Charging battery options

[Paul G2]

 

Sorry guys, don't mean to get at anyone, honest I must say that I do so often see things that Gibbo or Arnot or I have offered over the years regurgitated inappropriately and frequently it gets in the way. Everyone just falls over themselves to be helpful, which is nice. I think the best way to become competent is the same as anything else, carefully guided and supported hands on experience. Sometimes it is possible to diagnose at a distance. I recall once sending someone a replacement part for an alternator together with instructions on how to fit it to solve a problem diagnosed solely through the forum. I suspect there may be a diode blown in this alternator and if D+ is about a volt higher than B+ then that confirms it. Some things you see so many times y'know. Favourite saying of mine..... "if you don't know how it works, how the f**k do you expect to work out why it don't?" If you know the system and understand electricity then it is really surprising how easy it is to come up with a theory and suggest a test to prove it one way or another. It's also easy to get lost in a static of happy waggy tail guessing and the dreaded "Read a book" syndrome.

thinking about it, I could save myself a lot of repetition if I wrote and illustrated a couple of tutorials on alternators and starters.

 

 

You may be a fantastic electrician, but, if this thread is any indication, you are a horrible teacher. You've spent the vast majority of your time criticizing others who are legitimately trying to help, while offering only vague advice to the OP. Reading what you have written, you are probably correct in what you are saying, but the way you are saying it is of no help to the OP.

 

Obviously the OP has limited understanding of batteries and electricity. The best advice you could probably give to someone like that is to get someone like you out to look at their electrical system, pay a professional to sort things out for them. However, if you're going to try to help them sort things out themself, then you need to "hold their hand" and take them through the process step by step. The OP has a number of problems. First and foremost, as you suggested, is to determine if his alternator is working properly and, if not, how to diagnose and repair/replace the alternator. After that is to determine if his batteries are any good and after that is to decide on a charging regimen that will keep his batteries charged. In this day and age, that regimen would logically include solar as running one's main engine every day to charge batteries is not an efficient use of resources.

 

Your idea of writing some tutorials is a good one. You could save them in Word and then copy and paste into threads like this. It would save you a lot of typing and be of tremendous benefit to people like the OP - certainly a lot more benefit than just ragging on the people who are trying to help. I apologize for being sanctimonious, but you apparently have valuable expertise that you are willing to share, you just seem to be going about it in a rather peculiar way.

[Tony Brooks]

Tried the tutorial/guide idea and made them freely available BUT it simply does not work. Gibbo got well peed off with people ignoring him and got very shirty at times. All I see is SirN being treated the same way. I think his tone is a reflection on the way he feels the forum is treating the OP and himself.

 

I kept out of this thread because I was pretty certain it would turn out like it has.

 

It took several posts before the OP decided to give us a voltage reading and many more before we got a second one. What is NOW clear is the the batteries are probably now very badly suphated and within the limits of what the OP has seen fit to tell us his alternator is probably faulty - even though the warning lamp is going out.

 

Now in this situation it is madness to push solar as the first option and that is the message much of the early posts seemed to concentrate on. Sir N is correct, the charging system needs diagnosing and if I was not away on holiday I would do if for the OP (living in Reading). Only then should the OP look at solar as a means of AUGMENTING his alternator charging and in that way making his charging systems better fit his lifestyle.

 

SirN and myself (on the basis of what we have been told) suspect that he may have a main diode failed in the alternator - we do not know, but it looks like it may be.

 

There is no easy way in this area. Each boater has to do some work and understand how his systems work or have a very large wallet to diagnose things properly. I said as much in a related thread less than a week ago yet the OP and others seem not to look back at a few threads and then certain people seem to get a bit upity when .someone who knows about the things in question gets frustrated at apparently being ignored.

 

Solar is not suitable as the sole charging system for a heavy electrical use narrowboat. To make it so in winter would be, in my view, uneconomic and possibly impossible because of space for panels. Engine, generator or shoreline charging will be needed at times to supplement the solar.

 

A livabord with frugal electrical needs may well find solar is adequate for much of the year at an economic price but a backup will be required in some periods if battery damage is not to ensue.

