Alternator, ACR and battery monitor

[Submariner]

The ACR's have a Green light that will turn on when the ACR is closed. The ACR has a small ground terminal 12 ga wire yellow that must be attached to the correct terminal ( Ground). If it is attached to terminal (start isolation )or ( LED light) it will not turn on. This has happened many times to Ranger and Cutwater owners. It is an easy installation mistake to make.

I can speak to experience here as a Ranger owner: It's also fairly easy to stuff things into the port lazarette and accidentally knock off that yellow ground wire to the ACR. With the Garmin running, radar, sonar, vhf, etc... it was about 2 hours underway until I would get a "11.8 low voltage alarm", at which point I'd go back and parallel the engine and house batteries. Took me a bit to realize that an ACR wasn't working, thus my house battery was not being charged when underway.

I now have up on my Garmin dash System Voltage and Engine Voltage. They should both read either 13 or 14.something. If one were to read 12.6 and the other is 14.4, I'd start with the ACR ground wire.

 

[Red Raven]

How does current going in run through the shunt?

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When wired correctly, the house bank charge current (from alternator/shore charger/solar) goes into the House Battery positive terminal (via the ACR if required) and runs out through the house bank negative and then the shunt to the system negative ground and back to the applicable (alternator/shore charger/solar) charging system.

This, of course, assumes the ACR is connected properly as Submariner describes above.

Curt

 

[Red Raven]

So, I waited until full darkness to make sure solar didn’t interfere. I disconnected from shore power and turned the house bank battery switch to off. Battery monitor, predictably, went to zero amps.

I raised and lowered the trim on the outboard 3x. I could see voltage drop on the engine battery, but amps on the house bank remained at zero the entire time.


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CruisingElvingRay,

This result does not confirm the start battery negative cable is connected properly for the house battery monitor to function properly as Hamster describes. I assume the engine trim motor is connected to the start battery positive and not the house positive (which was turned off in your case anyway). Because of this, whether the start and house battery negatives are connected together (or not) the current will return directly to the trim drive and not through the shunt. For the current to be measured by the Balmar monitor it must pass through the positive, then negative, and then the shunt of the house bank circuit.

I am not suggesting your system is wired wrong only that this test does resolve the issue. The result would be the same with either wiring arrangement.

For proper house battery monitor function, only the house battery negative can be connected to the one side of the shunt. ALL other negative connections must be on the other (system) side of the shunt.

I hope this helps,

Curt

 

[CruisingElvinRay]

Please explain a scenario where I would get an incorrect reading from the battery monitor because the battery banks are bonded together on the negative. I don’t mind moving the banks to the bus, I just want to understand when the monitor would incorrectly calculate the difference in energy out of the house bank and back through the shunt.


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[Submariner]

Please explain a scenario where I would get an incorrect reading from the battery monitor because the battery banks are bonded together on the negative. I don’t mind moving the banks to the bus, I just want to understand when the monitor would incorrectly calculate the difference in energy out of the house bank and back through the shunt.
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It's a house bank battery monitor. With two house batteries... follow the yellow cables. It should go from House1 negative to House 2 negative, to the shunt. The other side of the shunt then goes to the negative of the thruster battery, or negative bus bar, whatever you have on your boat.

If there are any other connections on the negative terminals of any of your house batteries, that is a situation in which that device will bypass the shunt, and thus you will get inaccurate readings.

For example: If you left the inverter negative connected to either house battery, then when the inverter is running the battery monitor won't see its consumption. If the solar charger negative were connected to a negative post on a house battery, the battery monitor wouldn't see the amp-hour gain from the sun.

On our R27-OB, with a Victron BMV712, I have been able to measure engine amp input at idle (600 RPM gives me 20 amps). If I bump the RPM to 1000 RPM, I see 30 amps going in. If I run the T9.9 kicker, I have to be at 3/4 throttle to break-even on the battery usage (it's only an 8 amp alternator on the kicker, so it struggles to keep up with electrical loads). Most of the time if I'm on the kicker it's like I'm at anchor, consuming electrical.

I published this not too long ago that illustrates the above. Start at the 19:00 minute mark.
https://youtu.be/TGgO3_CycE0

 

[Hamster]

Martin - I’m glad to see this description and that your monitor reads amps coming in from the engine while cruising. That is what I was missing. Question: was your engine start battery grounded to the house battery with a jumper when you got the boat and moved it?

Second question: why aren’t you out chasing halibut today? 🙂

 

[Red Raven]

Thanks, Martin, for backing me up. 😀

...Question: was your engine start battery grounded to the house battery with a jumper when you got the boat and moved it? ...

