ML ACR

[QueenandI]

2001 Diplomat Cummins 330 ISC

4000 posts on this have been read on this topic but no clear answer to the following. I have it installed, wires ran to the front for switch and it works. The questions are;

1. With the wire to the Genset to isolation circuit, anytime the generator is running, the ML ACR will not auto-connect the 2 sets of batteries? So to connect the chassis to coach, setting the switch to "On" would force the two sets together. This would be need when dead/low chassis batteries after boondocking.

2. Or does it take 2 isolation circuits, one on the Engine ignition and one on the Genset, and only then does it auto-disconnect the 2 circuits when both are charging? 

3. Or no wiring for isolation circuits is done and the worse thing that happens is you get the low alternator light on and no damage is being done, don't worry about it. I know that I can switch off and on when running the generator down the road, but I am trying to make it smooth and seamless for the Queen when she travels by herself. 

Thanks!

HOOK

[Cubflyer]

You have a Queen that will drive that coach?? Much less one that will drive it alone!!  Wow is all I can say….  
As for the ML ACR, my switch stays in Auto, unless operating the engine with an operational alternator AND the Genny with an operational generator …. And in that case, I isolate the two sources of power, by selecting OFF.  It is bad practice to provide more than one source of charging power to the ML ACR…. I did that once and got an ALT (fail) light on my dash…. Only time I would lock it ON would be if I needed house batteries to start/boost chassis batteries

 

Ken

[jacwjames]

Initially I didn't wire in the sense circuit for the generator.  Then I thought about it and did wire in both the generator and starting isolation but left the fuses out thinking I'd use then if I ever had a problem.  So far I haven't had a problem so we'll see what others have done.  Worse Case Scenario I can switch the Blue Sea off .  Will be interesting to see what others are doing. 

FWIW,

We first bought a Class C and my wife drove the wheels off of it going to dog shows.  I only got to use in on vacation a couple times a year so probably less then half the total miles put on the rig the ~11 years we owned it.

We then bought the Windsor and she pretty much continued her dog show trips while I worked, never really paid attention to the miles until in 2012 I was shocked when I changed the oil and saw that she had put on ~12K miles.   I was working/living in Upper Michigan and she stayed in the house in E TN until she drove the rig north for a couple months during the summer.  I was traveling a lot and didn't take many trips in the the RV probably traveling +200 days gone mostly out of country.  Found out that on her way home in the fall she zig-zagged her way way back going to different dog shows.  Yikes, 12k miles.  Luckily it has slowed down as far as the shows but still has dogs.  Her latest acquisition is an Anatolian Sheppard, ~140 pound gentle giant who watches over the Pekingese . 

[QueenandI]

5 hours ago, jacwjames said:

Initially I didn't wire in the sense circuit for the generator.  Then I thought about it and did wire in both the generator and starting isolation but left the fuses out thinking I'd use then if I ever had a problem.  So far I haven't had a problem so we'll see what others have done.  Worse Case Scenario I can switch the Blue Sea off .  Will be interesting to see what others are doing. 

FWIW,

We first bought a Class C and my wife drove the wheels off of it going to dog shows.  I only got to use in on vacation a couple times a year so probably less then half the total miles put on the rig the ~11 years we owned it.

We then bought the Windsor and she pretty much continued her dog show trips while I worked, never really paid attention to the miles until in 2012 I was shocked when I changed the oil and saw that she had put on ~12K miles.   I was working/living in Upper Michigan and she stayed in the house in E TN until she drove the rig north for a couple months during the summer.  I was traveling a lot and didn't take many trips in the the RV probably traveling +200 days gone mostly out of country.  Found out that on her way home in the fall she zig-zagged her way way back going to different dog shows.  Yikes, 12k miles.  Luckily it has slowed down as far as the shows but still has dogs.  Her latest acquisition is an Anatolian Sheppard, ~140 pound gentle giant who watches over the Pekingese . 

That's what got us our DP, the dog shows. Couple vacations together, she goes to her shows with our Bassets, I maintain it and get to tailgate with it. 

I've got the wires in the right spot, just need to connect if it's in the best interest of the batteries, alternator and inverter. 

Edited January 29, 2023 by QueenandI

[jacwjames]

Probably the best option.  I did put fuses in that I could pull pretty easy so I just left them out for the time being. 

Since installing the MLACR I've been on a number of trips but never ran the generator so don't know if there would be an issue or not.   Not sure if my wife ran the generator for the AC's when she went to dog shows, sometimes she does and other times she doesn't.  That would be my biggest concern. 

[bmulvenna@hotmail.com]

Can you post a diagram of how you have it wired?

[jimc99999]

1 hour ago, jacwjames said:

Probably the best option.  I did put fuses in that I could pull pretty easy so I just left them out for the time being. 

Since installing the MLACR I've been on a number of trips but never ran the generator so don't know if there would be an issue or not. 

I've left the ML-ACR in auto mode while driving with the generator running, it doesn't seem to matter. Batteries are often charged from multiple sources. You don't disconnect your solar while driving or running the generator.  The inverter/charger's AGM charging profile is a little more aggressive (higher voltage) than the alternator, so it should handle the bulk of the house battery charging if the batteries are low when you're driving. And either way, the chassis batteries will stay charged. 

[63Hotrod]

I have to select Off when running the Gen other wise I get an alt fail message. Same message if I start the coach when connected to shore power.

