–but that's beyond my (financial) means. My next choice would be 2 volt cells from Surrette. That is also too much "ouch" for my pocket book.

Here is what is may be done to keep lead acid batteries happy.

1. sufficient capacity in amp hours so that the battery is never taken below 50% of capacity. The more amp hours the merrier.

2. sufficient capacity so that when high watt items such as an electric water heater are used that no battery has more than a 25 amp hour draw (or less–the smaller this number the better).

3. a three stage charging system that is temperature compensated. This may easily be accomplished with solar panels where there are 60 watts of panels per 100 amp hours of capacity.

4. routine maintenance such as watering cells and keeping corrosion down.

5. all batteries to be of same capacity and similar age. It is probably best if they are from the same maker, too.

6. if there is space for an "odd" number of batteries then the first parameter may favor 12 volt units.

7. cost per amp hour is "king", assuming that deep discharge batteries are being considered.

If all these conditions are met the batteries may last a long time.

Hi all,

I believe that wiring 12 volt batteries together is not well understood by most installers. It is important to "do it right". If there are only two 12 volt batteries involved then method #2 or #3 from this page will work:

http://www.smartgauge.co.uk/batt_con.html

If there are an *odd* number of batteries then only method #3 will work correctly.

If there are an even number of batteries then method #3 or method #4 will work.

If the batteries are six volt it somewhat harder to "get it wrong", as there can only be an even number of batteries, and most folks don't get more than four–which makes method #2 correct–and method #1 wrong. The installer is likely to "get it right" when there are only two choices.

So far I've not seen correct wiring diagrams on any of the battery makers pages–so no wonder the installers are unaware of the problem. Most of the diagrams I've found are method #1 which is blatantly incorrect and will lead to early failure of the first battery in the "chain". Sometimes method #2 is illustrated–which if there are three or more batteries will result in early failure of two of three batteries.

I believe that errors in wiring have helped to create the myth that "six volt batteries are better".

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Hi all,

Here is yet another battery information page:

http://www.engineersedge.com/battery/battery_knowledge_menu.shtml

Hi all,

For those who prefer AGM batteries!

http://www.zimmermanmarine.com/docs/AGM%20article.pdf

And a tongue in cheek comparison of batteries and man's best friend!

http://www.mpoweruk.com/papers/lees_wisdom.htm

I happened upon a how long a battery will last java calculator.

http://www.gizmology.net/batteries.htm

Scroll down the page one screen.

It may be useful to those of us who are "high amperage" users!

Hi all,

Yet another link to a battery information page. The information here would favor 2 volt cells.

http://www.rpc.com.au/products/batteries/deepcycle_faq.html

Hi all,

Be sure to check the shipping date on the units–stale batteries are not a good buy at any price. The shipping code usually appears on a sticker on the battery or a stamp burned into the battery case itself.

The code is a string of letters numbers, but all the real information you need is in the first two characters. Usually, the code starts with a letter that corresponds with the month–'A' for January through 'L' for December (some manufacturer's codes omit 'I'; for them, 'M' indicates December). The second character of the code is a numeral that stands for the year. Thus, a code starting 'A2' indicates that the battery was shipped in January 1992;