2010 Bavaria 32 Cruiser battery alarms

[Adam Turner]

We had one of those days yesterday, generating a number of issues.

One was repeated engine battery alarms. These displayed as the battery icon on the rev counter.  Engine is VP D1-20 and has had very little use under previous owner (now only 350 hrs total). I had work done including service by a reputable firm before the start of this season.

We had coastal sailed and motored the previous week covering approx. 20-30 nm per day with no issues. Yesterday we had been under power for 5 hours. 2,000-2,250 rpm, 4-5 knots, calm conditions. Alarms sounded with varying frequency of between 2hrs. and 10 mins, and did not show any pattern of becoming more or less frequent through the day.

When the alarms went, we checked battery levels on instrument panel, starter and service batteries were between 13.5 and 13.8 each time. Back under power for a while up to 14V plus.

This morning after being on shore power, we're at 13.9V both batteries.

With a twist, the alternator does go past the quarter turn without much difficulty (I'll try to attach a picture). So I'm inclined to adjust that first. There was no "fan belt squeal."

Could it be that the battery (ies) are near end of life? The boat's been kept on shore power/inverter off season.

Do these belts stretch a bit after service? (some car ones used to back in the day, but materials science has solved that. Wondering if the marine sector has caught up).

Other thoughts/input welcome. Happier to venture offshore once I have a definite fix, rather than experimenting.

Kind regards,

Adam

 

[symphony2]

More likely to be loose or dirty connections at either the alternator or the panel end. Suggest check those first.

[Adam Turner]

OK I tried tightening the alternator belt but couldn't loosen the top mounting nut of the alternator (soft alloy, spanner rounded it). Calling for back up.
 

[SYJetzt]

The Workshop Manual States following:

Battery warning
Fault indication
Tachometer:
The tachometer LCD screen will show a flashing bat- tery icon and the alarm buzzer sound.
Alarm display:
The battery indication flashes in the alarm display + audible warning.
Fault tracing
Fault condition 1
The voltage input at the MDI is 15V or higher for more than 30 seconds.
Possible reason
• Faulty alternator regulator.
Suitable action
1. Try another alternator.
 Fault condition 2
The voltage input at the MDI is 13V or less for more than 10 seconds (engine running).
Possible reason
• Too slack alternator belt tension.
• Faulty assembled connectors.
• Poor condition of the cables in the charging sys- tem.
• Faulty excitation voltage/current to the alternator. The alternator does not charge.
• Damaged or worn brushes.
• Faulty regulator.
Suitable action
1. Check the alternator belt tension.
2. Check that all connectors at the alternator and at the battery is correct assembled.
3. Check the conditions of all cables in the charging system.
4. Check that the alternator recieves correct excitation voltage/current.
5. Check the brushes length and condition.
6. Try another alternator 
BR
Robert

[Adam Turner]

Thanks Robert. Looks like I'm on the right track. Low engine hours would counter-indicate brushes and duff alternator, so we'll try to get belt right...if only I had the skills to undo a nut without rounding it.

[Yngmar]

I see some belt dust on the alternator, which shouldn't happen on a properly tensioned multi-v belt, so I'd be inclined to blame belt slippage, which is in line with the fault coming and going. Belt load varies with alternator output, which varies with engine rpm and battery state of charge/power consumption. So it could have been slipping during periods of increased demand and then gripping again.

Clean up the belt dust when you've tensioned so you can tell if fresh dust is arriving after.

To undo bolts, make sure you have the right size nut (these should all be metric) and put it on straight!

[Adam Turner]

Thanks Yngmar, good spot.

The top nut securing the alternator may not be metric, according to the guy in the hardware store where I bought a replacement, here in Spain. This may be why I rounded it with my 13 mm spanner.

Got the belt adjusted and ran engine at tickover for half an hour with no alarm sounding. Warm belt tension OK. We'll see what happens under more load.

I'm in confirmation bias territory but optimistic as belt is now appreciably tighter (quarter turn by hand is as far as it goes without maxing the effort).

Kr,

Adam

[Adam Turner]

So we adjusted the alternator belt. It's a V belt and now only JUST displaces 10mm with thumb pressure (so if anything, a little tight). I'll be slackening a touch in the next stage.

We did a test run, into wind at 2100 rpm/4.2 kn.

Initially, starter batt 14.2V service 14.0V (after being on shore power)
Alarm after an hour, panel indicates 13.8 and 13.6V

Turned home (tailwind)

Alarms again 13.6 and 13.4V
Alarms cease, voltage returns to approx. 14V
Alarms then begin again as we enter harbour, ie low revs.

Engine is 2010, but VERY low use, now only 370 hrs. total, so I'm leaning away from wear-related issues, dirty contacts etc. but am not experienced in marine engines. So am I right in thinking we're definitely not charging properly, and that instruments and alarms are operating correctly, rather than this being spurious readings/dirty contacts etc.?

