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Thread: Problem with ACR
06-13-2011, 02:07 AM #1
Problem with ACR
I'm having a problem with my Blue Sea ACR not combining. I have two stereo batteries that are wired together in parallel (as one bank) plus a starter battery. I added a digital voltmeter at the helm that is connected to the stereo bank. I have the stock voltmeter connected to the starting battery. I have a remote led at the helm connected to the ACR. I have the ProMariner ProSport 20 and plug it in after each use.
SO here's the problem. The ACR will not combine as indicated by the blinking led. Engine is running, stereo bank voltmeter reads 12.7 and starting battery voltmeter reads around 14v indicating that it is receiving charging current. So why won't the ACR combine?Al
2006 Mobius LSV
06-13-2011, 08:04 AM #2
06-13-2011, 09:32 AM #3
Thanks, I had not seen that. Looks like I have a faulty ACR. I'll give blue sea a call.Al
2006 Mobius LSV
06-13-2011, 10:34 AM #4
Regardless of whether you have a bad ACR or not, as your audio system current draw and your depleted batteries current draw and your boat operations current draw collectively exceed your alternator output, you have also excceded the functional limitations of your ACR. Its an issue I have been observing and speaking to for years now. Its not unusual. Remember that your alternator output is generally rated at a high rpm and for intermittent use rather than continuous duty. Amplifiers with higher current draw compound the issue and an ACR by nature increases your dependency on shore AC charging. As your ACR doesn't combine when expected this will in turn dominoe into deeper battery cycles, less battery lifespan, decidedly less audio output and can contribute to thermal problems in the peak heat of summer.
Also, consider that an ACR is NEVER used on a fishing/bass boat to combine the alternator or stator with the depleted trolling motor bank. They know that a current draw this large and battery bank this large will exceed the limitations of both the alternator and ACR as designed.
There are designs that circumvent theses problematic issues but they must be done in the context of a total audio system and total charging system instead of a collection of random parts. As you increase one part of the equation it will trickle down into the other components.
06-13-2011, 08:33 PM #5
Not sure I totally understand what you are saying but I think my problem is pretty basic. My dual battery bank is fully charged (12.7V) and the ACR does not combine (yes, I have waited out the two minute delay) when I can see that the starting battery is getting charging current from the alternator as it is showing nearly 14V. A working and properly wired ACR should combine under these conditions.
I called Blue Sea today and they told me to make sure the SI wire is connected to the correct terminal on the ignition switch (i.e., zero volts in the on position). Or better yet, disconnect the SI wire at the ACR and see if it still does not combile. If it doesn't, they said to send it in and they will send out a new one.
2006 Mobius LSV
06-13-2011, 08:54 PM #6
06-13-2011, 11:12 PM #7
Yes, it should combine under the conditions that you described and in your case you may have a legit defect or wiring issue. But I'll describe another scenerio.
210 amp hours of a stereo battery bank that is depleted down to 12.0 volts after a long stay at rest.
30 amps of initial demand until the above bank gets a charge.
Continuing to play a 3000 watt stereo that is at 50 percent efficiency at -3 dB of capacity and drawing 75 amps.
Driving the boat at a moderate rpm while the ignition and boat operations consume 20 amps.
A 90 amp alternator that is developing 75 continuous amps at this particular speed.
The starting battery is fully charged at 12.7 volts and the alternator is generating just above 14 volts. The sensing side measures at 13.7 volts and the ACR attempts to combine.
There is 125 amps of current draw and 75 amps available from the alternator.
The current differential must come from the starting battery. Keep in mind how significant the depleted capacity is of a stereo bank with so much reserves...in fact, its four times the amp/hour capacity of the starting battery. That translates to a major voltage drop in the starting battery when compared to a minor elevation in voltage of the stereo bank.
The voltage on the starting battery drops like a rock. The ACR bounces back open.
Now, some boaters will not tax the charging system to this degree and their ACR may combine and stay combined. Other boaters will run the batteries lower and continue to play the stereo at full tilt after a stay at rest. For those boaters:
The amplifiers will lose a third or more of their rated power.
The batteries will cycle deeper and replacement will come sooner.
The stereo batteries will not see an alternator charge at any time after the stay at rest.
As the stereo size gets larger and the stereo battery bank becomes larger the functional limitations of an ACR are exposed. The ACR is less likely to combine and you become more dependent on shore charging for restoration.
06-14-2011, 01:11 AM #8
06-14-2011, 01:13 AM #9
So I did some troubleshooting in the garage tonight and the ACR combines when it senses charging current coming from the on board charger. So I wonder why it won't combine when it senses charging voltage coming from the alternator when the engine is running?
I will call Blue Sea again tomorrow and see what they have to say.
2006 Mobius LSV
06-14-2011, 07:22 AM #10
That is pretty interesting, and makes alot of sense. Us guy with the older boats have it even worse, though. My boat has a 55 amp alternator (I think) and that does not help the situation. I find that if I don't AC charge my stereo battery after every trip, after about 8 hours of normal use, there will not be enough current to run the stereo. It will keep cutting on and off trying to power up, and that is pretty annoying.Brian Roberts
2001 Outback DD