Charging engine battery

[max from alaska]

My engine battery died to the point where the engine electronics failed. Can someone advise how this happened and how to prevent it? I would cruise with engine, thruster and cabin batteries on. Then when anchoring I would switch Engine and thruster batteries off. Then I would cruise home and not plug into shore power. Trusting that the solar panel would charge it all. When I cruised each trip it was at 14 kn for at least 6 hrs per trip. I never used AC power at any time or the inverter. I assumed the alternator would charge all batteries but apparently this did not work. Any suggestions on how to prevent this from happening again?
Thanks
Matt

 

[Submariner]

Which r27 do you have? The outboard engine or diesel?

 

[knotflying]

There are many reasons why a battery will fail. Since it was your engine battery and assuming you did not leave the key in the on position accidentally I would question the battery's condition first. How old is it and has it ever been accidentally discharged to a considerably low level? You may want to do a load test to check the condition. Is it AGM or flooded? If flooded has the water been regularly topped off and maintained? Are all your charging relay's working properly?

 

[max from alaska]

It’s a diesel R27.
The battery is a few years old and thanks for the tips on checking its condition. I’ll do that. I usually turn the ignition off with the key fob but it’s very possible I could have left it on that night.
Also I’m not certain as to whether the alternator should have charged the engine battery while cruising 3 hrs the day before, or whether there’s some sort of charging sequence where house or thruster batteries charge first before the engine battery receives a charge. That could explain a situation where the engine battery never gets a charge and eventually gets low. If that’s not how the batteries receive charge then I’ll not think about that possibility anymore.

 

[BB marine]

Three hours of running the engine should be more than enough time to fully charge a good battery. I'm not sure of which engine you have Volvo or Yanmar. lets assume that the alternator is putting out at least 100 amps based on you operating the boat at 14kts turning over 3000 rpm. A 100 amp hr battery should be charged along with the thruster and 2 house batteries. The order of charge should be engine battery gets charged first. Once engine battery reaches 13 volts for 90 seconds or 13.6 for 30 seconded the ACR (automatic charge relay ) closes and connects to the house battery and thruster battery is above 11Volts. If all batteries are GOOD but 50 % discharge after 3 hours of running with a good alternator operating at 3000 rpm you should have fully charged batteries even if the refrigerator and helm electronics are operating using house house batteries.

Variables.
alternator output yes/no
Battery connections clean and tight
Batteries good test battery condition

 

[max from alaska]

It’s a Volvo D3 200 hp. So if the engine battery always receives charge first, and:
- I run at over 3,000 rpm for at least 3 hrs every overnight trip, and
- the only time the engine battery is switched on is when I’m cruising (I always switch it off when anchoring or hauling out.)
- I have never run low on the two house batteries,
Then there must be something wrong as you’ve identified. I’ll run through the options you’ve pointed out.

Thanks!

 

[max from alaska]

Follow up:

- hooked up to shore power and all batteries are now at about 14V. Does this mean the engine battery is ok or is a test still needed.

- if all batteries charged ok on shore power does this mean the charge relays are ok? In other words does shore power run through the charge relays and they must be working if the batteries charged on shore power?

- if batteries and relays are ok but the engine battery died as described above, then is the only remaining culprit the alternator (ie could it have died during the last cruise and the engine battery was drained?) (note that the engine battery switch was turned off at the end of the last cruise, so discharge while on the trailer should not be a cause?)

Please note the battery terminals are clean and the batteries are AGM so don’t need fluid topoff

Appreciate any input, thank you

 

[iggy]

There are many reasons why a battery will fail. Since it was your engine battery and assuming you did not leave the key in the on position accidentally I would question the battery's condition first. How old is it and has it ever been accidentally discharged to a considerably low level? You may want to do a load test to check the condition. Is it AGM or flooded? If flooded has the water been regularly topped off and maintained? Are all your charging relay's working properly?

Yep! And I would do a load test after recharging.

