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Teach me about ACR charging relays when used with battery chargers, etc. Click-Click

Old 06-06-2019, 05:40 PM
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Question Teach me about ACR charging relays when used with battery chargers, etc. Click-Click

On the WorldCat I have a battery switch area. It comprises of:
HOUSE
PORT
STARBOARD
EMERGENCY PARALLEL
ACR w/LED light
ACR w/LED light

I think I have a basic knowledge that the ACR takes the charge from one source and distributes it to batteries. In my case, I believe, that since I have a total of 4 batteries (two house, two start) that one ACR handles the starts and one ACR handles the house (that's a hunch, I am not certain).

My question is that when the on board battery charger is on, the ACR relays will switch on and off sometimes individually, and other times together. Eventually they will stop.

Normal? Anything to know about this? I do not recall this being a "thing" in the past... but can't swear to it. All batteries pass a load-test.

Thanks,
Pete
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Old 06-06-2019, 05:45 PM
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Old 06-06-2019, 05:51 PM
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Normal in a typical situation. If you have a multi bank charger move the ACR leads to the motor/load side of the switches. Blue seas has a diagram illustrating this, and it’s an approved wiring method. In short it works as normal when on the motor charge system, and allows the charger banks to work independently from each other.
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Old 06-06-2019, 06:21 PM
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Old 06-06-2019, 06:22 PM
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Normal if the House batteries are a little discharged. Your likely set up is an ACR from each Start batt to the House Batt. When the voltage on a charging Start batt exceeds a certain level the ACR will couple it to the House Batt so the House batt can charge as well. Trouble is that if the House Batt is low it will pull down the Start batt voltage when the ACR couples them and the ACR will then reach it's 'uncouple' voltage and turn off. Then the Start batt voltage goes back up on the charger and the cycle repeats. The ACR's appear to be 'pulsing'. Eventually all the short couplings bring the House batt voltage up enough that it doesn't drop the Start batt below the ACR trigger volts when coupled and everything stays connected to the charger. A larger charger will reduce the pulsing as it can hold the battery voltage up better when the batts couple. If you see this happening when you have the engines idling on the water, try lifting the rpms to say 2500rpm and you will probably see the pulsing quickly stop due to the higher alternator outputs.
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Old 06-06-2019, 06:41 PM
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Originally Posted by autobaun70 View Post
Normal in a typical situation. If you have a multi bank charger move the ACR leads to the motor/load side of the switches. Blue seas has a diagram illustrating this, and it’s an approved wiring method. In short it works as normal when on the motor charge system, and allows the charger banks to work independently from each other.
I am looking at connecting to the output side of the switches and called Blue Seas-the tech I spoke to indicated that it can be done but they don't list it as a diagram anymore due to the potential for user error. The tech told me that if you had the house switch on but not the start switch then you could potentially pull the starting current through the smaller wiring of the ACR if the ACR was closed. I am not sure I fully understand because if the house battery were fully charged it still should not close the ACR unless it was charging in which case the engines are running and the start battery switch is on or you turned it off while engines were running and now you fried the alternators. I am likely changing to the Yandinas as they seem simpler.
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Old 06-06-2019, 06:48 PM
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I guess potentially you could have the charger connected, ACR operated, and start the engines at home to test or flush etc. Depending on what Yandina item you are looking at, it may be the same ACR or VSR. all the same thing.
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Old 06-06-2019, 07:06 PM
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Originally Posted by Chilly1034 View Post
I am looking at connecting to the output side of the switches and called Blue Seas-the tech I spoke to indicated that it can be done but they don't list it as a diagram anymore due to the potential for user error. The tech told me that if you had the house switch on but not the start switch then you could potentially pull the starting current through the smaller wiring of the ACR if the ACR was closed. I am not sure I fully understand because if the house battery were fully charged it still should not close the ACR unless it was charging in which case the engines are running and the start battery switch is on or you turned it off while engines were running and now you fried the alternators. I am likely changing to the Yandinas as they seem simpler.
acr’s don’t read based on state of charge. Just voltage differential, with a slight time delay. Basically if one battery is higher voltage than the other, and also above a certain set point (12.7 I think, don’t hold me to that) it closes. Their reasoning for getting rid of that diagram makes sense to a degree, however they did call for fuses on the ACR wiring on the old diagram which would protect from such. Also if wired to a multi function switch vs an old style “1-2-both-off” switch its pretty much a non factor.