 

Solar is excellent as an auxiliary charging system that is used to prolong the period between long engine runs or shore line use or to fully charge the batteries while the boater is back home.

 

Which ever way you look at it effective solar would almost certainly cost far more getting the OP's charging system sorted.

[RLWP]

 

You may be a fantastic electrician, but, if this thread is any indication, you are a horrible teacher. You've spent the vast majority of your time criticizing others who are legitimately trying to help, while offering only vague advice to the OP. Reading what you have written, you are probably correct in what you are saying, but the way you are saying it is of no help to the OP.

 

 

 

Off-Topic

 

It is tricky trying to be helpful to a poster with a problem and at the same time be nice to people making suggestions you know are inappropriate. The worst I find is handling false hope based on wrong information.

 

Richard

[smileypete]

Often with these sort of topics the original poster is non technical, and probably wants to stay that way - if they can possibly help it...

 

So while I'm a diehard fan of diagnosing things systematically (and people who want to do otherwise are maddeningly frustrating ), I'm actually coming round to the view that an initial simple 'probabilistic' answer could be best, then IF the original poster comes back with more info and shows further interest, add the details a stage at a time.

 

So in this case from the initial low charge voltage reading it could be say an 80% chance of a loose belt or cooked alt. If the belt tension is fine, a local alternator rebuild place will be able to check the alt, but failing that, to diagnose it more accurately means getting hold of a multimeter. For check belt tension a google search may turn up some useful help:

 

https://www.google.co.uk/search?q=alternator+belt+tension+check

 

 

There is no easy way in this area. Each boater has to do some work and understand how his systems work or have a very large wallet to diagnose things properly. I said as much in a related thread less than a week ago yet the OP and others seem not to look back at a few threads and then certain people seem to get a bit upity when .someone who knows about the things in question gets frustrated at apparently being ignored.

 

Dunno if you're still involved with the course, but something I thing could be of great help to the students is to give them some feel of what happens over a typical batt charge cycle, like what happens with the voltage and current plus the importance of correct charge voltage.

 

cheers, Pete.

~smpt~

[nb Innisfree]

Folk often want a simple answer, problem is it's rarely simple.

 

Before a question is asked some basic knowledge is required to enable the questioner to know how to ask and therefore understand the answers and be able to pick out the best ones.

 

Chicken and egg I think.

[mibix]

Thanks everybody. Here's a load more information, I hope it helps clear anything up......

 

I'm pretty competent with electronics and DC in general. I've made quite a few Arduino projects, and I'm handy with a soldering iron. Engines, battery charging and alternators are not my strong points however...

 

I recently replaced the alternator belt as my old one was shot and snapped. I replaced it from a thin one with teeth, to a thicker solid one at the advice from an engineer who replaced the flexible coupling and engine mounts.

 

I have tightened the belt as much as I can - it could be tightened a little bit more, but I can't get the alternator to budge any further (2 of us used thick mooring pins to lever it and there's about 15-20mm of give when you press the belt down. Unfortunately, the alternator is not mounted to the engine, it's mounted to the hull, as the engine bracket has snapped, so there is a little bit of movement when the engine is on.

 

I disconnected 1 battery, so we were just using 2x110Ah batteries. Yesterday afternoon, the batteries were about 11v (my voltmeter gauge on the instrument panel is slightly out - my multimeter always showed about 0.3v higher than the gauge in the past). I left the engine running with high revs for a while - gauge showed 13v whilst charging. We turned off the engine, and went to the pub so that we didn't use any power, and let the float voltage balance out.

 

When we got back, the gauge was now showing 12v - it's charged a bit, and held it. We didn't use any power before bed. This morning the gauge still showed around 12V. So the battery still seems to have held its charge. My multimeter needs a new 9V battery, which I don't have - when turned on it shows a default reading somewhere between -0.1 and -0.4V. I don't have a new battery so can't do accurate readings until I get one.

 

I turned on the engine this morning, and the charge voltage was still 13V. I tightened the alternator as best I could again before starting the engine.

