2013 Interstate BIM replacement with ML-ACR
Maybe someone can comment on the below issue I've uncovered.
Love to hear what you have to say, thanks!
There are may threads about replacing the stock Precision circuits battery isolator/combiner with the Blue sea ML-ACR unit. After reading these threads I went ahead and took out my Precision Circuits for all the benefits they said such as better switching voltages and minimal parasitic draw and replaced it with the Blue Sea ML-ACR. Then, while reviewing the documentation on the Precision circuits 00-10021-000 I found a functionality which the blue sea does not appear the have.
The Precision circuits unit has a feature which disconnects the engine from the coach batteries after one hour of driving time, then looks at the coach battery voltage and waits until they discharge to 80% before reconnecting the engine battery/charging circuits again. This on/off feature is designed to protect the coach batteries from being overcharged by the alternator when you were on the road for many hours.
The scenario would be the first hour of driving the car alternator is charging the batteries at Absorb voltages (14.1-14.2), then after an hour the switch opens, charging to the coach batteries stops and doesn't resume until the coach batteries drop to 80%. Im, not sure exactly what voltage they used for 80% , but its not a fully charged battery and I think that is the point, to wait until they drain down before applying more charge to the battery from the engine.
I believe there is a problem using the ML-ACR in this application because that unit will keep the switch closed as long as one side of the switch is at 13V or higher , thereby keeping coach batteries hooked up to the engine charging circuits as long as the engine is running, whether they need to be charged or not. Also, the 2013 Interstate is set up for a wet cell engine battery and the alternator puts out a voltage of 14.1-14.2 sometimes higher while driving which would keep the coach batteries in a constant state of charge at "Absorb" voltage levels for as long as you are driving, never reducing to the AGM float level of 13.3V therefore constantly overcharging the batteries reducing their life every time I go on a road trip.
Does this make sense to anyone?
I'd appreciate and insight you may have.
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