Battery Wiring

[drisso88]

Recently purchased a new 2023 255 FSH Sport E. I'm hoping somebody in here has the answer so that I dont have to start opening up wire bundles, but I noticed that when I only have my house battery on, the 7" display doesnt come on and therefore the stereo doesn't work. The SIMRAD doesn't turn on either until I hit the power button, but I don't see a power button on the other display. I cant really see what all runs into the batteries because they're just labeled "house" and "start". Seems counterintuitive that the stereo wouldnt pull from the house batteries when the boat is off. In my other boat, everything other than the starter was wired to the house batteries. Am I missing something?

Separately, but same topic, do I need to do anything weird with my batteries or whatever Yamaha uses as a switch? I’m coming from a perko switch that seemed much simpler than what I’m reading about this one. I set it to “all” when riding to charge all batteries, then “2” when parked to listen to music. Never had to use “1”. I have 2 lithium batteries in parallel for my house batteries, then the lead acid that came with the boat as my starter. I have a NOCO genius 10x3 as a tender/charger. I’ve read that this switch will cause it to overcharge them? I don’t really want my starter and house batteries connected at all, since they’re different battery types. Hopefully there’s an easy solution.

 

[FSH 210 Sport]

Welcome and congrats on the boat!

First let’s talk about the stock / oem battery switch and it’s use. It’s a BEP marine battery switch with a DVSR (digital voltage sensing relay).



This switch is meant to leave both the start and house switches on all the time during operation and the DVSR keeps the start battery isolated. The DVSR closes the contact when either battery reaches 13.4 volts paralleling the start and house batteries, the little red is on when the DVSR has the switch closed and the start and house batteries are paralleled





and the DVSR opens the contact when the voltage reaches 12.8 volts breaking parallel or isolating the start and house batteries. Since you have LFP house batteries who’s resting voltage is 13.6 volts, you are going to need to reconfigure the DVSR for ignition or storage mode which is part of its design. Use the link below to see the operation sheet and the different operating modes.

Here is the spec sheet on the DVSR and it’s operating modes.

BEP DIGITAL VOLTAGE SENSITIVE RELAY User Manual

View and Download BEP DIGITAL VOLTAGE SENSITIVE RELAY instruction manual online.

manualmachine.com

Since the DVSR will activate with the LFP house batteries you have, the LFP batteries will start to discharge into your lead acid starter battery due to the higher voltage of the LFP batteries, thus the lead acid battery can overcharge. Doing the DVSR mod will alleviate that.

Since you have LFP house batteries you need to set up the DVSR so that it becomes active either when the engines are running or set it up to operate manually. I also have a LFP house battery and I have mine set up to operate manually from a rocker switch on the dash, I may go to the fuel pump hot set up this season, but so far I let the start battery come up to 14.4 volts before switching the DVSR on. Other members here have tapped onto one of the fuel pump hot wires so that the DVSR activates when that engine is running.



The advantage of having the little red wire tied to a fuel pump hot is that is a fire and forget and operates automatically through the day when ever the engine is on, this is how @WiskyDan set his up. @lazergeek set his up with a couple of relays so that which ever engine is on the DVSR operates. Either way this is a very simple modification to make, there are also guys who set the dvsr to operate when they turn on their batteries so that their batteries charge independently but that is for lead acid batteries. This is an elegant battery switch that does all the battery management for you, no having to remember to switch from 1&2 to 1 or 2 when you stop cruising… I have 563 hours on my boat now and the BEP marine battery switch has worked flawlessly.

As far as getting all of your accessory loads on the house battery goes you should probably get a service manual for your boat, there are single line wiring diagrams in the back of this manual, there has been some other members here who have moved accessory loads onto their house battery so that the starter battery is truly isolated with the dvsr is inactive. Here is my best guess on your set up, the sound system is controlled by the connext screen, but I’m going to guess that the sound system itself draws off of the house battery.

Another thing I think you will find very useful is a Victron Energy smart shunt to your house battery. This device measures voltage, current in and out of the battery, Ah’s & KWh’s used and state of charge-tge state of charge updates as the battery charges. It also has an auxiliary lead for watching the voltage on your start battery. This device will let you KNOW how much energy you have drawn out of your house battery and what remains, anything else is just a guess. It is configurable for any battery chemistry, size and voltage.

