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moiuk

How hard can I drive my 95A alternator ?

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FWIW Beta build engine power plants to be be price competitive while satisfying what they thought would be the average demand for their perceived customer base (and looking at the OP's engine bay) - were not too space hungry.

IMHO what they have fitted to your '43  will not take kindly to running at peak power regularly - especially if it's been tweaked to go the extra mile.

What you need is a lorry / bus type unit.

If you can find out what was fitted (ask Beta very politely - with the engine number- what the unit and if you're lucky you'll find the standard power curves on the net. IIRC they used to fit ISKRA alternators - mid range kit....

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3 hours ago, jonesthenuke said:

You will not get full current (or anywhere near it at idle speed)

I never suggested he would. 

 

It’s very simple really. When charging, raise the engine revs until the current stops increasing. With LA the current will eventually start reducing and so the revs can be similarly reduced over time. With Lithiums the revs will need to remain high until the BMS switches off.

 

I hope OP has an LA dump load :)

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On our Beta 43 with 175A alternator, idle is 850 rpm and full output is available at around 950-1000 engine rpm, ie just a little above idle. It is all about the pulley ratios of course. When the rpm is increased above 1000rpm the max output doesn’t increase, but of course the cooling air flow does. Therefore as has been suggested, avoid running the engine at just enough rpm to get max output, instead run it quite a bit faster to lower the alternator internal temperature.

  • Greenie 1

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A different approach is to use that employed by Cereal Tiller. Bung a thermostat in/on the alternator somewhere which switches the field current (I think it was) on and off according to temperature, thereby turning the charge current on and off to prevent the machine temperature rising too high.

 

 

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Curious. If alternator fans draw air from back to front as someone stated earlier, isn't this opposite to the natural flow of air in a vehicle (from which many of these engines are spawned) where air is pushed front to back by the forward motion of the vehicle?

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1 minute ago, Stephen Jeavons said:

Curious. If alternator fans draw air from back to front as someone stated earlier, isn't this opposite to the natural flow of air in a vehicle (from which many of these engines are spawned) where air is pushed front to back by the forward motion of the vehicle?

Most engines mounted transverse these days?

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56 minutes ago, Stephen Jeavons said:

Curious. If alternator fans draw air from back to front as someone stated earlier, isn't this opposite to the natural flow of air in a vehicle (from which many of these engines are spawned) where air is pushed front to back by the forward motion of the vehicle?

 

 

The airflow underneath a car bonnet will be turbulent rather than laminar, very turbulent! So I take take with your assertion there is a.’natural flow’ under the bonnet caused by the forward motion if the vehicle. 

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On 08/06/2019 at 18:00, moiuk said:

I have a 95A alternator on my Beta 43 engine and looking at a Lithium install so it will pull pretty much the full amount of current that I configure it to from the alternator.

 

I would like to pull as much current from it as possible to recharge the batteries and reduce the amount of time I need the engine running, but also want to not destroy the alternator in the process.

 

 

Moiuk,

I have the same set up as you. A 2002 Beta 43 (with a flat poly V belt) driving the ISKR 90A alternator .....looks same as yours, feeding a 480Ahr bank of LiFePo4's. We've now been out for 6 weeks with them.

My biggest concern when fitting the Lithiums was the alternator, having read all sorts of stories of woe from the American site (Marine know how .....or wotever). I normally dont pay too much attention to detail there but you take your chance. These bog standard alternators are not meant for 100% duty. Small frame alternators are not designed for it. I decided to limit my output to 50A initially and see how it goes. I control my Amps out via a Sterling AtoB which allows me to change battery type settings....and on the lowest output setting I get 50A on start up which drops to around 40 something when the alternator gets hot. On tickover, when using locks, it drops to 30A but as soon as we are over 900rpm, its up to 40 odd A.

I am concerned over temperature. Belt wear seems fine. Temp in the middle of the top of the alternator is 90°C (via infrequent red thermometer). Temp of the housing above the didodes is circa 55-60°C. I am happy at that temperature and performance of the alternator has not changed in 100hrs of engine running (we only average 3 hrs every couple of days). For me, charging at 40A is acceptable as I know I will get 40A in rather than the 20A or 10A I would be seeing with LA's. I reckon I am running the engine half the amount I did last year on LAs but that is very dependent on how much sun.

Now, this week, once the sun goes in today, we wont see it again until the weekend and I will experiment and go to the next battery setting so likely to start with 60A going in decaying with the heat to 50A. I will keep a close watch on the temps and report back. I think that will be pushing it. I doubt these 90A alternators can work at more than 50% output continuously. I have been looking at replacements and Balmar claim to be one of the better ones, but even these are not rated at continuous output.

