Question For DC Experts

[Ventana]

Are you suggesting that the ACR life could be only 12 months?

I have ACRs that have seen over 10 years of commercial use and are still working fine. The different units are rated for different maximum amperage and I would guess that if you are regularly exceeding that rating that they would fail. That would be an issue with your use and not with the design.

 

[CMS]

I run the genset in the evening and charge everything up. The ACR relays since it senses a charge source. Next morning I start the engines and off we go. Now there is a charging source from the alternators. So the ACR relays again. And not only keeps the starts charged but also the large house bank - which the 4K inverter is using to run a house which currently included a large domestic fridge freezer AND a chest freezer. I don't know the ampage of my alternators but my theory is that they can't manage that load and do the engine starts are getting drawn down.

The ACR opens at a voltage slightly above the full charge point of the batteries, 12.8V, so it can't be drawing the start bank down as it will open before that happens. However the relay could be relay cycling and the engine has enough DC load on it to pull the start bank down such as pre-heaters etc.. Also with small alts and large loads, you may just be in bulk charging for a long time before the ACR gets to combine level..

We really do need more info on the wiring,loads and what is charging what...

The article below should help explain anything you want to know about ACR's or combining relays..

Making Sense of Automatic Charging Relays (LINK)




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[CMS]

I have ACRs that have seen over 10 years of commercial use and are still working fine. The different units are rated for different maximum amperage and I would guess that if you are regularly exceeding that rating that they would fail. That would be an issue with your use and not with the design.

We have yet to see a Blue Sea ACR fail and we see far too many of them installed incorrectly, grossly abused and yet still plugging along.

Had one guy charging a single G-24 bow bank from a house bank and whacking the 120A rated ACR with a 400A bow thruster. Darn thing was still going strong at year ten. Also seen customers throwing 150A across a 120A model and it too was still going strong 8+ years in.

While I am certain you can find a way to kill one, we have seen them viciously abused and still plugging along.

 

[menzies]

The ACR opens at a voltage slightly above the full charge point of the batteries, 12.8V, so it can't be drawing the start bank down as it will open before that happens. However the relay could be relay cycling and the engine has enough DC load on it to pull the start bank down such as pre-heaters etc.. Also with small alts and large loads, you may just be in bulk charging for a long time before the ACR gets to combine level..

We really do need more info on the wiring,loads and what is charging what...

The article below should help explain anything you want to know about ACR's or combining relays..

Making Sense of Automatic Charging Relays (LINK)


.

The problem seems to have been that the ACR switch was set to ON, so it never opened. So when there was a charging source both house and startst were being charged, and when there was no charging source both were being drawn down. Now it is set to AUTO, it is working as designed.

 

[JDCAVE]

Now the question I need to answer (but can wait until I am at home dock) is what does Off do?

I can tell you that from newbie experience!

Early on in my particularly neophyte days, I was told by someone who was old school to never combine the batteries. I didn’t understand the function of the ACR, because I had THOUGHT that my starter bank was charged by my Balmar digital duocharge, so I had turned the ACR to OFF. Now, in my case, the windlass runs off the starter bank. So after a 7 day trip I checked the voltage on the starter bank, 2 G24’s, and found them at 12.5 volts! I had started the engine and raised and lowered the anchor multiple times. So, what happens is your starter bank gets no charge!

I’ve changed a few things in my system with a separate Pro-6 charger for the starter bank, and a Mastervolt battery mates, so it’s belts and suspenders, and ropes and chains now. I don’t currently use the Blueseas, ACR for its intended use for charging, except to combine the batters (set to “on”) position, when I’m hauling the anchor. I switch it back to “off” once completed.

The function of the Balmar DDC is to charge the thruster bank. And I don’t think that’s the best source for this purpose either.

Jim

 

[menzies]

Jim, are you saying that the OFF position means that alternators are not charging the starts when your engines are running?

I would think they have to be as they would be damaged otherwise.

 

[Fletcher500]

I lost track. Are you saying if you had left your ACR’s in the Auto position (which is the normal SOP for these switches unless combining is needed or other odd instances occurr where they should be opened), there would not have been any issues?

 

[menzies]

I lost track. Are you saying if you had left your ACR’s in the Auto position (which is the normal SOP for these switches unless combining is needed or other odd instances occurr where they should be opened), there would not have been any issues?

Yes, it was left in the ON position. Creating the issue.

Now it is left in the AUTO position. Which means there are no issues.

The new learning was not on the charging, but the draw when the ACR is "ON". ON apparently parallels permanently - both ways, charge and draw.

 

[Bigsfish]

Menzies

Congrats, you solved your problem and it didn’t cost anything. That so uncommon in boat ownership you need to put a plaque on the sea bottom to always remember.

Enjoy the remainder of your trip, I wish I was anchored near you (not real close). LOL

 

[JDCAVE]

Jim, are you saying that the OFF position means that alternators are not charging the starts when your engines are running?

I would think they have to be as they would be damaged otherwise.

The alternator used to be connected to the house batteries. Now it is connected to the Mastervolt battery mate, which distributes charging to the house, starter and Genny batteries.

Jim

 

[psneeld]

Menzies

Congrats, you solved your problem and it didn’t cost anything. That so uncommon in boat ownership you need to put a plaque on the sea bottom to always remember.

Enjoy the remainder of your trip, I wish I was anchored near you (not real close). LOL

All you need is a circle of boating friends or a forum that is sprinkled with boating professionals.
How many problems here are solved every day?
I can fix most things, but sometimes a person familiar with a certain piece of equipment starts the ball rolling, I have had lots of good tips here to prevent calling in a repair guy.

 

[menzies]

... a forum that is sprinkled with boating professionals...

I would suggest "sprinkled with experienced boaters."