 

So yesterday, batteries were 11V, charge voltage was 13V, today batteries are 12V and charge voltage is still 13V.

 

I have some thick battery cable, but no lugs. I will get some lugs, and see if the B+ if giving out a different voltage than the spade connections. I will also get a new battery for my multimeter, and do some accurate readings.

 

My batteries have a little traffic light system on them - a little indicator that changes colour. Green = Good condition, White = Needs Charging, Black = Bloxed battery. All batteries are green.

 

I could do with replacing a lot of the cabling as the loom is very messy, and god knows where some of the wires are going.

 

I hope this clears up anything.

Edited July 9, 2014 by mibix

[mibix]

I'm not afraid to get stuck in and dirty. As I said I'm not that good with the engine/alternator side of things, but I am technically minded and willing to learn, diagnose and generally do as much as I can.

 

If there's a systematic method I can go through to test the whole system, I'm all for it. I installed the domestic batteries and voltage sensing relay myself. The engineer who came to fix an engine problem had a quick look at all the connections, and commented that it was set up correctly, and I'd done a proper job with the connections, so I wouldn't say I'm afraid of it getting technical and doing it proper!

 

Thanks for all your help and comments so far.

[by'eck]

Thanks everybody. Here's a load more information, I hope it helps clear anything up......

 

I'm pretty competent with electronics and DC in general. I've made quite a few Arduino projects, and I'm handy with a soldering iron. Engines, battery charging and alternators are not my strong points however...

 

I recently replaced the alternator belt as my old one was shot and snapped. I replaced it from a thin one with teeth, to a thicker solid one at the advice from an engineer who replaced the flexible coupling and engine mounts.

 

I have tightened the belt as much as I can - it could be tightened a little bit more, but I can't get the alternator to budge any further (2 of us used thick mooring pins to lever it and there's about 15-20mm of give when you press the belt down. Unfortunately, the alternator is not mounted to the engine, it's mounted to the hull, as the engine bracket has snapped, so there is a little bit of movement when the engine is on.

 

I disconnected 1 battery, so we were just using 2x110Ah batteries. Yesterday afternoon, the batteries were about 11v (my voltmeter gauge on the instrument panel is slightly out - my multimeter always showed about 0.3v higher than the gauge in the past). I left the engine running with high revs for a while - gauge showed 13v whilst charging. We turned off the engine, and went to the pub so that we didn't use any power, and let the float voltage balance out.

 

When we got back, the gauge was now showing 12v - it's charged a bit, and held it. We didn't use any power before bed. This morning the gauge still showed around 12V. So the battery still seems to have held its charge. My multimeter needs a new 9V battery, which I don't have - when turned on it shows a default reading somewhere between -0.1 and -0.4V. I don't have a new battery so can't do accurate readings until I get one.

 

I turned on the engine this morning, and the charge voltage was still 13V. I tightened the alternator as best I could again before starting the engine.

 

So yesterday, batteries were 11V, charge voltage was 13V, today batteries are 12V and charge voltage is still 13V.

 

I have some thick battery cable, but no lugs. I will get some lugs, and see if the B+ if giving out a different voltage than the spade connections. I will also get a new battery for my multimeter, and do some accurate readings.

 

My batteries have a little traffic light system on them - a little indicator that changes colour. Green = Good condition, White = Needs Charging, Black = Bloxed battery. All batteries are green.

 

I could do with replacing a lot of the cabling as the loom is very messy, and god knows where some of the wires are going.

 

I hope this clears up anything.

 

Tightening the alternator belt the way you have described suggests it may be over-tight and so wear the alternator rotor shaft bearings prematurely. Its difficult to describe the ideal tension but most workshop manuals show a movement of a half inch either way on longest belt run when moderate finger pressure is applied.

 

I wouldn't take too much notice of your sealed battery indicators. Even if they are working properly the batteries needs to be shaken slightly to get them to give a true reading.

 

First I would check the accuracy of the voltmeter you are using. You keep mentioning you only ever see13 volts (at batteries, alternator or both?) when engine is running. If this is from one of those cheap engine panel battery meters with range coloured in red and green, I would ignore it and measure with a good quality multimeter on DC volts range.

