Dead House battery cause limp mode / no start or could there be other issues?

[MrBubbaGump]

My wife saw this post on Yamaha FSH Owners Group on Facebook yesterday. and brought it up to me because we had almost the same issue on the same day! The post reads: "Help please: I’m out on the bay, 15 miles from “home”. Both TR-1 motors have been functioning fine all day. Just went to start it and head back and the starboard engine will not start. It turns over but never starts. Lacking fuel or spark I suppose. Any tips?"

Now my issue was almost the exact same except when I cranked the port engine I got a warning to turn off the port engine and contact my dealer and it didn't want to go above around 2500 RPM. Starboard would crank but not start.

Things to note: house battery was almost completely dead. Tried putting into emergency parallel incase it needed some more juice for some of the components? - No luck

Ran on port engine for a little bit, shut it all down. Started the port back up no problem still had the warning and alarm to shut down engine but now it had full RPM. About 5 more attempts and the Starboard engine started and ran fine no warnings. Took it back to the dock with no issues other than an alarm constantly going off but no messages popped up.

Plugged the batteries in to charge at the house, just went outside to start the engines and check out the issue.... Both start right up, no alarms no warnings...

My question is can a house battery really cause all these issues!?

 

[EastonRob]

I had a similar experience at the beginning of last year with my '21 FSH 255. Out enjoying the bay with friends and playing some music just drifting. When it came time to go home, port engine started but wouldn't go into forward or reverse and I had the "go to dealer immediately" (or whatever it was) warning. Starboard engine cranked strongly but would never fire. After a few minutes running the port engine in neutral, it finally went into forward and we limped home at 6 mph. At the dock, I charged the batteries for a couple of hours and both engines started and ran fine, and the error message went away.

Later that week I took the batteries to a battery specialist be checked and possibly replaced. Turns out I had two start batteries and didn't know it. A start battery is intended for short bursts of lots of power, and a house battery should be a deep cycle for longer, lower amperage draws. Perhaps something had drained without me knowing. Perhaps I had the batteries hooked up incorrectly. Perhaps I did something wrong when I modified the DVSR for independent charging (it seems to be fine now). At this point I don't know exactly what happened, but I bought a deep cycle for my house battery and haven't had a problem since.

I think part of what threw me off is that the starboard engine cranked normally but wouldn't fire at all. And the port engine fired up but wouldn't go into gear until, presumably, the alternator charged up something enough for that function to work.

So in answer to your question "can the house battery really cause these issues?" -- in my experience, yes. Make sure you have a fully charged deep cycle battery for house. Make sure your DVSR functions properly and you are charging both while running.

 

[MrBubbaGump]

Wow its just crazy because why would you have a separate start battery that wont allow the boat to function properly if the house battery dies?

 

[EastonRob]

Assuming the batteries are connected properly I have the same question.

 

[unknownghosted]

2023 AR220 - Same issue last night! After 2 hours floating around, engines wouldn't start...both batteries were showing 11.3v

When floating, I do turn off the Start switch and leave the House on to listen to music... the parallel switch is off...

Port engine finally was cranking but wouldn't start, had opened the parallel switch, starboard wouldn't crank at all...after a stressful hour port engine fired up, thankfully limped home, both batteries reading 12.3v.....

This morning batteries reading 12.3v..... both engines fired up straight away..... have them charging on Noco Genius Gen5X2 now... it read batteries as 25% charged...

 

[FSH 210 Sport]

Interesting post! I can’t believe I missed it from June.. I have yet to experience this, but then again I keep a watchful eye on the house battery. It sure seems weird that one engine would start and not the other.

First, never turn off the start or house battery switches while on the water. The DVSR isolates them when the bus voltage drops to 12.7 Volts, and connects them together when the voltage reaches 13.2 volts.

Second, get yourself a jump pack from Anti Gravity or one of the other jump pack companies. I charge mine at the beginning of the season and it stays charged for the whole season.

Suggestion: If this ever happens again, leave the throttles in neutral and put the No Wake in step 3 to get the engine up to 2100-2200 rpm, this will dramatically increase the power output from the alternator(s). FYI full output is at 3500 rpm. At full output the alternator is producing roughly 14 amps per engine, at idle its about 7 amps, at 2100 its probably about 10 amps.