I am happy with ours giving 40A at revs and 30A at tickover ......and we can be in locks for 3 hours on long flights. I dont think I would like to see 60A at tickover on my engine.

Maybe worth asking @MoominPapa and @Tom and Bex how they are getting on with their alternators. Moominpapa has had his on for 4 months now and Tom has had his since last year, both relying on alternators to charge the lithiums.

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13 hours ago, Dr Bob said:

Moiuk,

I have the same set up as you. A 2002 Beta 43 (with a flat poly V belt) driving the ISKR 90A alternator .....looks same as yours, feeding a 480Ahr bank of LiFePo4's. We've now been out for 6 weeks with them.

My biggest concern when fitting the Lithiums was the alternator, having read all sorts of stories of woe from the American site (Marine know how .....or wotever). I normally dont pay too much attention to detail there but you take your chance. These bog standard alternators are not meant for 100% duty. Small frame alternators are not designed for it. I decided to limit my output to 50A initially and see how it goes. I control my Amps out via a Sterling AtoB which allows me to change battery type settings....and on the lowest output setting I get 50A on start up which drops to around 40 something when the alternator gets hot. On tickover, when using locks, it drops to 30A but as soon as we are over 900rpm, its up to 40 odd A.

I am concerned over temperature. Belt wear seems fine. Temp in the middle of the top of the alternator is 90°C (via infrequent red thermometer). Temp of the housing above the didodes is circa 55-60°C. I am happy at that temperature and performance of the alternator has not changed in 100hrs of engine running (we only average 3 hrs every couple of days). For me, charging at 40A is acceptable as I know I will get 40A in rather than the 20A or 10A I would be seeing with LA's. I reckon I am running the engine half the amount I did last year on LAs but that is very dependent on how much sun.

Now, this week, once the sun goes in today, we wont see it again until the weekend and I will experiment and go to the next battery setting so likely to start with 60A going in decaying with the heat to 50A. I will keep a close watch on the temps and report back. I think that will be pushing it. I doubt these 90A alternators can work at more than 50% output continuously. I have been looking at replacements and Balmar claim to be one of the better ones, but even these are not rated at continuous output.

I am happy with ours giving 40A at revs and 30A at tickover ......and we can be in locks for 3 hours on long flights. I dont think I would like to see 60A at tickover on my engine.

Maybe worth asking @MoominPapa and @Tom and Bex how they are getting on with their alternators. Moominpapa has had his on for 4 months now and Tom has had his since last year, both relying on alternators to charge the lithiums.

This is really very helpful. My backup plan is to switch it out for the 175a alternator, which should be a straight swap according to the engineer who serviced my beta, but I would rather not have to.

 

I also will be putting 480Ah of lithium in, but on days like today I don't want to run the engine for 5 hours, and so I really do want to charge at the max, which is around 90a with the 12/200 bms I have chosen.  3 hours vs. 5 hours is a big difference for me.  Interested in your findings, and I'll share mine too when my electrics are upgraded at the end of this month.

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1 hour ago, moiuk said:

I also will be putting 480Ah of lithium in, but on days like today I don't want to run the engine for 5 hours, and so I really do want to charge at the max, which is around 90a with the 12/200 bms I have chosen.  3 hours vs. 5 hours is a big difference for me.  Interested in your findings, and I'll share mine too when my electrics are upgraded at the end of this month.

 

LiFeP04 batts need using in the SoC band 20% to 80% really, so your 480AH bank will have a useable capacity of 288AH. 

 

288AH will be replaced in 3.2 hours at your specified 90A. And that is only after you have used 288AH in the first place. Where are you getting your five hours of engine running from? Are you accounting for your solar input (you DO have oodles of solar I take it?) too?  And the fact that you may not be draining the batts fully every day? What are you doing to burn 288AH a day anyway? I use about 60AH!

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Sorry to hijack the thread, but one of those posts got me wondering if anyone used a bilge blower or fan to bring cool air from outside into the engine room to reduce alternator temperature and also improve engine efficiency?

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3 hours ago, blackrose said:

Sorry to hijack the thread, but one of those posts got me wondering if anyone used a bilge blower or fan to bring cool air from outside into the engine room to reduce alternator temperature and also improve engine efficiency?

I had given some thought to this issue when I upgraded to a 90amp alternator and concluded that the engine was using a large volume of air just to run so my thinking was the engine was using hot air in the engine bay   replenished by air drawn from around the deckboards. I  simply fitted a clamshell vent to allow a lot more cool air to be drawn in. I coupled this with a computer fan directed onto the alternator. This arrangement seemed to work OK.

Phil

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4 hours ago, blackrose said:

Sorry to hijack the thread, but one of those posts got me wondering if anyone used a bilge blower or fan to bring cool air from outside into the engine room to reduce alternator temperature and also improve engine efficiency?

