Cutwater 28 - ACR Behavior

[Eric R]

Is it expected that when the ACR combines the house bank to the engine bank to charge from the alternator, it will stay combined until the engine shuts off? From the things I've read on the Blue Seas website (and other sources), it sounds like this should be the case unless you have extenuating circumstances. However, it seems everything that I read also says the alternator should be hooked to the house bank and not the starter battery. That is not the case on my boat.

I'm seeing what I feel is some weird behavior. Let's say that I'm heading out for a trip. After firing up the engine, the ACR will combine shortly after startup, and I will see like 13.6V on the Garmin Unit Voltage. I also confirm this with my multimeter on the actual house batteries, and by checking the LED on the ACRs (lit on both the house and thruster ACRs). That all tells me that things are working as expected and everything is charging from the alternator.

However, shortly after I will see that 13.6V on the Garmin drop to 12.8, then 12.6, then 12.4, and so on. This is also confirmed with my multimeter at the batteries themselves, and then a visual check of the ACRs also confirms that neither is active and all the charge is going to the engine battery again. Once the Garmin gets down to about 12.1V it seems that the ACR will once again combine and things jump back to 13-13.6V for a short period of time, before going through the same routine all over again with the drop down to 12.0-12.1V.

During some research on this again last night I came across this article about cycling. It feels like this is what is happening, and that it isn't normal.

https://www.bluesea.com/support/art...ensitive_Relays_and_Automatic_Charging_Relays

I don't have any major loads on the house bank. Yesterday it was nothing more than the Garmin, the autopilot, and the VHF. I have also done tests with and without the refrigerator on, figuring that is the heaviest typical load, and that also seems to make no difference in behavior.

Note: All batteries were just replaced, so in my mind that rules out it being old, tired batteries.

Thoughts?

Thanks!

 

[Kevin Lamont]

Is it expected that when the ACR combines the house bank to the engine bank to charge from the alternator, it will stay combined until the engine shuts off? From the things I've read on the Blue Seas website (and other sources), it sounds like this should be the case unless you have extenuating circumstances. However, it seems everything that I read also says the alternator should be hooked to the house bank and not the starter battery. That is not the case on my boat.

I'm seeing what I feel is some weird behavior. Let's say that I'm heading out for a trip. After firing up the engine, the ACR will combine shortly after startup, and I will see like 13.6V on the Garmin Unit Voltage. I also confirm this with my multimeter on the actual house batteries, and by checking the LED on the ACRs (lit on both the house and thruster ACRs). That all tells me that things are working as expected and everything is charging from the alternator.

However, shortly after I will see that 13.6V on the Garmin drop to 12.8, then 12.6, then 12.4, and so on. This is also confirmed with my multimeter at the batteries themselves, and then a visual check of the ACRs also confirms that neither is active and all the charge is going to the engine battery again. Once the Garmin gets down to about 12.1V it seems that the ACR will once again combine and things jump back to 13-13.6V for a short period of time, before going through the same routine all over again with the drop down to 12.0-12.1V.

During some research on this again last night I came across this article about cycling. It feels like this is what is happening, and that it isn't normal.

https://www.bluesea.com/support/art...ensitive_Relays_and_Automatic_Charging_Relays

I don't have any major loads on the house bank. Yesterday it was nothing more than the Garmin, the autopilot, and the VHF. I have also done tests with and without the refrigerator on, figuring that is the heaviest typical load, and that also seems to make no difference in behavior.

Note: All batteries were just replaced, so in my mind that rules out it being old, tired batteries.

Thoughts?

Thanks!

Hello,

When the system is working correctly the first bank to get charged will be house, then engine and finally thruster. This is true with shore power too. I assume everything was working and charging correctly before the batteries were replaced? Have you made sure that ALL cables and wires were hooked back up correctly, even the smallest wire can make an issue. Also here is a link to the online version of the C26/28, viewtopic.php?f=20&t=4518, once you have opened it scroll down to page 34 and it should be the wiring diagram for the batteries, switches, ACR's etc. and I would double check that everything is where it needs to be. Also have seen ACR's fail before. Hope this helps.

Thanks,

 

[Eric R]

Is it expected that when the ACR combines the house bank to the engine bank to charge from the alternator, it will stay combined until the engine shuts off? From the things I've read on the Blue Seas website (and other sources), it sounds like this should be the case unless you have extenuating circumstances. However, it seems everything that I read also says the alternator should be hooked to the house bank and not the starter battery. That is not the case on my boat.

