By: Scott
Fratcher - Marine Engineer/Captain
On this dual alternator discussion I received a well thought
out email from Alan concerning second alternators and other charging
issues.
I am going to do my best to answer, but first let me give you
a brief background of where the information I'm going to present
comes from. I normally stay away from personal history because
it has little to do with charging systems, or the other DIY articles
I write, but in this instance my experience is significant to
the ideas I am going to present.
My wife and I left San Francisco cruising on our 42ft steel ketch
in 1987. Since then we have covered well over 150,000 miles on
many boats, mostly without marina stays.
My wife and I departed San Francisco with 30 dollars and a boat
load full of tools. Our idea was to support ourselves while sailing
by performing whatever work along the way we could. This was a
time just pre GPS and not many yachts were sailing compared to
today. Two years later GPS became universally available and yachting
has changed forever, or until the satellites fall from orbit.
The advent of a real time navigation system meant high priced
yacht owners suddenly had confidence to head offshore. I was sailing
in Mexico at the time working on worn out cruising yachts and
trying to keep beans in the cooking pot.
Next thing we know a dozen fully decked out yachts showed up.
Each one seemed to have every imaginable electrical device installed.
Computers, refrigeration, deep freeze, navigation systems, big
battery banks, water makers, high wattage electric lamps and some
even had electric trash compactors. On our boat we were still
using kerosene running lamps and had none of that high priced
gear. It was the start of what has become the modern capable cruising
yacht.
Since most of these boats were fitted out in Seattle or San Francisco
they were built for cold conditions. Soon as the boats hit the
tropics the fridge and freezer began pulling double amperage while
the single 55 amp engine alternator overheated and failed. It
was common for yachts to run the main engine 4-8 hrs a day just
trying to keep the beer cold.
Being the business man that I am (see “How
to make money with boats” at Yachtwork.com or Boatbooks)
I formed a team and we began trying to solve the big yacht charging
problem.
We identified a group of boats that were big enough to have the
electrical toys, but did not want to dedicate space to a generator
and concentrated on solving the charge issues.
Our customer base for our high amperage kits include:
- Offshore cruising yachts
- Charter yachts such as the Moorings fleet
- Beneteau production yachts
- Marine electricians wishing for an easy method of driving
a large frame alternator.
- Yachts with moderate electrical loads that do not wish to
dedicate space, effort and spares to a genset.
- Large 700+ amp hour battery banks
- Yachts that wish to shut down the genset while using the
main engine
- Batteries such as AGM that can take high charge rates
- Split voltage charge systems IE 12/24 volt electrical systems
- Yachts with large inverter loads ie. washer/dryer
- Yachts that wish for a back up charge system for safety
- Yachts that wish to utilize short engine run times to quickly
recharge batteries such as cruising boats that only run the
engine when lifting anchor.
- Yachts with large electrically driven motors such as electric
bow thrusters and electric anchor winches
We tried every imaginable charging combination over about ten
years. We built wind generators, trolling generators, rewinding
alternators to get more amperage, petrol deck generators and
second alternators. Solving the battery re-charge problems was
the topic of radio nets and cruiser parties. Battery regime
and charge rates were spoke of of instead of great dive sites.
Because our work shop was built into our cruising yacht we sailed
along with our customers following the season. I would make two
or three installations and then sail with the group to our next
destination. In this way I was able to experience firsthand the
results of our efforts.
Of course our own boat was slowly loading up with all the latest
gadgetry also.
What we found was this. Alternative power was good, but it only
supplemented the main charge from the genset or main engine. The
key was more charging amperage. Like they say “There is
no substitute for horsepower”. We began rewinding alternators
for more output, but the math is bad. We have to remove the 55
amp alternator to install a 100 amp thus gaining only 45 amps.
Eventually we set upon installing second alternators. The idea
instantly caught on and solved the majority of yacht charging
issues in just a few days labor. The constant battle of keeping
the yacht batteries charged became a non issue.
On every yacht we installed a second alternator the crew stopped
talking about amps, watts, charge, fridges, and began getting
on with cruising. The wives stopped threaten to move off the boat
and "camping" on the water became a lifestyle of relative
luxury.
Building second alternator mounts became a big part of our income.
It was great. Cruising our boat around installing duel alternator
kits and making people happy at the same time.
If you’re interested in doing the same type thing I put
out a book “How
To Make Money With Boats” that is for sale in NZ (yachtwork.com
or Boatbooks) explaining the step by step process of buying a
boat cheap and using it as an economic support platform while
cruising. It’s really a great system and in use by hundreds
of people today.
In the 1990's I did a count and found I had over 100 dual alternator
designs in the field. I don't know how many designs I now have
out, but it's a lot. Not only my designs, but the number or re-designs
I regularly get called to fix.
It's tricky to make a one off bracket that will last the life
of the engine. The failures I get called to typically revolve
around systems that vibrated and cracked a bracket, or maybe the
pivot point was not right so the belts would not tension correctly.
Sometimes the electrical would be done well but the welding was
poor, or the other way around. See, it's difficult to find someone
that can design and install the electrical and the mechanical
side of a dual alternator kit.
The thing is I have NEVER yet come across a yacht that has told
me "You know the thought of rebuilding my second alternator
kit is too much to bear. Let's just remove it".
