Blue Sea ML-ACR Automatic Charging Relay Clicking In and Out

[gksmith]

I have been stationary for several days, connected to shore power. However, I have noticed that my Blue Sea ML-ACR Automatic Charging Relay clicks in out fairly frequently. I am wondering if this is normal? I am assuming that the engine battery loses voltage, the relay connects it to the coach batteries, charges up the engine battery, and then disconnects the engine battery. This happens about 2 to 3 times per hour. Does this seem normal? I have never noticed this before when we have been on the road and boondocking for a night or two.

Thanks in advance!

[markopolo]

Did you solve Coach Batteries Not Charging On Shore Power problem? - http://www.classbforum.com/forums/f2...html#post86201

If not, maybe it's all related.

I noticed my inverter/charger cutting in and out on shore power once. It was only when there was very light or no AC loads. It turned out to be the campground power post. Any load caused a bit of heat and the connection would be OK. No loads, no heat & the connection was intermittent. The campground replaced the outlet and all was fine after that.

It's possible something similar is occurring in your coach. I suggest checking for loose wires in the AC panel and the both ends of the shore power cord.

[gksmith]

First, thank you for the reminder about my original problem regarding coach batteries not charging on shore power. I have now responded to that thread, stating that it was due to improper installation by the RV technician, not connecting one wire.

Now for my current situation, I have been staying at my daughter's driveway for two weeks. I did not notice not intermittent connecting and disconnecting until a few days ago. I am quite certain that the connection to 110 is satisfactory. The power usage in the coach has been quite minimal, as we only use it for sleeping and for my wife's daily makeup routine. We do keep the ceiling vent fan running constantly, but nothing else.

One thing that has changed, is that the first week, almost daily we would move the van out of the driveway so that the garage could be used. We would move it a couple times a day, but only to the street and then back. But the last week we have just kept it in the driveway, not moving it. After some thought, I am theorizing that when moving the van, the alternator kept the engine battery charged, even though it ran for only a short time. However, when we did not move the van, no charging took place by the alternator, but there was some drain on the engine battery, causing the Blue Ray Relay to connect the engine battery to the coach electrical system to recharge it. However, this would imply that the Blue Ray relay is that sensitive to voltage variation. Does this seem reasonable??

Comments will be appreciated.

[markopolo]

Next would be to keep your voltmeter handy and record the voltages when the relay disconnects and again when it reconnects.

After that, you'll have to figure out if the relay or the charger is causing the problem. I'm assuming you're using your new PD charger.

My understanding of the Blue Sea ACR is that it shouldn't disconnect until the voltage drops down to 12.75V - the PD charger output should be a minimum of 13.2V.

Are you also using solar for charging?

[gksmith]

Thanks. That gives me something to go on. Yes, I am using the PD converter--once it got properly installed, it has been great. I do use a 12V USB converter that has an LED voltmeter built into it. It is plugged into the chassis 12V system and I noticed this AM that it read 12.75V, but I did not check the status of the BS relay. I will be on the road today and in the next 10 days, so I will see if it continues, or if driving makes a difference.

The situation is no especially bothersome, but I do not want to be ignoring something that might be a symptom of future difficulties. I appreciate you input.

[booster]

You may want to give a quick check to the ground quality on the ACR. When you are close on voltage even a bit of loss at the ground can be an issue as that loss is subtracted from the voltage the ACR sees.



If it is a shore power issue, there could also be a resistance in the engine to chassis ground, which is commonly a flexible strap from the engine to the frame. Simple to check with an voltmeter when running charger. You can also just add a wire between the ACR and frame to see if the problem goes away.

[markopolo]

Great point about checking the ground connections. If you installed an optional switch on the ACR ground wire then it also could interrupt the ground so that's worth checking.

[gksmith]

Originally Posted by booster

You may want to give a quick check to the ground quality on the ACR. When you are close on voltage even a bit of loss at the ground can be an issue as that loss is subtracted from the voltage the ACR sees.

If it is a shore power issue, there could also be a resistance in the engine to chassis ground, which is commonly a flexible strap from the engine to the frame. Simple to check with an voltmeter when running charger. You can also just add a wire between the ACR and frame to see if the problem goes away.

Excellent point regarding the ground. Before I installed the Blue Sea ACR, I had a malfunctioning diode isolator so I had to remove it and installed a battery disconnect on the engine battery ground terminal post for protection until I got a replacement device. This is where I also have the current ACR ground connected. Lately I was having starting problems due to the battery disconnect not having good contact with the ground post, so I took it off about a week ago, not needing it anymore with the Blue Sea ACR installed. Consequently the ACR ground wire was unattached in the removal process. But the ACR ground wire is an extremely small wire with no terminal on the end, so I very well might have not made a very good connection when reattaching the ground wire--possibly good enough for the ACR to work, but not good enough for it to work properly. I will try to remedy this situation once I get home, if not before!

I am amazed at all of the good advice and help given by the contributors on this forum. Once again, thanks!

[gksmith]

I found the solution to my problem, and it was not one of the possibilities suggested. The root of my problem was OWNER FROGETFULLNESS! By happenstance a click took place while at the front of the coach. Out of curiosity, I opened the hood to look at the ACR to determine what state it was in. I discovered that the ACR was in LOCKED position! I evidently put the ACR into the locked out position when I removed the battery disconnect device from the battery as I previously mentioned in this thread. And it evidently took several days for the voltage differential between the engine battery and the coach batteries to become enough for the ACR to try to tie the battery systems together. This also gave me plenty of time to forget about my locking out the ACR, hence the oncoming futile attempts by the ACR to connect the battery systems. Once I put the ACR into normal operating mode, the clicking stopped.

Thanks once again to all of you that tried to help!

[rowiebowie]

Thanks for closing the loop. Glad it worked out for you.