We have been running the MLACR three years and love the system

[jimc99999]

2 hours ago, 63Hotrod said:

I have to select Off when running the Gen other wise I get an alt fail message. Same message if I start the coach when connected to shore power.

We have been running the MLACR three years and love the system

The only time I've seen the "alt fail" light is when the alternator was actually failing. Or, with the 28si self-exciting alternator, if the revs don't go high enough to excite the alternator on startup the alt fail light will be lit until I rev the motor a enough to start up the alternator.

It's possible your alternator doesn't start producing current if the battery voltage is higher than normal resting voltage. And that's probably fine, if your generator is running there's no real need for your alternator to produce charging voltage.

What alternator are you running? If you start the motor while connected to shore power and your alt fail message displays, does it go away and the alternator starts charging when you disconnect shore power? 

[Cubflyer]

 

[Cubflyer]

The stated purpose of the ML ACR is:  'An automatic charge relay (ACR) performs several tasks. It combines two battery banks to charge them from a single source'  The original "BigBOY" relay it replaced,  just combined the two banks of batteries for starting.

....Single source of charging,....... the engine alternator output is connected to the chassis battery at the ACR, the house charger (inverter) is connected to the house batteries at the A+ and Negative of the house batteries, therefore when the inverter is a 'source', powered by either shore power or the genny, and you are running the engine there are two charging sources.  As for the third (solar) charging source (in my MH connected directly to the house batteries)  it is not a very large output, just a few amps verses an engine driven alternator or an inverter.... so it does not seem to interfere with the engine alternator when the house and chassis batteries are combined. 

FWIW....I did not connect the brown isolation wire up, so maybe that would isolate the two batteries when running the engine and it would (automatically) be isolating the house and chassis batteries when the ignition switch was on (engine running)......... Ken

Edited January 29, 2023 by Cubflyer
clarification

[63Hotrod]

Jim not sure what alt we are running The alt fail might go away with more RPM not sure. But thanks for the information

Ken I didn’t connect the brown wire either. I think this is only to isolate things during starting. 

[Cubflyer]

1 hour ago, 63Hotrod said:

Ken I didn’t connect the brown wire either. I think this is only to isolate things during starting.

I'm not sure what the brown wire does/interacts with the ACR either.  My ACR works for me as advertised without the brown wire connected.

  My ALT light did not come on immediately, it took a while on the road for it to start 'glowing' faintly, I uncoupled the battery banks with my remote switch, allowing them to charge/operate separately and the light went out... Again, having all the batteries connected together and having the engine alternator and the inverter 'charging' them, just did not play well, I sure did not want to chance hurting my alternator or my inverter, and I viewed the ALT fail light as fair warning.... others experiences may vary..... 

Ken

[jacwjames]

[Cubflyer]

Yep, The brown wire would isolate the two banks of batteries-house/chassis while cranking the coach engine.  Now I'm remembering why I did not make that brown wire connection... I do not crank up the coach when connected to shore power or running the genny... just a "me" thing...  Maybe, now that I have become aware of this connection I will make it...-Ken

From the install instructions:

Start Isolation The ML-Series ACR can be configured to automatically open temporarily (3-5 minutes) when voltage is sensed on any one of up to three start-isolation inputs. Enable this feature to isolate Start circuits from the House circuit and prevent starting current transients from interfering with sensitive house electronics. To enable Start Isolation: • Connect the brown wire (ISOLATION #1) from the harness to the terminal or wire running from the start key switch to the starter solenoid. Make this connection through a 2 Amp in-line fuse. This connection can be made at the start key switch or at the starter solenoid, but must be to the line that is positive only when cranking the engine. as shown below.

[QueenandI]

I had a simple White-Rogers/RBM relay with an IRD, both of which were in the battery bay. Straight forward to move the batteries from the large terminals on White-Rogers/RBM relay to A&B on ML ACR. The IRD had an Ignition lead to it for the Pigtail Brown Isolation #1. Picked up a ground for the Pigtail Black in battery bay. Purple wire from White-Rogers/RBM relay ran to Alt Start switch and used it for the RED wire from ML-ACR pigtail. Alt Start switch had a (+) wire that ran from the front run bay fused (7.5 amp) and jumped it from Spade 8 to Spade 3 on new switch. Alt Switch had a ground as well Spade 1. Ran a 5 wire conductor from battery bay to Front run bay to. Used one wire from new 5 wire conductor for Pigtail Yellow to new switch. Used another wire for Pigtail Green Isolation #2 to Genset light on dashboard. Stole Picture from Cubflyer above.

This project had been on my to do list. Started it now because my Alternator light came on coming home in December from East Lansing. DUVAC alternator was producing <11v at it terminals. Pulled it, ordered a new one, had the old rebuilt and while doing research came across vanwill52 post 

Decided to move this project from the to do list to the done list. Also, discovered that the Chassis battery cutoff switch had been removed, so added a BlueSea switch and replaced the Coach battery switch with new as well. It was Vanwill's post that made it clear the process, especially ok-rver post with pic of with a similar setup up. Since there was no BIG boy, Solid State Isolator (SSI) or a Lambert Charger in my setup, finding something similar was the key to confidence to upgrade to ML ACR. 

I did find a 30amp fused blue wire hooked directly to the large battery terminal on White-Rogers/RBM relay. No clue where it goes but will save that for another day. 

Thank you for your responses and previous posts!!!!