automatic charging relay

[Russell]

Has anyone successfully installed a Blue Sea Systems SI-ACR? I just installed one primarily for the protection of my electronics and even though the LCD indicates that the batteries are separated the electronics still turn off during engine cranking. This happens whether the battery switch is set at 1 or 2. The line from the ignition switch is connected according to the instructions. I suspect something is wired differently than other boats because my engine will start on either switch position 1, 2 or both. In other words there is not really a dedicated start battery. Any advice would be appreciated.

[Beta Don]

SI (Starter Isolation) is an optional feature on the Blue Sea 7610 ACR. Do you have a wire connected to the SI terminal on the ACR running to the positive terminal on the starter solenoid? When you turn the key to start, it sends 12 volts to the solenoid to engage the starter and that same 12 volts sent to the ACR opens it's contacts before the starter current drops the voltage so that your electronics running on your house battery won't see the voltage drop

It won't do anything though if you have the battery switch set so that you're using the starter with the same battery bank that is also powering your electronics

Don

[catalina_mike]

There is other wiring required as well.. The electronics and the starter are fed from the common output from the battery switch normally. So the ACR will disconnect the batteries from each other but there is also , depending on what you are trying to do, a different battery switch necessary. http://assets.bluesea.com/files/resourc ... 170140.pdf

[Russell]

The wire is connected to the SI terminal and the start contact on the ignition switch. The ACR seems to be working properly. The problem is that everything works on either position 1 or 2 of the battery selection switch. Apparently the starter circuit and the house circuit are combined on one pole of the switch. I may have to change from a 3 pole switch to a 4 pole as shown in the Blue Sea instruction diagrams. I will try calling them tomorrow to see if that is correct.

[catalina_mike]

That is correct you need to isolate the starting battery and starter from the house. I was having similar issues and actualy just finished replacing my ends on all battery loads and replaced my switch. I had bad ends and a switch that needed replacement. I passed on the acr method and went anouther path with charging optimization using a promariner device.

[DesertAlbin736]

I recently purchased but have not yet installed the Blue Sea Systems "Add A Battery" kit which includes the SI-ACR relay. I would think this type of 4 post main battery switch would solve your problem, since unless the engine is actually running and producing charging voltage your start and house batteries are completely isolated from each other. The switch is either "off" or "on", in which the "on" position connects start battery to engine starter circuit and house bank to house loads. The SI-ACR relay activates and connects both banks together in parallel only for charging when charging voltage is sensed. When the engine shuts off and voltage drops to battery voltage (12.6 V for fully charged batteries) it goes back to isolating the two banks with no user action needed. Also has a manual override position that can force house and start banks into a "both" configuration.

I'm installing this primarily as an upgrade project as part of relocating my batteries to make room for a larger holding tank, and in the process switching from flooded wet cell to AGM type batteries, which in addition to the new switch and SI-ACR also includes upgrading to a AC on board Pronautic Plus "smart charger" that has the option for an AGM charging profile, and ditto for upgraded alternator regulator and solar panel charge controller since AGM's need a reduced float charge voltage of 13.6-13.8 V.

[Russell]

Yes, I purchased that battery switch and now everything works the way it should. The electronic display does not blink when the engine is started and I like that the two circuits are completely isolated when the engine is not running. Takes the worry out of leaving the display on during long drifts. This wiring setup should be installed at the factory but the extra cables and fuse boxes cost more than the SI-ACR.

[jleonard]

I have one of these relays that I'll sell cheap. The system didn't work for me. According to Blue Seas techs my battery banks were too unbalanced. It was only in the system for a week or two.

[catalina_mike]

I went ProMariner because of the optimized charging. It prioritizes the starting battery and charges it first then switches to the house. This way the one you need to start the motor with gets charged first.

[DesertAlbin736]

I have one of these relays that I'll sell cheap. The system didn't work for me. According to Blue Seas techs my battery banks were too unbalanced. It was only in the system for a week or two.

Unbalanced in what way? Different type batteries, different size? Old mixed with new? The SI-ACR has the option of installing a manual cut out switch in the sensing wire that can switch out the unit for long term storage so it doesn't drain batteries.

I went ProMariner because of the optimized charging. It prioritizes the starting battery and charges it first then switches to the house. This way the one you need to start the motor with gets charged first.

Besides the Add A Battery I'm replacing my old 15 amp analog charger with a ProNautic 1215P that can run separate charging leads to 3 banks. My new batteries are Group 27 AGM dual purpose, one for start and two house batteries linked in parallel. All three the same type batteries. Also changing out my anchor light and all my cabin lights to LED's for low current draw while on the hook.

None of these have been installed yet, but as soon as the holidays are over I'm going to get to work. Still have to measure & size wire lengths, buy new wires and cable since this is a relocation project, buy terminal fuses, AC breaker panel, etc. I buy a lot of my stuff online from Amazon, Defender, Go2Marine, etc, one reason I'm waiting for the Christmas shipping rush to be over. Then I get to rip out the old holding tank and install a bigger one, which is the whole point for getting into this project.

B.O.A.T !!! $$$$$$!!!!

All this in preparation for next year's plan to return to the San Juans in WA and Gulf Islands in BC and hopefully make it as far North as Desolation Sound.

