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junior

Additional Alternator

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Can i put Petter stuff in the Lister forum?

 

Anyhow.....

 

I have put an offer in on a boat (hanging by the phone to see if it's accepted). If it is, one of the first jobs will be to get the electrics re-fitted and upgraded. At the moment the boat has only one starter battery and one leisure battery. The only means of charging them is via an alternator on the Petter PH2 engine.

 

I hope to add 2 more laisure batteries giving me a combind 330AH leisure bank. I'm guessing that the alternator that is on there at the moment won't be sufficient to charge all 4 batteries. So, i'm looking to get an additional alternator fitted to the engine.

 

Where should i go to have this done? Can anyone give me any recommendations? Any forum members up to the job? Also, can anyone offer me a ball park rough estimation as to what they think i might have to pay to have this done as i'm trying to budget it in to all the other work that will need to doing (stand-by for more threads).

 

Here is the existing engine and alternator.....

9512891998_fc2bb885d4_z.jpg

9510103017_9c792c8d8b_z.jpg

9512892174_bb038c9558_z.jpg

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Yes that looks to be one of the older acr alternators 25/30 amp. I think you would find upgrading to a 70a replacement would be adequate for 3 + 1 starter. You can do that job yourself for less than 50.00 if you source the alt from somewhere like Middletons in Manchester

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Consider the cost of the new one and how much they will give you on exchange for your current one.

Just going for the 70 a upgrade is the way to go as advised by blodger but you then consider keeping your current and less powerful one for a future upgrade (or breakdown) if required.

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I can't really answer your specific question, but a few points might be worth bearing in mind:

 

The size of the alternator is not really determined by the size of the battery bank, but more by how much charge you intend to take out of the batteries. Even then, what is affected is how long it will take to recharge. Even a small alternator will get there eventually.

 

Provided the engine starts reasonably well, the starter battery is only slightly discharged by starting and will be recharged in a few minutes, so it barely comes into the equation.

 

There is a limit to the size of alternator for a couple of reasons, one is the shear horsepower required to run it with low batteries and propel the boat at the same time. Your engine is not hugely powerful, and therefore for example fitting a 175A alternator would be a bad idea. As you fit a larger alternator, more HP is needed to run it and the engine doesn't produce this at idle, therefore you would have to geared to only run at adequate speed for charging with the engine running quite fast. That would be a pain! We have a 43hp engine and it manages to charge at full output pretty much at idle, but you can hear it struggling.

 

Then there is the amount of load you can put on a normal belt. Too big an alternator with a normal belt means it will be prone to slipping, therefore it will have to be highly tensioned, therefore the belt won't last long and the alternator bearings will wear rapidly. Larger alternators need the likes of a polyvee belt, but of course you need a completely new engine pulley for that.

 

So in summary I would say that 70A alternator is the most you should fit. Your existing alternator looks relatively modern, what is its output? It might be quite straightforward to swap for a 70A one.

 

The other consideration since you are going to live aboard, is to get a generator instead. Then you don't have to wear out your expensive main engine just to recharge the batteries. And of course solar for the summer.

  • Greenie 1

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Thanks for the replies. Very good news indeed as replacing the current alternator for a 70amp one is bound to be far cheaper than fitting a second. Thank god!

 

The boat needs to be Epxoxied which is just about going to wipe out the whole budget i had set aside of upgrading the boat to a liveaboard standard. Therefore i'm having to prioritise what needs doing with the small ammount of money that is left. Top of that pile is getting some more batteries and installing the ability to hook up to the mains (it has no mains hook up capability at the moment), so not needing an additional alternator is a relief!

 

Generator and solar will have to come at a later date.

Edited by junior

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It's possible, but as been mentioned consider how much power it will take from the engine and what you can drive on a single belt. I think I'm right in saying about 95a/h.

 

I did it Blog Linky but this is to charge up a 1200a/h bank. Consider also putting on an alternator charge modifying device. I went with a Sterling one Blog Linky

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If you have mains don't worry about charging the battery from the engine- buy a 3-stage battery charger and put it on the mains. It will be much cheaper to run and will not wear the engine out. Do a power audit- see Tony Brooks site - and get one which will supply enough (or nearly enough) Amps for your maximum power demand so that the charger is doing the work, not the batteries.

 

A 70A Lucas A127 would be a good replacement for the alternator. It will only be needed when you go off-mains so you can save some money till then. Buy one with a 14.6v regulator (or a tractor regulator) so that you don't need an alternator controller/battery boiler. An A127 should fit the existing mounts but you may need to shim it to get the two pulleys in line or the belt will wear quickly. You should look at the charging cable from the existing alternator- it may not like 70A through it or it may cause a voltage drop which will impede charging.

 

Also have a look at the existing master switch. It might be coping now but if you are going to upgrade the system and put more demand on it, the cheapy ones are renowned for dropping volts and failing under load.

 

N

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It's possible, but as been mentioned consider how much power it will take from the engine and what you can drive on a single belt. I think I'm right in saying about 95a/h.

