Alternator, ACR and battery monitor

[briandunnington]

I know this thread went all over the place, but I had a (hopefully) related question: I have wired up my Victron monitor as described above with *nothing* but the house negative on the battery side of the shunt:

H1<-->H2<-->SHUNT<-->everything else (including engine negative)

The battery monitor seems to be working, but two things confuse me:

1. When I run something that requires electricity from the engine battery (like tilting the motor up/down), the battery monitor shows the draw (as if it were from the house bank). Is that correct? If so, why? If not, what could be the cause given my wiring above?

2. My house and engine voltage always appear to be nearly identical (within 1/100 of a volt or so). Granted, this is just sitting on the trailer in the driveway (no engine running, etc). I would have thought they might differ but maybe they are topped off and just remaining close to each other?

 

[Submariner]

I know this thread went all over the place, but I had a (hopefully) related question: I have wired up my Victron monitor as described above with *nothing* but the house negative on the battery side of the shunt:

H1<-->H2<-->SHUNT<-->everything else (including engine negative)

The battery monitor seems to be working, but two things confuse me:

1. When I run something that requires electricity from the engine battery (like tilting the motor up/down), the battery monitor shows the draw (as if it were from the house bank). Is that correct? If so, why? If not, what could be the cause given my wiring above?

2. My house and engine voltage always appear to be nearly identical (within 1/100 of a volt or so). Granted, this is just sitting on the trailer in the driveway (no engine running, etc). I would have thought they might differ but maybe they are topped off and just remaining close to each other?

You don't specify which boat you have. I'm assuming you have a solar panel.

The solar panel up top is a charging source. It'll cause the ACR's to close which will put all three of your battery banks in parallel. To test, you need to create a situation with the boat that isolates all 3 battery banks. Voltage should be under 13 volts. Perform the testing after sunset (or throw a blanket over the solar panel). Then you need to run something to bring down the voltage a little. Turn on the inverter and run the microwave for 1 minute heating a glass of water. Then you should see different voltages for all three banks as the ACR's will both open and isolate the battery banks from each other.

 

[briandunnington]

You don't specify which boat you have. I'm assuming you have a solar panel.

Ah yes - the old 'leave out the important information and hope that you all can figure it out telepathically' trick. Sorry 'bout that - yes, you read between the lines correctly and I do have a solar panel (on a 2018 R23).

The solar panel up top is a charging source. It'll cause the ACR's to close which will put all three of your battery banks in parallel. To test, you need to create a situation with the boat that isolates all 3 battery banks. Voltage should be under 13 volts. Perform the testing after sunset (or throw a blanket over the solar panel). Then you need to run something to bring down the voltage a little. Turn on the inverter and run the microwave for 1 minute heating a glass of water. Then you should see different voltages for all three banks as the ACR's will both open and isolate the battery banks from each other.

This all makes sense now. I figured they must be combined somehow, but ACRs didnt cross my mind. I had put a blanket over the solar panel while I was doing the wiring, but had taken it off before testing out the app. Last night I waited til after dark and then ran down the power a bit as you suggested and confirmed that 1) the house and starter voltages appeared unique, and 2) engine-only loads like tilting the motor no longer affected the usage of the house bank.

Thanks again for setting me straight - was starting to think I was going crazy. (And in a bit of desperation, I entirely removed the B2 wire (starter voltage monitor wire) and *it still showed a voltage*! It was not the same as the house bank (closer to ~11 volts) and then over the course of the next hour it slowly trickled down to about 0.2v. Perhaps that was the ACRs slowly closing or the last bits of the 10% of solar power being directed to the engine battery? Strange that it registred anything with no wire attached at all, but no matter - it is all working as expected and I learned something in the process.)

EDIT: I wrote up the process here in case any future searchers are looking for info: https://briandunnington.com/ranger_tug_ ... ry_monitor

 

[Deb2021]

Hoping to tap your collective knowledge...
I want to install a battery monitor in a new-to-me 2011 RT25 SC.
1. Where is best location to install?
2. Are you using blue tooth to monitor on a phone/tablet?
3. If I were to mount the monitor with the other instruments at the helm what’s the easiest way to run wire from main 12v distribution panel to the battery compartment?
TIA...DB

 

[Red Raven]

Hoping to tap your collective knowledge...
I want to install a battery monitor in a new-to-me 2011 RT25 SC.
…
3. If I were to mount the monitor with the other instruments at the helm what’s the easiest way to run wire from main 12v distribution panel to the battery compartment?
TIA...DB

Since the battery monitor will only be measuring the House Bank there really is no reason to mount the monitor at the helm. I usually check the house batteries in the morning when getting up and when retiring in the evening, not when driving the boat. I installed our monitor in our R27 Classic using a wooden bezel just inside the cave. An easy short wiring run from there to the batteries. Should be similar on an R25SC.

Curt

 

[CruisingElvinRay]

I did not mount the monitor at the helm. Space and wiring issue. Mine is mounted on the main electrical panel.

Yes, I monitor it via Bluetooth from the helm. It’s one of the apps I swipe between while cruising.

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