Electricky Dicky wrote in
:

snippage


Yahoo found lots of digital hydrometers....some with probes you can
mount...

http://shopping.yahoo.com/search/;
_ylc=X3oDMTJuYWNqZDEzBF9TAzk2MDc5MjYwBGFkZ3JwAzI4N zA1NjUyMwRldnQDODc3NzE1Mw
RrA2RpZ2l0YWwgaHlkcm9tZXRlcgRvbW0DYnJvYWQEc2VjA2ti BHNsawN0aXRsZQ--?
view=l&p=digital+hydrometer&sp=pall&no_truncation= 1&sem=google

http://tinyurl.com/2kq62e
same URL...much easier to click.

Larry
--
While in Mexico, I didn't have to press 1 for Spanish.
While in Iran, I didn't have to press 1 for Farsi, either.
While in Florida, I had to press 2 for English.
It just isn't fair.

On Sat, 28 Jul 2007 22:37:14 +0000, Larry wrote:

reasonable length of time

= 5 hours from 40% down....(c;

Larry

That's too long for practical usage. Let's run the numbers:

Trojan L16s are approximately 400 AH, 2 in parallel, 800 AH.

Max recharge rate in bulk charge mode at 25% = 200 amps, 150 if you're
conservative and temperature limited.

AH to be replaced at 40% down up to 80% of full charge = 160 AH (going
above 80% takes too long so must of us settle for that or slightly
higher)

Time to achieve 80% is approx 1 hour, 90% about 2 hours, and that's
good enough. My batteries have been lasting 3+ years with that kind
of usage and I'm OK with it given the amount of time I spend onboard,
and the amount of geneator time the inverter saves me.

Wayne.B wrote in
:

On Sat, 28 Jul 2007 22:37:14 +0000, Larry wrote:

reasonable length of time

= 5 hours from 40% down....(c;

Larry

That's too long for practical usage. Let's run the numbers:

Trojan L16s are approximately 400 AH, 2 in parallel, 800 AH.

Max recharge rate in bulk charge mode at 25% = 200 amps, 150 if you're
conservative and temperature limited.

AH to be replaced at 40% down up to 80% of full charge = 160 AH (going
above 80% takes too long so must of us settle for that or slightly
higher)

Time to achieve 80% is approx 1 hour, 90% about 2 hours, and that's
good enough. My batteries have been lasting 3+ years with that kind
of usage and I'm OK with it given the amount of time I spend onboard,
and the amount of geneator time the inverter saves me.


That'll work.....It's fine.....

I just don't want to be aboard any boat with 120A applied to these
batteries, sealed away in a really tight box where there is ZERO cooling,
effectively, for hours on end. I'd hate to be the one they blame when
the plates warp and touch each other, resulting in an acid steam
explosion.

Have you ever seen one? Even the stainless flatware sealed away in a
drawer far away from the batteries was just eaten alive...pitted by acid
fumes. All the clothes in the cabinets way up in the V-berth were acid
eaten, too! Everything aboard had to be tossed...anything fuming
sulfuric acid gas could eat. I certainly wouldn't want to be stranded
aboard in some hermit's cove on the hook when it happened! BOOM! The
one I saw was caused by a big battery charger at the dock whos electronic
controller malfunctioned leaving the 40A beast on full current way past
time to shut down, which it couldn't do. I wondered how high the voltage
got at 40A when she blew!

Larry
--

On Sun, 29 Jul 2007 03:56:48 +0000, Larry wrote:

I just don't want to be aboard any boat with 120A applied to these
batteries, sealed away in a really tight box where there is ZERO cooling,
effectively, for hours on end.

That can not happen with a proper 3 stage charge regulator. It
certainly is not going to happen on a sailboat using the aux engine to
recharge batteries. No one wants to run that engine longer than
necessary.

Lew Hodgett wrote:
Skip Gundlach wrote:

I'm obviously missing a great deal of intelligence here.

I had thought we'd properly sized our bank and input sources to allow
for our anticipated usages.

Obviously I was mistaken; I need a large-frame alternator and the
appropriate drive components, in order to only bring my bank to 90%.

Wet cell batteries are a very mature technology.

The rules for them are very simple.

1) If you want to consume 200AH/day, you must generate 250AH/day of
replacement energy.

You can play all kind of regulator games, but in the end, the overall
average replacement rate is about 15% of the bank capacity or in this
case, 15%(750)=112.5A.

The minimum recharge time will be: 250/112.5=2.2 hours.

The only way to reduce the recharge time is to increase the size of
the battery bank which in turn allows for a higher recharge rate.

Still no free lunch, but does reduce the recharge time.

Batteries to a cruising sailor are like clamps to a wood worker, you
can never have too many.

How you choose to get it done is your business, but the above rules
define the task.

Solar:

For an engineering estimate, use a 2ftx4ft,80W panel which translates
into 10W/sq ft.

Derate 50% for dirt, clouds, angle of attack, etc, thus 5W/sq ft.

As a year around average use 12 hours/day, thus 12hours(5W/sq ft))=60
watt-hours/sq ft/day.

60watt-hours/12volts=5amp-hours/sq ft/day.

To generate 250AH of solar you need 250/5=50sq ft or at least 7 2ftx4ft
panels.

Probably not going to happen unless you build a hard bimini so you have
a place to plant your solar garden.

That's why alternators like the L/N 4800/4805 family exist.

Modest size, only 145/165 output depending on model, but either deliver
in excess of 100A at 2,000 alternator.

Ya pays ya money, ya takes ya pick.

Lew

OldNick wrote:

I agree largely with you Lew, but I reckon that you are being a bit
_generous_ with the solar panels' capabilities.

That is why it was called an "engineering estimate"

If you vary more than a few degrees from the equator, you will need
more panels for sure.

Lew

On Jul 31, 12:38 am, Lew Hodgett wrote:

Batteries to a cruising sailor are like clamps to a wood worker, you
can never have too many.

How about 2 alts and 2 banks, use the banks alternately so one is bulk
charged while the other is absorption charged at the same time. Plenty
of redundancy too.

Maybe 2x 75A alts and controllers are cheaper than a 150A alt and
controller.

Also solar will work better with a bank that is between 50-85% state
of charge.

cheers,
Pete.

On Thu, 02 Aug 2007 04:29:11 -0700, Pete C
wrote:

Maybe 2x 75A alts and controllers are cheaper than a 150A alt and
controller.

The battery bank in question is close to 800 AH and can not be
recharged from 40 or 50% depletion in a reasonable length of time by a
75 amp alternator. The main cost of the 200 amp alternator is in the
installation work, also an issue with a dual alternator set up.