I'm seeing what I feel is some weird behavior. Let's say that I'm heading out for a trip. After firing up the engine, the ACR will combine shortly after startup, and I will see like 13.6V on the Garmin Unit Voltage. I also confirm this with my multimeter on the actual house batteries, and by checking the LED on the ACRs (lit on both the house and thruster ACRs). That all tells me that things are working as expected and everything is charging from the alternator.

However, shortly after I will see that 13.6V on the Garmin drop to 12.8, then 12.6, then 12.4, and so on. This is also confirmed with my multimeter at the batteries themselves, and then a visual check of the ACRs also confirms that neither is active and all the charge is going to the engine battery again. Once the Garmin gets down to about 12.1V it seems that the ACR will once again combine and things jump back to 13-13.6V for a short period of time, before going through the same routine all over again with the drop down to 12.0-12.1V.

During some research on this again last night I came across this article about cycling. It feels like this is what is happening, and that it isn't normal.

https://www.bluesea.com/support/art...ensitive_Relays_and_Automatic_Charging_Relays

I don't have any major loads on the house bank. Yesterday it was nothing more than the Garmin, the autopilot, and the VHF. I have also done tests with and without the refrigerator on, figuring that is the heaviest typical load, and that also seems to make no difference in behavior.

Note: All batteries were just replaced, so in my mind that rules out it being old, tired batteries.

Thoughts?

Thanks!

Hello,

When the system is working correctly the first bank to get charged will be house, then engine and finally thruster. This is true with shore power too. I assume everything was working and charging correctly before the batteries were replaced? Have you made sure that ALL cables and wires were hooked back up correctly, even the smallest wire can make an issue. Also here is a link to the online version of the C26/28, viewtopic.php?f=20&t=4518, once you have opened it scroll down to page 34 and it should be the wiring diagram for the batteries, switches, ACR's etc. and I would double check that everything is where it needs to be. Also have seen ACR's fail before. Hope this helps.

Thanks,

Kevin - Thanks for the quick response.

I was having this same odd behavior even before battery replacement, when everything was as it came from the factory. In fact, one time last year the house bank got so low on a long cruise that I got the warning about low voltage on the Garmin. My hope was that the batteries were just getting older and replacing them all would resolve things, so I was a little deflated when I realized yesterday that it did not. 😀

The alternator is wired to the engine start battery on my boat (2017 C28), and then ACR'd to the two house batteries. The Volvo display shows that battery getting the typical 14.2-14.4V at all times when the engine is running. I'm just not sure what is causing the ACR to keep disconnecting/cycling and letting the house bank drop down until it decides to turn back on again. I have never seen the Garmin ever show a consistent voltage with the engine running. After talking to a few others today it seems that I should be seeing a consistent 13V+ on the Garmin while underway, and the ACR should only really disconnecting when shutting the engine down. Would you agree that should be the case?

Also, yes, when the batteries were swapped all cables were bundled/taped together before removing them from the terminals to ensure everything 100% went back where it came from.

Thanks again.

 

[BB marine]

The correct battery routing on the C28 is alternator to starter to battery switch to engine battery.The engine battery charges first. Once the engine battery reaches 13 volts for 90 seconds or 13.6 volts for 30 seconds it should combine the house bank (Green lights on) and the thruster bank ( Green lights on) They will stay combined as long as the engine battery stays above 12.75 V . If engine battery voltage drops below 12.75 for more than 30 seconds The ACR's will open. The engine battery is the driver because it has the charging circuit. The ACR are not polarity sensitive. The ACR's need one bank to be at 13 V to close and all banks must have a charge of 9.5 V or they will lock out. The one function not talked about is voltage output alternator to engine battery. You have engine voltages recorded at 14.2 to 14 .4 and house batteries at 13.6. I believe that if all batteries are combined (ACR's closed ) the battery banks voltages should all be the same. Max Voltage voltage output is controlled by the alternators voltage regulator. It should maintain less than 14.7 V. If the regulator is not working properly it could spike the voltage higher. If the Voltage hits 16 V the ACRs will open until the voltage drops. I doubt this is happening but something to consider.