 

Not sure if you have mentioned the output amps of your alternator. If its a relatively low current (50 amp or less) one, even just 3 x 110 Ah flat batteries will hold its output voltage low whilst it works flat out giving close to its max current. This assumes its working correctly and doesn't have say a blown diode which would severely limit its performance.

 

Even if your means of measuring voltage is correct, don't get too excited about 12 volts, since it equals almost completely flat battery. With fully charged batteries I would expect, and get myself around 12.8 volts under the same circumstances you describe.

 

Carry out the other voltage tests you intend to do with an accurate and working meter and let us know. A clamp on DC amp meter (not too expensive on eBay) is a useful diagnostic tool. With accurate both voltage and current measurements to batteries under charge, a lot can be diagnosed.

[Paul C]

Thanks everybody. Here's a load more information, I hope it helps clear anything up......

 

I'm pretty competent with electronics and DC in general. I've made quite a few Arduino projects, and I'm handy with a soldering iron. Engines, battery charging and alternators are not my strong points however...

 

I recently replaced the alternator belt as my old one was shot and snapped. I replaced it from a thin one with teeth, to a thicker solid one at the advice from an engineer who replaced the flexible coupling and engine mounts.

 

I have tightened the belt as much as I can - it could be tightened a little bit more, but I can't get the alternator to budge any further (2 of us used thick mooring pins to lever it and there's about 15-20mm of give when you press the belt down. Unfortunately, the alternator is not mounted to the engine, it's mounted to the hull, as the engine bracket has snapped, so there is a little bit of movement when the engine is on.

 

I disconnected 1 battery, so we were just using 2x110Ah batteries. Yesterday afternoon, the batteries were about 11v (my voltmeter gauge on the instrument panel is slightly out - my multimeter always showed about 0.3v higher than the gauge in the past). I left the engine running with high revs for a while - gauge showed 13v whilst charging. We turned off the engine, and went to the pub so that we didn't use any power, and let the float voltage balance out.

 

When we got back, the gauge was now showing 12v - it's charged a bit, and held it. We didn't use any power before bed. This morning the gauge still showed around 12V. So the battery still seems to have held its charge. My multimeter needs a new 9V battery, which I don't have - when turned on it shows a default reading somewhere between -0.1 and -0.4V. I don't have a new battery so can't do accurate readings until I get one.

 

I turned on the engine this morning, and the charge voltage was still 13V. I tightened the alternator as best I could again before starting the engine.

 

So yesterday, batteries were 11V, charge voltage was 13V, today batteries are 12V and charge voltage is still 13V.

 

I have some thick battery cable, but no lugs. I will get some lugs, and see if the B+ if giving out a different voltage than the spade connections. I will also get a new battery for my multimeter, and do some accurate readings.

 

My batteries have a little traffic light system on them - a little indicator that changes colour. Green = Good condition, White = Needs Charging, Black = Bloxed battery. All batteries are green.

 

I could do with replacing a lot of the cabling as the loom is very messy, and god knows where some of the wires are going.

 

I hope this clears up anything.

 

If you're measuring voltages to 0 decimal places, then its not accurate enough to diagnose things properly (as by'eck's post also says). The battery green/red/black is to do with specific gravity of ONE CELL and is also too inaccurate for any meaningful diagnosis (except when a battery is obviously completely dead). Yep, your multimeter will need a few battery to measure accurately, PP3 probably. Worth getting though - can you borrow one (TEMPORARILY!!!) from a smoke alarm?

[mibix]

Coo

 

 

Tightening the alternator belt the way you have described suggests it may be over-tight and so wear the alternator rotor shaft bearings prematurely. Its difficult to describe the ideal tension but most workshop manuals show a movement of a half inch either way on longest belt run when moderate finger pressure is applied.

 

I wouldn't take too much notice of your sealed battery indicators. Even if they are working properly the batteries needs to be shaken slightly to get them to give a true reading.