You should have gotten a low voltage alarm on the connext scree if the voltage gets too low. Another thing to look at is what is the voltage on the start battery while it is cranking, less than 10.4? You’ve got a weak battery. This is why it is so important to leave your boat plugged in while it is not in use, personally, I’d have noting less than a 10A per battery charger.

With flooded lead acid batteries you need to run an equalizing charge on them once a month during the season, at least the house battery. But more importantly you need to use a hydrometer to check the cells for proper specific gravity and balance, the equalizing charge dose a few things, it will balance the cells, will stir the electrolyte as it will stratify over time-the need for a 10A charger, but a 5A should work, and will do a good job of cleaning the plates of sulphate. Make sure all battery connections are clean an tight, also make sure the grounds on the motor mounts are also clean and tight. Look at your chargers instructions and there should be a procedure as to what button to push and hold to initiate a manual equalizing charge, I know that NOCO and MinnKota chargers have this. Once the equalizing charge is done re check the cells with a hydrometer to see the cells are balanced and if the specific gravity is where it should be, if it is not at the best level then you can try running another manual equalize charge or you may have to use a shop style charger with a manual charge rate and a timer. Doing this will get you the top level of performance out of your batteries, the difference will be quite notable, do the start battery as well.

The DVSR has a red indicator light on it when it is closed, but, you can just watch the volt meters on the connext screen, the start battery should start coming up in voltage and when it hits 13.2 Volts or so it should drop some and the house battery voltage should start coming up. Again, if you have to run the engines for a while to get the house battery voltage up, use the No Wake Mode switch to raise the rpms up to 2100 to get the most charge while sitting still and be mindful of the exhaust and CO, no one sitting on the swim deck and bow into the wind. Better yet, just go for a slow cruise with the engines at 4000 rpm for a while to bet max charge current out of your batteries. Make sure that both the red leads from the engine are connected to the start battery.

@MrBubbaGump have you had another occurrence of this happening? Did you figure out what caused this if anything? Did you change your batteries?

@EastonRob did you find out anything? Were your batteries and DVSR hooked up properly? No more occurrences of this happening again? It’s interesting that both you and Bubba had the same engine start when the batteries were low …

 

[Judge]

This is a good post!

I bought a '22 275SD this time last year and have never got it into the water because of Hurricane Ian last September and then some traveling. After a 3-month RV trip to Alaska I am prepping the boat to finally get in the water and I wanted to share my experience from last year that is slightly similar to the above posts.

The boat sat for about 2 months after I picked it up last year and both engines fired up fine... but the buckets would not engage and the nozzles would not move (the 275SD has power steering and electronic buckets). The Connex display was showing voltages just under 12V so I charged the batteries but I was still having issues.... mind you the boat only had 1/2 hour on it from the dealer shake down. I opted to disconnect the batteries since there were many posts about it rebooting the ECU to clear errors. I ended up disconnecting both batteries and then with both batteries fully charged, the problems went away.

I have had the batteries on a Noco 2-Bank Charger since then. The dealer installed two Interstate M-24MS batteries and after closer inspection this week I found out these batteries only have a 6-month warranty from Interstate and they are wet cell batteries even though there are no caps to check the electrolyte level and add water. I assumed they were AGM's when I bought the boat because they were sealed but that isn't the case. The bottom line these are cheap batteries and not surprising that the dealer would choose them for new boats.

Given the technology on the newer Yamaha boats.... their sensitivity to proper voltages / currents.... and that I will be boating in the Gulf and Intercoastal in Florida, I have decided to replace my batteries preemptively even though I put a battery load tester on them and they show they are ok.

Batteries Plus has a 15% Off Sale this weekend I am going to buy two new deep cycle Duracell AGM Marine batteries. I am going with the Group 27 batteries since they offer a little more capacity than the Group 24's I have installed now (the battery trays are big enough to accept the slightly bigger 27's).

https://www.batteriesplus.com/productdetails/battery/marine-and-boat/deep-cycle/sli27magmdc

I had good luck with Duracell batteries in my motorhome several years ago and they are made in the USA. They also have a 30-Month Free Replacement Warranty. The AGM's are more expensive but are a better choice for boats that bounce around a lot on the water. These batteries also have the ability to start the engines as well as provide power for floating around and can go through many discharge cycles without harming the batteries.

