Larry, the question on the table concerns the regulator.(Is it 3 stage or
not). Your reply, while correct in procedure, deals with testing battery
condition. Let's not confuse the poor person further.

--
Dennis Gibbons
S/V Dark Lady
CN35-207
email: dennis dash gibbons at worldnet dot att dot net
"Larry" wrote in message
...
The voltage you read on an unloaded battery is of no consequence. A
battery that won't pull the starter will read good voltage with no
load.

Go to an auto parts place and buy a 50A battery tester, the cheapest
one they have. I paid $18 for mine from a Chinese-made hardware store
called Harbor Freight and it works great.

These testers have two heavy clamps to clamp to the battery terminals
and an analog voltmeter calibrated for no load---loaded for 10
seconds, 30 seconds or some time as the voltage drops over time when
loaded down at 50A. Then there's a load switch you have to hold on
that connects a nichrome heater wire inside the box where the vent
holes are because it really gets HOT. 12V X 50A = 600 watts. The
resistor element glows like an electric heater and isn't made for
continuous duty.

Follow the directions that come with the tester. Hook it up to each
12V battery bank INDIVIDUALLY. If you have a bunch of deep cycle
batteries in parallel, you'll have to disconnect the negative post on
each battery so you only test THAT battery with the meter.

This loaded meter allows you to compare the parallel battery
capacities on your house batteries, too. They should all be the same
capacity, not one small battery in parallel with 2 big ones, of
course, but that's exactly what you'll have after a couple of years of
use in a boat. What you do is to TIME how long it takes each
battery's voltage to drop to the bottom of the loaded range, usually
about 11 volts. If one battery drops to 11V after 48 seconds when the
other batteries take over a minute to drop, this battery is missing
some plates, or the plates are eaten and sulphated away or the plates
have holes in them, or there is one or more cells that have lower acid
content, usually from someone pouring tap water into them instead of
DISTILLED water. Calcium in tap water reacts with the sulphuric acid
just like lead does.....consuming the acid as it makes calcium
sulphate, a stable salt.

If you have a group of boaters who are all friends, one meter for the
group to share is fine. They don't need constant testing, just every
few months or when you suspect trouble, like now.



On Thu, 14 Aug 2003 21:35:51 GMT, jeannette
wrote:

On 14 Aug 2003 12:49:08 -0700, (john s.) wrote:


Jeannette, after you have let your batteries rest overnigt, do they
still show 14.4 V. My expectation is that you would foind them
shoiwing 12.8 V which indicates a fully charged battery. The three
stages are different in the amps delivered by the alternator to the
batteries, bulk is about 25% of their capoacity, acceptancea around
10% and float about 1% of the capacity, but always at 14.4 V - it's
only the "equalization" which your smart regulator may not have that
injects 16 V at low amperage to remove the sulfation of the plates by
making the battery "boil" for about half an hour, after which you;ve
got to add some distilled water to bring back the level of electrolyte
john

When I disconnect the batteries from everything, they read around
12.80. I also check the specific gravity and they are all correct. My
concern was that I have read and also that I can see on my shore
charger that when a 3 stages charger goes to float, the voltage comes
down to about 13.7. This charger keeps outputting 14.40 at all times
even after several hours of running like when I motored to Bodega Bay
for 6 hours.
The charging current does go way down though. Maybe I worry for
nothing.
Why is it that all the 3 stages chargers I read about go to float at
13.7?. Why doesn't this one do it?


Jeannette Bristol 32, San Francisco
http://www.eblw.com/contepartiro/contepartiro.html

Larry

Extremely intelligent life must exist in the universe.
You can tell because they never tried to contact us.