Instead what I hear is "Just fix it. Do what needs to be
done, but keep my second alternator installed". I consider
this a testament to the fact that a second alternator solves the
majority of long term yacht charging problems and it's worth the
cost to most owners.
A couple more points to mention. Every system I work on I live
with. My wife and I have been constantly sailing for over 20 years.
When we run out of cruising money we jump to another yacht or
boat to work. All the while our comfort level depends on how well
we can keep the mechanical systems running at capacity.
We live with what we service. Our main engine has a dual alternator
system. I have a seven horse power Yanmar diesel that belt drives
a 120 amp alternator. We also have two wind generators, a trolling
generator and six solar panels.
I keep careful tabs on the amount of power we use and how we
replenish it. The majority of our charge while cruising comes
from the big alternator off a small diesel.
Of course while sitting at anchor the solar and wind can keep
up, but when on passage the sails shade the solar, and the big
electric auto pilot consumes a lot of extra power not to mention
navigation lights, radar, night reading lights, and all other
electrical demands that are increased when a boat is run24/7.
Our typical charging regime is a fast charge from the alternator
early in the day while also charging any laptops, fridges, etc.
We shut down the engine in time for the sun to take over the charge.
We never seem to want for more electricity, but we use a lot of
it.
So, on to Alan's letter
Because I can't change the text color in the forum text I'm going
to give my opinions in capitals. I know many people say it's the
same as shouting in text. I'm only trying separate my comments
compared to Alan's.
One more thing, these are just my quick opinions. Every yacht
situation is different, but this is what I see from the designer/installer/consumer
point of view…
Hi Scott,
I have been interested to read your various articles on alternator
upgrades (Tradeaboat, your site & your recent crew.org postings).
Having been thru one of these upgrades on my own boat it was interesting
to compare notes. I do feel there are a few points you should
clarify/elaborate in your writings to ensure people are better
informed, all of which I am sure you are aware of. My first suggestion
to anybody wanting a better understanding of marine electrics
is to buy Nigel Calder's Maintenance guide – it seems to
have become the definitive reference book
I AGREE. NIGEL IS A FANTASTIC INFORMATIVE READ ON JUST ABOUT ANY
TOPIC HE WRITES ABOUT.
SORRY ABOUT LIMITING THE AMOUNT OF INFORMATION I, BUT TRADEABOAT
ONLY HAS SPACE FOR ABOUT 2500 WORDS A MONTH. IT SHOULD BE NOTED
2500 WORDS SHOWS THE AMOUNT OF INFORMATION KIWI'S ARE ABLE TO
CONSUME. WHEN I WRITE FOR US MAGAZINES THEY ASK FOR 800-1000 WORDS.
Battery Capacity
– before worrying about the alternator is there enough
battery capacity. It is incredible when you look at the standard
specs for the Euro-trash boats NZ is being inundated with how
small the standard battery package is – Bavaria 42, 46,
50 and Oceanis 43 all nominating a single 140 ah battery as standard
(I know most have battery upgrades but leaves people like yourself
to address the charging problem). So bigger is generally needed
and I know the selection between wet/gel/agm/hybrid gel types
is a never ending debate in itself. My feeling for cost /benefit
is to go with T-105 6V type wet cells in the appropriate bank
size providing there is adequate external ventilation, maybe with
Hydrocaps.
THIS IS A GOOD POINT. MOST EURO CRUISING YACHTS ARRIVE WITH NEXT
TO NO BATTERY CAPACITY, BUT SEEM TO NEED ABOUT 500-800 AMP HOURS
TO CRUISE. THE SYSTEM WE BUILT FOR ROSS BLACKMAN’S BENETEAU
43 HAS AN 800 AMP HOUR BANK AND HE REPORTS NEVER GOING BELOW 700
AMP HOURS. IF HE HAD A 300 AMP HOUR BATTERY BANK THE SYSTEM WOULD
NOT WORK NEARLY AS WELL.
THIS IS IMPORTANT BECAUSE IN ORDER TO FAST CHARGE WE NEED A LARGER
BATTERY BANK. AMAZINGLY MANY U.S. BOATS TOP OUT AT OVER 1600 AMPS.
THE TROJAN 105 AND THE 220 RED TOP 6V BATTERIES SOLD IN NZ ARE
MY PREFERRED CHOICE. THEY ARE RUGGED DEPENDABLE, FORGIVING, CHEAP,
AND SEEM TO LAST SIX TO EIGHT YEARS WITH GOOD CARE.
Engine Mounting configuration –
having sorted the batteries & determined a second alternator
is necessary there is one aspect I feel you should touch on, the
matter of allowable sideways loading on the front crankshaft bearing.
I went thru this with Power & Marine on my new installation
(Yanmar 4JH4 56 hp), in 2005 they were adamant that the max size
alternator to hang off the side was 120 amp. In the finish on
my installation we went to a jack shaft as I have a refrigeration
compressor & Jabsco bilge pump to run as well as the 140 amp
alternator. I believe Yanmars have a reputation for being light
in the front bearing size, whereas Kubota derivatives can handle
a lot higher loading. Have Yanmar since changed their position
on the issue of side loads?