 

[knotflying]

After a full charge disconnect the battery cables and let it rest for at least 30 minutes or so. Then do a load test.

 

[BB marine]

My engine battery died to the point where the engine electronics failed.

This battery discharge happened on your way back from your trip ? On the trailer after the trip?

If during the trip back I would suspect the alternator has limited or no output.

If after your trip and on the trailer I would suspect a bad battery.

The fact that all batteries over a period of time charged to full capacity of 14V while using the on board charger really only means that the 3 battery banks combined fully charged while being on the charger. When the battery charger is on and charging the battery voltage of the house bank reaches 13V and satisfies the ACR requirements all batteries become one bank. They maintain as one bank until one or more batteries fall below 12.75V for more than 30 seconds. I am stating this so you don't get a false sense of full charge of your engine battery. As Mike and Iggy stated full charge and test batteries. Load test if you have a load tester. If not, after fully charging the batteries shut all battery switches off. Remove all ground leads from each battery . Use a VOA meter check battery voltage at each battery bank. Write the exact values down, check again after a few hours, write the values down. Check after 24hrs write the values down. Each bank is on its own but should maintain very close to the same values. If you have a battery with a compromised cell, bad cell you will see a significant difference in your voltage readings with that battery of batteries. A fully charged good battery should charge to about 13 to 13.2 volts after a charge with the charger off. It takes about 12 to 24 hours for the battery charge to settle. A good battery should maintain a charge of 2.1 volts per cell or 12.6 to 12.7 Volts after the battery is taken off the charge. You want to see readings at this voltage with all you batteries. If you are seeing readings below this 12.4 or lower I would replace the battery or batteries.

 

[max from alaska]

Iggy, knotifying and Brian, thanks for your help on this.

The engine battery died on the trailer in my driveway. (Or maybe it came to near death while cruising back) I had cruised to port after several hours at over 3000 rpm, hauled it out, turned off the engine battery switch, and driven home. Then after two days I turned the engine battery switch on and got a bunch of power module fail alarms at the helm. I didn’t check battery voltage because I was confused, but I did immediately hook up shore power and the AC charger. After two weeks on the shore power I got it into the Volvo mechanic who said the engine diagnostic had a low engine battery code, but that the engine ran fine. He said everything looks good. I disagree....how did the battery die with all that cruising and the prioritization of it on the ACR.

I’ll load test the batteries now. Thanks. Also wonder if the alternator failed during the cruise and the battery didn’t get a good charge while cruising back. Should the engine diagnostic check that was done revealed a bad alternator?

 

[BB marine]

I disagree....how did the battery die with all that cruising and the prioritization of it on the ACR.

If the alternator was not charging when you were running you would have had a low voltage warning while running back. The ACR's would have never closed to charge the house or thruster batteries. Remember the Alternator is wired to the start battery. Once start battery is maintained at the voltage threshold requirements of the ACR the ACR closes and parallel's the thruster and House battery banks. Engine battery first (Volvo D3 set up) ACR closes house and thruster now charge.

Keep it simple.

*Charge engine battery to at least 12.6 V to 12.7 V ( confirm Voltage measurement with a VOA) check voltage at battery post and at the alternator battery terminal. Voltages should be the same. record

* start the engine let it run a few minutes at idle then increase the rpm to 1500 rpm repeat the previous voltage checks with the engine running. Voltage readings should be 13.6 to 14.6 V there should be no more than a .2 voltage drop between the alternator voltage reading and the battery voltage reading.

* If you see no voltage increase when operating the engine and the values do not closely resemble the 13.6 to 14.6 V at both battery terminals and battery terminal at the alternator. The Alternator would be suspect.


My opinion is you have a bad engine battery

The Volvo technician said that while running a diagnostic review saw that there was a low battery code. This was not a hard code. If it was the engine would not run right. When he was checking with the VODIA diagnostic tool for a battery charging issue he would have checked the voltage values of the operating engine. The EECU monitors charging status and if it was not functioning properly the technician should have picked up on it.