SmartShunt - Victron Energy

The SmartShunt is an all-in-one battery monitor, only without a display. Your phone acts as the display. The SmartShunt connects via Bluetooth to the...

www.victronenergy.com

It would be pretty easy to put the smart shunt on the start battery for a test to see how much power is being drawn from the start when it is on and powering the connext screen. That way you’ll know if you need to move any devices to the house battery. My guess is power draw will be negligible, but I could be wrong.

I know you have the NOCO charger and I’ve never seen a problem with them on this site, and its good you got the 10Ax3 as LFP batteries usually require 10A minimum charging current. Having said that I have moved to the Victron Energy IP67 chargers from my MinnKota 10A chargers, I think the IP67’s are superior as they can charge up to 25A which will cut your LFP battery charge time down by more than half. The IP67 chargers are highly configurable, can be used with any battery chemistry and size, the charging amp range is from 3A to 25A, have blutetooth connectivity so you can see what the chargers are doing and have done.

Blue Smart IP67 Charger Waterproof - Victron Energy

The Blue Smart IP67 Waterproof Charger is the new professional battery charger with built-in bluetooth. Find a Victron Energy dealer near you.

www.victronenergy.com

The Victron app is free and will work with all of Victrons devices.

You might want to read through this thread, thats my journey with LFP batteries and where I’m at now.

Thread 'Conversion to LiFePo batteries'

Oct 22, 2021

After having my boat for a second and full season, I found that can get about 10 miles out of my trolling motor battery, or about 6 hours of use at 1.8 mph, which is not enough for my average day of fishing which is 10-12 hours. So I was messing around with idea of replacing my trolling motor battery SLA batteries with lithium batteries, and possibly my house battery as well. I haven’t seen a thread detailing the math of LiFePo batteries, only that they are lighter, have more energy than SLA batteries, and most are super happy with them. Hopefully some of you will find the following...

• FSH 210 Sport
• Replies: 128
• Forum: Electronics-Stereo/GPS/Chartplotter/Electrical etc

• 
• 

What size LFP batter do you have in parallel?

Hope that answered all of your questions… if you need any help shoot up a flare and let us know.

P.S. If you use the sites search engine you will find that there is a ton information here that may solve any future questions you have.

 

[drisso88]

Thank you for the detailed response! After a few hours of searching last night, I found the below diagram which looks like it accomplishes my goal by moving the wire from one side of each isolator to the other, if I'm looking at it correctly. I don't have an aversion to cutting wires, but I will avoid it if I can.
I don't think it will overcharge during usage with this setup, just want to make sure I'm covered while it's in storage.

As far as the radio goes, I'd imagine you're correct. I will upgrade the sound system in the near future and I'll probably just get a separate head unit dedicated to it so that I can control everything straight from the house battery.

I have 2x 100ah LiFePO batteries in parallel for my house batteries, and then for now just the lead acid starter that came with the boat. I'll upgrade that to an AGM soon to get rid of the maintenance. I thought about getting a LiFePO for that as well, but I've heard a lot of mixed review about using that as a starter due to low CCA's.

Follow up question- My 2 OEM batteries were connected by a short negative wire. I'd imagine I do not want that connected anymore, do I have to connect it somewhere else or can I just reuse it elsewhere? I think it was there for the "emergency parallel" feature which I will never use. In the highly unlikely case I kill all 3 of my batteries somehow, I always have a jump box with me. Thanks again!

 

[FSH 210 Sport]

That set up by moving the wires will take care of the DVSR not operating when the switches are off, and that is it, this is an easy solution for those who have lead acid batteries and want the batteries to charge without the DVSR operating, as well as your application when the battery switches are off.

But you will need to do the storage / ignition modification, cutting the small red wire, so that when you are on the water with both battery switches on that the DVSR only operates if you want it to=manually via rocker switch or when the engine is running tying into a fuel pump hot. Otherwise the DVSR will close and stay closed throughout the day.

In my opinion keeping the lead acid battery for a start battery is a great choice. Even the non start rated LFP batteries will work as start batteries as the amperage to start our engines is quite low compared to outboards or I/O’s. But lead acid batteries can deliver more amperage for start purposes.

200Ah of LFP batteries is a lot of power. One of my favorite sayings is “overkill is underrated”. And you definitely have a lot of overkill going with that set up. There are a few guys as I mentioned that have LFP batteries in their house set up, one guy has two 100Ah in parallel like you do for his monster sound system, he has a smart shunt but have not heard back from him on his usage he spends 6-8 hours at the sand bar with the sounds booming… @WiskyDan has found that the most he has used out of his LFP house battery while at the sand bar is 25% if memory serves. The lowest I have seen my 100Ah Battle Born LFP battery use is roughly 35% and that was with the live well running, stock sound system=very small draw and my MFD. The other really cool thing about the LFP batteries is that they are a great marriage with our small alternators that only put out roughly 13A per engine, these batteries charge five times faster than lead acid, you can watch the amount of amps going into your battery bank via the smart shunt.