I am dry storing my boat on a rack and will be on the top level so I decided to also add a Renogy 100W flexible solar panel on my hard top with Renogy PWM charge controller. This will help keep my batteries charging when floating around and also maintain / charge them when the boat is on the rack since I won't have access to power without having the boat dropped to a maintenance rack.

One other thing worth noting.... the user manual for my 275SD indicates the battery capacity should be 85Ah. The Owners Manual or Service Manual doesn't state whether it should be a Group 24, 27, 31, etc. but I suspect the 85Ah is an important minimum number for these boats.

The Duracell Group 24 Deep Cycle AGM's only list a capacity of 80Ah while the Group 27's list a capacity of 100Ah. That is another reason I am opting for the Group 27's. I would make sure your current batteries or any new battery you are considering has a capacity of at least 85Ah. I also recommend Deep Cycle AGM's for this application. They are more expensive but a better battery for these boats.

 

[unknownghosted]

2023 AR220 - Same issue last night! After 2 hours floating around, engines wouldn't start...both batteries were showing 11.3v

When floating, I do turn off the Start switch and leave the House on to listen to music... the parallel switch is off...

Port engine finally was cranking but wouldn't start, had opened the parallel switch, starboard wouldn't crank at all...after a stressful hour port engine fired up, thankfully limped home, both batteries reading 12.3v.....

This morning batteries reading 12.3v..... both engines fired up straight away..... have them charging on Noco Genius Gen5X2 now... it read batteries as 25% charged...

Update :

Firstly, thankyou ever so much for taking the time for the advice, it is very much appreciated....

Yesterday, dropped boat into water, neither engine would crank.... on display Start and House were showing 12.5v.
Checked basic stuff, nothing, raised boat out of water on hydrolift, both engines fired up - dropped both into water very quickly
Took advice on wake-mode cruising for 90+mins, both batteries showing 14.4v
Docked, turn off engines. Tried to turn back on.... wouldn't crank, both batteries showing12.5v.
Left batteries on overnight charging Noco Genius Gen5X2 - display showed 25%.
This morning - Noco shows error on 1 battery and 50% on other - see photos.
I put the Noco in Repair mode, lets see how that works...

Seems I have two Starter/Cranking batteries also....

Thinking I just get 2 x SLI27MAGMDC Duracell Ultra BCI Group 27M 12V 100AH 620CCA AGM Deep Cycle Marine & RV Batter as Judge suggested... are they enough oomph to be used as a starter? Thinking I need 2 Deep Cycle for House and using my existing Interstate 24M-XHD for Starter...

Still don't understand how my Starter battery drained, thought it was isolated from House battery (and my music Kicker 2 x 600w amps, 4 x 6.5in in boat speaks, 10in enclosed sub - 2hrs at sandbar, not playing loud at all...)

 

[Judge]

Update :

Firstly, thankyou ever so much for taking the time for the advice, it is very much appreciated....

Yesterday, dropped boat into water, neither engine would crank.... on display Start and House were showing 12.5v.
Checked basic stuff, nothing, raised boat out of water on hydrolift, both engines fired up - dropped both into water very quickly
Took advice on wake-mode cruising for 90+mins, both batteries showing 14.4v
Docked, turn off engines. Tried to turn back on.... wouldn't crank, both batteries showing12.5v.
Left batteries on overnight charging Noco Genius Gen5X2 - display showed 25%.
This morning - Noco shows error on 1 battery and 50% on other - see photos.
I put the Noco in Repair mode, lets see how that works...

Seems I have two Starter/Cranking batteries also....

Thinking I just get 2 x SLI27MAGMDC Duracell Ultra BCI Group 27M 12V 100AH 620CCA AGM Deep Cycle Marine & RV Batter as Judge suggested... are they enough oomph to be used as a starter? Thinking I need 2 Deep Cycle for House and using my existing Interstate 24M-XHD for Starter...

Still don't understand how my Starter battery drained, thought it was isolated from House battery (and my music Kicker 2 x 600w amps, 4 x 6.5in in boat speaks, 10in enclosed sub - 2hrs at sandbar, not playing loud at all...)