NOW THIS IS FUNNY TO HEAR BECAUSE I WAS SENIOR TECHNICIAN FOR
YANMAR ENGINEERING SERVICES THAT WAS COUPLED TO POWER AND MARINE
AND THE BLUE PACIFIC SALES TEAM. I THINK I WAS THE ONE WHO DECIDED
ON THE 120 ALLOWABLE AMP DRAW ON YOUR ENGINE. IT WAS A POINT OF
DISCUSSION AMONG THE TEAM.
I NORMALLY SPEC ON THE LOWER SIZE OF SAFE BECAUSE A COUPLE YEARS
LATER I TEND TO HEAR REPORTS SUCH AS YOURS WHERE THE USER INCREASED
THE AMPERAGE OF THE ALTERNATOR AND ADDED A COUPLE OTHER DEVICES
LIKE THE FRIGE COMPRESSOR.
REMEMBER THE MANUFACTURER WAS SAYING NOT SAYING WHAT THE ENGINE
WILL HANDLE BUT WHAT THEY ARE WILLING TO WARRANTY. IT’S
AN AGREEMENT OF RISK.
A SIDE TOPIC TO MENTION IS YOUR ALTERNATOR AND REEFER PUMP BOTH
ARE SMOOTH LOADS. THIS SMOOTH LOAD IS A GOOD THING AND GREATLY
IMPROVES THE CHANCES OF A TROUBLE FREE LIFE.
WATERMAKER PUMPS, HIGH PRESSURE WASH DOWN PUMPS AND HYDRAULICS
NEED “HARD” HITS TO PRODUCE THE HIGH PRESSURE THEY
RUN AT. THIS IS MUCH MORE OF A SHOCK LOAD ON THE COMPLETE SYSTEM
ESPECIALLY THE CRANKSHAFT. ONE WAY AROUND THIS PROBLEM IS ADDING
A SMALL NITROGEN CUSHION CARTRIDGE TO THE PUMP INSTALLATION TO
SMOOTH THE LOAD.
SO HERE ARE THE YANMAR ALLOWABLE HORSE POWER NUMBERS AS I REMEMBER
THEM FOR THE JH4 SERIES ENGINE. WE ARE ALLOWED UP TO SEVEN HORSE
POWER CONSUMED FROM THE FRONT OF THE CRANK AT MAX RPM'S. THE SLAVE
PULLEY SHOULD BE WITHIN 15 DEGREES ABOVE OR BELOW THE CRANK.
SINCE THE GRAPH IS RPM RATED IF WE WANT TO KEEP RIGHT IN THE
ALLOWABLE HP CURVE WE CAN CALCULATE OUR PULLEY SIZE TO MATCH THE
HP THE ALTERNATOR CAN CONSUME.
HORSE POWER TO AMPS PRODUCED IS ALSO A POINT OF CONTENTION. MANY
TECHS REPORT 25 AMPS AT 12 VOLTS PER HP. I THINK IT'S MORE LIKE
20 AFTER TESTING MANY SYSTEMS IN THE FIELD. SO SEVEN HORSE POWER
WOULD BE 140-175 AMPS.
IN PRACTICE YOU WOULD NOT BELIEVE THE AMOUNT OF GEAR I SEE BOLTED
TO THE FRONT OF YANMAR ENGINES. MOST SEEM TO KEEP WORKING. THE
OTHER DAY I SAW A PHOTO OF TWO 200 AMP ALTERNATORS DRIVEN BY AN
OLDER YANMAR. I WOULD NEVER TRY TO DESIGN SUCH A WORK HORSE, BUT
SEEING IT IN OPERATION I HAVE CONFIDENCE THE LOWER AMPERAGES WE
DESIGN WON'T FAIL IN THE LONG TERM.
AFTER ALL THAT DISCUSSION WE CAN NOW THINK ABOUT SIDE LOAD. YOU'LL
NOTICE THE ALTERNATOR BRACKETS WE PRODUCE PLACE THE SECOND ALTERNATOR
ALMOST EXACTLY OPPOSITE OF THE ORIGINAL YANMAR ALTERNATOR. THIS
IS NOT BY CHANCE, BUT OUR ATTEMPT TO BALANCE THE LOAD ON THE CRANK.
WE ALSO MAKE A HIGH AND LOW VERSION MOUNT. THE LOW VERSION IS
THE BEST BALANCE WITH THE ORIGINAL ALTERNATOR.
ANOTHER ASPECT TO CONSIDER IS THE SIZE OF THE DRIVE PULLEY. THE
LARGER THE DRIVE THE MORE SIDE LOAD. FOR THIS REASON WE ARE USING
A 120 MM PULLEY ON OUR JH4 ALTERNATOR KITS. THIS SIZE ALLOWS THE
ALTERNATOR TO BE RIGHT IN IT'S POWER CURVE AT ABOUT 1400 ENGINE
RPMS AND STILL PRODUCE RESPECTABLE AMPERAGE AT LOWER RPM'S.
IN CORRESPONDENCE WITH STEVE DASHEW HE MENTIONED A YANMAR SUGGESTION
OF TWO SMALLER ALTERNATORS MOUNTED ON EACH SIDE OF THE CRANK TO
BALANCE THE LOAD. I JUST CAN'T GET BEHIND THIS IDEA AS EACH CHARGE
SYSTEM HAS SOME MAINTENANCE AND A TRIPLE ALTERNATOR SYSTEM SEEMS
LIKE A LOT OF COMPLICATION FOR ABOUT THE SAME CHARGE RATE AS A
DUAL SYSTEM.