 

First I would check the accuracy of the voltmeter you are using. You keep mentioning you only ever see13 volts (at batteries, alternator or both?) when engine is running. If this is from one of those cheap engine panel battery meters with range coloured in red and green, I would ignore it and measure with a good quality multimeter on DC volts range.

 

Not sure if you have mentioned the output amps of your alternator. If its a relatively low current (50 amp or less) one, even just 3 x 110 Ah flat batteries will hold its output voltage low whilst it works flat out giving close to its max current. This assumes its working correctly and doesn't have say a blown diode which would severely limit its performance.

 

Even if your means of measuring voltage is correct, don't get too excited about 12 volts, since it equals almost completely flat battery. With fully charged batteries I would expect, and get myself around 12.8 volts under the same circumstances you describe.

 

Carry out the other voltage tests you intend to do with an accurate and working meter and let us know. A clamp on DC amp meter (not too expensive on eBay) is a useful diagnostic tool. With accurate both voltage and current measurements to batteries under charge, a lot can be diagnosed.

 

 

 

If you're measuring voltages to 0 decimal places, then its not accurate enough to diagnose things properly (as by'eck's post also says). The battery green/red/black is to do with specific gravity of ONE CELL and is also too inaccurate for any meaningful diagnosis (except when a battery is obviously completely dead). Yep, your multimeter will need a few battery to measure accurately, PP3 probably. Worth getting though - can you borrow one (TEMPORARILY!!!) from a smoke alarm?

 

Cheers guys. I'm going to order a clamp-on ammeter now (off the internet, unless you know a shop that will sell them), but won't get it for a couple of weeks (going to my parents in a couple of weeks and will order it to there). Should I order a -30:30 or -75:75? I presume the -75:75 as my alternator is a 70-amp one...

 

Here's the manual for my alternator... http://www.prestolite.com/literature/alts/PP1184_Buyer_Guide_alt.pdf - it's the AS123 - connections shown on page 33. It's currently connected by the 2 ++ spade connecters, and not the B+ connector. I'll pop to the co-op and get a 9V battery for my multimeter today. I'll also see if I can find some lugs in my box of bits to connect the B+ instead of the spade connectors.

 

By-'eck, do you mean that the alternator will always show a low voltage when charging flat batteries? Yes, the 13V reading is one of the panel ones, but it doesn't have green/red - it simply has a range. I did some measurements with my mulitimeter at the batteries, and saw a slowly rising voltage, even with the dodgy readings. Will do some proper readings after I've replaced the battery in the multimeter.

 

PS. I just gave the batteries a shake, and the colour things have gone to the "Needs Charging" state.

Also, the output of the alternator goes to the starter, then to the batteries. The earth goes from a mounting nut, to the starter, to the battery. Should I check the voltage at both the battery and the alternator? If I'm checking from the alternator, shall I check at the starter (it's only a few inches from the alternator) or from the spade terminals on the alternator? I presume it's safe to stick the multimeter probes on the connectors even though a fair few amps will (probably) be kicking out?

 

Cheers

[Tony Brooks]

 

snip

 

 

Dunno if you're still involved with the course, but something I thing could be of great help to the students is to give them some feel of what happens over a typical batt charge cycle, like what happens with the voltage and current plus the importance of correct charge voltage.

 

cheers, Pete.

~smpt~

 

No, I gave both courses up but did make what is needed clear to the chap RCR asked to run the electrical one.

 

That is exactly what I spent some time doing because it is useless relying on voltage and amperage readings for alternator diagnosis that are taken at the same time. I agree that this is possibly the most vital thing boaters need to get their heads round. The we need to tattoo 12 volts does not indicate a fully charged battery on the inside of their eyelids.

[by'eck]

 

By-'eck, do you mean that the alternator will always show a low voltage when charging flat batteries? Yes, the 13V reading is one of the panel ones, but it doesn't have green/red - it simply has a range. I did some measurements with my mulitimeter at the batteries, and saw a slowly rising voltage, even with the dodgy readings. Will do some proper readings after I've replaced the battery in the multimeter.

 

PS. I just gave the batteries a shake, and the colour things have gone to the "Needs Charging" state.