These are considered dual purpose batteries…. starting and hanging out with the tunes on.

I used these to start a Cummins Onan Diesel Generator on my motorhome plus power two refrigerators on an Inverter.

You will be good to go!

 

[FSH 210 Sport]

Update :

Firstly, thankyou ever so much for taking the time for the advice, it is very much appreciated....

Yesterday, dropped boat into water, neither engine would crank.... on display Start and House were showing 12.5v.
Checked basic stuff, nothing, raised boat out of water on hydrolift, both engines fired up - dropped both into water very quickly
Took advice on wake-mode cruising for 90+mins, both batteries showing 14.4v
Docked, turn off engines. Tried to turn back on.... wouldn't crank, both batteries showing12.5v.
Left batteries on overnight charging Noco Genius Gen5X2 - display showed 25%.
This morning - Noco shows error on 1 battery and 50% on other - see photos.
I put the Noco in Repair mode, lets see how that works...

Seems I have two Starter/Cranking batteries also....

Thinking I just get 2 x SLI27MAGMDC Duracell Ultra BCI Group 27M 12V 100AH 620CCA AGM Deep Cycle Marine & RV Batter as Judge suggested... are they enough oomph to be used as a starter? Thinking I need 2 Deep Cycle for House and using my existing Interstate 24M-XHD for Starter...

Still don't understand how my Starter battery drained, thought it was isolated from House battery (and my music Kicker 2 x 600w amps, 4 x 6.5in in boat speaks, 10in enclosed sub - 2hrs at sandbar, not playing loud at all...)

You either have bad batteries, a wiring problem, or a drain somewhere.

Question, do you have any loads connected directly to the battery besides the factory bilge pump that bypass the battery switches?

Boat on lift switch configuration; all battery switches off.
Boat on water configuration; Start and house switches on, emergency parallel off.

Take the batteries to a Autozone or some place that has a true load tester, its like a toaster but in a big silver box with a meter on it.

Secondly, I’m assuming that you are turning your battery all battery switches off when it is not being used, and that you keep the emergency parallel switch in OFF when the boat is being used. Get a good multi meter, and with nothing on it the boat, place the tester in Miliamp mode and remove a ground wire from a battery and use the multimeter leads as the feed through to check for a draw.

Thirdly go through and check every electrical connection you can find in your boat especially the ones that use screws or bolts, but all of them.

 

[unknownghosted]

Update :

Firstly, thankyou ever so much for taking the time for the advice, it is very much appreciated....

Yesterday, dropped boat into water, neither engine would crank.... on display Start and House were showing 12.5v.
Checked basic stuff, nothing, raised boat out of water on hydrolift, both engines fired up - dropped both into water very quickly
Took advice on wake-mode cruising for 90+mins, both batteries showing 14.4v
Docked, turn off engines. Tried to turn back on.... wouldn't crank, both batteries showing12.5v.
Left batteries on overnight charging Noco Genius Gen5X2 - display showed 25%.
This morning - Noco shows error on 1 battery and 50% on other - see photos.
I put the Noco in Repair mode, lets see how that works...

Seems I have two Starter/Cranking batteries also....

Thinking I just get 2 x SLI27MAGMDC Duracell Ultra BCI Group 27M 12V 100AH 620CCA AGM Deep Cycle Marine & RV Batter as Judge suggested... are they enough oomph to be used as a starter? Thinking I need 2 Deep Cycle for House and using my existing Interstate 24M-XHD for Starter...

Still don't understand how my Starter battery drained, thought it was isolated from House battery (and my music Kicker 2 x 600w amps, 4 x 6.5in in boat speaks, 10in enclosed sub - 2hrs at sandbar, not playing loud at all...)

You either have bad batteries, a wiring problem, or a drain somewhere.

Question, do you have any loads connected directly to the battery besides the factory bilge pump that bypass the battery switches?

Boat on lift switch configuration; all battery switches off.
Boat on water configuration; Start and house switches on, emergency parallel off.

Take the batteries to a Autozone or some place that has a true load tester, its like a toaster but in a big silver box with a meter on it.