NOW AFTER YEARS WORKING IN THE FIELD I HAVE ONLY ONCE COME ACROSS
A PROBLEM FROM SIDE LOAD AND THAT WAS ON A 4JH2 WHERE THE DRIVE
PULLEY CRACKED AT THE KEYWAY. THE ENGINE WAS STILL RUNNING FINE,
BUT THE PULLEY WAS LEAKING OIL. THIS INSTALLATION WAS DRIVING
A WATER MAKER PUMP.
The "R" word –
surprised that no where have you mentioned the need for an external
regulator, preferable of the 3 step type.
Maths of adding an alternator – the comment about adding
a 130 amp alternator to an original 55 amp installation sending
a battery boosting 185 amps into the electrical system is surely
a little loose. I expect your installations follow customary practice
of directing the charge from the large alternator to the house
bank and the original engine alternator to the starting battery,
ie the two alternators are complimentary, not additional. I believe
the only way to send the sum of current outputs to the house bank
would be to replace the engine alternator with an externally regulated
alternator and fit one of those fancy Ample Power/Balmar or other
regulators with 2 field outputs. Those little 80 amp internally
regulated/alternator sensed Hitachi alternators fitted as standard
to 4JH Yanmars would struggle to produce more than 50 amps even
for an almost dead battery and would be totally confused trying
to charge a battery already receiving charge from a high output
alternator.
EVERY ALTERNATOR INSTALLATION IS BOAT SPECIFIC, BUT MY STANDARD
INSTALLATION IS TO DIRECT THE SECOND ALTERNATOR TO THE HOUSE BANK
AND THE ORIGINAL ALTERNATOR TO THE ENGINE START AND THEN INSTALL
A VSR TO COMBINE THE BATTERY BANKS SOON AS ONE ALTERNATOR HAS
SPARE AMPERAGE.
IN PRACTICE THE YANMAR ORIGINAL 80 AMP ALTERNATORS PRODUCES THE
80 AMPS THEY CLAIM. I REGULARLY CONFIRM THIS BY USE OF A DC CLAMP
AMP. THE STANDARD YANMAR HITACHI ALTERNATORS ARE PARTICULARLY
DIFFICULT TO EXTERNALLY REGULATE. THIS IS BECAUSE THE REGULATOR
AND BRUSH HOLDER ARE BUILT INTO THE SAME HOUSING.
TYPICALLY AN EXTERNAL THREE STEP REGULATOR CAN PASS 10 AMPS THROUGH
THE FIELD CIRCUIT. A STANDARD ALTERNATOR USES FOUR AMPS TO POWER
THE FIELD SO RUNNING TWO ALTERNATORS OF DIFFERENT AMPERAGES IN
PARALLEL FROM ONE FIELD SOURCE IS DONE ALL THE TIME. IN ORDER
FOR THIS TO WORK ALL BATTERIES MUST BE IN PARALLEL DURING THE
CHARGE CYCLE.
I HAVE NOT WRITTEN MUCH ON THE THREE STEP REGULATORS CAUSE THERE
IS SO MUCH GOOD INFORMATION THAT I HAVE NOTHING CONSTRUCTIVE TO
ADD EXCEPT TO RECOMMEND NEXT STEP AND BALMAR AS MY FIRST CHOICE.
FOR THE BROKE CRUISER IT’S WORTH MENTIONING THE THREE STEP
REGULATORS WILL COST ABOUT 250 TO 400 DEPENDING ON MODEL. IF YOU
JUST CAN'T AFFORD THE COST THE NEXT BEST THING IS THE MOTOROLA
REGULATOR FOUND ON THE BACK OF THE LN 130 AMP LOAD HANDLERS. THEY
TEND TO HOLD VOLTAGE WELL AND CAN BE REMOTE MOUNTED. THEY DON’T
NEED AN IGNITION WIRE AND CAN REMOTE FEED TO AN ALTERNATOR. THEY
HAVE A VOLTAGE SELECTIVE SCREW POT FOR FINE ADJUSTMENTS.
YOU MENTION THE 50 AMPS A TYPICAL YANMAR 80 AMP ALTERNATOR PRODUCES.
IF YOU CHECK AT THE BACK OF THE ALTERNATOR OFTEN YOU WILL FIND
THE VOLTAGE IS STEADY AT 14.2 AT 50 AMPS AS IT SHOULD BE, BUT
THE TINY STANDARD WIRE ON THE BACK OF THE ALTERNATOR HAS A VOLTAGE
DROP AND THUS THE BATTERIES ARE STILL SITTING 13.6 OR SO.
TO BE CLEAR YOU ASKED ABOUT FEEDING A LARGE OR COMBINED BATTERY
BANK WITH BOTH THE THREE STEP REGULATED HIGH OUTPUT ALTERNATOR
AND AT THE SAME TIME THE YANMAR STANDARD 80 AMP ALTERNATOR. THE
ANSWER IS THIS IT’S DONE ALL THE TIME.
