Advice on refridgeration unit please
 

" wrote in news:b2e0cf11-1ba5-4e82-
:

Also, I don't follow you point. Are you saying 2.4Kw is too much
power for any battery bank or were you making a specific point?



Think about the heat from 2,400 watts, about twice what comes out of an
electric heater turned up full....but now confined really hard inside the
rolled up lead and gauze of an AGM battery sealed inside a plastic tube.

Don't you think that MIGHT cause something inside all that insulation to
HEAT UP and maybe MELT way down in the core? What if it boils the gauze
soaked in acid into acid steam expanding exponentially in the little
plastic case?

2400 watts is a LOT of power! It will also create a LOT of HYDROGEN GAS
once the surface charge of all those amps insulates the plates from their
SLOW CHEMICAL ACTION OF 14 HOUR NORMAL CHARGING!

Yeah, I'm saying 2400 watts is WAY too much power....same old crap a boater
trying to recharge dead house batteries in an hour a day.....geez.

Advice on refridgeration unit please
 

" wrote in news:d58baedd-dd67-
:

On Jul 19, 5:22*pm, Brian Whatcott wrote:
..
Still, give a person credit for gun-shyness from a battery fast-
charge
accident! ...

Oh yes. An exploding battery while offshore is a nightmare! I
appreciate the concern. I think Larry is incorrect in his assertion,
but I'm listening because if he convinces me that he isn't then I'm
going to change my ways fast.

-- Tom



I heard a noise about taking the VOLTAGE REGULATOR off the alternator
and putting a manual current control on the field winding so it can be
"cranked up" to whatever charging current some idiot wants. Look back,
I forgot who said it. This is the absolute stupidest idea I've seen
about battery charging. I know why they are doing it. they've been
watching that ammeter that starts out charging like hell for the first
few minutes, then DROPPING LIKE A ROCK as the surface of the plates
becomes replated and the ions in the near-plate electrolyte are used up.
Right there at the surface of the plates, in the worst possible place,
there's a tiny slice of battery that has already charged. When more and
more current is shoved through it, by cranking up the charging (voltage
is the ONLY way to overcharge ANY lead-acid battery) that little slice
turns current directly into heat, gassifying the water at the barrier
into O2 and H2 and heating those plates!

I'm in FULL AGREEMENT of 14.2 to 14.8V REGULATED VOLTAGE charging....the
way the damned alternator was delivered. BUT, alas, this will NOT
recharge those batteries in an hour! The voltage rises very quickly up
to over 14V to the regulation point because the charge right there on
the surface causes the cell voltage to rise quickly as it runs out of
free ions to convert until more MIGRATE....SLOWLY....IN HOURS....to
replace the ones the initial current shock used up so quickly at high
current.

The boater, of course, with his eye glued to the AMMETER sees the
charging voltage max out the regulator and that LIFE THREATENING CURRENT
DROP happen so quickly, coming off the current limit of the alternator's
winding resistance and field strength. THAT BATTERY IS NOT CHARGED! If
you PROPERLY measured its specific gravity, you'd see the electrolyte
gravity hadn't moved hardly at all. Of course, in the wonderful AGM
battery you cannot MEASURE the specific gravity of the soaked up gauze
electrolyte so you have no idea of its charge condition.

Just because the voltage went up and the current went down DOESN'T MEAN
THIS BATTERY HAS CHARGED! It means this battery is in the process of
charging and has caused the charging current to drop back to a SAFER,
more sane level...tapering off because of the VOLTAGE REGULATOR, not the
charging level, to a long-term, plate-soaking true charge that soaks
INTO the plates....not plated upon its surface.

Battery charging takes 14 hours......REALLY! You cannot get 90% from
50% using a NORMAL, voltage regulated alternator in 60
minutes...CHEMISTRY won't allow it.

This will soon change as we leave these 1885-era chemical monstrosities
behind us. A fantastic technology is coming. You charge it at a
thousand times its AH rating for SIXTY SECONDS to 80% charge and 3
minutes to 100%! Read he
http://www.physorg.com/news3539.html

Your problem with the new battery is providing it the 8000A to recharge
it in a minute from your measily 55KW diesel aux engine....NOONE will be
overcharging this puppy!

Advice on refridgeration unit please
 

Bruce in Bangkok wrote in
:

Since here in Thailand, and probably all over the third world, they
are happily using R-12, and dumping it to atmosphere it probably goes
to prove that the Americans were responsible.



Not to mention the extensive air pollution controls on all those thousands
of 2-stroke little trucks running old motor oil at 15:1 premix....

It's those damned Americans....every time. They love to be blamed.