Secondly, I’m assuming that you are turning your battery all battery switches off when it is not being used, and that you keep the emergency parallel switch in OFF when the boat is being used. Get a good multi meter, and with nothing on it the boat, place the tester in Miliamp mode and remove a ground wire from a battery and use the multimeter leads as the feed through to check for a draw.

Thirdly go through and check every electrical connection you can find in your boat especially the ones that use screws or bolts, but all of them.

Yep - all battery switches off when it is not being used, and that the emergency parallel switch is OFF when the boat is being used

I’ve removed the power feed to amplifiers (live connected to house battery terminal, neutral to shared grnd bar that the Starter battery is connected to, the House neutral is wired directly to Starter neutral).

Ive tested for parasitic draw on Starter battery seeing 0.25 to 0.30 amp even with Starter switch in closed position …. The House battery shows zero until I turn on the House switch , then draws about the same …. Thinking that is OK?

both batteries been on repair since this morning - reading 13.2v

both engines start …. Do I risk a day on the water … jumpstart not arriving till Tuesday

I have ordered the 2 xSLI27MAGMDC Duracell Ultra BCI Group 27M 12V 100AH 620CCA AGM Deep Cycle Marine & RV Batteries

Think I need a bigger boat now …..

 

[FSH 210 Sport]

Yep - all battery switches off when it is not being used, and that the emergency parallel switch is OFF when the boat is being used

I’ve removed the power feed to amplifiers (live connected to house battery terminal, neutral to shared grnd bar that the Starter battery is connected to, the House neutral is wired directly to Starter neutral).

Ive tested for parasitic draw on Starter battery seeing 0.25 to 0.30 amp even with Starter switch in closed position …. The House battery shows zero until I turn on the House switch , then draws about the same …. Thinking that is OK?

both batteries been on repair since this morning - reading 13.2v

both engines start …. Do I risk a day on the water … jumpstart not arriving till Tuesday

I have ordered the 2 xSLI27MAGMDC Duracell Ultra BCI Group 27M 12V 100AH 620CCA AGM Deep Cycle Marine & RV Batteries

Think I need a bigger boat now …..

Are you saying there is .25A or .25 MA? If it is .25 or 1/4 of an amp that is significant, if it is .025A 25 MA then that is okay, this is with the draw off of the start battery with all the battery switches off?

The auto side of the bilge pump is wired directly to one of the batteries, which one I cannot be certain at the this moment, if you really want to chase it down, pull the fuse out of the individual fuse holder on the bulk head wall labeled bilge then retest the draw with switches off.

Having the amp wired directly to the house battery was not good, it defeats the purpose of a battery switch. I’m curious to know if there was any parasitic draw going to the amp though, and its good you put it on the switched side of the battery switch.

Do you have a hydrometer? If not you should get one and measure each cell to check for balance and proper specific gravity.

Have you always had the batteries on the NOCO 5x2?

Here’s the thing with batteries that are sulphated, they will look fine voltage wise but as soon as you apply a load the voltage craters. There is a minimum voltage that the ignition needs to fire, and if it is too low the ignition will not fire.

When you try starting the engines next time pay careful attention to the volt meter on the connext screen, it should not dip below 10.4 volts if the batteries are in good condition.

That’s interesting that those batteries you ordered have less CCA than your interstates label shows, are those Duracell just a deep cycle or are they a deep cycle cranking battery? Its usually best to have a dedicated start battery and a deep cycle for the house load.

You say both engines start, and that the batteries have been on repair since this morning, did the repair cycle finish and they engines started ? Or are the batteries still on repair? By the way, have you checked the electrolyte level in the batteries?

As far as taking the boat out on the water, I don’t know, if they engines start a few times without issue then I’d say your chances are pretty good that will not have an issue, I don’t know that I would do it without having completed a load test and the other checks that I mentioned.

 

[MrBubbaGump]

Interesting post! I can’t believe I missed it from June.. I have yet to experience this, but then again I keep a watchful eye on the house battery. It sure seems weird that one engine would start and not the other.

First, never turn off the start or house battery switches while on the water. The DVSR isolates them when the bus voltage drops to 12.7 Volts, and connects them together when the voltage reaches 13.2 volts.

Second, get yourself a jump pack from Anti Gravity or one of the other jump pack companies. I charge mine at the beginning of the season and it stays charged for the whole season.

