previously installed battery charger and ACR

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JeffJuneau
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previously installed battery charger and ACR

Post by JeffJuneau » Sun Nov 15, 2020 10:11 pm

Hi Again, I have a 2007 ProMariner ProSport 12 battery charger and a Blue Sea SI-ACR -Automatic Charging Relay (ACR) installed in my 26M Mac. The battery charger is hooked up to shore power. Currently the Blue Sea ACR is disconnected from the starting and house batteries by the previous owner ( I don't know why), while the battery charger is connected to both the starting and house batteries. Before I reconnect the ACR to test it, I have a question about how the voltage sensing functions of both of these electrical devices keep from stepping on each other. I have a crude and possibly wrong understanding of how each of these devices work. The ACR is supposed to combine batteries during charging and isolate batteries when discharging and when starting engines. It does that by sensing voltage or amperage (I am not sure which). However, the battery charger is also always sensing voltage in each battery and distributing charging in the correct amounts to each batteries. It seems like they potentially have some overlapping functions, so I don’t understand how they avoid conflicts during charging the batteries with shore power. Can anyone explain if this is a common system to have installed, and if there is an issue with both of them being connected at once? I realize that I probably won't very often start the engine at the same time I am charging the batteries, but it could see where it might happen. Also, does it matter whether the main 3-way switch for the batteries is in the off, 1, 2 or 1+2 position when charging the batteries with the ACR connected? Thanks, Jeff

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Jimmyt
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Re: previously installed battery charger and ACR

Post by Jimmyt » Mon Nov 16, 2020 5:55 am

JeffJuneau wrote:
Sun Nov 15, 2020 10:11 pm
Hi Again, I have a 2007 ProMariner ProSport 12 battery charger and a Blue Sea SI-ACR -Automatic Charging Relay (ACR) installed in my 26M Mac. The battery charger is hooked up to shore power. Currently the Blue Sea ACR is disconnected from the starting and house batteries by the previous owner ( I don't know why), while the battery charger is connected to both the starting and house batteries. Before I reconnect the ACR to test it, I have a question about how the voltage sensing functions of both of these electrical devices keep from stepping on each other. I have a crude and possibly wrong understanding of how each of these devices work. The ACR is supposed to combine batteries during charging and isolate batteries when discharging and when starting engines. It does that by sensing voltage or amperage (I am not sure which). However, the battery charger is also always sensing voltage in each battery and distributing charging in the correct amounts to each batteries. It seems like they potentially have some overlapping functions, so I don’t understand how they avoid conflicts during charging the batteries with shore power. Can anyone explain if this is a common system to have installed, and if there is an issue with both of them being connected at once? I realize that I probably won't very often start the engine at the same time I am charging the batteries, but it could see where it might happen. Also, does it matter whether the main 3-way switch for the batteries is in the off, 1, 2 or 1+2 position when charging the batteries with the ACR connected? Thanks, Jeff
The ACR is an automatic battery combiner. The SI model provides start isolation (un-combines during starting), and un-combines when one bank gets low, or when the system is not charging. Having your battery combiner switch in the A+B position will defeat the ACR and SI functions.

Your charger probably is two chargers in one housing, since you say it is wired to both batteries. You need to check your manual info to be sure. Depending on how you have it all wired, as soon as the ACR sees above 13 volts for a pre-determined period on EITHER BATTERY (or bank), the ACR will combine - disabling any independent sensing feature the battery charger may have. You would probably want to disable the ACR when using shore power charging (or call blue sea and get their recommendation for wiring it). Again, having your battery switch in the A+B position will disable any independent charge sensing feature in your battery charger, also.

Most importantly, having your battery switch in the A+B position will defeat the under voltage protection feature of the ACR, allowing you to fully discharge BOTH banks. :|

Or, you can read the unabridged version at: https://marinehowto.com/automatic-charging-relays/

The more stuff you connect, the more difficult it is to make sure it's working properly, and/or harmoniously. You just need to add solar and a charge controller to complete the circus. :D
Jimmyt
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Russ
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Re: previously installed battery charger and ACR

Post by Russ » Mon Nov 16, 2020 6:26 am

You seem to be overthinking this. Or I am underthinking this.

I have a similar setup.

Here's my understanding.
When the charger is connected, it's like 2 chargers, each one connected to each battery. They are separate charging circuits and do not combine the batteries.

