House bank not charging

[undercutter]

Originally Posted by Hadjiosif

Jacana, what you described is normal. The engine will charge ONLY the battery bank that was used to start that engine...unless you switch the the switch to the other bank or both.

Except he is talking about the house bank, not the independent starter batteries, isolated, one for each engine.

[kas_1611]

Originally Posted by Wotname

Whoa there....
I'm pretty sure the "rev meter" on a 3GM30 does not work directly from the alternator. I think (but don't know) that it works from a magnetic pickup on the flywheel; happy to be proved wrong but....

Same here but as far as I know {most} tachometers run from the alternator charge. I do remember having to drive my car without the alternator attached (yes it did work without it) and the tacho didn't show any revs but that was an old car many years ago.

[Wotname]

Originally Posted by kas_1611

Same here but as far as I know {most} tachometers run from the alternator charge. I do remember having to drive my car without the alternator attached (yes it did work without it) and the tacho didn't show any revs but that was an old car many years ago.

FWIW, the 2GM20 uses a flywheel pickup so tach works regardless of alternator - I'm 99% sure the 3GM30 is the same.

[kas_1611]

Originally Posted by Wotname

FWIW, the 2GM20 uses a flywheel pickup so tach works regardless of alternator - I'm 99% sure the 3GM30 is the same.

So scratch that idea then It is still a valid check for many engines though so don't discount it.

First job to do then is check the Port alternator is working correctly then check and trace the charge wiring from the Port side to ensure there is actually a domestic/house charge circuit from that engine.

[goat]

Originally Posted by Wotname

FWIW, the 2GM20 uses a flywheel pickup so tach works regardless of alternator - I'm 99% sure the 3GM30 is the same.

My 2gm20 tachometer definitely gets its signal from the alternator. I had almost the same thing happening, the PO had installed a external manual regulator. I checked the connections (well, just wiggled them) and the ammeter and the tach jumped back into service. Tracked it down to a poor connector. Replaced with a crimp connector.
Good luck.

goat

[Pete7]

I take it both engines are supposed to be connected to the house bank and not just one, you would hope so, but are they?

Bit like power steering on twin engined boats, often only one engine runs the power steering.

Pete

[pcmm]

Originally Posted by Jacana

Amendment.Starboard engine is charging the house bank ,port engine isn't.
Carsten- starting battery is still being charged and no warning light on panel re faulty alternate/generator.
Pccm-have separate starting batteries for each engine.Faulty wiring could be the cause any ideas re wiring as to how to trace back to try and find the fault?CheersGeoff.

You didn't mention that you have more than one engine. We really need a schematic of your wiring setup. could just be that it was wired so that one engine charges the start batteries and one charges the House batteries, but its all just a guess without more info.

[pcmm]

Originally Posted by goat

My 2gm20 tachometer definitely gets its signal from the alternator. I had almost the same thing happening, the PO had installed a external manual regulator. I checked the connections (well, just wiggled them) and the ammeter and the tach jumped back into service. Tracked it down to a poor connector. Replaced with a crimp connector.
Good luck.

goat

Yes the 3GM30 definitely uses a flywheel pickup for the tach sensor ( so does the 4JH2E ) its listed on page 343 of the service manual. the sensor is mounted to the flywheel housing on the starboard side. you can have the alternator OFF the engine and you will still see RPM on the gauge. That is unless someone has hacked into the system and replaced the TACH ( which does happen as the Yanmar tach is stupid expensive to replace when it dies). Same applies to the 2GM20 and 1GM20 all use a flywheel sensor for tach not alternator.

[Jacana]

Thanks for the ideas to hopefully solve the problem.
Note - RPM gauge still works on both engines.
- both engines have always been charging the house bank and not a problem over the last 10 years,haven't had to hook up to shore power for at least 4 years and I use my boat daily recently clock up 7000 hrs on each.
Not good at electrical issues but do like to work through problems to try and learn to fix instead of getting someone to do the fix and not learn anything.
So please keep the suggestions coming ,first step today will be to check the alternaters voltage which I thought if it wasn't working the charge warning light we come on on the panel.PS 2 alternaters on both engines.Thanks Geoff.

