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Battery warning

Printed From: myHanse.com
Category: Hints & Tips
Forum Name: 345/348
Forum Description: 345/348 Hints, Tips and News
URL: https://www.myhanse.com/forum_posts.asp?TID=12486
Printed Date: 28 March 2024 at 17:43
Software Version: Web Wiz Forums 12.06 - https://www.webwizforums.com


Topic: Battery warning
Posted By: bigcat
Subject: Battery warning
Date Posted: 22 January 2021 at 23:58
Recently, while motoring, after a while the display starts beeping and shows a battery symbol with exclamation mark.

Sometimes, increasing or decreasing rpm's will make the warning go away.
Sometimes we have to turn the engine off and back on for the warning to go away.

A brief search indicated several potential issues, including alternator or cabling issues or time to replace the batteries (?).

Has anyone else experienced this? Any hints on how to best root-cause?

Thanks much!



Replies:
Posted By: H8jer
Date Posted: 23 January 2021 at 11:11
Hi

As I don't have the same model Hanse as you, I can only give general advice.
What instrument is showing the battery symbol?

Because the symptom you describe is only when the engine has run for some time? this is intermittent behavior and it points to heat or vibration(when hot) to advance the root cause.
So check all connectors... 

To troubleshoot you should first get a "clamp-on multimeter" (With DC amps). eg. a cheap one like this UNI-T UT203(review  https://youtu.be/96d5-APZhww?t=127" rel="nofollow - https://youtu.be/96d5-APZhww?t=127 ) or ut204+. With this you can measure the voltage or the current going to the batteries.



When engine is cold, look at the cables to the alternator if they are tight. Also the alternator belt must not flex more than 10mm when pushed by hand. Also check the engine where all the negative cables are connected to the engine. They need to be tight.

At the battery-compartment check that all connections are tight. When charging by engine or Shore-power the battery-terminals should not get hot. If they are heavily oxidized (white/green powder) they can interrupt a solid connection and can only supply voltage but not current. They can also get hot from bad connection.

/H8jer





-------------
Hanse 370#487 30HP 3-cabin


Posted By: bigcat
Date Posted: 23 January 2021 at 18:39
hi H8jer,

thanks for the reply!

The warning shows and sounds on the instrument panel (MDI) in the cockpit where the engine is started.
To measure current and voltage to the batteries, what are correct readings?

I will check connections on the boat tomorrow for looseness and corrosion. I don't expect corrosion to be an issue since the engine was replaced as part of a Volvo emissions recall 2 years ago. But perhaps some connections were not properly fastened in that process...

Also good tip on checking the alternator belt. 

I will update on my findings tomorrow.


Posted By: kipwrite
Date Posted: 23 January 2021 at 19:55
My understanding is that this battery alarm/light will trigger if the alternator output voltage falls outside a 13v-15v range. If the alternator voltage is inside this range I’d suspect a bad battery or more likely the black MDI box itself, many of which are subject to recall. Good luck. 

-------------
Kipwrite


Posted By: bigcat
Date Posted: 23 January 2021 at 21:48
Thanks kipwrite. We actually had the MDI unit replaced already because it would not turn on at some point preventing us from starting the engine. Since then I also installed a bypass for the engine start using instructions from another member on this forum.

Since the replacement we haven't had issues with the MDI unit. Batteries are 6 years old so replacement will become due I guess. But I would want to make sure that to be the cause of the issue before making that investment.

Originally posted by kipwrite kipwrite wrote:

My understanding is that this battery alarm/light will trigger if the alternator output voltage falls outside a 13v-15v range. If the alternator voltage is inside this range I’d suspect a bad battery or more likely the black MDI box itself, many of which are subject to recall. Good luck. 


Posted By: H8jer
Date Posted: 24 January 2021 at 06:17
Originally posted by bigcat bigcat wrote:

To measure current and voltage to the batteries, what are correct readings?


This depends on battery technology, but if nothing is switched on and the batteries are idle - they should be aprox. 12.9v-13.2v.(excl. Lifepo4/lithium)
This is measured on the battery-terminals.

With engine started, the voltage measured at the same location should be aprox. 13.8v-14.8v

If you have a relay or other stuff dividing the charging current/voltage from the alternator to both starter and consumer batteries, the charge perhaps first starts when the starter is topped up first.
If the battery symbol starts when this happens, it can be that the consumer batteries are very low in voltage(old/bad batteries) or if you mesured them to be fine, it instead again can be the supply (loose terminals, alternater belt, too thin cables)

If the batteries are fully charged the will not recieve a lot of current. So with a clamp-on multimeter on the main negative to the consumer batterie would perhaps show aprox. 20amps right after start an then dropping to 1-10 amps quickly.
Perhaps the error only occurs when the batteries are not fully charged?

