fitting a larger alternator beta 20

justjane · Member

fitting a larger alternator beta 20

Keith · Veteran Member

Hello

The largest alternator we can fit in the primary position on the Beta 20 is a 70amp and with this we recommend the use of the 4K poly-vee belt system which is supplied with corrosion resistant aluminum pulleys.

To enable us to cost this for you we need to know the build specification for your engine. Please contact us on (877) 227 2473 (toll free) and let us know the WOC number. This number starts with a 'K' and can be found on the test documentation that was supplied with the engine or on the Beta Marine label which will be found on the valve cover or inboard side of the heat exchanger of the engine.

Bob

justjane · Member

hi bob and thanks for reply ,i was asking mainly if there was any specific model or tricks others may have come across ,as today , the engine room in new zealand are going to order one for me ,the engine room only new with beta agentsey are looking after me , i didnot want to have to chop and change the engine box to fit everything ,does the new pully set up protrude farther out than the original ,many thanks ,,grant

Keith · Veteran Member

Hello again,

There is nothing special or really difficult. To ensure the correct parts are ordered you can see the parts needed in this illustrated parts book that is available on Beta Marine UK's website.

http://www.betamarine.co.uk/newsite/downloads/spares/Mini.pdf

After fitting the crankshaft pulley will protrude another half inch (12mm) but normally that should not be a problem.

Bob.

justjane · Member

hi bob does the existing crank pully come off or does the new fit over top ,my battery is 125 amp ,and am running a isotherm fridge ,,electric,,, i am hoping that i wont have to run motor as much as i have in the past ,many thanks ,,grant

Keith · Veteran Member

Grant,

The new crankshaft pulley will fit over the existing pulley and will be retained in placed by 3 bolts. The existing pulley should already be drilled and threaded to accept them.

The larger alternator should definitely reduce your run time for charging but do not expect to reduce the frequency of charging as that is determined by your battery capacity and the load you have on them.

Bob.

justjane · Member

hi bob and thanks for your input ,today it was put to me to have the alternator de regulated and fit a three stage regulator ,all this is to give more umph at the begining of charge cycle , to help combat the fridge, what do you think, i dont know much about these things ,being a house builder but i can under stand , there is a bloke on our marina who is an marine electrican who i talk to at times, and i will get to fit the new alto when it arrives ,many thanksgrant

Keith · Veteran Member

Grant,

So you are proposing to use the standard 40 amp alternator and use an external 3 stage regulator, correct?

It is not difficult to eliminate the internal regulation in an alternator and to use an external three stage regulator or even to do the same with a larger alternator. What is difficult is to ensure the belt drive system is in alignment if changing the alternator and capable of handling the additional power transfer requirements of the alternator and the long term reliability of the charging system due to the additional complexity of the charging ciruit. Also, be aware that modification will also void any warranty of the item.

Here is some additional notes to consider.

High output and externally regulated alternators invariably require a belt drive system that is capable of loads of 4 or 5 horsepower. This is the power required by the alternator as it 'loads up' based on the instructions of the external regulator. Standard belt systems are unable to handle this reliably and the belt skids in the pulleys and wear is accelerated. When this happens the belts can squeal and the alternator output falls. Owners then adjust the belt and most overtightening the belt to overcome this repeated situation. The belt continues to wear and eventually starts to run on the bottom of the vee making the situation worse. A further side effect of the over-tightning is early failure of the fresh water circulation pump bearings due to the higher lateral loading placed on the pump drive shaft.

Beta Marine overcomes this by fitting a sepentine style flat poly-vee belt system in preference to the dual vee-belt system preferred by other manufacturers, this system is much more reliable and does not need so much maintaining due to the use of aluminum pulleys that do not abrade the belts like steel or cast iron pulleys.

Electrically a 3 stage external regulator instructs the alternator to put out more amps at lower engine RPM's, it does this by controlling the voltage to the field windings of the alternator based on the charge state of the batteries. They can be very effective at this but must be set up correctly for the type of batteries being used, this also means that you must also use the same battery technology both for the engine cranking battery and the house batteries.

Also, be aware there is a type of external regulator that works in parallel to the internal regulator of the engine and if the external regulator fails, the internal regulator takes over. Let me know if you need any information on this.

justjane · Member

hi bob .i may have not asked it right ,this was to be the 65 amp one wich is on the water as we speek on its way to nz ,and only a question ,i dont want to complicate things , it was a sugestion put to me rom the sparkie ,the ships power system is good ,but at a week at sea tells how good ones batterys are ,and ,with all the mod cons ,tv dvd gps .water pump ,lights ,etc all handle well BUT the isotherm fridge ,is hungry ,and with small alternator the battery never tasted real power ,was only a question ,thanks ,the nz boat show is on this week and the beta agent will be on display ,and they have my boat any time as a model ,and some pic of the instalation , looking foward to it many thanks grant

justjane · Member

hi bob, its been some time ,but my alternator arrived and i fitted it to day ,complete with the new pullys ,and flat belt .all plug and play as beta send it ,and all well thought out by them i have one query, the wiring allso was plug and go and straight foward , except one wire left over , the brown , ,and no other place to conect it to ,i started the motor and charging was good ,ran motor 30 minuites ,alls good ,tested the brown while running and it was live 12 volts , the beta book saies in one caption , to tie back the brown ,so have done so so all went well but 10, points to beta for the way the kit came and thought gone into the kit to make it simple ,i could have fitted it at sea , ,can any body tell me what the brown wire is for .and why it is not used ,many thanks ,,,,grant

Stanley · Guru

Hello Grant,
The small brown wire is no longer needed. It gets its power from the AC terminal at the back of the ignition switch. I suggest that you disconnect it from there.
Regards, Stanley