BACK IN THE 80’S DOUBLE REGULATION SEEMED BE A BIT OF A
PROBLEM, BUT SINCE THEN I HAVE NEVER HAD A COMPLICATION WITH RUNNING
MULTIPLE ALTERNATORS INTO ONE COMBINED BATTERY BANK EVEN IF THE
COMBINATION IS THROUGH PARALLEL BATTERY SWITCH.
EACH CHARGE SOURCE HAS A SET VOLTAGE AND SIMPLY TURNS OFF WHEN
THAT VOLTAGE IS REACHED. THIS MEANS ONE CHARGE SOURCE WILL ALWAYS
BE LAST IN TURNING OFF BUT IT HAS NOT SEEMED TO MATTER IN PRACTICE.
WHEN CHARGE VOLTS OR AMPERAGES BECOME UNSTABLE IT CAN NORMALLY
BE TRACED BACK TO A GROUND LOOP OR GROUND FAULT. THIS IS PART
OF THE FLOATING GROUND ISSUE YOU MENTION LATER.
YOU MENTION KUBOTA. I SHOULD SAY KUBOTA ENGINES DON'T TEND TO
GIVE US MANY MOUNTING BOLT HOLES. THE TIMING COVER AND OTHER BOLTS
SEEM VERY SMALL COMPARED TO OTHER SIMILAR ENGINES. EVERY TIME
I COME ACROSS A KUBOTA TO BUILD A DUAL ALTERNATOR KIT FOR I HAVE
TO SCRATCH MY HEAD TO MAKE A GOOD LONG TERM BRACKET.
Battery charge acceptance rate –
subject to battery type and internal resistance. In short the
alternator is unlikely to achieve its theoretical rated current
output for a given rpm for any time because of the fast resistance
build up. I noted from a recent article of Calder's in Professional
Boat builder magazine (talking about the new Odyssey batteries)
where he quoted the experience of his Malo 45 (450 amp/24V Lifeline
AGM bank with 180 amp alternator) finding that after 15 minutes
the charge pulled back to 100 amps (ie about 25% of battery capacity
and a lot less than the 40% charge rate commonly touted for AGM's)
YES, THE ACCEPTANCE RATE OF BATTERIES IS AN ISSUE. THIS IS ONE
OF THE REASONS YACHTS KEEP ADDING LARGER BATTERY BANKS. THE IDEA
IS A LARGE AMOUNT OF AMPERAGE CAN BE REPLACED IN THE FIRST HOUR
OR SO WITH AN ALTERNATOR THEN THE SOLAR AND WIND TAKES OVER FOR
THE LAST BATTERY TOP UP. CHARGE TO 80% DISCHARGE TO 60% AND LET
THE SOLAR AND WIND TAKE CARE OF THE REST.
THIS HAS BEEN OUR CHARGE REGIME FOR YEARS. WHEN THE BATTERIES
REACH 60% WE DIESEL CHARGE AND SHUT DOWN AT 80% AND USE SOLAR.
IT'S BEEN A FAIR SOLUTION.
YOU MENTION AGM BATTERIES AND I'M PROBABLY GOING TO GET SOME
NASTY EMAILS BUT I STAY AWAY FROM THEM. THE FAILURE RATE IN THE
FIELD IS VERY HIGH AND HAVING BATTERIES SHIPPED TO SOME FAR OFF
LAND IS A CHALLENGE THAT CAN RUIN A CRUISING SEASON. ONE SET OF
AGM'S THAT WE REPLACED IN EL SALVADOR COST THE OWNER OVER 5K IN
SHIPPING.
A GOOD TEST OF YOUR YACHT CHARGE SYSTEM IS TO RUN YOUR BATTERIES
DOWN TO 50%. DO THIS BY MEASURING THE AMPS CONSUMED (NOT VOLTAGE).
START THE ENGINE AND TURN ON THE FRIDGE AND ALL OTHER DEVICES
NORMALLY CHARGED WHEN THE ENGINE IS RUNNING. I.E. LAPTOPS AND
CELL PHONE CHARGERS ETC. MEASURE THE VOLTAGE AT THE BATTERIES.
TIME HOW LONG IT TAKES TO REACH 14.5 OR WHATEVER YOU HAVE YOUR
BULK BATTERIES VOLTAGE SET AT.
MANY YACHTS TAKE ONE OR EVEN THREE HOURS TO GET THE BATTERIES
UP TO VOLTAGE ON A 400 AMP HOURS BATTERY BANK. A DUAL ALTERNATOR
SYSTEM PUSHES THE VOLTAGE RIGHT UP TO 14.2 (OR YOUR CHOSEN VOLTAGE)
THUS SAVING THAT HOUR OR THREE IN DAILY CHARGE TIME.
FAST CHARGE ELECTRICIANS ALSO CLAIM THAT BY CHARGING AT LOW VOLTAGE
THE BATTERIES DO NOT GAS SO THE ACID DOES NOT GET STIRRED THUS
SHORTENING BATTERY LIFE.
ANOTHER WAY TO LOOK AT THIS IS AN 80 AMP ALTERNATOR MIGHT BE
CHARGING AT 50 DUE TO POOR CABLING. THE FIRGE IS PULLING 8 AMPS,
AND A LAPTOP MIGHT USE 5 AMPS AND MAYBE ANOTHER 5 AMPS USED IN
THE BOAT SOMEWHERE. THAT IS A NET CHARGE AROUND 30 AMPS. BOLT
IN A SECOND 145 AMP ALTERNATOR AND WERE SUDDENLY SEEING 175 AMPS
AT THE BATTERY. NO WONDER THE VOLTAGE IS PUSHED RIGHT UP TO SPECIFICATIONS.