 

Cheers

 

It will show a lower voltage yes. With a fully functioning alternator, the voltage should initially rise quickly above the 12 volts you measured with the batteries off load (flat batteries) as soon as the engine is started and running at a fast idle. Typically this rise will slow to the point where its almost stationary in the 13 to 14.4 volt range dependant on alternator and battery capacity, until the batteries approach near full charge (which will likely be several hours), when the alternators regulator fixing the voltage at a typical 14.4v, will cause the charge current to tail off.

 

Glad you are now aware of the vagaries of those tell-tale indicators.

[smileypete]

Couple of the cheaper DC clamp ammeters are the Mastech MS2108A and Unitrend UT203, probably quite similar though the former takes 3x AAA batts which I'd prefer, eg:

 

http://www.ebay.co.uk/itm/NEW-MS2108A-Digital-Clamp-Meter-Multimeter-AC-DC-Current-Volt-Tester-/221477764736

http://www.ebay.co.uk/itm/UT203-Clamp-LCD-Digital-Multimeter-AC-DC-Volt-Amp-Meter-Ohm-Hz-Tester-/251487494091

 

There are cheaper clamp ammeters around but these only measure AC current so no much use on a boat.

 

cheers, Pete.

~smpt~

Edited July 9, 2014 by smileypete

[Sir Nibble]

Right, looked at the manual and ID'd the type and connections. Firstly, you do need to move the main connection to the stud B+ terminal. The spade connectors in the euro plug are only rated at 30A each and are prone to heat damage. I am delighted to hear that you are up to speed on DC and electronics. The output from the alternators ac is passed through a 3 phase bridge rectifier with two sets of +ve diodes, one to output and one to supply excitation current to the coil generating the magnetic field that drives excitation of the ac. The voltage regulator also reads this voltage to determine alternator output. If one of the main +ve output diodes fails, then this will clearly seriously reduce the output, however, the regulator is watching a different output from different diodes and fails to compensate. I suspect either a diode failure as I have described, or a serious volt drop between alternator and starter, possibly the terminals on the alternator.

Sorry for being a crap teacher, though I have won awards for my classroom work.

Oh yea, thanks Tony, right on the button.

[Tony Brooks]

I have concerns about the belt. The "one with teeth" is a notched belt and is designed to drive round smaller diameter pulleys than the "solid" belts. Typically marine alternators use small pulleys so they still charge at idle speed. I doubt this is the immediate problem but notched belts would be my choice for marine work.

 

Next V belts come in a variety of cross sections and need to be matched to the pulleys in use. They should not be changed for a different profile unless you know what you are doing. Going "thicker" is less likely to cause problems than going thinner although they may still slip and wear faster than the correct profile.

 

I am not impressed with your engineer although your way of fitting a split charge relay is fairly typical. You need to minimise the current flowing through the relay contacts so you get a long life. The way to do this is to connect the alternator direct (via the master switch for the BSS) to the domestic bank and the use the relay to link the domestic bank to the engine battery.

 

I have just realised that if the charging voltage really is only 13 volts then the relay may not close so the domestic bank may not be getting any charge.

 

Definitely get a good lug connection onto B+.

 

Then stick the voltmeter between the B+ and the warning lamp terminal with the engine revving. If it reads close to 1 volt or above then SirN is correct, get it to Burghfield Alternator & Starter Services behind the Esso garage or Thames Valley Electro Diesel in the industrial estate by Morrisons.

 

Once that is sorted I would put the voltmeter between the B+ terminal and domestic positive and rev the engine. Expect less than 0.5 volt (0.3 is better). If its higher do the same across the domestic maser switch, then each lead in the main positive charging cable.

 

Do the same from the alternator case or B- terminal to the battery negative terminal.

 

On no account accept as much as 1 volt of voltdrop.

[Sir Nibble]

I don't think it necessary to check any further towards the battery than the starter for this level of volt drop, if it were any further I doubt the starter would work.

[Phil Ambrose]

On behalf of many I would like to thank Sir Nib and Tony for their sensible input and long may they do so.

