On Sat, 24 Jan 2004 05:00:54 -0600, "Rick & Linda Bernard"
wrote:

Anyone have a good way of testing 12V deep cycle batteries?

What I was figuring on doing was using a 50watt 12V lightbulb and measuring
voltage with time. The only problem is that this may take a few hours.


I use a hydrometer, myself. The specific gravity of the cells tells
you what condition they are in. 1.270 is a fully charged lead-acid
battery at 72F. Be sure to get a good hydrometer with a built-in
thermometer and calibration chart because the specific gravity of the
electrolyte is very dependent on temperature.

If you find a cell with gravity lower than the rest, be assured it has
suffered sulphation where the lead sulphate has crystalized and will
soon have a "dead cell", if it's not already.

If the cell has high specific gravity and the battery's voltage
doesn't drop under normal loads, it's fine. Just keep her topped up
with ONLY distilled water.

Of course, AGM batteries you have no way of knowing what the hell is
going on inside the sponges.....

Here's some references for you:
http://www.nwes.com/using_batteries.htm
http://www.thesolar.biz/Measuring_sp...ty_article.htm
http://www.usbr.gov/power/data/fist/...6/3_6_cont.htm
http://www.buchanan1.net/lead_acid.shtml
(people up Nawth need to pay particular attention to the table on
the bottom of this webpage relating to the electrolyte freezing
temperatures as related to cell specific gravity (charge).)
http://www.rpc.com.au/products/efn/e...ries_care.html
http://www.solartech.com/aboutbat.htm

and I think this cool instrument would be a great replacement for the
Link, which I don't think gives you an accurate assessment because the
Link runs on an assumed A-H battery rating and that rating is ONLY
good at a SPECIFIC LOAD CURRENT at a SPECIFIC TEMPERATURE none of you
are running on these batteries. The actual specific gravity is the
ONLY way of actually measuring a battery's condition. This neat
$US110 instrument stuck in one cell will constantly measure that
gravity. Isn't this actually CHEAPER than the Link?!....(c; I know
it's more accurate.
http://www.electrosense.com.au/
Wonder how long it will last in the acid environment?


Larry W4CSC

Is it just me or did the US and UK just capture 1/3
of the world's sweetest oil supply? What idiot wants to
GIVE IT BACK?!!