Alternator selection matters to consider:
Needs to match battery bank size/charge acceptance rate with
reference to its output curve (easy to get curves for Leece Neville,
not so easy for Delco in my experience) at fast idle speeds
Needs to be externally regulated (I was surprised to find when
I purchased my Leece Neville 8LHA that it was not and needed to
be converted, Delco CS 144 appears to have options which need
to be nominated on ordering)
YES, FOR SURE. IF I HAVE ANY DOUBT ABOUT ALTERNATOR SIZE I GO
FOR LARGER CASE AND MORE AMPERAGE. THE REGULATOR WILL THROTTLE
BACK THE AMPERAGE AS NEEDED.
THE DELCO ALTERNATOR LINE HAS THE OUTPUT GRAPH POSTED IN THE
USER MANUAL AND I CAN NORMALLY FIND THEM ON LINE WHEN NEEDED,
BUT THE IMPORTANT ASPECT YOU MENTION IS THE CHARGE RPM CURVE.
AN ADVANTAGE OF LARGE CASE ALTERNATORS IS THEY PRODUCE MORE AMPERAGE
AT LOW RPM’S. THE OUTPUT IS ABOUT 90% AT 3000 ALT RPM'S
OR SO.
GOOD ON YOUR FOR CALLING THE DELCO CS144. THIS HAS ALWAYS BEEN
ONE OF MY FAVORITE ALTERNATORS. THIS IS THE ALTERNATOR I TYPICALLY
USE TO BUILD ARC WELDERS (SEE TRADEABOAT FEB). MOST ANY DELCO
HAS TO BE OPENED TO EXTERNALLY REGULATE IT. I NORMALLY DO THIS
BY BREAKING OPEN THE REGULATOR AND USING IT AS A CONNECTION BLOCK.
THE REGULATOR TABS THEN BECOME THE FIELD BRUSH TABS LEAVING A
CLEAN LOOK.
The fan must be correct for the direction of rotation
THIS IS A GOOD POINT AND OFTEN OVER LOOKED. NOT ONLY THE FAN
BUT REVERSE SPINNING AN ALTERNATOR CAN HAVE OTHER ISSUES. IS THE
PULLEY KEYED? NOT ALL NEED IT AS THE DELCO 22SI HAS PROVED, BUT
IT MUST BE CONSIDERED. ALSO CHECK IF THE FIELD BRUSHES ARE MEANT
TO DRAG BOTH DIRECTIONS.
It should be hot rated,
ie be able to achieve nameplate output at 90 deg C
Its max rpm rating needs to be considered in selecting pulley
size -most go to 10,000 rpm but some only reach 8000. This can
be a problem getting sufficient output for 3600 rpm engines at
low speeds.
THIS IS ANOTHER IMPORTANT POINT. I CAN SEE YOU HAVE BEEN STUDYING
ALTERNATORS. DELCO'S ARE RATED AT 200F (ABOUT 90C). THAT IS A
GOOD HONEST RATING. A TYPICAL 145 AMP ALTERNATOR MAY PUT OUT 185
FOR TEN MINUTES, BUT THEN LEVEL OUT AROUND THE RATED 145. MANY
AFTER MARKET ALTERNATOR MANUFACTURES RATE THEIR ALTERNATOR AT
40C AND THIS IS NOT A FAIR RATING FOR THE YACHT USER.
FROM EXPERIENCE AND A LASER TEMP GAUGE IT SEEMS AN ALTERNATOR
CAN RUN AT ABOUT 120c ALL DAY LONG WITHOUT DAMAGE AND THE DIODE
PACK CAN RUN AT OVER 150c AND SURVIVE.
Ideally should have isolated casing with positive and negative
output terminals (not earthling thru engine block)
YOUR COMMENT IS REALLY TWO ISSUES. EARTHING THROUGH THE ENGINE
AND FLOATING GROUNDS.
EARTHING THOUGH THE ENGINE SHOULD NEVER BE DONE. ANYBODY WITH
A HIGH OUTPUT ALTERNATOR SHOULD CHECK THEIR SYSTEM FOR A GROUND
CABLE DIRECT TO THE BATTERY OR AT LEAST CAPPED RIGHT TO THE NEGATIVE
FEED TO THE ENGINE. THE ENGINE HEAD OR BLOCK IS NOT MEANT TO CARRY
240 AMPS. GROUNDING THROUGH THE ENGINE BLOCK IS THE NUMBER ONE
REASON I SEE DIODES FAIL.
MAIN ENGINE FLOATING GROUND IS THE SECOND ASPECT TO TALK ABOUT.
THIS IS A BIT MORE TRICKY AND BOAT SPECIFIC. GENERALLY IF THE
ENGINE HAS A FLOATING GROUND THEN THE ALTERNATOR SHOULD ALSO.
IF THE ENGINE HAS A PERMANENTE GROUNDING TO BATTERY THE ISSUE
IS NOT SO GREAT.