Suggestion: If this ever happens again, leave the throttles in neutral and put the No Wake in step 3 to get the engine up to 2100-2200 rpm, this will dramatically increase the power output from the alternator(s). FYI full output is at 3500 rpm. At full output the alternator is producing roughly 14 amps per engine, at idle its about 7 amps, at 2100 its probably about 10 amps.

You should have gotten a low voltage alarm on the connext scree if the voltage gets too low. Another thing to look at is what is the voltage on the start battery while it is cranking, less than 10.4? You’ve got a weak battery. This is why it is so important to leave your boat plugged in while it is not in use, personally, I’d have noting less than a 10A per battery charger.

With flooded lead acid batteries you need to run an equalizing charge on them once a month during the season, at least the house battery. But more importantly you need to use a hydrometer to check the cells for proper specific gravity and balance, the equalizing charge dose a few things, it will balance the cells, will stir the electrolyte as it will stratify over time-the need for a 10A charger, but a 5A should work, and will do a good job of cleaning the plates of sulphate. Make sure all battery connections are clean an tight, also make sure the grounds on the motor mounts are also clean and tight. Look at your chargers instructions and there should be a procedure as to what button to push and hold to initiate a manual equalizing charge, I know that NOCO and MinnKota chargers have this. Once the equalizing charge is done re check the cells with a hydrometer to see the cells are balanced and if the specific gravity is where it should be, if it is not at the best level then you can try running another manual equalize charge or you may have to use a shop style charger with a manual charge rate and a timer. Doing this will get you the top level of performance out of your batteries, the difference will be quite notable, do the start battery as well.

The DVSR has a red indicator light on it when it is closed, but, you can just watch the volt meters on the connext screen, the start battery should start coming up in voltage and when it hits 13.2 Volts or so it should drop some and the house battery voltage should start coming up. Again, if you have to run the engines for a while to get the house battery voltage up, use the No Wake Mode switch to raise the rpms up to 2100 to get the most charge while sitting still and be mindful of the exhaust and CO, no one sitting on the swim deck and bow into the wind. Better yet, just go for a slow cruise with the engines at 4000 rpm for a while to bet max charge current out of your batteries. Make sure that both the red leads from the engine are connected to the start battery.

@MrBubbaGump have you had another occurrence of this happening? Did you figure out what caused this if anything? Did you change your batteries?

@EastonRob did you find out anything? Were your batteries and DVSR hooked up properly? No more occurrences of this happening again? It’s interesting that both you and Bubba had the same engine start when the batteries were low …

No other occurrences with this issue, I added a 3rd battery for the stereo and just recharged the house battery.

 

[FSH 210 Sport]

No other occurrences with this issue, I added a 3rd battery for the stereo and just recharged the house battery.

Thanks for the reply… that is interesting that there wasn’t a “cause” you found, but, glad it has not happened again.

 

[EastonRob]

@FSH 210 Sport : No, I haven't experienced this issue again. But honestly, I'm so cautious now on the water that I don't spend much time in float mode fishing or otherwise just drifting that I really haven't put the batteries to the test. They are always on my NOCO 5x2 charger at the dock, and I know I have the DVSR wired correctly. The suggestion about putting it in No Wake Mode to at least get the charging going is a good one I'll have to remember should that happen again.

I agree with the others that electronics on these boats are just so sensitive that battery voltage anomalies end up causing really weird responses.

I'm going through a major exercise to rewire and modernize the battery / charging setup on my sailboat. I might be able to use some lessons from that at some point about how to actually isolate banks....

 

[FSH 210 Sport]

@FSH 210 Sport : No, I haven't experienced this issue again. But honestly, I'm so cautious now on the water that I don't spend much time in float mode fishing or otherwise just drifting that I really haven't put the batteries to the test. They are always on my NOCO 5x2 charger at the dock, and I know I have the DVSR wired correctly. The suggestion about putting it in No Wake Mode to at least get the charging going is a good one I'll have to remember should that happen again.

I agree with the others that electronics on these boats are just so sensitive that battery voltage anomalies end up causing really weird responses.

I'm going through a major exercise to rewire and modernize the battery / charging setup on my sailboat. I might be able to use some lessons from that at some point about how to actually isolate banks....