Hamster, All boats from the factory will have all the negatives tied together either at a negative buss bar or directly on one or more of the the battery posts. This is because they do not have a shunt installed on factory boats. On our boat there were several connections made at the battery posts that needed to be moved when I installed the shunt. I also needed to make up an additional cable to make it all work.

CruisingElvinRay,
Martin gives several good examples of what incorrect measurements you can get from any cables tied to the wrong side of the shunt. Another one relevant here is Hamster’s situation where the start battery negative is on the wrong side. The current from the alternator that goes into the house returns directly to the engine negative (and thus the alternator negative) via the start battery negative bypassing the shunt. That is likely why he does not see charge from his engine alternator on his meter (also assuming his alternator is working!).

Curt

 

[Submariner]

Martin - I’m glad to see this description and that your monitor reads amps coming in from the engine while cruising. That is what I was missing. Question: was your engine start battery grounded to the house battery with a jumper when you got the boat and moved it?

Second question: why aren’t you out chasing halibut today? 🙂

On round-1 of upgrades on our boat, a bunch of negative cables were moved off our house bank.
On the R27-OB, there is no bus bar near the port lazarette.. So every negative cable that was connected to the house battery was moved to the negative post of the thruster battery. The T9.9 kicker, solar charger, battery charger, inverter, house loads, ACR's, etc... All that can remain is a yellow jumper that connects House1 and House2 negatives, and a yellow jumper that goes from either house negative to the shunt. The other end of the shunt then connects to the negative side of the Thruster battery with everything else (there's like, 6-8 things that end up being on the thruster negative post).

Technically, all the 12v negatives are all connected to each other. (Thruster, Engine, House). If they weren't, the parallel switch wouldn't work. Then when the ACR's are closed they put the thruster and engine battery in parallel with the house. Being that there is nothing else on the negatives of the house bank, all the return to the house bank must traverse through the shunt. Whether power is going in or coming out, the battery monitor sees it.

When I did round-2 of the battery upgrade (and put in the firefly batteries and relocated the batteries to the center lazarette), I added two bus bars (positive and negative). I connected every load (battery charger, T9.9 kicker, house loads, solar charger, inverter, ACR's, etc...) to the + and - bus bars. Then I just ran a jumper from the negative bus bar to the shunt, from the other side of the shunt to the negative of the house bank. The house negatives have jumpers between them. Nothing else connects to the house bank battery terminals with one exception. A Victron battery voltage and temp sensor that pairs with the Victron solar controller to provide voltage drop and temperature compensated charging. Otherwise, my battery terminals just contain jumpers needed to connect them together, in parallel..

For the drawing, look at the 10:00 minute mark.
https://www.youtube.com/watch?v=AehPUYetDzU&t=996s

2nd Question: I'm headed out Saturday to try my luck at Halibut again. Probably going to hit up Mutiny bay as it's a little closer and my dock neighbor scored a nice fish out there last Thursday. 🙂

 

[CruisingElvinRay]

I will move the cable connecting the thruster and house negatives and see what happens next time I’m out. I’ll have to check the 3rd house battery on the other (Starboard) side to see if the thruster battery connects to it. May get a little complicated. I’ve been wanting to move the engine battery to starboard and the 3rd house battery to port so the house bank is all in one spot. This may get me to start that project.

Thanks for the answers.


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[Submariner]

Thanks, Martin, for backing me up. 😀

...Question: was your engine start battery grounded to the house battery with a jumper when you got the boat and moved it? ...

Curt

No prob. 🙂
We're just now starting to enjoy our new battery set up. We were at Hunter bay at anchor a month ago, woke up in the morning and the hot water was warm, not hot. So I powered on the inverter and the hot water heater and let it run for about 40 minutes. I took the batteries down to -150Ah. Voltage remained constant, the inverter didn't beep at me while pulling -85 amps. Then I took a hot shower.

This past weekend we were at Mackaye harbor at anchor, then went halibut fishing. We ended up at Lopez Islander resort. I didn't even plug into shore power until the next morning. I was down -163Ah after heating hot water. I plugged into shore power, turned on both of my battery chargers, had the solar panel going (obviously), and I idled the engine while at the dock. Saw +70 amps go back into the house bank.

I'm still figuring things out. I first went with 2 firefly batteries and sized my additional charger accordingly. Firefly's want 20% minimum charge rate. Now that I added the 3rd firefly, my charger is undersized (which was why I idled the engine while on shore power). So I'm shopping for a 70amp charger (20% of 348Ah = 70amps). And when we got back last Saturday my two new solar panels arrived. Should have them installed in a couple of weeks. Once I have the 70amp charger in and 400 watts of solar up top, we should be good for awhile.

 

[Red Raven]

Nice! Sounds like a great setup.