THE BIG POINT IS TO TEST THE ALTERNATOR AT FULL CHARGE WITH A
CLAMP AMP. YOU SHOULD BE ABLE TO TRACE THE CHARGE ALL THE WAY
TO THE BATTERY. THE ISSUES START WHEN AN ALTERNATOR IS PRODUCING
125 AMPS BUT TEN AMPS ARE FINDING PARALLEL PATHS TO THE BATTERY
THROUGH MAYBE YOUR SSB OR THE BONDING SYSTEM. WITH A CLAMP AMP
YOU WILL SEE RIGHT OFF IF VOLTAGE/CHARGE IS LEAKING THROUGH A
PARALLEL PATH POSSIBLY CAUSING SOME CORROSION ALONG THE WAY. DON'T
FORGET TO CLAMP THE PROP SHAFT AS THIS IS A COMMON CONDUIT OF
ELECTRICAL LEAKS AND THUS CORROSION.
Installation matters
Ensure there is adequate cooling air for the alternator (rarely
addressed)
YES, THIS IS IMPORTANT. ALTERNATORS PRODUCE A LOT OF HEAT AND
THAT IS THE LIMITING FACTOR TO HOW MUCH AMPERAGE A GIVEN CASE
SIZE CAN PRODUCE. WHEN YOU SEE AN ALTERNATOR ZOOPED UP TO 200
AMPS IT SOUNDS IMPRESSIVE, BUT THE CASE CAN ONLY DISSIPATE SO
MUCH HEAT SO IT'S KIND OF A LOST VALUE TO HAVE LARGE WINDINGS
THAT CAN’T BE COOLED.
ANOTHER COMMON TRICK IS TO FEED THE ENGINE ROOM AIR SOURCE RIGHT
TO THE BACK OF THE ALTERNATOR. OFTEN WITH JUST A BIT OF EXTRA
DUCTING THE ALTERNATOR CAN BE MADE TO RUN SIGNIFICANTLY COOLER.
A FRIEND JUST TOLD ME THEY NOW SELL A PLASTIC HOUSING THAT MOUNTS
TO THE BACK OF LARGE FRAME ALTERNATORS THAT COUPLES TO A RULE
3" BILGE BLOWER. THIS FORCES A 3" COLUM OF AIR RIGHT
INTO THE BACK OF THE ALTERNATOR SIGNIFICANTLY INCREASING THE COOLING
EFFECT. I LOOK FORWARD TO TRYING THIS UPGRADE.
Suggest a regulator on/off switch, to give the engine a little
time to catch its breath on starting before getting whacked with
the alternator's load.
YES THIS TENDS TO BE AN ISSUE IF THE YACHT DOES NOT HAVE A THREE
STEP REGULATOR INSTALLED. THE TYPICAL THREE STEP REGULATOR WAITS
60 SECONDS BEFORE IT BEGINS TO RAMP UP THE FIELD CURRENT.
ANOTHER REASON TO HAVE THE ALTERNATOR SHUT OFF SWITCH IS IN THE
UNLIKELY EVENT YOU HAPPEN TO NEED ALL YOUR HORSE POWER SENT TO
THE PROP. LIKE IF YOU WOKE AND FOUND YOURSELF DRAGGING ANCHOR
AND WERE ABOUT TO LOOSE THE BOAT INTO THE SURF. THAT IS JUST THE
WRONG TIME TO DIVERT 7 HP TO THE BATTERIES.
IF I REMEMBER RIGHT THE JH4 SERIES YANMAR CAN HAVE THE KEY SHUT
OFF WHILE RUNNING DISABLING THE GAUGES AND ALTERNATOR BUT LEAVING
THE ENGINE RUNNING AS NORMAL. THIS HAS BEEN USED AS AN EMERGENCY
ALTERNATOR DISCONCERT TO DISABLE THE 80 AMP (4HP) FACTORY SUPPLIED
ALTERNATOR.
For dual belt installations ensure the belts are a matched pair
YET ANOTHER IMPORTANT POINT. DUAL BELTS NOT ONLY LAST LONGER,
BUT THEY ALSO DON'T NEED TO BE RUN AS TIGHT AS A SINGLE BELT THUS
REDUCING SIDE LOADS. ANOTHER POINT ABOUT DUAL BELTS IS THEY TEND
TO LAST NEAR FOREVER. I HAVE A SET OF DUAL BELTS ON MY ENGINE
THAT ARE NEARLY 10 YEARS OLD WHILE THE SINGLE BELTS GET REPLACED
EVERY OTHER YEAR.
I HEAR A LOT OF TECHS TELL ME MATCHED BELTS ARE NO LONGER AN
ISSUE AS LONG AS THE BATCH NUMBER IS THE SAME. IN OTHER WORDS
THE FIRST SET OF SMALL PRINTED NUMBERS AND NOT THE FINAL SEQUENTIAL
ORDER. IN PRACTICE ONE BELT ALWAYS SEEMS TO BE LOOSER THAN THE
OTHER EVEN WHEN I START WITH MATCHED BELTS BUT HAS NEVER BEEN
A PROBLEM.