I have one extracting hot air from in front of the alternator, certainly reduces temperature can't say about efficiency.

  • Greenie 1

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Given the volume of air a1500 cc engine will consume at 1000 rpm I very much doubt a computer fan will make any appreciable difference. Positioning the air cleaner intake close to the front of the alternator might. When I fitted the "sound proof" case to my boat I kept the back/stern end board sitting on the engine beds so there is the full bed depth to suck air into the box and made sure the side vents in the cockpit upstand were of more than adequate size. I position the air cleaner spout pointing forwards and roughly in line with the front of the engine. I have had no indication of alternator overheating but this is with lead acid batteries.

 

As someone said, look into the possibility of finding a commercial vehicle alternator. Don't know if CAV AC5s are still available in 12V  second-hand.

 

I think the duckmaster has the right idea in starting with the maximum setting low and increasing it & monitoring it to assess the effect.

On 09/06/2019 at 23:26, Mike the Boilerman said:

 

A different approach is to use that employed by Cereal Tiller. Bung a thermostat in/on the alternator somewhere which switches the field current (I think it was) on and off according to temperature, thereby turning the charge current on and off to prevent the machine temperature rising too high.

 

 

 

On the alternator in question it would require surgery to break into the rotor circuit. If you do that you can then have total control over the output and even stop charging without a dump load.

 

 

 

 

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7 minutes ago, Tony Brooks said:

Given the volume of air a1500 cc engine will consume at 1000 rpm I very much doubt a computer fan will make any appreciable difference. 

Mine is not a computer fan, its a 3" snail blower something like this;

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F112559833366

Ducted up through the roof, good for warming hands on a winters day.

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10 hours ago, moiuk said:

 

I also will be putting 480Ah of lithium in, but on days like today I don't want to run the engine for 5 hours, and so I really do want to charge at the max, which is around 90a with the 12/200 bms I have chosen.  3 hours vs. 5 hours is a big difference for me.  Interested in your findings, and I'll share mine too when my electrics are upgraded at the end of this month.

Moiuk,

No, you are not thinking this through properly. You are still in Lead Acid mode. You dont need to run your engine each day.

Take the example of a 480Ahr bank (LA's). Lets say you use 150Ahrs per day. On a poor summers day you may get 20-50Ahrs in from Solar.....but today it will only be 10Ahrs. Ditto if you park under trees. So net input needed is 100Ahrs per day after solar. With LA's you had to run your engine 3 hrs + to get to 100% SoC. It is far better to do this everyday and cycle 100% down to 80% rather than 100% down to 60% and put the 5-6hrs back in every other day as the cycles to death is exponential. More engine running but longer battery life. You may be lucky and get a sunny day so your solar goes up but I tended to make sure I was full with the engine in case the sun didnt show up.

Now consider Lithiums. You dont need to go to 100%. So, start at full and park under trees. After day one you are 100Ahrs down, after two days you are 200 Ahrs down, after 3 days you are 300Ahrs down, so time to run the engine for an hour to get to 250Ahrs down. After 3 days maybe the sun will come out and put 100Ahrs in. If it doesnt a 3 hr motor to the next mooring will get you back to -100Ahrs. No need to go higher. So that is 4 hours of running compared to 2-3hrs per day on LA's. The key is topping up when needed for power the next day.....not having to get to 100% every other day.

With Lead Acids I found my solar (500W) was very inefficient with very often the mppt in float mode mid afternoon after a mornings cruise. The 3-4 hours motoring had filled the LA's and no room for any solar in the afternoon. Li's are SO different. We are never above 80% so there is oodles of room for all the solar can throw at it. If I know we are going to do a 4+hr day in a few days time then I will run the batteries right down and use the eberparcky thingy to heat the water rather than run the engine.

Now, in winter mode it will be different as you can forget solar (mostly), but most of the same holds true. More engine running needed but a lot of that will be when moored and you can crank the revs up and set the alternator power higher. No problem then about slow speed revs and high alternator demand, plus the air is colder.

Have a look at the graph below. It is our SoC% over the last 3 weeks. It goes up and down but never reaches 80-90% (the SoC has drifted on the BMV and is reporting about 5-10% too high...so take off 5% and it should be right....from the BMV voltage. I will probably take it back to 100% in 3-4 weeks time to re-set the SoC on the BMV). We tend to do 2-3 hours every other day with an hour of engine each day when we park to heat the water when we are not moving.

@Mike the Boilerman is right though, you really need to work out what your power demand will be. Our 150Ahrs per day is highish.....and a lot more than many peeps on here but we are on the boat most of the day and use a lot of 240V stuff.