 

[CruisingElvinRay]

Red Raven, you and Submariner were absolutely right. I shut everything down except the engine bank (hence the darkness around the iPhone).

Had a baseline of +.12 Amps on the monitor (I will run a a calibration tomorrow), house battery bank at ~72%

Started engine at idle. +.34 Amps in my current configuration with the house and engine banks tied together on the negative.

Moved the engine battery negative to the negative bus (on the other side of the shunt).

Started the engine at idle. +20.79 Amps.

Thanks for helping my understand the issue.

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[Red Raven]

CruisingElvingRay,

Nice! Glad to see it worked out!

Curt

 

[Submariner]

Red Raven, you and Submariner were absolutely right.
Had a baseline of +.12 Amps on the monitor (I will run a a calibration tomorrow), house battery bank at ~72%

Started engine at idle. +.34 Amps in my current configuration with the house and engine banks tied together on the negative.

Moved the engine battery negative to the negative bus (on the other side of the shunt).

Started the engine at idle. +20.79 Amps.

That's fantastic!!

On your BMV712 configuration, don't forget to change the 6 digit pin to something other than 00000. Also it helps (a lot) to change the name of your monitor to something meaningful. I learned this when ours was first installed, I brought up the bluetooth app and accidentally logged into the boat next to me, and I accidentally upgraded their firmware thinking it was ours. Its' common to walk through a marina and find that there are many of these things deployed out there.

Another good experiment to do would be to throw a blanket over the top of your solar panel. Fully charge your batteries. Power off most things on the boat, as if you left it at the dock, but leave the refrigerator running, the DC switch should be on and disconnect from shore power. Come back in 12 hours and see what the Ah consumed is, as that'll give you an idea of how much capacity goes to the boat for the bare essentials. On our R27-OB, it'll go through 23Ah every 12 hours. (50Ah a day).

 

[BB marine]

It was interesting to see what the charge output was at idle 20.79 amps. The rated output for this engine is 50 amps at WOT. I looked at an Alternator output chart and was surprised to see that the output at idle is 28 amps. The engine it self requires some of that amperage to run just guessing 8 to 10 amps. The published alternator output chart for a 200 hp Yamaha shows max output at approximately 3000rpm (50 amps) with a straight line across the rpm range from 3000rpm to 6000rpm. I believe the max output for charging purposes would be more like 40 amps not 50 amps because of the engines consumption of current to operate. My point is that is a decent amount of charge capacity at lower rpms for an outboard that the charging system is flywheel driven.

This thread has been a good read. It seemed as it started as an issue of charging but in reality it was an issue of the proper way to install an add on component. Balmar SG200 battery monitor. I never gave one of these monitors much thought in the past but after reading this thread and reading the Balmar published information and installation I can see the advantage of having the monitor set up for the house battery bank. I don't think my use would be how much charge am I receiving from the charging system. If I question my charging system input I will dig deeper than a battery monitor. I feel its advantage is when the charging system is not in the equation, reading battery amperage consumption while on the hook and seeing battery state of charge. I have always used battery voltage in a bank to determine that and used a rough estimate of what each user is drawing (refrigerator ,freezer, lights ,head, inverter ...... When anchoring which we like to do. We have found the biggest disadvantage of doing this in a small boat is Battery capacity. The weight and room to add more capacity is not feasible. At least in my option. Our other issue is water capacity but that another subject.

I may have to throw old school away and install a monitor!!! I will follow the instructions and put the engine or any other users ground at or before the “CABLE” stud on the SmartShunt".

 

[CruisingElvinRay]

It was interesting to see what the charge output was at idle 20.79 amps. The rated output for this engine is 50 amps at WOT. I looked at an Alternator output chart and was surprised to see that the output at idle is 28 amps. The engine it self requires some of that amperage to run just guessing 8 to 10 amps. The published alternator output chart for a 200 hp Yamaha shows max output at approximately 3000rpm (50 amps) with a straight line across the rpm range from 3000rpm to 6000rpm. I believe the max output for charging purposes would be more like 40 amps not 50 amps because of the engines consumption of current to operate. My point is that is a decent amount of charge capacity at lower rpms for an outboard that the charging system is flywheel driven.

This thread has been a good read. It seemed as it started as an issue of charging but in reality it was an issue of the proper way to install an add on component. Balmar SG200 battery monitor. I never gave one of these monitors much thought in the past but after reading this thread and reading the Balmar published information and installation I can see the advantage of having the monitor set up for the house battery bank. I don't think my use would be how much charge am I receiving from the charging system. If I question my charging system input I will dig deeper than a battery monitor. I feel its advantage is when the charging system is not in the equation, reading battery amperage consumption while on the hook and seeing battery state of charge. I have always used battery voltage in a bank to determine that and used a rough estimate of what each user is drawing (refrigerator ,freezer, lights ,head, inverter ...... When anchoring which we like to do. We have found the biggest disadvantage of doing this in a small boat is Battery capacity. The weight and room to add more capacity is not feasible. At least in my option. Our other issue is water capacity but that another subject.

