Could My ACR Be Stuck Open ?

[Defiance II]

My first post to the forums. I am also relatively new to boating - but I am learning.

My starter batteries are not charging. My house bank is separated from starter batteries by Blue Sea Automatic Charging Relay (ACR) with all charging sources going to house bank. System has worked fine without problem. Recently, when charging (from Xantrex inverter/charger), the undervoltage indicator light on the ACR remains on, which I believe indicates that the ACR is open (starter batteries not combined with house bank and therefore not getting charged). When charging, the voltage on the housebank is over 14v and my starter batteries are now 11.8 V. My suspiscion is that the ACR may be malfunctioning and is stuck open. Do these things malfunction? What might I be missing?

Note: After first noticing the problem, I had the starter batteries tested, and some cells were dead so I replaced them - but charging problem still persists.

(I did a search on the forums and didn't find anything right on point - if there are past threads on this issue please direct me to them and accept my apology)

[Unicorn Dreams]

Welcome Aboard Cruisers Forum

[knottybuoyz]

Switch the leads to the different battery banks from the ACR and see if the situation reverses itself.

[btrayfors]

Sounds very much like the ACR is shot. But, before you do anything, very carefully check all connections and connectors. Be absolutely sure you have good, clean, tight connections.

Then, measure the voltage at the start battery while the house batteries are charging. If it's less than 12.6 or so, then the ACR is shot.

I'd replace it with an EchoCharge (I don't like battery combiners...relays can go bad, and there's absolutely no need to "combine" a start battery with a large, possibly 50% depleted, house battery bank, thereby creating a huge inrush of current to the lesser charged batteries).

Bill

[velero]

The light on means that it is working - connecting both banks. From the ACR manual:

Features
• Automatically combines batteries during charging, isolates batteries when discharging and when
starting engines
• Allows temporary isolation of house loads from
engine circuit during engine cranking to protect
sensitive electronics—starting isolation indicated
by blinking LED
• Supports high-output alternators up to 120 Amps
• Ignition protected-safe for installation aboard
gasoline powered boats
• Under voltage lockout will not close when the
lower battery is below 10.8V @ 12V operation or 21.6V @ 24V operation—lockout indicated by
blinking LED
• Built in LED light indicates when batteries
are combined


Is the starting battery above 10.8 volts (at rest - turn charger off and wait 10-15 minutes before measuring voltage)? Use the bluesea diagnostic flowchart to find out whats going on. I had one go bad, they have lifetime warranty I had mine replaced by Bluesea. LED light tells you when the ACR is combining (not open). Also keep in mind that there is a delay from both the charger and ACR which could be as much as 5 minutes before you see any current flowing/equal battery voltage.

[Defiance II]

What great forum boards! I had been looking all over the net for that specific flowchart and couldn't find it. Thanks for the suggestions - I will be at my boat tonight to troubleshoot further, and will let you know how things work out.

Terry

[Andina Marie]

Originally Posted by btrayfors

Sounds very much like the ACR is shot. But, before you do anything, very carefully check all connections and connectors. Be absolutely sure you have good, clean, tight connections.

Then, measure the voltage at the start battery while the house batteries are charging. If it's less than 12.6 or so, then the ACR is shot.

I'd replace it with an EchoCharge (I don't like battery combiners...relays can go bad, and there's absolutely no need to "combine" a start battery with a large, possibly 50% depleted, house battery bank, thereby creating a huge inrush of current to the lesser charged batteries).

Bill

Combiners are very reliable and come with an unlimited warranty so the relays apparently don't go bad or it couldn't carry that warranty. At half the cost and twice the charging current it seems a better deal. Combiners are not just a "voltage sensitive relay", they regulate the amount of current sent to the depleted battery to avoid overloading the alternator or the wiring.