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Posted: **Thu Aug 07, 2025 11:52 pm**

The voltage reported by the Garmin is sent over the CAN bus so that voltage is the engine voltage. Would be interesting to see if the house battery is the one powering the Garmins but my bet would be that its the engine battery...would be easy to test that theory.

The ACR us just a relay that connects two batteries together. It doesn't adjust anything. It senses voltage from either battery and connects the relay over a certain voltage threshold and doesn't let them connect if the voltage on one of the batteries is below a voltage threshold.

Personally, can't see how a bad ACR would be an issue. A check with a voltage meter(helm voltage and house battery voltage) would be all that is needed to check that theory.

Posted: **Sun Aug 10, 2025 7:03 am**

Anchor86 wrote: Mon Aug 04, 2025 5:11 am We just had same issue with our `20 R7. We replaced the blue sea automatic charging relay (ACR) box mounted behind the battery switch. It automatically adjusts voltage between the 2 batteries. $65 and easy to swap out . I swapped the relay out prior to this and still had displays going out and fosgate head unit displayed “low voltage”. 4hours since new ACR and all is good.
The following is from our cobalt dealer:

On Garmin display have unit voltage and engine voltage displayed. You can’t diagnose the switch unless you can test the voltage on the batteries when the engine is running. With dual Garmin screen screens and you should be able to view the engine voltage and the unit voltage. If the unit voltage is coming up to over 13 with the engine voltage while the engine is running when the switch is in the ON position, that means your automatic charging system is working properly. If it’s not, then it’s not working properly and I’d recommend you run the boat on combine until you get that part repaired.

I have both the engine and unit voltage displayed on my panel and it will tell you if the ACR is working. With engine off the unit voltage will begin to drop as you pull power from it like running the stereo. When you start the engine the engine battery will jump to +13V and you will see the unit voltage increase to that same voltage indicating the unit battery is charging

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R7 acting a little weird

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Re: R7 acting a little weird