 

I did it Blog Linky but this is to charge up a 1200a/h bank. Consider also putting on an alternator charge modifying device. I went with a Sterling one Blog Linky

 

I hope you mean 95 amp wink.png - amp hours refers to battery capacity. I agree with the figure though for an single A groove drive belt. My installation uses the same for a hard working 90 amp alternator. You need to check belt tension regularly though when working close to this limit.

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As everyone else says the A127 70 amp is the way to go.

Just remember to check the direction of rotation when viewed from the pully end of the alternator. Clockwise means that you can use an inclined blade fan similar to that currently fitted, anti clockwise will need the straight (radial) bladed fan as inclined blade anti clockwise fans can be difficult to find for A127 type alternators. The existing setup could well be happy regardless of direction of rotation, but the higher output A127 will need the correct fan to provide adequate cooling.

Nice looking engine - enjoy :-)

Steve (Eeyore)

Edited by Eeyore

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Just in case its any use at all, which it most likely isn't I have an 18inch aluminium pulley, currently machined to fit a 2inch shaft, which is too good to throw away but have been set unused since it came off emilyanne 5 years ago.

 

 

Daniel

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In the first photograph the engines and alternators pulleys look out of alignment to me. It might be an optical illusion or a photo quirk. Its important that they are perfectly in line.

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In the first photograph the engines and alternators pulleys look out of alignment to me. It might be an optical illusion or a photo quirk. Its important that they are perfectly in line.

 

Fatal error: Out of memory (allocated 7864320) (tried to allocate 122880 bytes) in /home/ggbqjfrf/public_html/forums/admin/sources/classes/session/publicSessions.php on line 388

 

Hmmmm. I THINK it's just the picture, but the survey should pick up any problems. I'm not going to be at the boat now until survey day.

 

So I know what alternator I need, unfortunately the rest of the comments about making sure the fan blades are the right way round etc, whilst much appreciated, is gobbledygook to me and means unfortunately I am going to have to take it somewhere for someone else to do, rather than just buying one of eBay and doing a straight swap myself.

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Mains electricity costs less than any generation. If you have the chance use shoreline and a clever charger (three stage).

A single V belt will not happily transmit much more than 70A otherwise you may need twin V belts or a polyVee pully machining to fit your flywheel.

As long as you get the charge and isolating circuit right a single alternator will work fine

High rated alternators get hot -make sure that there is ventilation in the engine room and that the alt has the correct fan.

 

Remember that solar power is free in the, and in the summer may be all you need, a small solar panel just to keep the starter battery full is a great idea.

It's up to you to determine the cost/value of running the main engine or an external generat

 

or to charge batteries and provide 240vAC

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Sorry Junior, didn't mean to confuse you.

Take a piece of chalk with you on survey day. Stand over the engine as in your second picture and note which way the flywheel moves as you operate the starter.

Put a chalk arrow on the flywheel to indicate the direction of rotation and take another picture to post on here.

Someone,if not myself, will let you now which rotation you have.

Just for interest at this point here is a picture of a typical bi directional (radial/straight bladed) fan.

Notice how the blades come out from the centre, unlike the one in your picture.

They are not quite as good as ones designed for one direction of rotation, but are equally effective in either direction.

 

25109-bi-directional-fan-for-delco-19si-

Steve (Eeyore)

Edited by Eeyore

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Sorry Junior, didn't mean to confuse you.

Take a piece of chalk with you on survey day. Stand over the engine as in your second picture and note which way the flywheel moves as you operate the starter.

Put a chalk arrow on the flywheel to indicate the direction of rotation and take another picture to post on here.

Someone,if not myself, will let you now which rotation you have.

Just for interest at this point here is a picture of a typical bi directional (radial/straight bladed) fan.

Notice how the blades come out from the centre, unlike the one in your picture.

They are not quite as good as ones designed for one direction of rotation, but are equally effective in either direction.

 

25109-bi-directional-fan-for-delco-19si-

Steve (Eeyore)

That makes sense, thanks very much. I'll doit on survey day.

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Right, i've been back to the boat today to attend it's survey.

 

I tried to work out what i was looking for on the alternator but couldn't. So i took a couple of photos in the hope that someone can tell me if i need a clockwise or an anti-clockwise replacement alternator?

 

Here are the photos.....

 

9637376447_ce6fa70afe_b.jpg

 

9637376755_902411baa8_b.jpg

 

The alternator that is on there at the moment is an LRA 127. My surveyor says this will not power my proposed 330AH battery bank that is going in next week. I plan to upgrade to the alternator mention earlier in this thread.

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Well the LRA 127 is 55A, the proposal is 70A so not a quantum change. I wouldn't put it as first priority when you get the new boat. A 70A alternator might take off 30 mins - 1hr from your charge time from 50% SoC, nothing much from charge time from 80%. On the other hand its fairly cheap so worth doing some time. The idea that it won't recharge your 330A bank is an exaggeration.