I may have to throw old school away and install a monitor!!! I will follow the instructions and put the engine or any other users ground at or before the “CABLE” stud on the SmartShunt".

Just keep in mind that the monitoring I posted pictures of is a Victron, not the Balmar.

Also, I can’t wait to get on the water and see what the charge rate is at my normal cruise of 4600 rpm, then see what happens when I turn on the A/C. 😉


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[Submariner]

It was interesting to see what the charge output was at idle 20.79 amps. The rated output for this engine is 50 amps at WOT. I looked at an Alternator output chart and was surprised to see that the output at idle is 28 amps My point is that is a decent amount of charge capacity at lower rpms for an outboard that the charging system is flywheel driven.

I don't think my use would be how much charge am I receiving from the charging system. If I question my charging system input I will dig deeper than a battery monitor. I feel its advantage is when the charging system is not in the equation, reading battery amperage consumption while on the hook and seeing battery state of charge. I have always used battery voltage in a bank to determine that and used a rough estimate of what each user is drawing (refrigerator ,freezer, lights ,head, inverter ......

The 75amp alternator on the Yamaha outboard (speaking specifically of the F225/F250 and F300) is a marine alternator designed to put out most of its amperage at the low end, closet to idle. Yamaha's graph on the F300 shows 55amps output at 1000 RPM where the Victron see's 30 amps of actual charging. I use our F300 as a generator on occasion. It's quiet and the CO exhaust is routed overboard. As I've said earlier in a post, I have measured 20 amps at idle (600 RPM) and if I bump up the RPM to just 1000, I will see 30 amps going into the house bank off the engine. Why is this important? Because when I recharge my battery bank I'm only going back up to 80% SOC, never 100%. I want to stay out of the absorption phase because it takes too long to get from 80 to 100% and that wouldn't be worth the engine wear and tear.

For example, the battery monitor will show me that -154Ah's are consumed. I could then idle the engine to charge batteries until I see -80Ah are consumed at which point I'd stop charging. Between the solar panel, the current weather, the F300 and our current SOC, I'm able to stay within the bulk charging phase of the battery to put back what we've consumed relatively quickly. Knowing our own usage... I may simply charge from -150ah to -100ah, knowing that'll buy me one more night on the hook. Upgrading the solar panel simply means I'll idle the engine even less and will also help with speeding up charging (i.e. 30amps from the F300 and another 20 amps from Solar).

I was also curious myself on the F200 as I know it's got a 50 amp alternator and is quite a bit different than the F225/F250/F300 Yamaha outboard. It's great to know that even the R23, if they idle their engine, are putting in 20amps to the house bank, which is exactly what the battery charger on shore power would provide.

 

[Hamster]

I appreciated all the trouble shooting and learning, too. Thanks so much.

I included the alternator and ACR in the subject because I had no way of knowing whether the engine was putting power back into the house unless I got my volt meter out and tested. My worries stemmed from losing my house batteries after two years, thinking that maybe the alternator or ACR were not working which caused the house bank to discharge too low. I had assumed that the person who installed my monitor did it correctly.

The other learning experience for me was to look at how my boat is grounded. To be honest, I’m still not sure. This daisy chain looks continuous. House battery to engine battery to thruster battery. The grounds for the ACR are in a bundle that head towards the back of the boat. Where it all terminates is a mystery. But, I think it is really important to know in the event something goes wrong, so I’m intent on chasing those yellow cables to their terminus, too.

The guy who didn’t install this correctly is going to fix it Tuesday. Then, I will head out for a couple days and look forward to seeing the house bank replenished from the Yamaha OB. Happy cruising!

 

[Nwdiver]

I was poking around the Yamaha website, they have a new outboard that outputs 92 amps at idle. Before you go looking, I don’t think it will fit on a tug or cutwater, it is 450 hp and weighs about 1000 pounds. So it is a race to see if your batteries charge or your transom gets ripped of. Here’s hoping they bring the new charger system to the 250/300 outboards 😀

 

[Submariner]

I was poking around the Yamaha website, they have a new outboard that outputs 92 amps at idle. Before you go looking, I don’t think it will fit on a tug or cutwater, it is 450 hp and weighs about 1000 pounds. So it is a race to see if your batteries charge or your transom gets ripped of. Here’s hoping they bring the new charger system to the 250/300 outboards 😀

The Cutwater 32 has a pair of F300's hanging off the back. That'd be a 75amp alternator times two! 🙂