Phil

[mibix]

Thanks everybody for your help.

 

I have concerns about the belt. The "one with teeth" is a notched belt and is designed to drive round smaller diameter pulleys than the "solid" belts. Typically marine alternators use small pulleys so they still charge at idle speed. I doubt this is the immediate problem but notched belts would be my choice for marine work.

 

Next V belts come in a variety of cross sections and need to be matched to the pulleys in use. They should not be changed for a different profile unless you know what you are doing. Going "thicker" is less likely to cause problems than going thinner although they may still slip and wear faster than the correct profile.

 

I am not impressed with your engineer although your way of fitting a split charge relay is fairly typical. You need to minimise the current flowing through the relay contacts so you get a long life. The way to do this is to connect the alternator direct (via the master switch for the BSS) to the domestic bank and the use the relay to link the domestic bank to the engine battery.

 

I have just realised that if the charging voltage really is only 13 volts then the relay may not close so the domestic bank may not be getting any charge.

 

Definitely get a good lug connection onto B+.

 

Then stick the voltmeter between the B+ and the warning lamp terminal with the engine revving. If it reads close to 1 volt or above then SirN is correct, get it to Burghfield Alternator & Starter Services behind the Esso garage or Thames Valley Electro Diesel in the industrial estate by Morrisons.

 

Once that is sorted I would put the voltmeter between the B+ terminal and domestic positive and rev the engine. Expect less than 0.5 volt (0.3 is better). If its higher do the same across the domestic maser switch, then each lead in the main positive charging cable.

 

Do the same from the alternator case or B- terminal to the battery negative terminal.

 

On no account accept as much as 1 volt of voltdrop.

Thanks for a detailed explanation. I'll get on it ASAP.

The original belt was a thicker 'teeth' type, and that bust due to the lack of engine mounts putting mega strain on the belt. We bought a new one, but that was a frail, thin one. The new belt we got was from Aldermaston Marina. We got the original sized belt, but solid instead of teethed at their recommendation. The new belt sits in the pulley snugly.

I'll have a look at the wiring.The relay is rated at 100A.

Couple of the cheaper DC clamp ammeters are the Mastech MS2108A and Unitrend UT203, probably quite similar though the former takes 3x AAA batts which I'd prefer, eg:

 

http://www.ebay.co.uk/itm/NEW-MS2108A-Digital-Clamp-Meter-Multimeter-AC-DC-Current-Volt-Tester-/221477764736

http://www.ebay.co.uk/itm/UT203-Clamp-LCD-Digital-Multimeter-AC-DC-Volt-Amp-Meter-Ohm-Hz-Tester-/251487494091

 

There are cheaper clamp ammeters around but these only measure AC current so no much use on a boat.

 

cheers, Pete.

~smpt~

 

I was looking at this ammeter.. http://www.ebay.co.uk/itm/CLIP-ON-TEST-METER-AMMETER-AMP-GAUGE-75-0-75-CURRENT-INDUCTION-INDICATOR-DURITE-/251563333315?pt=UK_CarsParts_Vehicles_BoatEquipment_Accessories_SM&hash=item3a9257d6c3

 

It turns out that my multimeter is knackered and not a flat battery so these you've suggested look perfect - hit 2 birds with one stone!

 

Right, looked at the manual and ID'd the type and connections. Firstly, you do need to move the main connection to the stud B+ terminal. The spade connectors in the euro plug are only rated at 30A each and are prone to heat damage. I am delighted to hear that you are up to speed on DC and electronics. The output from the alternators ac is passed through a 3 phase bridge rectifier with two sets of +ve diodes, one to output and one to supply excitation current to the coil generating the magnetic field that drives excitation of the ac. The voltage regulator also reads this voltage to determine alternator output. If one of the main +ve output diodes fails, then this will clearly seriously reduce the output, however, the regulator is watching a different output from different diodes and fails to compensate. I suspect either a diode failure as I have described, or a serious volt drop between alternator and starter, possibly the terminals on the alternator.
Sorry for being a crap teacher, though I have won awards for my classroom work.
Oh yea, thanks Tony, right on the button.