The ACR combines batteries based on Voltage. Mine is wired to go both ways. (It also will refuse to combine if the low battery is TOO low.)
House and Starter batteries are normally isolated.
When my starter battery is charging from the motor (+14v) the ACR will combine the starter with house. If for some reason the house battery voltage goes high (+14v) the ACR will combine to charge the starter battery.

Therefore, the "dual" AC charger really is redundant. It could simply charge only one battery and both would combine when voltage goes high because the ACR will combine.
However, the AC charger is probably more efficient and adjusts charging voltage to each battery.

With that said, you may be right and the ACR would step on that logic. Ideally, if the AC Charger is running, disabling the ACR would be best so the AC charger could regulate each battery separately. With that said, I've never had an issue with the Charger/ACR setup.

This is how Blue Water Yachts wired my boat and it's worked like a champ.
I have no idea how an A/B switch would work with combiners or why it's necessary.
--Russ

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Tomfoolery
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Re: previously installed battery charger and ACR

Post by Tomfoolery » Mon Nov 16, 2020 6:42 am

Russ wrote:
Mon Nov 16, 2020 6:26 am
With that said, you may be right and the ACR would step on that logic. Ideally, if the AC Charger is running, disabling the ACR would be best so the AC charger could regulate each battery separately. With that said, I've never had an issue with the Charger/ACR setup.
That's what concerns me about ACRs, and why my dual-channel charger goes to each battery separately. If the needs of each battery are different, I don't want to combine them.

Since it has shore power all the time, there's no advantage to me to even have an ACR other than the OB charging both batts, but they're both marine 'deep cycle', and I just alternate between them on every excursion.

My knowledge of 12V battery systems is a bit light, so I just do what I do, and I get 6-7 years out of my batteries, with the ages staggered a few years. Cheap and simple works for me. If I really need to charge both at the same time on the water, I can always just A+B them with the switch, though I've never had the need to do that. So far. :wink:
Tom
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Russ
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Re: previously installed battery charger and ACR

Post by Russ » Mon Nov 16, 2020 9:23 am

Tomfoolery wrote:
Mon Nov 16, 2020 6:42 am
That's what concerns me about ACRs, and why my dual-channel charger goes to each battery separately. If the needs of each battery are different, I don't want to combine them.
Right. If the batteries are dissimilar in type and discharge level their charging needs will be different.
FWIW I use matching deep cycle for both batteries. We don't need cranking amps.
Since it has shore power all the time, there's no advantage to me to even have an ACR other than the OB charging both batts, but they're both marine 'deep cycle', and I just alternate between them on every excursion.

My knowledge of 12V battery systems is a bit light, so I just do what I do, and I get 6-7 years out of my batteries, with the ages staggered a few years. Cheap and simple works for me. If I really need to charge both at the same time on the water, I can always just A+B them with the switch, though I've never had the need to do that. So far. :wink:
My marina has no shore power, so we live "off the grid". I have a solar panel connected to the house battery and the combiner will charge both if voltage goes up from the solar. Charges both when the motor is running. I don't have to think about it.
With an A/B Both switch on the other boat, I had to remember to combine them while motoring and then switch back when not.

In a perfect world, it might be possible to install a relay that disconnects the ACR when shore power is applied so the charger can apply separate charging to each.
--Russ

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Jimmyt
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Re: previously installed battery charger and ACR

Post by Jimmyt » Mon Nov 16, 2020 10:06 am

One other "feature" of the blue seas SI is; if one battery drops below 9.5 volts, that battery will not be combined and will be essentially locked out of the combine feature. So, if you totally deplete the house battery, motoring will not recharge it - unless you have a manual combiner switch...
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Russ
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Re: previously installed battery charger and ACR

Post by Russ » Mon Nov 16, 2020 3:12 pm

Jimmyt wrote:
Mon Nov 16, 2020 10:06 am
One other "feature" of the blue seas SI is; if one battery drops below 9.5 volts, that battery will not be combined and will be essentially locked out of the combine feature. So, if you totally deplete the house battery, motoring will not recharge it - unless you have a manual combiner switch...
Yes. I found this out the hard way. I thought it wasn't working. Prevents a damaged battery from pulling down a healthy one.
--Russ

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Re: previously installed battery charger and ACR

Post by Starscream » Mon Nov 16, 2020 4:49 pm

Hi Jeff,

Is it possible that the P.O. originally had a single-bank charger and used the ACR to allow that single-bank charger to charge both batteries, and then disconnected the ACR when he/she added the dual bank charger? Even if that was the case, the ACR is still useful when motoring since it will distribute the alternator amps to charge both batteries automatically.

