We are listed on
Marine high output alternator and second alternator discussion
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:
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…
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.
– 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 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 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.
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
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
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.
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
Yanmar turbo charged kit in the shop
Close up of Yanmar JH4-TE alternator kit by Yachtwork.com
One of our first kits from years gone by
This kit sold well, but has now been upgraded and is much cleaner
This Yanmar marine alternator kit is in use on Beneteau boats all over Europe
One of our best selling kits
The Beneteau 43 alternator kit
You can see how clean and tight this kit is. Lot's of mesuring went into this project
We now make all our marine alternator kit projects with a laser cutter
Yanmar second pulleys are made on a CNC lathe for speed, price and accuracy
The Yanmar aluminum pulleys in production
Sailing forum links
|© Team Yachtwork 2009|