Wayne.B wrote in
:

reasonable length of time

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

Larry

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.