Move or remove a trip-hazard alternator?

[Rendelf]

Hideehi wondrous canal-skaters!

 

 

Our engine room is a mess! The floor above the engine is held up by bits of wood, nailed into other bits of wood, which are glued to the paint on the hull..... several rust patches attest to the silliness of this plan! The glued bits of wood seem to be for guiding things like fuel lines ... not for load-bearing!

 

 

Eventually, I want to build a new platform above the engine, with a steel frame. It should be much quieter, boxed in. Even so, when walking between the engine room and the boat, we have to step over this great big alternator, which is often moving! One should not wear flowing cotton dresses when crossing this point, which is a shame.

 

We have two alts, one at 110Amps for the 450AH leisure (above) and a smaller one (90ish Amps) for cranking. The engine is an Isuzu 42. My plan of the moment, is to either move the larger alternator to the opposite side of the engine, or to just swap it with the smaller one.

 

If I move it, it'd have to be mounted not on the engine, but on a piece of steel I'd have fabricated, mounted on the same girder that the engine is mounted on.

 

If I swap it, the now lone alternator would have to charge both batteries. I don't think that this would be a problem..... both are charged by a fairly large solar panel; we stopped for two weeks without running the engine, and had no problems. That said, split relay charging systems have their own issues.

 

 

The 110A alternator is on the left here. I think it could be mounted on the girder on the right, if I invert it 180 degrees, keeping the wheels lined up. Not sure if the direction of travel matters, or if it can't be mounted on the not-engine. (I figure that the fanbelt with absorb any movement?)

 

 

Any ideas/input/abuse enthusiastically received!)

 

PS, it's nearly 3am, and I'm sat in the fields, in a canal drinking good scotch, using my laptop with wireless broadband, powered by solar energy*! Life is good.

 

.

*and a little bit of diesel

Edited May 20, 2015 by Rendelf

[MtB]

Hmmmm that's my style of boating too! Which good scotch, exactly?

 

I think the sticky outy alternator is best just removed and use the other one to charge both batteries. Most boats manage fine with one alternator but it depends on your leccy demands. You don't seem the type to need electric kettles, toasters, hair straighteners, 48" flat screen TVs etc. Computers use a fair bit of power if used all day and evening though.

 

Never mind split charging systems, I have a battery master switch on each of my battery banks and I just turn the starter battery isolator OFF when not cruising. Works well for me. Simple is ALWAYS better when you're me. Or even a bit like me.

 

 

MtB

 

 

 

(Edit to improve clarity.)

Edited May 20, 2015 by Mike the Boilerman

[blackrose]

I think I'd just live with it and avoid long flowing dresses, or build a floor and a wooden box around the alternator, painted red so it's a much more obvious trip hazard.

Edited May 20, 2015 by blackrose

[ROBDEN]

Can't you tuck your dress into your tights??

 

Rob....

[Barry]

I think the second alternator needs to mounted directly on to the engine, not to the boat structure.

 

Mounting the alternator to the engine means that as the engine moves on its flexible mountings the alternator moves in the exactly the same way in all three dimensions

 

Therefore, relative to each other, they are fixed. thus removing the constant stretching and flexing the alternator drive belt would be subject to. What that extra stress on the drive belt would do to the belt itself and the alternator shaft bearings, I'm not sure. But I can't see it being good for either.

[DeanS]

Your concern is justified. My last boat alternator was in the exact same position. It had a wire mesh protector around and over the engine, but there was a gap near the alternator. One of my kids trouser legs got sucked in by the belt, and luckily help was on hand to pull them out...ripped trouser legs and all. Very scary. You can get wire mesh to go over it, but make sure you do a good job of it.

 

 

this sort of thing round the engine....

 

Edited May 20, 2015 by DeanS

[Arthur Brown]

If you need the electrical output the you need to generate it safely. Polyvee belts are very fussy about tension -it must be right. all belts are fussy that they are correctly aligned. Can you simply raise the floor enough?

[Tony Brooks]

On the face of it changing the large alternator to the other side and fitting a split charge system (VSR) - sorry MIke - would probably answer as long as your power audit came out OK but there is a problem. You need an ordinary V belt to drive the water pump otherwise the engine will boil while the large output alternator may well eat ordinary V belts. Maybe you could get a pollyvee belt pulley for the water pump but even then water pump pulley will not line up with the pollyvee pulley on the crankshaft. I suspect you would struggle to source the parts you need to make such a conversion work as reliably as your existing system. My take on the problem is guard the alternator or box it in.

[DHutch]

I would move it, to the otherside, mounted to the engine.