The other way to accomplish the same thing is to put switches on the ground side leads of the ACR’s, and flip them off any time the charger is in use.
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Old 06-06-2019, 07:36 PM
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Originally Posted by Aliboy View Post
I guess potentially you could have the charger connected, ACR operated, and start the engines at home to test or flush etc. Depending on what Yandina item you are looking at, it may be the same ACR or VSR. all the same thing.
Originally Posted by autobaun70 View Post


acr’s don’t read based on state of charge. Just voltage differential, with a slight time delay. Basically if one battery is higher voltage than the other, and also above a certain set point (12.7 I think, don’t hold me to that) it closes. Their reasoning for getting rid of that diagram makes sense to a degree, however they did call for fuses on the ACR wiring on the old diagram which would protect from such. Also if wired to a multi function switch vs an old style “1-2-both-off” switch its pretty much a non factor.

The other way to accomplish the same thing is to put switches on the ground side leads of the ACR’s, and flip them off any time the charger is in use.
Agreed about not sensing state of charge-ACR shows >2min and 13 v or 13.6 at >30sec will close it---the Yandina is 13.3 but I did not find the time delay. I originally was going to use the switch at the neg of the ACR when charging but that is where I am most likely to forget to turn them off when plugging into the multi-bank. Yandina is cheaper, draws no voltage when open, and can be wired to off or auto so I am still deciding which one to use. Either way I am going to connect to output side of dual switches and will fuse the leads to whichever I choose.
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Old 06-06-2019, 07:44 PM
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Originally Posted by Chilly1034 View Post
Agreed about not sensing state of charge-ACR shows >2min and 13 v or 13.6 at >30sec will close it---the Yandina is 13.3 but I did not find the time delay. I originally was going to use the switch at the neg of the ACR when charging but that is where I am most likely to forget to turn them off when plugging into the multi-bank. Yandina is cheaper, draws no voltage when open, and can be wired to off or auto so I am still deciding which one to use. Either way I am going to connect to output side of dual switches and will fuse the leads to whichever I choose.
had yandina on my old boat. Have blue seas currently. Like the blue seas hands down better. Yandina was sporadic. A bit more wiring, but works much better.
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Old 06-06-2019, 07:48 PM
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Originally Posted by autobaun70 View Post


had yandina on my old boat. Have blue seas currently. Like the blue seas hands down better. Yandina was sporadic. A bit more wiring, but works much better.
Good to know. Thanks.
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Old 06-07-2019, 05:25 AM
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Originally Posted by Chilly1034 View Post
Good to know. Thanks.
no problem. Forgot to add a couple of things Regarding forgetting to flip the switch(s) to isolate the banks, for most chargers that would not create an issue at all. It would not let it provide an individualized charge to each bank, but wouldn't cause any harm.

On my single engine boat, I am using the load side wiring option, and also have the isolate under cranking lead hooked up (had forgotten about that earlier in this thread). With it hooked up, the concern the blue seas folks have would be impossible, as it would disconnect the ACR as soon as the start relay lead energizes, making it impossible to overload the ACR wiring/circuitry.
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Old 06-07-2019, 05:52 AM
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Here is a good article on how ACRs work. I had to read it a couple of times to really understand the finer points. It may help you solve your issue.

https://marinehowto.com/automatic-charging-relays/
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Old 06-07-2019, 06:29 AM
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Originally Posted by bilbndr View Post
Here is a good article on how ACRs work. I had to read it a couple of times to really understand the finer points. It may help you solve your issue.