 

Thanks for explaining it all. It makes more sense than ever. You're a better teacher than you think!

 

 

Thanks to everyone for your help. I'm going to ask the local post office tomorrow if I can get the ammeter/multimeter posted there so I can get it in the next couple of days instead of waiting a couple of weeks 'till I go to my parents.

 

Thanks again for all your help. I'll go though all the steps you have said, and report back with the outcome (good or bad!)

[by'eck]

Thanks everybody for your help.

 

I was looking at this ammeter.. http://www.ebay.co.uk/itm/CLIP-ON-TEST-METER-AMMETER-AMP-GAUGE-75-0-75-CURRENT-INDUCTION-INDICATOR-DURITE-/251563333315?pt=UK_CarsParts_Vehicles_BoatEquipment_Accessories_SM&hash=item3a9257d6c3

 

 

 

Something like this or this would be far more versatile and little more expensive. More in line with the suggestions you have received.

 

With respect the device you linked to looks little more than a toy.

Edited July 10, 2014 by by'eck

[George94]

I suspect that the "for some reason" is "hey! it worked for me, now I'm an expert!" Which is a great deal easier than gaining the required knowledge to actually know what you're doing. In my experience this comes from an apprenticeship and college, you can't short cut it by becoming an instant pro from an internet forum. Trouble is, the OP can't tell a pro from someone who is recirculating inappropriate advice from another thread.

No way would I shell out for solar panels based on a guess.

 

Nobody said that you should do so based on a guess. But whatever the cause of his present discontent, solar panels are the best way to replenish batteries for 9 months of the year, if a mains connection is not available. They should be fitted anyway.

[Sir Nibble]

A different discussion I think.

[George94]

Thanks for explaining it all. It makes more sense than ever. You're a better teacher than you think!

 

There was never any doubt about Sir N's qualities on this side of the Atlantic.

A different discussion I think.

 

Indeed.

[mibix]

Hello!

 

I've ordered one of the clamp on ammeter/multimeters, but won't get it until next week when I go see my folks. I rang up the Diesel Engine place near Morrisons in Reading, and they said they'd check the alternator for a fiver. I took it there and they said it's all fine.

 

I've replaced the 2 spade connections with a proper lug connection and nice thick cable (the spades were actually corroded/dirty). I removed a load of the cables, gave the terminals and connections a clean, and made sure everything was tight.

 

I've re-installed it, and it seems much better... The dash gauge shows a bigger increase in extra voltage when charging than before (don't have my ammeter yet for proper tests), and I stuck the inverter on with some appliances, and didn't see a major drop in voltage.

 

The alternator is getting hot (I presume that's because it's actually kicking out some major power nows). I've just charged 30 mins, and will let it cool, and do the same again after a walk to Morrisons.

 

I'm going to go though the whole electrical system, and tidy it all up and label everything at some point soon. Everything's a mess - Just a messy loom of wires (especially behind the instrument panel). At least then I know what's what, and can check bad earths and shorts. And install a proper fuse box. And busbars instead of the mess that's there. A whole overhaul is probably needed!

 

Is the alternator supposed to get hot? Is it because it's now supplying all it can to charge the batteries? I let it cool down, and it's not getting hot without being on (was worried it was pulling in power from the battery).

We plan to go for a full days cruise tomorrow. Will the alternator be OK being hot for so long?

Cheers

[Tony Brooks]

Yes they do get hot, some can almost burn you after they have been on high output for a while.

 

I forget what engine you say you have but if its an air cooled Lister make sure the alternator fan is either a universal one or one for the correct alternator rotation. The wrong handed fan makes them get much hotter and could fry them.

[mibix]

Yes they do get hot, some can almost burn you after they have been on high output for a while.

 

I forget what engine you say you have but if its an air cooled Lister make sure the alternator fan is either a universal one or one for the correct alternator rotation. The wrong handed fan makes them get much hotter and could fry them.

 

Hi. It's a raw water cooled Yanmar YSE12.

 

Glad to know it's safe to go! :0

 

Cheers