If so, am I also right to go to change alternator brushes first, then if that fails, swapping the alternator? I'm not seeing instructions on changing alternator brushes in the operator's or workshop manual, although alternator swap looks straightforward enough (undo mounting bolts, swap unit and re-tension belt).

I'm moderately willing to have a go myself, up to a point, but don't want to make things worse.

Given all that, do members think:

1. Know when you're beaten and get a pro in
2. Change the brushes first, then if that fails, change the alternator
3. Just change the alternator

Input welcome, valued and appreciated.

Adam

[Yngmar]

SYJetzt posted the instructions from the electrical manual. The conditions under which the MDI triggers the battery alarm are

• The voltage input at the MDI is 15V or higher for more
  than 30 seconds.
• The voltage input at the MDI is 13V or less for more
  than 10 seconds (engine running).

Your measurements match neither of these. So either you have a contact problem, where the MDI sees different voltages (so like the manual says, measure at the MDI, not at the batteries) or your MDI is confused. Contact issue is more likely.

[SYJetzt]

Assuming you have a proper multimeter and the stated voltages at your batteries, the charging system seems to be OK.
Obviously you have a problem with the MDI or the cabling around.
Perform a  voltage measurement between  the terminal on the mdi (see attached picture) and engine ground. If the voltage is within 13 to 15V you have a problem with the MDI itself, otherwise check the cabling once again. Usually there are diode splitters or VSR in the cabling for charging circuits, which are prone for corrosion or to get loose

[Adam Turner]

Thanks all for your responses.

We feel a bit like deep-diving into this is 'above our pay grade,' and have found a boat electrician who is supposed to be very good and is willing to investigate. He is coming on Sat morning.

In the meantime I found that the nut circled in the photo was so loose I could twiddle it with my fingers. I tightened it, obviously.

From your experience, and looking at the general condition of the installation (which looks very clean and tidy to me), how likely do you think this is the cause of the problem?

Thanks!

Adam

[Yngmar]

Quite likely! 

[Adam Turner]

So we motored into a 20-25 kn headwind at 2000-2250 rpm for 1.5 hrs. Checked batteries every 20 mins, Starter 14.7 V service 14.6V constant. Sailed for 3 hrs. then restarted engine without difficulty, so I'm assuming that's case closed.

Thanks for assistance.

Adam

[JannePar]

Hi,

This is very interesting. We have exactly the same issue but the voltages from the panel has been 14,9 V for starter battery (sometimes even 15,1 V) and 14,8 V for service. We have 32 Cruiser with VP D1-20 as well, from year 2011 (420 hours). Belt is tight, also the connections are fine. Batteries do not feel warm when the alarm comes. And the alarm comes and goes, it can come on with 1500 rpm or at cruising speed 2300 rpm. It may go away when speed is reduced and then it might stay off even when speeded back up to 2300 rpm. There is no logic when it comes or goes away, it does not come every day.

I posted this issue to a local Bavaria forum and there one guy said that he had exactly the same issue and he cleaned the connections from the panel (rpm and alarm) with CRC and did not receive any alarms anymore. I will try this tomorrow.

Interesting to hear if you got rid of the issue and it does not come back..

[Yngmar]

15V coming out of an alternator is extremely likely to be a fried regulator. They can be replaced, you don't need to buy a whole new alternator. The alarm will come and go as the battery bank and consumption pushes the voltage below the 15V alarm threshold. With full batteries and consumers turned off, it will probably always be on. This will in the long run cook your batteries if left unrepaired.

[Adam Turner]

I would check those nuts on the back of the alternator as this may be an easy fix.

The MDI appears to be a frequent source of woes:

https://nordkyndesign.com/engine-reliability-a-look-at-the-volvo-penta-mdi-black-box/

So we took the precaution of moving it off the engine block, which was a matter of undoing a couple of bolts and re-securing it with cable ties. It is very light.

[JannePar]

15V coming out of an alternator is extremely likely to be a fried regulator. They can be replaced, you don't need to buy a whole new alternator. The alarm will come and go as the battery bank and consumption pushes the voltage below the 15V alarm threshold. With full batteries and consumers turned off, it will probably always be on. This will in the long run cook your batteries if left unrepaired.

Thanks Yngmar for your response. I think that the VP D1-20 alternator does not have a separate regulator. Or am I wrong? If I understood correctly the results of my diving in to the internet the regulator is built in to the alternator in which case the alternator should be changed.

[Yngmar]

The regulator is internal, but can be replaced rather than replacing the whole alternator. Much cheaper that way.

Looks like it's a Mitsubishi alternator: https://www.ebay.co.uk/itm/173644030490

[David Light]

The top nut securing the alternator may not be metric, according to the guy in the hardware store where I bought a replacement, here in Spain. This may be why I rounded it with my 13 mm spanner.

It's a 12mm nut. Definitely metric. I almost made the same mistake a couple of weeks back.