Daniele Fua wrote in news:J8VIg.85744$zy5.1465697
@twister1.libero.it:
a "smart" regulator would fit. I understand that there should be a way
to cheat the regulator and force a higher charge for at least some
reasonable time. Anybody knows how?

Don't! You cannot get a good charge on any lead-acid battery by heaving
great gobs of current to it for 10 minutes. You get what's known as a
"surface charge", a quick, but useless conversion on the surface of the
plates that goes away, as you have obviously discovered, very quickly.

Batteries must be charged SLOOOOOWWWLLLYYY to get a good charge, the
slower the better. That 20A you're getting is the battery's chemistry
resisting having its guts heaved out by the 14V applied...and is NORMAL
AND DESIRABLE as it reduces charging time to something, while not ideal,
at least a little more reasonable. A good charge happens at 10% of
capacity...20A on a 200AH battery. The chemical reaction of our archaic
lead-acid batteries just happens slowly recharging. Don't go screwing
around trying to overhead and warp the plates on them in 10 minutes.
Next time someone has a battery explode on their boat, wait 4 days then
go look at what that looks like and you'll very quickly PUT THIS NOTION
OUT OF YOUR MIND!...(C;

However, just over the horizon of battery technology is just what all
boaters are looking for....INSTANT CHARGING BATTERIES are HERE! Look at:
http://www.physorg.com/news3539.html
http://www.technewsworld.com/story/hardware/41889.html

http://www.worldchanging.com/archives/002435.html
"The excellent recharging characteristics of new battery are not its only
performance advantages. The battery has a long life cycle, losing only 1%
of capacity after 1,000 cycles of discharging and recharging, and can
operate at very low temperatures. At minus 40 degrees centigrade, the
battery can discharge 80% of its capacity, against 100% in an ambient
temperature of 25 degree centigrade)."

Even Yankees freeze solid at -40C!

These Li-Ion batteries will be in hybrid and electric cars very soon. In
a boat the DENSITY of the technology is going to be MOST welcome! The
capacity of your huge battery bank will be reduced to the size of a loaf
of bread with HUGE conductors attached to it so we can charge it at 400A
or 4000A or more! THEN, your charger is going to be the issue....too
small....little diesel. The entire output power of your Perkins 4-108
COULD, with this new battery, be converted to charging current...AND THE
BATTERY WILL ABSORB IT AND CHARGE IN MINUTES, NOT HOURS.

In vehicles, dynamic braking, which is currently too much power in too
short a time to be of much use, will store most all the energy of braking
right back into the battery bank to be used to boost you away from the
traffic light, to the amazement of that little ******* with the noisy
Honda who always goes shooting off ahead of you, now.

Back to the calculator.....

Let's say we're going to get 400AH of "house battery" in the new
technology. 3 minutes, to fully charge it to 100%, is .05 hours. So, if
we're going to charge a 400AH/12V nanoLithium in 3 minutes, we're gonna
need:
400AH divided by .05 = 8000 AMPS for 3 minutes! Boy, that's gonna put a
sweat on those v-belts...(c; 8000 AMPS! Hmm...746 watts = 1 hp, give or
take a little. 8000A at 14V = 112,000 watts divided by 746 = 150 HP
(plus any inefficiency of the charging system, of course.) We're gonna
need a bigger ENGINE...not to mention alternator!

When this technology emerges, I hope the boat business will have enough
brains to switch to diesel-electric, traction motor drives. You'll have
that 100KW electric power plant....well, maybe 50hp, 1/3 of that....and
will be able to charge the new battery bank in 10 minutes at FULL POWER
or switch the electrics to the traction motors for propulsion (and bow
thruster??)....(c;


--
There's amazing intelligence in the Universe.
You can tell because none of them ever called Earth.