Advice on refridgeration unit please
 

Brian Whatcott wrote in
:

I don't think so - they are integrated induction motors and
compressors in a can. There's a capacitor that splits the phase, but
they slip the rotating field depending on load - if I recall

B

The capacitor lags the phase so you don't have to spin start them by
hand....they do run at the power line frequency....minus a little phase
slippage caused by the load.

Listen to one that has just started up and note its musical note. Notice
how the note hardly varies as the head pressure comes up to maximum, and
only the running current increases to maintain it.

Invented by Nikola Tesla, Father of Modern Electricity.

(I'm a fanboi...(c;)

If it had DC motors in it, those compressors would run like your universal
series wound vacuum cleaner or a drill/saw motor....varying widely in speed
as the load doubles/triples from idle.

The smooth steady hum of a compressor reeks of an AC induction motor,
capacitor start/capacitor run.

Advice on refridgeration unit please
 

jeff wrote in
:

1 kWh per day.
Supplying this with an inverter would take over 100 AmpHours.

1KWh at 13.8V = 72AH per day....1000/13.8V

Not much of a problem for a 330AH golf cart pair....

Advice on refridgeration unit please
 

" wrote in
:

http://www.rparts.com/Catalog/Major_...rs/Danfoss/dan
f
oss.asp

Hmm.....

Basic Specifications:
bullet Refrigerant:
HFC-134a, CFC-12
bullet Speed Range:
2,500 - 4,400 rpm
Yep, it's DC allright...

bullet Capacity:
934 Btu/hr (274 Watts)
I don't understand how they get 274 watts of cooling with only 168 watts
input. Must be physics magic!

bullet Max Evap (2.5k rpm)
+23F (-5C)
bullet Max Evap (4.4k rpm)
+23F (-5C)
bullet Power Input (max):
168 Watts

Arithmetic: 168W/13.8V=12.17 amps.

In comparison, the bar fridges draw LESS POWER off AC motors. The 2.2
cuft I got yesterday draws 1.08A (measured) pumping hard on a hot box
after 10 minutes of stabilzation...That's 120x1.08=129.6 watts/.95 (95%
efficient inverter)+ 5 watts idling = 141.4W after conversion....still
20 watts less than the Danforth. My 4.4 cuft $129 Magic Chef draws 148
watts (measured) and through inverter would be about equal....but $850
cheaper. As it sits full of beer right next to my desk, I can estimate
its duty cycle at 10% just sitting there after stabilization. Solid
foam insulation form fitted leaves only the door seal, same as any
marine fridge, magnetic strips with accordion folding pressure, as the
leakage point. It doesn't leak much as the case is never wet and
there's no doorseal heater strips in it....too cheap.

I still contend the SMALL INVERTER/cheap AC fridge is very competitive
without taking out a mortgage. For a 150W box, you need a 200-300W
inverter....not that 4KW monster with the 4 fans from Waste Marine. The
little inverters draw almost no idle power, unlike the big beast. It's
insignificant, even for boat battery banks. You want it mounted...I use
steel angle brackets and toggle bolts through the thin walled case
CAREFULLY drilled away from where it gets hot (condensor coils buried
under the skin). The old R12 I got yesterday has external coils out the
back...MUCH MORE EFFICIENT but vulnerable to breakage.



bullet Height:
5.39" (137 mm)
bullet Weight:
9.5 lbs (4.3 kg)

Advice on refridgeration unit please
 

On Jul 19, 7:34*pm, Larry wrote:
" wrote in news:b2e0cf11-1ba5-4e82-
:

Also, I don't follow you point. *Are you saying 2.4Kw is too much
power for any battery bank or were you making a specific point?

Think about the heat from 2,400 watts, about twice what comes out of an
electric heater turned up full....but now confined really hard inside the
rolled up lead and gauze of an AGM battery sealed inside a plastic tube.

Seems to me that most of the energy must go into the chemical
reaction. As the heat builds up the internal resistance will go up
and the voltage will go up and the controller will reduce the amps...
No? Anyway, there's no way that that much heat is being produced.
The batteries are cool to the touch when charging, so there is
something wrong with you analysis. Also, just so you know, my AGM are
made of rectangles of lead and glass sandwiched together. No tubes.

...
2400 watts is a LOT of power! *It will also create a LOT of HYDROGEN GAS
once the surface charge of all those amps insulates the plates from their
SLOW CHEMICAL ACTION OF 14 HOUR NORMAL CHARGING!

You're yelling, dude. Given how long my batteries have lasted I don't
think they can be outgassing all that much hydrogen. I also think you
need to look at a charging curve. Yes, getting to 100% charge takes a
long time, but the curve is nowhere near linear. Most of the time
involved is taken going from ~80-100% and the charge rates at that end
are very small (ending at less than an amp). However, from ~50%-80%
the charge rates are quite high particularly with AGMs which have low
internal resistance.