ONE MORE REASON TO USE DOUBLE BELTS IS THEY RARELY LEAVE THAT
BLACK STICKY RUBBER DUST. ALL OUR MAIL ORDER MOUNTS ARRIVE WITH
DOUBLE ‘A’ SECTION PULLEYS. THIS HAS BEEN A GOOD COMBINATION
AS BELTS ARE AVAILABLE EVERYWHERE AND NO SPECIAL PARTS SHIPPING
HAS TO TAKE PLACE.
Ensure the output wires are adequately supported and some form
of nylok or lockwashers used on the studs
YES, AND YOU WOULD NOT BELIEVE HOW OFTEN A FEED CABLE COMES LOOSE
RUINING THE ALTERNATOR DIODES AND MAKING A POSSIBLE FIRE HAZARD.
Ensure lock washers and Locktite'd bolts used on new crankshaft
pulley
Only used tinned copper wire (surprised that ISO standards do
not demand this whereas the more stringent ABYC standards do)
MANY ELECTRICIANS CLAIM TINNED WIRES DON'T HAVE TO BE OVERSIZED
FOR FUTURE CORROSION SO THE INSTALLATION COST IS ROUGHLY THE SAME.
A debatable item – whether the output cable should have
a fuse in it or not??
FUSING IS INDEED A DEBATABLE ITEM. THE QUESTION IS NOT JUST THE
FUSE BUT ALSO WHERE TO FEED THE BATTERIES.
YACHTWORK HAS TEAMED UP WITH GREG LEWIS FORMERLY OF TEAM NZ TO
BUILD BENETEAU KITS WE SEND TO EUROPE. GREG WIRES OUR SYSTEM TO
RUN THE ALTERNATOR CABLES DIRECT TO THE BATTERIES THROUGH A 250
AMP FUSE ON THE POSITIVE SIDE AT THE BATTERIES. OVER THE YEARS
THIS HAS BECOME THE LEAST PROBLEMATIC OPTION. NOBODY CAN TURN
OFF THE BATTERY SWITCH AND THE FUSE CAN EASILY BE PULLED TO ISOLATE
THE ALTERNATOR FOR SERVICE.
Miscellaneous
I noted your comment about $300 Delco alternators – is
this in NZ (seems very cheap) or mail order from USA?
MY TRICK TO BUYING ALTERNATORS IS TO USE A MAJOR COMPANY LIKE
NATIONAL ELECTRIC (ON THE NET) OR http://www.alternatorparts.com/21-22si_dual_rect.htm
AND BUY A NEW 145 AMP DELCO22SI OR 21SI FOR ABOUT 145 USD. A DOUBLE
‘A’ SECTION PULLEY IS 50 AND THE BIDIRECTIONAL FAN
IS ANOTHER 50. I SEND IT ALL PARCEL POST FOR JUST OVER 20 BUCKS
AND HOPE FOR THE BEST. SO FAR THE MAIL HAS BEEN PRETTY DEPENDABLE.
THE ALTERNATOR COMES IN UNDER 400 NZ SO THERE IS NO DUTY TO BE
PAID.
I HAVE USED THIS LARGE FRAM DELCO FOR YEARS AND IT'S A REAL POWER
HOUSE. IF YOU WANT A MEDIUM FRAME ALTERNATOR THE DELCO CS144 YOU
MENTION IS WONDERFUL. FOR A SMALL FRAME THE DELCO 12SI HAS BEEN
A DEPENDABLE WORK HORSE.
I picked up a Craftsman multi meter/tong tester (AC and 400
amp DC) from Sears for US$60. Obviously not as good as a Fluke
but has had good reports for occasional use.
YEP I THINK I KNOW THE CLAMP AMP YOU MENTION. THESE LITTLE POCKET
SEARS CLAMP AMPS ARE A GOOD VALUE. A GOOD ALL AROUND CHEAP METER
THAT GIVES DEPENDABLE SERVICE. IF IT'S THE SAME METER I'M THINKING
OF THE JAWS ARE SMALL SO IT CAN REACH INTO TIGHT AREAS. IT MEASURES
DOWN TO .1 AMPS AND THIS IS GOOD FOR FINDING STRAY CURRENT.
ANOTHER OPTION JUST COMING ON THE MARKET IS AN AC/DC CLAMP AMP
WITH A BUILT IN LASER TEMP. THIS IS GETTING CLOSE TO THE STAR
TRECK TRICORDER WE SAW AS KIDS.
Amp hour meters
I think in spite of all the fancy amp hour meters available,
a good analogue ammeter is very useful. I crewed in the Fiji race
couple of years ago and the yacht only had an EMON unit, which
went on the blink and on top of this had a regulator problem.
I had a multi meter so could check voltage but no way of checking
current. Carrel and Carrel in Kingsland will make ammeters and
shunts up to 200 amps for very reasonable prices (used to supply
BEP in the early days).
I hope you find these comments of use/interest. This is a subject
like so many in boating where there are always various views and
opinions. I am happy to be corrected if I have got any of my facts
wrong, we can all learn something new every day.
Regards
Alan
ALAN-YOU SEEM VERY UP ON THE CHARGING AND YACHTS IN GENERAL.
IF YOU GET BOARD CRUISING THERE IS PLENTY SIDE JOBS ALONG THE
WAY FOR GUYS WITH YOUR KNOWLEDGE BASE.
I HOPE MY THOUGHTS ARE OF USE.

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