Very interested to hear how you get on. It would be interesting to quiz Victron on the best alternators to use.  I think ultimately I will put a new alternator on but very nervous about a 175Ahr one as not sure if our engine is one of the ones where the key on the main shaft cant handle it. What age is your engine?

289 power mid may 3 weeks.png

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My problem is that I have calculated my energy usage to be high (Round 300Ah a day) and in planning for winter mode aka no solar, I do need to be running the engine each day. In summer sunny days i should get all of that from solar . I work from home/boat so will be running my desktop computer and a couple of monitors. Add to this my much needed nespresso machine to help me work, charging my tablet and phone, girlfriends 2 laptops (she works from home/boat too). And then the TV and microwave and even my girlfriends hairdryer....  we consume a lot of electricity and would like to live like this on the boat too.  I am trying to make the technology work for me rather than change how I work.

 

I think it will work, but reducing down the number of engine hours each day will make a significant difference over the months..

 

Driving the alternator I have harder might not work, but I'll give it a go and report back. Backup plan a) is to upgrade the alternator . Plan b) is to upgrade the battery charger and get a generator. These are obviously less desirable than making my current alternator work a bit harder..

 

All your suggestions so far have been really helpful in me checking the air flow and temperature of the alternator  and see if I can make it work.. thank you :)

 

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3 hours ago, Dr Bob said:

I think ultimately I will put a new alternator on but very nervous about a 175Ahr one as not sure if our engine is one of the ones where the key on the main shaft cant handle it. What age is your engine?

289 power mid may 3 weeks.png

 

 

Dr Bob, the damage to the keyway on early Beta 43 engines occurs when trying to drive 2 alternator and the 240 volt Travel Power alternator. Unless the boat had previously had a Travel Power which has already damaged the keys at it should be OK. If the keyway or key is damaged, then there will be slight movement on the pulleys when gently prised with a lever.

 

The early Beta 43 engines had the splined crankshaft extension cut off, and the short stub machined out to accept a keyway to hold the pulleys in place. The later ones (frome sometime in 2006 onwards) left the splined cranshaft extension in place and used splined pulleys to drive up to three alternators, so you can easily check which your engine is.

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52 minutes ago, cuthound said:

 

 

Dr Bob, the damage to the keyway on early Beta 43 engines occurs when trying to drive 2 alternator and the 240 volt Travel Power alternator. Unless the boat had previously had a Travel Power which has already damaged the keys at it should be OK. If the keyway or key is damaged, then there will be slight movement on the pulleys when gently prised with a lever.

 

So that gives me a bit more confidence I can put a bigger alternator on if mine fails. I am a bit worried about the load a bigger alternator would put on the engine at tickover speeds - which we end up for long periods of time at locks or when following slow boats past linear moorings. Being able to up the power output of the alternator when stationary however and increasing the revs will be a good option if I get a bigger alternator.

2 hours ago, moiuk said:

My problem is that I have calculated my energy usage to be high (Round 300Ah a day) and in planning for winter mode aka no solar,

 

Wow.  That is a lot of power.

Li's are the answer so you have made a good choice. I would defo get Victron to advise on the best choice of Alternator.

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8 hours ago, Tony Brooks said:

Given the volume of air a1500 cc engine will consume at 1000 rpm I very much doubt a computer fan will make any appreciable difference. 

 

I agree. I was thinking of installing a bilge blower next to a vent to bring in cool air.

Edited by blackrose

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1 hour ago, blackrose said:

 

I agree. I was thinking of installing a bilge blower next to a vent to bring in cool air.

I fitted a bilge blower to extract hot air from the engine space, it does stay cool.  One word of caution, the first one I bought was cheap and I did not realise but was only rated intermittently - it lasted a few months.  The replacement is now a couple of years old and still running fine.

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2 hours ago, Chewbacka said:

I fitted a bilge blower to extract hot air from the engine space, it does stay cool.  One word of caution, the first one I bought was cheap and I did not realise but was only rated intermittently - it lasted a few months.  The replacement is now a couple of years old and still running fine.

 

Do you think fitting it to extract hot air is a better idea than it pulling cool air in and the hot air simply being forced out of the vent on the opposite side of the boat? 

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10 minutes ago, blackrose said:

 

Do you think fitting it to extract hot air is a better idea than it pulling cool air in and the hot air simply being forced out of the vent on the opposite side of the boat? 

My thinking is if you site the blower where it will extract the hottest air (high up above the engine as hot air rises) it will reliably remove the hottest air.  Cold air inlets can be ducted to discharge by the alternator.  If you blow cold air in, it may blow across the engine space and straight out the vent so leaving pockets of hot air.  Most equipments also extract hot air rather than blowing in, so there must be a good reason for doing it that way.

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