/h8jer


-------------
Hanse 370#487 30HP 3-cabin


Posted By: bigcat
Date Posted: 07 February 2021 at 06:41
I went back to the boat today. 

This time the MDI unit did not turn on! 
We already had the MDI unit replaced once and we were told that Volvo fixed the issues with the reliability of these? Interestingly, I had wired a bypass button similar to what some others have done on this forum and the bypass also would not start the engine...

I took out the starting battery and measured it at home. It reads 12.89V. Is that an acceptable reading?
This is a Varta Professional Dual Purpose AGM 840 095 085.

Thanks much!

-BC


Posted By: H8jer
Date Posted: 07 February 2021 at 07:46
Originally posted by bigcat bigcat wrote:

It reads 12.89V. Is that an acceptable reading?
This sounds acceptable but more importantly is it cranking/turning the engine?

Your battery has a cranking power of 850amperes when new. That is a lot, and should have no trouble.

If it only makes a large click-sound or turn the engine very slowly, then the battery is ready for replacement because even though it might read 12.89v it drops rapidly under the load of the starter.

Sounds from your post that everything was completely dead?
If so I would put the battery back and check that voltage is present at the right places when the master/engine-switch is turned on.

Btw. I store lead-acid batteries in the boat also during winter. When they are fully charged, it is the best storage place. No need to lift heavy batteries. My 3x100Ah Lifepo4 (weight only 13kg each) I store at home, because Lifepo4 does not like to be charged in sub-zero temperature. Lead-acid has no problem with being recharged in the cold.
/H8jer



-------------
Hanse 370#487 30HP 3-cabin


Posted By: bigcat
Date Posted: 07 February 2021 at 22:53
Yes, everything was dead. Which made me suspect the MDI box. But it was weird that even the bypass button did not work...is the MDI box powered by the same (starting) battery?
I had one case 2 months or so ago where the MDI would not turn but the bypass button worked and at that point the MDI also turned on (display in the cockpit)...does that make sense?

Originally posted by H8jer H8jer wrote:

Originally posted by bigcat bigcat wrote:

It reads 12.89V. Is that an acceptable reading?
This sounds acceptable but more importantly is it cranking/turning the engine?

Your battery has a cranking power of 850amperes when new. That is a lot, and should have no trouble.

If it only makes a large click-sound or turn the engine very slowly, then the battery is ready for replacement because even though it might read 12.89v it drops rapidly under the load of the starter.

Sounds from your post that everything was completely dead?
If so I would put the battery back and check that voltage is present at the right places when the master/engine-switch is turned on.

Btw. I store lead-acid batteries in the boat also during winter. When they are fully charged, it is the best storage place. No need to lift heavy batteries. My 3x100Ah Lifepo4 (weight only 13kg each) I store at home, because Lifepo4 does not like to be charged in sub-zero temperature. Lead-acid has no problem with being recharged in the cold.
/H8jer



Posted By: Sarang
Date Posted: 08 February 2021 at 00:13
It may be useful to load test the battery. Some batteries will have a normal voltage, but once it is loaded, the voltage rapidly drops, indicating it needs to be replaced.


Posted By: bigcat
Date Posted: 09 February 2021 at 18:32
Yes I plan to do this when I'm back at the boat this weekend. I don't have a load tester but I think I can measure the voltage under load on the boat?

I just received a quote from the Volvo dealer for a new MDI box should it be broken (again)..these are $800 and unreliable!

Originally posted by Sarang Sarang wrote:

It may be useful to load test the battery. Some batteries will have a normal voltage, but once it is loaded, the voltage rapidly drops, indicating it needs to be replaced.


Posted By: bigcat
Date Posted: 16 February 2021 at 02:02
Well it looks to be another broken MDI unit.

Reading through the forums it appears even the latest incarnation (which we have) breaks:
https://www.cruisersforum.com/forums/f54/volvo-penta-mdi-black-box-failures-188440-4.html" rel="nofollow - https://www.cruisersforum.com/forums/f54/volvo-penta-mdi-black-box-failures-188440-4.html

I believe Volvo Penta is now on revision 7 of this computer, over a span of 4-5 years?
Apparently the newer engines that were part of the EPA recall run warmer to improve internal combustion and hence the MDI units are even more prone to failure.
Some recommend mounting these units on a bulkhead instead of directly on the engine (which is how VP delivers them).

I have contacted our local VP service contact and of course they don't support moving the unit because it would require modifying the wiring harness and it is not an official VP authorized procedure.

This repair is not covered under warranty, so they suggest we reach out to VP to see if they will credit the cost of the unit ($800) as 'goodwill'...

Isn't this a class action lawsuit in the making ??
Without a bypass button the engine may not start mid-sea or while entering port...super dangerous.




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