 

[Eric R]

The correct battery routing on the C28 is alternator to starter to battery switch to engine battery.The engine battery charges first. Once the engine battery reaches 13 volts for 90 seconds or 13.6 volts for 30 seconds it should combine the house bank (Green lights on) and the thruster bank ( Green lights on) They will stay combined as long as the engine battery stays above 12.75 V . If engine battery voltage drops below 12.75 for more than 30 seconds The ACR's will open. The engine battery is the driver because it has the charging circuit. The ACR are not polarity sensitive. The ACR's need one bank to be at 13 V to close and all banks must have a charge of 9.5 V or they will lock out. The one function not talked about is voltage output alternator to engine battery. You have engine voltages recorded at 14.2 to 14 .4 and house batteries at 13.6. I believe that if all batteries are combined (ACR's closed ) the battery banks voltages should all be the same. Max Voltage voltage output is controlled by the alternators voltage regulator. It should maintain less than 14.7 V. If the regulator is not working properly it could spike the voltage higher. If the Voltage hits 16 V the ACRs will open until the voltage drops. I doubt this is happening but something to consider.

Thanks for the info!

I am taking another trip tomorrow and will be testing things again. The 14.4V that I stated for the engine is just based off the Volvo display. Will check it with the multimeter to see what it’s showing on that battery both with and without the ACR combined.

I know the crossover switch combines the house with the engine battery in case you need the extra juice for starting. Does having the crossover on also force it to charge from the engine, essentially bypassing the ACR?

 

[Wee Venture]

I know the crossover switch combines the house with the engine battery in case you need the extra juice for starting. Does having the crossover on also force it to charge from the engine, essentially bypassing the ACR?

Yes. When the “combine” switch is on, the house and engine battery banks essentially become one combined bank, making the ACR irrelevant. The thruster battery is still separate, however, so the ACR on that side is operative. And as Brian said, the alternator basically must charge the engine battery first, since by definition the engine battery is connected to the starter (through the switch); and since the alternator is also connected to the starter, the alternator’s charging current must travel back on the same cable to the same battery that started the engine. In actual practice, however, it is only 30 to 90 seconds in the vast majority of cases till the ACRs combine all three banks.

John

 

[Eric R]

I know the crossover switch combines the house with the engine battery in case you need the extra juice for starting. Does having the crossover on also force it to charge from the engine, essentially bypassing the ACR?

Yes. When the “combine” switch is on, the house and engine battery banks essentially become one combined bank, making the ACR irrelevant. The thruster battery is still separate, however, so the ACR on that side is operative. And as Brian said, the alternator basically must charge the engine battery first, since by definition the engine battery is connected to the starter (through the switch); and since the alternator is also connected to the starter, the alternator’s charging current must travel back on the same cable to the same battery that started the engine. In actual practice, however, it is only 30 to 90 seconds in the vast majority of cases till the ACRs combine all three banks.

John

Thanks! Although I wish I wasn’t having any issues, I do enjoy learning new things all the time. This community is great.

 

[BB marine]

Have you checked all connections of the battery cables from the engine battery positive to the ACR House and Thruster bank. I believe on my boat the Cable (RED) comes for the engine battery + post to the house ACR post. There is a cable (red) that comes from the house ACR to the Thruster ACR ( the positive battery red cables are daisy chained. If the connection between the engine battery and the ACR's is compromised (poor connection ) this would cause the ACR to open because it is not sensing the 12.7+ volts to maintain a closed position. Your issue is really a process of elimination. One other check would be make sure the small yellow ground wire at the ACR has a good connection. If there is a compromised connection there the ACR will open. If all wiring checks out ok I would think about replacing the ACR.

 

[Eric R]

Have you checked all connections of the battery cables from the engine battery positive to the ACR House and Thruster bank. I believe on my boat the Cable (RED) comes for the engine battery + post to the house ACR post. There is a cable (red) that comes from the house ACR to the Thruster ACR ( the positive battery red cables are daisy chained. If the connection between the engine battery and the ACR's is compromised (poor connection ) this would cause the ACR to open because it is not sensing the 12.7+ volts to maintain a closed position. Your issue is really a process of elimination. One other check would be make sure the small yellow ground wire at the ACR has a good connection. If there is a compromised connection there the ACR will open. If all wiring checks out ok I would think about replacing the ACR.

I plan on doing that again today. Last I checked, all connections were tight, still looked brand new, and the ground wire was good.

I feel like I’m getting closer to try an ACR replacement, but what are the chances it’s two of them? The thruster ACR light seems to go out anytime the house one does.



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