 

 

Daniel

[bizzard]

I can't quite see properly but it might be possible to swing the alternator inwards by a couple of inches. If another bolt hole is drilled a couple of inches in from the present hole on the end of the adjustment bracket where it's attached to the engine and a shorter belt fitted.

[andyb116]

I have to agree with Bizzard's idea on this, I have done this in the past to the same engine and alt setup, only problem I found was the plastic protection on the back of the alt was hitting the protruding engine mounting stud, easily cured with a grinder and cut off disc, plus it looks like it would help take some of the tension off the main charging lead on the alt.

[Rendelf]

Hmmmm that's my style of boating too! Which good scotch, exactly?

 

Never mind split charging systems, I have a battery master switch on each of my battery banks and I just turn the starter battery isolator OFF when not cruising. Works well for me. Simple is ALWAYS better when you're me. Or even a bit like me.

 

 

It was 'Talisker Syke', brought to me direct from Skye! The run through the fields to catch a train the next morning did hurt though...

 

We don't use that much power. Laptops run from a DC>DC step up... all LED...we do have a screen, but it draws tiny amounts of juice, and runs on a native 12v

 

I'm not sure I understand your set up there.... does that mean that all the batteries are effectively the same bank when you are cruising, and that you then separate them when not? If that's the case, our cranking battery is quite a distance from the leisure bank... not good to have different lengths or connectors in a battery bank, but unsure if this remains the same when only charging?

[Rendelf]

Can't you tuck your dress into your tights??

 

Rob....

 

Tights don't work well with my hairy legs... I can use a garter, but then I'd want heels... and that's a whole other set of issues.

 

 

If you need the electrical output the you need to generate it safely. Polyvee belts are very fussy about tension -it must be right. all belts are fussy that they are correctly aligned. Can you simply raise the floor enough?

 

It's not an ideas solution, as that'd effectively make the door to the interior shorter.... but worth considering. It'd improve storage, but mean I'd have to stoop in the engine room.

 

 

On the face of it changing the large alternator to the other side and fitting a split charge system (VSR) - sorry MIke - would probably answer as long as your power audit came out OK but there is a problem. You need an ordinary V belt to drive the water pump otherwise the engine will boil while the large output alternator may well eat ordinary V belts. Maybe you could get a pollyvee belt pulley for the water pump but even then water pump pulley will not line up with the pollyvee pulley on the crankshaft. I suspect you would struggle to source the parts you need to make such a conversion work as reliably as your existing system. My take on the problem is guard the alternator or box it in.

 

Power would be fine. I'm unsure of how the V best drives the water pump..... shall have to do some (more) reading. My understanding is that the water pump cools the engine by circulating coolant (water?) through a radiator, which passes heat through a skin into the canal. It also circulates the (same?) cooling circuit.

 

I presume from what you say, that the V belt is the smaller belt that runs the smaller alt?

I can't quite see properly but it might be possible to swing the alternator inwards by a couple of inches. If another bolt hole is drilled a couple of inches in from the present hole on the end of the adjustment bracket where it's attached to the engine and a shorter belt fitted.

 

This is the less ideal plan.... but would increase system robustness... (2 alts are better than one?) I think the alt can be turned through about 70 degrees, so that it's higher up, but rotated away from the walk way.

 

Will have a look....... could run an angle grinder off the inverter...!

[Tony Brooks]

 

Power would be fine. I'm unsure of how the V best drives the water pump..... shall have to do some (more) reading. My understanding is that the water pump cools the engine by circulating coolant (water?) through a radiator, which passes heat through a skin into the canal. It also circulates the (same?) cooling circuit.

 

I presume from what you say, that the V belt is the smaller belt that runs the smaller alt?

 

 

The V belt is the thinner one of the two, the one closest to the engine. It runs over three pulleys, the crankshaft pulley that drives it, the engine water pump that is driven and the alternator that is driven. All three pulleys should use the same belt BUT the larger alternator needs a pollyvee belt because it would likely destroy ordinary V belts.

 

If you were to convert to a single alternator ideally it would be the larger one but that needs the wider belt and pulley and the driving (crankshaft) pulley for that belt is farther forward than the water pump and small alternator. this presents engineering challenges that probably make trying to do it a bad idea for many boaters.

 

The small alternator looks as if its around a 50 to 70 amp unit, I suspect 50, but can not read the label. If 50 amps is enough then you could disconnect the large alternator and use a split charge relay or 1,2,both, off switch to split the charge between the two banks but only you can work out if 50 amps or less is enough.