Should the engine diagnostic check that was done revealed a bad alternator?

yes.

 

[Cessna172]

Iggy, knotifying and Brian, thanks for your help on this.

I’ll load test the batteries now. Thanks. Also wonder if the alternator failed during the cruise and the battery didn’t get a good charge while cruising back. Should the engine diagnostic check that was done revealed a bad alternator?

My experience with the AGM battery load test was inconclusive. My house batteries would not hold charge. Numerous "Low Voltage" warnings at nominal amp draws. I tested the batteries with a 100 amp load tester several times - each time the test results were satisfactory.

At wits-end, I replaced the 2.5 year old batteries. This completely resolved the issue. Seems to me a 100 amp tester would certainly stress a 110 amp battery enough to determine it's capacity. I could be wrong as I am most often...

Gary

 

[knotflying]

I put my money on a bad engine battery or parasitic draw. As Brian said, charge them up, disconnect the grounds and do the voltage tests at the prescribed intervals. If the battery is still good after the tests I would see if there is amperage being drawn when all is shut down. If that checks out okay then it could be the alternator. You need to search electrical issues one step at a time. If you start doing everything at once you won't find your problem. Start with the easiest and then go from there.

 

[Hydraulicjump]

You have had the smartest electronic gurus weigh in on this, so I will not add anything but personal experience. I had been having lots of similar problems, albeit with the house batteries, often involving bizarre electrical malfunctions. The batteries held a charge just fine, but would go off a cliff in voltage when put to a sustained load (like lights, fridge, other draws). I spent weeks using my clamp multimeter trying to trace electrical vampires, which was a good exercise since now I know precisely the amp draw of just about everything on the boat (chronicled in my log book).

I got one of these new generation of battery testers (there are lots on the market): Ancel BST-200. Sure enough, this tester showed that when fully charged the capacity of my house batteries had dropped to just 40%, which explains why they held a charge just fine but cratered when loaded, even lightly.

I replaced the house batteries with new ones (a painful exercise) and all electrical problems, previously blamed upon mysterious vampires populating every corner of the boat, disappeared. I was on the boat for seven weeks this summer and everything ran to perfection. Lesson learned.

Advise getting one of these cheap, easy to use battery testers to go with the other most essential tool, the clamp multimeter.

Jeff

 

[max from alaska]

This is a wealth of great info. I now have a better understanding about how things work so thank you everyone for sharing your expertise. I'll let you know how it turns out!

 

[marcham]

1. Did the starter battery fail with the engine running or with the boat in storage? Was the voltmeter indication abnormal on the last leg? Any low voltage alarms?

2. What do you mean with the engine electronics failed? They were damaged? They stopped working due to low voltage?

3. What is the configuration of you acr(s)? Does it combine banks when the 120v AC charger or solar charger are powered or does it only combine banks when the alternator is running?

4. On which bank is the solar controller wired to?

5. Are your ACR fused? Any blown fuses?

6. AGMs can fail early. Usually due to mishandling, sometimes due to defect. High temperatures, over-voltage on charge or long periods without charge will do it. Over-voltage can be caused by an incorrectly set solar charge controller, 120VAC charger or in rare cases incorrectly set alternator (very rare now with electronic controls).

7. Troubleshooting electrical problems remotely is akin to doing remote surgery.... the key to any electrical diagnostics is 20% having the right tools and 80% being methodical. Batteries can be load tested without expensive test equipment. Do you have an inverter, microwave and a voltmeter? That combo can tell you lots. By isolating different banks, you can figure out what is doing what.

A failed battery is the most likely culprit. It's the easier to identify and the easier to rectify than most other electrical faults (other than blown fuse or tripped breaker). Now, did the battery die on it's own? Due to previous owner mistreatment or due to another fault in the system?

Even if you replace the battery, ensure you troubleshoot the system.
- Verify individual bank voltages while under the 3 separate modes of charging.
- Check the correct function of each ACR.
- Check that all wiring is in good condition (no corrosion on lugs) and all connectors are tight.