[DesertAlbin736]

Oh, by the way jleonard from CT, we were there in Mystic this past summer. Visited the seaport museum by land, but had our boat docked in a guest slip at Norwest Marine in Pawcatuck and did a couple short day cruises over to New London (my old sub school alma mater) and over toward Watch Hill Point.

[jleonard]

I have one of these relays that I'll sell cheap. The system didn't work for me. According to Blue Seas techs my battery banks were too unbalanced. It was only in the system for a week or two.

Unbalanced in what way? Different type batteries, different size? Old mixed with new? The SI-ACR has the option of installing a manual cut out switch in the sensing wire that can switch out the unit for long term storage so it doesn't drain batteries.

The banks were too much different in capacity. I worked with a tech for a while a couple of different times and it just didn't work like it was supposed to.
No matter, my system works just fine without it. I have cruised 2 full summers and never had an issue running out of battery power.

[jleonard]

Oh, by the way jleonard from CT, we were there in Mystic this past summer. Visited the seaport museum by land, but had our boat docked in a guest slip at Norwest Marine in Pawcatuck and did a couple short day cruises over to New London (my old sub school alma mater) and over toward Watch Hill Point.

I wish I had known. I was based out of Mystic all last summer. We could have gotten together for a cold one. We could have raced the boats to see who buys.....LOL That would be like watching the grass grow.
Watch Hill (Napatree) is one of my favorite anchorages. And we cruise the seaport by dinghy several times every summer.

[djpeewee]

I am not a big fan of the SI charge relays from BlueSea. I know they are rated fairly highly but I haven't had good experiences with them and I prefer a little more control over what is going on with the electrical system instead of just trusting that things are working like they should. I guess it's the electrician coming out in me.

The BlueSea ML series charge relays and battery switches are a lot different however. What I like about them is that they are easily controlled by an included rocker switch. The rocker switch is lighted for each of the 3 positions - on/auto/off. With these three switch positions you can get just about any functionality needed.

Auto is just like the SI charge relay - automatically joining batteries and disconnecting them depending on the voltage.

On/off is like a battery switch, but right at the helm, without having to go below or open the hatch.

They give lots of flexibility as far as being able to start from any battery, combine any/all batteries, disconnect your start battery, etc.

I added two of the ML remote battery switches as well to act as main disconnects for the main engine and generator.

This may be TMI (again), but below is a diagram of the electrical system redesign I did last year using the 3 x ML charge relays (ACR) and 2 x ML remote battery switches (RBS). It worked really well for the kind of flexibility and control I was after as well as piece of mind while on the hook for extended periods of time.

Trygon DC 3.jpg

[Beta Don]

My new batteries are Group 27 AGM dual purpose, one for start and two house batteries linked in parallel. All three the same type batteries.

As a general rule, hardwiring two batteries in parallel isn't the best idea. Even if they are identical and both are brand new, because as they age one battery will always be a bit stronger than the other and you will have current flowing between them which will shorten the life of both. This is what ACR's were designed for - Parallel the batteries for charging and separate them when discharging

"The main disadvantage is that as the batteries get old one will fail first, quite often by getting a shorted cell. It will very quickly damage the other batteries by causing them to be overcharged. When not charging the good batteries get worn out trying to charge the shorted battery. The end result is the entire bank quickly fails."

Even before you get to the point of a shorted cell, you'll have one of the 12 cells a bit weaker than the other 11 and when you take them off the charger, the stronger battery will give up some of it's power trying to bring the weaker battery up to the level of the stronger one - This is power lost you could have used to run your loads

"Advantages and Disadvantages of using two 12 volt batteries connected in parallel or two 6 volt batteries connected in series. - It would appear that there is no significant difference in capacity and voltage between these two examples. But this really is not the case. The plates designed for the T-105 use the same active material and alloy of the group 27 deep cycle batteries but both the T-105 negative and positive plates are 60% thicker than those found in the deep cycle 27 group sizes. The significance of this is that these 6 Volt batteries should have a longer lifespan than the two deep cycle 27 group sizes, if properly cared for. While the capacities are similar (220 versus 225 Amp Hrs.), battery longevity favors the two 6 Volt batteries. Why? Because a major cause of deep cycle battery failure is the shedding of active material from the battery plates."

If you need the capacity of a pair of Group 27 AGM's, may I suggest you look at a pair of AGM golf cart 6 volt batteries in series. You'll have a few more amp hours and no need to run paralleled batteries. The 6 volts in series should last at least 2X (or maybe even 3X) as long as a pair of paralleled 27's. I have a pair of flooded golf cart batteries in the engine room as my starting battery and a pair of AGM's (because they are located in the lazzarette which is technically part of the sleeping quarters on an A27.) which run the fridge and most other heavy loads. An ACR connects them all together when charging either from the 110 amp engine alternator, the 40 amp Shore power charger or the 320 watts of solar panels

If you cannot find 6 volt batteries of the required capacity to put in series to make a house bank, it is acceptable to parallel identical 12 volt batteries to double their capacity, but in parallel they won't last as long as a single 12 volt battery or a series bank of two identical 6 volts

I bought both the flooded and the AGM golf cart batteries from Sam's Club

I also switched out every single bulb on the boat for LED's. I use a pulse width dimmer for several of the interior LED's which enables you to use only the light intensity you want while saving even more juice. With a PW dimmer, 50% intensity saves you 50% of the energy

Don