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Old 03-30-2017, 10:50 AM   #1
Junior Member
Join Date: Mar 2017
Posts: 7
Relay Clicking

We bought a 2009 Berkshire 390BH about a year and a half ago and have lived in it for a little over a year. The house batteries were replaced in January 2016. When plugged into shore power, I normally hear a single clicking in the battery compartment every 30-120 seconds. Last night after arriving in beautiful Mobile, AL, the clicking comes in bursts of 20-30 in a group, spaced 3-5 seconds apart. And then sometimes it goes several minutes without a peep.

I checked the batteries to confirm that they are topped off with distilled water (no problems there), and everything works properly in terms of lights and appliances. I ran the generator from the Tallahassee area to here, but once I plugged in the clicking started. The sound appears to be coming directly from the Blue Sea "automatic charging relay".

In addition to the noise driving me batty, I figured that any change in sounds/behavior is probably (a) not a coincidence; and (2) not a good sign. If nothing else, I'd like to make the sounds go away. They are distracting from the voices in my head.

Thanks in advance for any thoughts or comments.
Rambling Sam is offline   Reply With Quote
Old 03-30-2017, 11:06 AM   #2
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Join Date: Jan 2015
Location: Englewood FL
Posts: 2,571
The ACR connects your house batteries with your engine batteries so that the converter and the alternator can charge both banks. It attempts to see if there is enough voltage on the primary bank (chassis when running the engine, house when running your generator or connected to shore power) and if so, is actively connecting all banks together for charging. In order to avoid constant switching with loads, it does this calculation over a period of time, usually 15 seconds to a couple of minutes.

It should not be continually switching back and forth and probably did not in the past. Sounds like it is unhappy with the voltage coming from your converter and can't make up its mind. You could have a failing converter or a corroded connection in the converter charging circuit. If you put a voltmeter on your house batteries, if this is the case you will see it going up and down and need to find out why. If the voltage is relatively constant (it should be at least 13.25 to 13.5 or higher when the converter is running) then either your chassis battery has a problem and is pulling it down when it is connected by the ACR or the ACR is failing.

Start with the voltmeter and then go from there. This used to be a significant problem for boondockers who had solar as they could hear the relay opening and then closing as the sun went behind a cloud and their solar voltage controller went up and down accordingly. Most newer systems are more forgiving (lower voltages and longer decision times) to avoid this.

2015 335DS
ScottBrownstein is offline   Reply With Quote
Old 03-30-2017, 02:10 PM   #3
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Join Date: Mar 2017
Posts: 7

Thank you for your quick and helpful response. I had hoped that the rains would let up so I could go in the basement to find my voltmeter and follow up, but it looks like that will have to wait until I arrive in New Orleans tomorrow. In the meantime I can focus on why the front AC is letting in drops of rain ...
Rambling Sam is offline   Reply With Quote

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