[Wotname]

Originally Posted by Jacana

......
So please keep the suggestions coming ,first step today will be to check the alternaters voltage which I thought if it wasn't working the charge warning light we come on on the panel.PS 2 alternaters on both engines.Thanks Geoff.

OK, still only speculating
This suggests that one alternator on each engine is the stock Yanmar and is only connected to the respective start batteries. The other alternator (presumably bigger) on each engine is connected to the house bank.

The charge light on the panel will be connected stock Yanmar alternator / start battery so that explains why it is not illuminated.

I suggest you swap the two "big" alternators to see if the fault transposes to the other engine. This will quickly tell you where to look next

Again this presumes the additional alternators are the same with a similar mounting arrangement. I also suspect this setup would have external regulation so there is another piece of equipment that can be transposed for fault analysis.

[Wotname]

Hmm... I should add there is an inherent danger when using the transposition method of fault finding I described earlier.

Sometimes there are two or more faults, one of which has killed a bit of equipment further along the circuit. When you transpose one bit of known good kit, the second fault kills the "good bit" and so on.

Doesn't happened often but when it does, it hurts

I once saw three multi thousand dollar autopilots killed before someone found a screw driven into the wiring loom behind a panel.

So yes, if you are comfortable with the slight risk, transposing known good with suspected faulty, then this is a quick and easy method otherwise a safer approach is measuring voltages etc. You do have the advantage of having one working system in order to make comparative measurements.

[Jacana]

Thanks Wotname ,yeah that sounds right .Will check the larger alternater.Thanks mate.

[Hobie_ind]

Get a copy of Calder's book (or a similar one). Also check out Balmar's website. They've got a troubleshooting guide to walk you through a troubleshooting procedure to help determine the possible causes.

Be prepared for it to take a while this way and likely chase up a lot of blind alleys like the tach/alternator issue. 24 posts in before it comes out that there's separate house bank and starter battery alternators on each engine and still no idea of basic information for troubleshooting information like if they're internally regulated or externally or even brands.

[undercutter]

Originally Posted by Hobie_ind

Get a copy of Calder's book (or a similar one). Also check out Balmar's website. They've got a troubleshooting guide to walk you through a troubleshooting procedure to help determine the possible causes.

Be prepared for it to take a while this way and likely chase up a lot of blind alleys like the tach/alternator issue. 24 posts in before it comes out that there's separate house bank and starter battery alternators on each engine and still no idea of basic information for troubleshooting information like if they're internally regulated or externally or even brands.

Well most add on alternators on engines are externally excited due to the fact that you do not want them loading the engine until they are running, not to mention the potential of running batteries down due to field current.

Usually this is controlled through the oil pressure switch or relay which then sends power to the controller. Either way, the first step is to see if the alternator is outputting by checking the voltage at the positive terminal on the alternator. The next step is to determine whether there is power on the exciter wire if the alternator is not working. If there is a break in the wiring from the alternator to the batteries such as a fuse then there will be no voltage at all on the positive post with the engine not running otherwise it should be almost the same as the house batteries (within .3 volts) again with the engine not running. With the engine running the voltage at the positive terminal on the alternator should exceed 14 volts unless your house batteries are completely flat which they probably aren't as you have other charging sources.

Start at the alternator and take the few simple measurements that I have suggested and then we can go from there.

[Wotname]

Originally Posted by Jacana

Thanks Wotname ,yeah that sounds right .Will check the larger alternater.Thanks mate.

Hey Jacana, please do get back to us when you have either solved the problem, had it resolved by others or have hit a brick wall.

It always interesting to see how internet problem solving from afar works out; it keeps us on our toes