Basic electrical tools required on any boat:
- Lug crimper
- Multi-mode voltmeter
- Clamp-on AC and DC amp meter
- Heat shrink tubi w. glue
- Liquid electrical tape
- Good quality terminal crimpers

"Most batteries don't die, they are murdered!"

Sent from my SM-T720 using Tapatalk

 

[max from alaska]

So I took the batteries to Batteries Plus and they load tested them. They said all the batteries are fine, except that the cranking voltage of the engine battery is reduced somewhat but still ok. (They said that a deep cell battery doesn't do well as a starting battery.) So the question at this point is where to go from here? I was thinking about swapping the thruster and engine batteries to use the better thruster battery for the engine. But does it make sense to replace the engine battery with a new one only because that's the one that died, just to be sure? I would have to special order a battery to get it up to Anchorage.

As noted above the engine diagnostics showed the alternator is ok.

Also as noted above I could search for a "parasitic draw"; however I'm unclear how to do so.

My goal is to make sure that everything is ok before next spring.

 

[allanrs74@gmail.com]

Max,
I ordered 3 X Group 31 AGM batteries from Monster Scooter Parts last winter for @ $180 each with no shipping costs to Anchorage for my 2016 R-27. I would take the strongest of your batteries and put it as the Engine Start battery, the next two best for House and the weakest for the Thrusters.

Regards,
Bob Allan
Annie M

 

[BB marine]

So I took the batteries to Batteries Plus and they load tested them. They said all the batteries are fine, except that the cranking voltage of the engine battery is reduced somewhat but still ok. (They said that a deep cell battery doesn't do well as a starting battery.) So the question at this point is where to go from here? I was thinking about swapping the thruster and engine batteries to use the better thruster battery for the engine. But does it make sense to replace the engine battery with a new one only because that's the one that died, just to be sure? I would have to special order a battery to get it up to Anchorage.

As noted above the engine diagnostics showed the alternator is ok.

Also as noted above I could search for a "parasitic draw"; however I'm unclear how to do so.

My goal is to make sure that everything is ok before next spring.

There is a big difference between a battery that load test ok ( marginal) and a cranking battery that was completely dead

Then after two days I turned the engine battery switch on and got a bunch of power module fail alarms at the helm.

It sounds like the battery was not dead just below the ECM's requirements and set a code. You charged the battery and when the technician troubleshoot the charging system all was good. Here is a simple bench test. Isolate the engine battery from the Thruster and house banks ( pull the small ground wire off each ACR. This will disable the ACR's) Charge the batteries for minimum of 24 hours using the ProMariner on board charger. Turn the charger off, battery switches off, and remove Yellow negative cables from each battery bank. Check the current battery Voltage. Record the values Example: engine 13.1 V, thruster 13.1 V, house 13.1 V. Check the voltages approximately 1 hour later, Record Example: Engine 12.7 V, thruster 12.7 V, house 12.7 V.

Now simulate problem : Then after two days I turned the engine battery switch on and got a bunch of power module fail alarms at the helm.

After two days of no charging check the battery voltages. Record : Example Engine 12.6V , thruster 12.6 V, house 12.6V these values would be Ok. If you see a values much lower than this I would start to question the Battery or batteries. The one in question is the engine.

From Volvo Manual.

If battery voltage falls below 12.4 V*, the starter motor will not be able to crank the engine at normal speed.

A fully charged battery has an open circuit voltage of about 12.7 V. When the open circuit voltage drops to 12.5 V, the battery is half charged.

If all batteries check fine go to step two.

Repeat the above steps only after fully charging the batteries and turning charger off leave the yellow Neg leads on the batteries. The results should be the same as first test if not it is time to look for a "parasitic draw"

This is a easy check that can be done with just a volt meter. Start simple eliminate the batteries but simulate the issue you had. Then work forward.