 

The engine water pump circulates coolant through a skin tank that should be a very thin but large area tank welded to the hull. IF there is no circulation through this tank the engine boils so the water pump must be driven.

 

The idea of drilling another hole in the large alternator's adjusting bracket so the alternator sits closer to the engine seems a good one to me that should be within the capabilities of most boaters. However I think the belt and pulley would still need guarding.

[David Mack]

My take on the problem is guard the alternator or box it in.

 

Boxing it in is the easiest option, but you would have to make sure that you maintain adequate airflow to keep the alternator cool. Not such as issue if you just use mesh, but that could look untidy and might still allow small fingers etc. access to moving parts.

[Rendelf]

I think that seeing as we're liveaboards and don't use much power, combined with the large solar panel and dual battery charger (which is currently putting out about 21V) - I might just remove the larger alt, make a relay for the other one, and see what happens.....

 

If we discover that when cruising, or in winter, we need more juice, I can try something else.

 

My understanding of charging both batteries with the single, 70A alt, is that the size matters not, but that the time to charge will simply increase. I.e. I'm not going to burn the smaller alt out, provided I don't run stupid loads when it's running.

 

Will also look at moving the existing mounting.

 

 

Thanks all for suggestions! Leaking stern gland and downright dangerous and unreliable wiring powering the bilge pumps currently takes precedent over working installations!.

[Arthur Brown]

Summer afloat is usually well supported by a solar array and a moderate generator. Deep winter is another story! You will need diesel generated power or mains shoreline.

 

Having a small alternator just means that the engine must run for longer to get the batteries full, or if the load is too great the batteries will never get to fully charged. When running the engine to make electricity the biggest generator that you can fit is a good plan! It gets the job done and over with in fewer hours and with less spend on diesel. Putting 2 BHP into a generator is a trifling task for any nb engine.

[Rendelf]

Thanks Arthur... I was (perhaps naively) thinking wind power for winter ..... the less we can use the engine, the better.

[MtB]

 

Having a small alternator just means that the engine must run for longer to get the batteries full, or if the load is too great the batteries will never get to fully charged. When running the engine to make electricity the biggest generator that you can fit is a good plan! It gets the job done and over with in fewer hours and with less spend on diesel.

 

Not necessarily in my experience!

 

A good deal depends on the capacity of the domestic battery bank, along with the depth of discharge. With my pair of 110 AH domestic batteries the 50 Amp alternator rarely charged at more than about 30 Amps on Reginald, and the only for a few minutes before subsiding to about 10 Amps. Aldebaran's charging system displays similar behaviour.

 

I remain to be convinced that just fitting a bigger alternator will necessarily charge the batteries any faster. As I understand it, the charge rate depends as much on the size, condition and SOC of the batteries as on the nominal peak output of the alternator. If the 50 Amp alternator is deciding to charge at 10 Amps, then a 130 Amp alternator would decide to charge at 10 Amps too.

 

To force faster charging I suspect one needs to add a third party controller that increases the output voltage of the alternator. The more clever ones fiddle with the charge rate in other ways too, I believe. The downside is you are relying on them being clever enough not to boil/mess up your batteries by charging them too rapidly or for too long.

 

 

MtB

Edited May 22, 2015 by Mike the Boilerman

[Rendelf]

 

Never mind split charging systems, I have a battery master switch on each of my battery banks and I just turn the starter battery isolator OFF when not cruising. Works well for me. Simple is ALWAYS better when you're me. Or even a bit like me.

 

 

MtB

 

 

 

(Edit to improve clarity.)

 

 

Does that mean that you have both babysits, arrange in parallel with the alternator?

[MtB]

Does that mean that you have both babysits, arrange in parallel with the alternator?

 

 

Assuming that's your autocorrect havin a larf and you meant batteries, then yes!

[Rendelf]

Parallel babysitters...provide equal care to one's offspring, regardless of their number?

 

So... Do alternators have a way of measuring SoC on batteries? Otherwise, wouldn't they overcharge?

 

If so, does arranging things this way confuse matters?

[Tony Brooks]

No they do not and in any case they do not need to. All the alternator needs to do is ensure that the maximum voltage it produces can not damage the batteries. Hence our typical 14 to 14.5 (ish) volts.

 

The basic rule is that the battery determines the charging current it will accept (at any given voltage) NOT the alternator. However if a battery wanted more current than the alternator can produce the alternator would reduce its voltage until the voltage was such that the battery only wanted the alternator's maximum current.

 

As long as the voltage regulator is working you can not overcharge the batteries. Paralleling the starter and domestic bank s no different to adding another parallel battery to the domestic bank.