https://marinehowto.com/automatic-charging-relays/
That's a really good article, however I disagree with them including the part about wiring the alternator output to the house bank. They aren't technically incorrect, however they are not accounting for how many alternators regulate voltage. Most alternators read the voltage via a particular pin in the regulator plug. This is almost guaranteed to be switched and running off of the start battery, as part of the main engine harness. Some have a separate S (Sense) & IG (ignition hot) hot terminals. Those would be easy to work around. Others have that function combined. The same bank that is receiving the primary output needs to be the bank that the voltage regulator is reading off of. If that's not the case, and overcharge situation can occur. Chances of that being catastrophic are minimal with a big bank, but are reasonably significant on a 1-2 battery house bank. Especially if for some reason the ACR doesn't close.
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Old 06-07-2019, 07:13 AM
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Originally Posted by OldPete View Post
On the WorldCat I have a battery switch area. It comprises of:
HOUSE
PORT
STARBOARD
EMERGENCY PARALLEL
ACR w/LED light
ACR w/LED light

I think I have a basic knowledge that the ACR takes the charge from one source and distributes it to batteries. In my case, I believe, that since I have a total of 4 batteries (two house, two start) that one ACR handles the starts and one ACR handles the house (that's a hunch, I am not certain).

My question is that when the on board battery charger is on, the ACR relays will switch on and off sometimes individually, and other times together. Eventually they will stop.

Normal? Anything to know about this? I do not recall this being a "thing" in the past... but can't swear to it. All batteries pass a load-test.

Thanks,
Pete
If your house bank is usually more discharged than your engine crank battery, consider connecting the alternator output to the house bank side of the ACR.
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Old 06-07-2019, 07:16 AM
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Originally Posted by bilbndr View Post
If your house bank is usually more discharged than your engine crank battery, consider connecting the alternator output to the house bank side of the ACR.
Can't really do that with outboards.

That said, they may have aux charging lead capability, which would pretty well make the ACR's unnecessary to start with.
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Old 06-07-2019, 07:32 AM
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Originally Posted by autobaun70 View Post
Can't really do that with outboards.

That said, they may have aux charging lead capability, which would pretty well make the ACR's unnecessary to start with.
good point - I know my Yamaha manual lists the AUX cable as an option that can be installed. My engine doesn't have but it is certainly simpler than using an ACR
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Old 06-07-2019, 08:16 AM
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Originally Posted by autobaun70 View Post


had yandina on my old boat. Have blue seas currently. Like the blue seas hands down better. Yandina was sporadic. A bit more wiring, but works much better.
what do you mean by “sporadic”?

A combiner is simply an on and off switch. It appears that the Yandina voltage spec is slightly higher, and the timing specs are slightly different, but on what basis do you say one set of specs is better than the other leading to an opinion the Yandina is sporadic?
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Old 06-07-2019, 08:34 AM
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Originally Posted by OldPete View Post
On the WorldCat I have a battery switch area. It comprises of:
HOUSE
PORT
STARBOARD
EMERGENCY PARALLEL
ACR w/LED light
ACR w/LED light

I think I have a basic knowledge that the ACR takes the charge from one source and distributes it to batteries. In my case, I believe, that since I have a total of 4 batteries (two house, two start) that one ACR handles the starts and one ACR handles the house (that's a hunch, I am not certain).

My question is that when the on board battery charger is on, the ACR relays will switch on and off sometimes individually, and other times together. Eventually they will stop.

Normal? Anything to know about this? I do not recall this being a "thing" in the past... but can't swear to it. All batteries pass a load-test.

Thanks,
Pete
It really should be an ACR from each start battery to the house bank, which allows each engine separately to put extra capacity into the house bank.
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Old 06-07-2019, 08:47 AM
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Originally Posted by Inlander View Post


what do you mean by “sporadic”?

A combiner is simply an on and off switch. It appears that the Yandina voltage spec is slightly higher, and the timing specs are slightly different, but on what basis do you say one set of specs is better than the other leading to an opinion the Yandina is sporadic?
This was on an older Johnson 2 stroke with limited output, and a fairly low voltage setpoint on the regulator/rectifier. With the higher setpoint on the Yandina, it would often disconnect unnecessarily (given the loads involved). This would frequently result in a somewhat discharged house battery, especially when trolling, as the output would barely hit 13V. Definitely more reflective of the capabilities and design of the charging system, main point being that the Blue Seas is more accommodating considering their combination of time/voltage, and that lower setpoint to combine after the slight 2 min delay. My current boat has a Mercury on it (2 stroke carb) which has a very similar charging system, though be it a slightly higher set point. I think the Yandina would be fine on it most of the time, but the Blue Seas has been flawless.
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