Thank you for the reply!

You know, intermittent electrical problems are the worst… After re rereading your post I see that you didn't mention using the emergency parallel switch, and I can see why, the engine cranked normally. However, I have to wonder what affect using the EPS would have had on the bucket operation.

Suggestion, pick up a jump pack and go use your boat to your hearts desire. Just check the connext screen start and house battery voltages every once in a while. Question, do you leave your screen on all day since you have tge push button start? Mine stays off most of the time when the engines are off. When I have been running my live well a lot in the past, and before switching my house battery to a 100Ah LiFePO4 battery, I’d turn on one ignition switch to check the voltage on the house battery, when the voltage got to 11.3 I’d start the engines and bring the voltage back up then turn the engines off. One time I remember getting a low voltage alarm on the house battery but in my case both engines started up normally.

Another thing now comes to mind that you or @MrBubbaGump didn’t try was turning the battery switches off and back on..still it doesn’t make sense that the stbd engine wouldn’t start, and that was the same on both boats, that’s either just a coincidence or there is a program logic in there somewhere either by design or accident.

Capt Obvious; In theory both engines should start and run fine if the house battery is very low, that’s the whole point of having two batteries and an isolater.

Im glad neither of you have had the issue again.

 

[FSH 210 Sport]

Just saw posted in the AR 250 fuel gauge thread by @BlueBulls how he connected the two battery grounds together to solve the fuel % gauge issue as well as other voltage related issues.

https://jetboaters.net/threads/2023-ar250-fuel-gauge.41000/#post-663950

You guys, @EastonRob @MrBubbaGump @unknownghosted might want check and make sure your two batteries grounds are tied together.

 

[MrBubbaGump]

@FSH 210 Sport I did not mention it but I did turn everything off and back on. We did have another post a while back where we talked about how these newer Yamahas are wired were the connext screen and seemly whole system is connected to only the house battery. Which I think is a terrible design from my understanding emergency parrallel only allows the extra juice to flow from the house battery to the start battery. So it allows you to crank but when that house battery is extremely low you get all kinds of faults when it actually fires up. I did make sure all my grounds are good to go all 3 batteries are tied together even though the 3rd is not tied to the boat for charging or any other system besides my amps.

 

[FSH 210 Sport]

@FSH 210 Sport I did not mention it but I did turn everything off and back on. We did have another post a while back where we talked about how these newer Yamahas are wired were the connext screen and seemly whole system is connected to only the house battery. Which I think is a terrible design from my understanding emergency parrallel only allows the extra juice to flow from the house battery to the start battery. So it allows you to crank but when that house battery is extremely low you get all kinds of faults when it actually fires up. I did make sure all my grounds are good to go all 3 batteries are tied together even though the 3rd is not tied to the boat for charging or any other system besides my amps.

When the EPS is ON, you create a common 12V positive buss, so if the house battery is low say 10.8 volts and the start battery is full say 12.5 volts, power will flow from the start to the house increasing the voltage on the house battery, that’s what is known as potential difference, there’s greater potential in the start battery than the house. Make sense?

So with that said, if the house battery was low and you turned the EPS ON, and with an engine running especially in no wake mode #3, it would help the house battery voltage recover much more quickly, and in theory clear up any issues the system was having with too low voltage and allow the second engine to start and then turn the EPS OFF and allow the DVSR to do its thing and bring the start battery up and then the house will charge.

 

[EastonRob]

FSH 210 Sport, yes, I did try using the EPS switch several times and cycled both switches multiple times. I think in my case having two start batteries aggravated the situation. You are correct - putting them together should equalize the volts across them.

I left the connext screen on as we were listening to music when this happened. What was so strange (to me at the time) was the fact that the starboard engine cranked strongly but refused to even fire once until I put the batteries on charge at the dock.

I just went down to the boat to verify while I'm in the middle of writing this:

House On/Start Off: SIMRAD works but not Connext
House Off/Start On: Turning ignition key you can hear fuel pump priming, but neither SIMRAD or Connext work. Pushing start button it did fire up.
House On/Start On: Of course, everything works.

Interesting. I've never tried to run it without Connext on. Not sure what would happen in terms of the ECM and basic functions.