I went the opposite path. I used to have a dual bank charger, then went to a single-bank with ACR when I added solar power. Both batteries are the same type, and I've never had an issue with the ACR properly taking care of both batteries. It senses a charging source connected to either battery, and distributes that source to both batteries simultaneously.

I like the set-it-and-forget it aspect of the ACR. Both batteries get a charge from the charger, the solar panels, or the motor, regardless of the selector switch position. I know that no matter what I forgot to do when I left the boat, both batteries will be well charged when I get back.

Here's a good information link: https://www.bluesea.com/support/article ... _Explained

JeffJuneau
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Re: previously installed battery charger and ACR

Post by JeffJuneau » Tue Nov 17, 2020 10:53 pm

Thanks for all the responses. There is a lot here to digest here. My DC electronics knowledge is really limited compared with the people that helped to answer my questions, so I need to read through the two URL’s you folks provided. Then I might have more follow-up questions. I am glad that I never intend to add solar too, jimmyt. It’s not much use in a rainforest anyway. I see how the currently disconnected ACR was hooked up to the 2- batterys because the terminals are located right at the respective 2-positive terminals of each battery and the negative for the ACR is still connected to the negative terminal of the starting battery. Yes, I do have the instruction manual for the ProSport12 battery charger, and I think you are correct jimmyt, that it is essentially two separate chargers in one housing.

Yes Russ, I think my Mac was originally wired by BWY too, but I don’t want to attribute any current wiring configuration to BWY, because I don’t know what a previous owner may have changed. Also, it sounds like my batteries are similar to yours; 2- deep cell lead acid batteries, new last year. I agree Russ, it does sounds like your charging system is set up like mine; which makes sense if they were about the same vintage of 26M (2007 and 2009) prepared by BWY. Someone either on this group or perhaps it was a BWY live-stream suggested that it is helpful to do a wiring diagram for a Mac and label the wires. I haven’t done that yet, but wondered if you have one Russ, for your 26M? Otherwise, if your system is set up like mine, and is working fine for you, than that partially answers my question about whether my system is possibly okay.

Starscream, to follow up on your comment/question: I am pretty sure that the PS12 charger and ACR-S1 were installed in the original 2009 build by BWY, but I will ask them sometime to be sure. You may be on to something. I know the previous owner purchased new batteries in the fall of 2019, then, he let them sit over winter without charging. Maybe when he charged them this spring, he disconnected the ACR, because he wasn’t sure how it would react to the charger connected to a single battery. I have ended up keeping my batteries charged the same way this winter by shifting an independent digital charger back and forth between the batteries every couple of weeks to a month. I have no idea what the ACR would do if it was hooked up while I was charging with my portable charger on one battery at a time. Maybe that would be a good way to see if the ACR was working properly? Both batteries would show that they are keeping fully charged…Right?
Again, thanks for all the help, Jeff

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Russ
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Re: previously installed battery charger and ACR

Post by Russ » Wed Nov 18, 2020 6:22 am

Mine is no longer stock/dealer. I've replaced the electrical panel, added a sub panel with a fuse battery terminal and solar.
I don't have a diagram. Might be a good idea to make one.

I wonder why the PO disconnected the ACR.

I would reconnect and call it good.
--Russ

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Re: previously installed battery charger and ACR

Post by Starscream » Wed Nov 18, 2020 1:02 pm

Careful with reconnecting the ACR. I recommend making a wiring diagram before doing that.

The ACR requires two massive 90A breakers for electrical safety.

Also, if you do rewire and test it, note that it takes a fair amount of time to recognize the charging source and click over into combine mode. There is a little green light that indicates combine mode engaged, but it doesn't light up for some time after the charging source is attached.

JeffJuneau
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Re: previously installed battery charger and ACR

Post by JeffJuneau » Fri Nov 20, 2020 2:29 am

Thanks for the information Starscream and Russ. Russ, my only guess is that the PO may not have known what the ACR was intended to do while charging individual batteries after the batteries were sitting for the winter. Yes Starscream, I plan to track down all the wiring an make sure the connections are good and grounds are working right. I will probably put together a wiring diagram and label all of the wires. Also, I didn't know there was a light indicator to show that both batteries are being charged on the the ACR, now that there is a delay in the relay acting to distribute current. That will help me in my testing. Jeff

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