Yeah, I'm saying 2400 watts is WAY too much power....

Regardless of battery bank size? Pity the poor diesel-electric
submarine boys, it must take them years to charge their batteries.

same old crap a boater
trying to recharge dead house batteries in an hour a day.....geez.

I'm not trying to completely recharge them in an hour a day. I am
getting a useful charge into them in an hour a day and fully
recharging them periodically. This has been working well for me for
some years now. I'm just reporting the facts, friend. There's no
need to yell. I'm listening to you, but I haven't seen much signal in
your noise yet.

-- Tom.

Advice on refridgeration unit please
 

On Jul 19, 7:27*pm, Bruce in Bangkok
wrote:
...
http://www.trojan-battery.com/Batter.../Charging.aspx

If you stop when the batteries first reach 14.8 you never fully charge
your batteries.

Good point. I use a three stage controller, too.
...

Note that my figures were too low for some batteries. Trojan
recommends 20% but other recommendations are in the 10 - 15% range
see:http://www.solarnavigator.net/battery_charging.htm
...

Yes. Interesting. Particularly the last link which says my Concorde
AGMs can be charged at C times 4 (400%) of the 20 hour rate! I guess
I need bigger alternators :) It isn't clear to me if some of the
charger links are minimum size recommendations or limits on the charge
rate. All the smart chargers I know of just assume that the battery
will come up to voltage before it is damaged by the amperage. That is,
they don't come with an amp setting, only a volt setting. But you
point is good about RTFM.

Thanks for the links.

-- Tom.

Advice on refridgeration unit please
 

On Jul 19, 7:37*pm, Larry wrote:
...
I heard a noise about taking the VOLTAGE REGULATOR off the alternator
and putting a manual current control on the field winding so it can be
"cranked up" to whatever charging current some idiot wants. *

That's just suicidal. I didn't see that suggestion, but it would be
absolutely insane and I hope that I didn't write anything that would
suggest otherwise.
...
I'm in FULL AGREEMENT of 14.2 to 14.8V REGULATED VOLTAGE charging....the
way the damned alternator was delivered. *BUT, alas, this will NOT
recharge those batteries in an hour! *...

Quite. But at lest with my batteries I do get a days worth of power
out of an hours charging (to be fair we usually get some sun on at
least some of the panels during the day, too).

... *Of course, in the wonderful AGM
battery you cannot MEASURE the specific gravity of the soaked up gauze
electrolyte so you have no idea of its charge condition.

To be sure. But, what I do know is that I've got enough amps to run
my stuff. Including the HF radio that demands voltage in excess of
12.
...

Battery charging takes 14 hours......REALLY! *You cannot get 90% from
50% using a NORMAL, voltage regulated alternator in 60
minutes...CHEMISTRY won't allow it. ...

I'm not claiming to get to 90% or even very exactly 80%. I am using a
normal voltage regulated alternator (well they're regulated
externally, but regulated none the less). I am able to put a
substantial and useful charge into my batteries in an hour. That's
just the way it is. Maybe it has something to do with the physical
make up of the batteries, maybe I'm using a smaller percentage of them
than I think I am (or than the controller is reporting). Whatever. I
don't know the why's. I'm not an expert. I did hire an expert to put
the system together and it works.

...
This will soon change as we leave these 1885-era chemical monstrosities
behind us. *A fantastic technology is coming. *You charge it at a
thousand times its AH rating for SIXTY SECONDS to 80% charge and 3
minutes to 100%! *Read hehttp://www.physorg.com/news3539.html

Man, that looks cool. Super-capcitor charge times with 1k cycle plus
life span deep cycling. Yes, yes, yes. Only problem I can see is that
it will cost more than my boat. :)

-- Tom.

Advice on refridgeration unit please
 

On Sat, 19 Jul 2008 19:03:33 -0700 (PDT), "
wrote:

On Jul 19, 5:22*pm, Brian Whatcott wrote:
..
Still, give a person credit for gun-shyness from a battery fast-charge
accident! ...

Oh yes. An exploding battery while offshore is a nightmare! I
appreciate the concern. I think Larry is incorrect in his assertion,
but I'm listening because if he convinces me that he isn't then I'm
going to change my ways fast.

-- Tom

If you are charging a battery fast enough to make bubbles in the
electrolyte you are venting hydrogen. I saw a Chinese bloke in
Singapore disconnect a battery charger without turning the charger
off. It made a spark and the whole shebang blew up. Had he not been on
a dock so he could dive in the water I suspect he would have received
severe acid burns.

After he stopped shaking he commented, "Never had that happen
before"....


Bruce-in-Bangkok
(correct Address is bpaige125atgmaildotcom)