Edited by nicknorman

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Looks like the alt spins clockwise, I believe the alt should be able to spin either way and it's just the fan that's handed.

 

If the fan won't come off at at all easily maybe buy one with a fan or take it in to an alt rebuild place if there's one local, they might do a part exchange.

 

A 95A one might work OK, the belt has a goodly amount of wrap and is toothed on the inside, but bear in mind the need for good ventilation to work reliably.

 

cheers, Pete.

~smpt~

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Looks like the alt spins clockwise, I believe the alt should be able to spin either way and it's just the fan that's handed.

 

If the fan won't come off at at all easily maybe buy one with a fan or take it in to an alt rebuild place if there's one local, they might do a part exchange.

 

A 95A one might work OK, the belt has a goodly amount of wrap and is toothed on the inside, but bear in mind the need for good ventilation to work reliably.

 

cheers, Pete.

~smpt~

 

I disagree. I think this is an anti-clockwise alt. (looking face on) It will spin and work either way and make a charge, but will it cool effectively? TBH I think a little 70a alt will cool spinning either way with any fan.

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It's clockwise, nearly all are. I am spotting rust on there though and would like to know if the paint has cooked off the pulley as that is a sure sign of belt slip.

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Right, i've been back to the boat today to attend it's survey.

The alternator that is on there at the moment is an LRA 127. My surveyor says this will not power my proposed 330AH battery bank that is going in next week. I plan to upgrade to the alternator mention earlier in this thread.

Hello Junior

Firstly just buy a 70 amp A127 type alternator with a bi directional fan, you can't be wrong if you do that; in fact buy 2 as they are as cheap as chips and by far the most common type in use. Its always a good idea to cruise with a spare.

 

A little something just for info:

The alternator currently fitted is designed to rotate in a clockwise direction when viewed as per your latest photos.

I don't think its an LRA127 (Lucas aftermarket exchange part number - not the same as an A127 Type) as that is a 70 amp Jaguar part!

The issue is that it may well be being driven in an anti clockwise direction as this is quite common on "vintage" engines installed in the same configuration as yours; also a close look at the black plastic back cover in your original photos suggests some distortion, probably caused by excess heat.

The 70 amp A127 will definitely overheat (and melt the soldered connections) if driven anti clockwise with a clockwise fan fitted if connected to a substantial battery bank.

I know this because I changed a friends 55 amp for a 70 amp, just swapped the fan and pulley to the new alternator and refitted, didn't even occur to me at the time to check rotation as the change was an upgrade and not a repair. Little globules of solder fell out as I removed it, I covered the cost of the repair, and don't want anyone else to learn that way. Still interesting that the 55 amp alternator survived; must have been running very hot though.

Steve (Eeyore)

Edited by Eeyore

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Hello Junior

Firstly just buy a 70 amp A127 type alternator with a bi directional fan, you can't be wrong if you do that; in fact buy 2 as they are as cheap as chips and by far the most common type in use. Its always a good idea to cruise with a spare.

 

A little something just for info:

The alternator currently fitted is designed to rotate in a clockwise direction when viewed as per your latest photos.

I don't think its an LRA127 (Lucas aftermarket exchange part number - not the same as an A127 Type) as that is a 70 amp Jaguar part!

The issue is that it may well be being driven in an anti clockwise direction as this is quite common on "vintage" engines installed in the same configuration as yours; also a close look at the black plastic back cover in your original photos suggests some distortion, probably caused by excess heat.

The 70 amp A127 will definitely overheat (and melt the soldered connections) if driven anti clockwise with a clockwise fan fitted if connected to a substantial battery bank.

I know this because I changed a friends 55 amp for a 70 amp, just swapped the fan and pulley to the new alternator and refitted, didn't even occur to me at the time to check rotation as the change was an upgrade and not a repair. Little globules of solder fell out as I removed it, I covered the cost of the repair, and don't want anyone else to learn that way.

Steve (Eeyore)

 

 

Hmm,interesting infomation, thank you. I'm afraid all this thread has done is left me very confused as i am the least technical person you will ever meet.

 

Today i bought a 70amp A127 alternator from Marine Engine Services in Uxbridge. They told me i can do a straight swap with my current alternator. I mentioned that somebody had suggested i needed to get the fan round the right way and he said not to worry, it will be the same.

 

He was very helpful and gave me comprehesive instructions on how to do the job myself. I will have someone of far greater experience (forum member) around when it comes to doing the change, so hopefully if it isn't a simple case of doing a straight swap he will notice.

 

They did tell me at MES Ltd that i will probably need to change the connectors/terminals as they won't be the same. But they said this will be obvious and any chandlers will sell the correct ones.

 

I'll be keeping the alternator that is currently on there as a spare should it be needed as an emergency in the future. If for any reason we are uncertain that it is not going to be a simple swap, i will leave the old one in place and seek further help.

 

Thanks everyone for the comments and help so far!

Edited by junior

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