You have to have all the grounds connected together, so leave the ground jumper in between the start and house battery. This ground also goes to the engines, and that provides the ground reference for everything on the boat.

The smart shunt connects via the battery ground, so you’d have a ground going from your house battery to the smart shunt, then on the system side of the shunt you’d have the ground that connects to the start battery and the ground to the engines. With the exception of a trolling motor battery bank or a totally independent system on your boat all the grounds should be tied together at the batteries. This prevents any weird transients trying to flow through other systems.

The emergency parallel ties the positive side of the start and house batteries together for starting. I also carry a jump pack. I’m curious why you wouldn’t want to use the emergency paralleling switch? Its right there and super easy to use. Chances are you won’t need it if you set the system up correctly so that the start battery is isolated.

There is another advantage to the DVSR system, in addition to isolating the starting battery from house loads, it also prevents any of the voltage transients associated with starting the engines from touching your electronics.

Also, be very careful when messing with the battery cables, more than one person has destroyed their connext screen by hooking up or accidentally connecting the batteries in reverse polarity, even a momentary brush in reverse polarity and the connext screen will be toast.

 

[drisso88]

That set up by moving the wires will take care of the DVSR not operating when the switches are off, and that is it, this is an easy solution for those who have lead acid batteries and want the batteries to charge without the DVSR operating, as well as your application when the battery switches are off.

But you will need to do the storage / ignition modification, cutting the small red wire, so that when you are on the water with both battery switches on that the DVSR only operates if you want it to=manually via rocker switch or when the engine is running tying into a fuel pump hot. Otherwise the DVSR will close and stay closed throughout the day.

In my opinion keeping the lead acid battery for a start battery is a great choice. Even the non start rated LFP batteries will work as start batteries as the amperage to start our engines is quite low compared to outboards or I/O’s. But lead acid batteries can deliver more amperage for start purposes.

200Ah of LFP batteries is a lot of power. One of my favorite sayings is “overkill is underrated”. And you definitely have a lot of overkill going with that set up. There are a few guys as I mentioned that have LFP batteries in their house set up, one guy has two 100Ah in parallel like you do for his monster sound system, he has a smart shunt but have not heard back from him on his usage he spends 6-8 hours at the sand bar with the sounds booming… @WiskyDan has found that the most he has used out of his LFP house battery while at the sand bar is 25% if memory serves. The lowest I have seen my 100Ah Battle Born LFP battery use is roughly 35% and that was with the live well running, stock sound system=very small draw and my MFD. The other really cool thing about the LFP batteries is that they are a great marriage with our small alternators that only put out roughly 13A per engine, these batteries charge five times faster than lead acid, you can watch the amount of amps going into your battery bank via the smart shunt.

You have to have all the grounds connected together, so leave the ground jumper in between the start and house battery. This ground also goes to the engines, and that provides the ground reference for everything on the boat.

The smart shunt connects via the battery ground, so you’d have a ground going from your house battery to the smart shunt, then on the system side of the shunt you’d have the ground that connects to the start battery and the ground to the engines. With the exception of a trolling motor battery bank or a totally independent system on your boat all the grounds should be tied together at the batteries. This prevents any weird transients trying to flow through other systems.

The emergency parallel ties the positive side of the start and house batteries together for starting. I also carry a jump pack. I’m curious why you wouldn’t want to use the emergency paralleling switch? Its right there and super easy to use. Chances are you won’t need it if you set the system up correctly so that the start battery is isolated.

There is another advantage to the DVSR system, in addition to isolating the starting battery from house loads, it also prevents any of the voltage transients associated with starting the engines from touching your electronics.

Also, be very careful when messing with the battery cables, more than one person has destroyed their connext screen by hooking up or accidentally connecting the batteries in reverse polarity, even a momentary brush in reverse polarity and the connext screen will be toast.

I must be overthinking this. Wouldn’t I want the DVSR to only be active when the engines are running and the switches are set to “on”? I would think my 3 scenarios I want are:
1- boat is parked in the storage unit and charging, DVSR off
2- boat is running, switches are on, DVSR on
3- boat is off, switches are on (music, sandbar), DVSR off so that my house batteries aren’t charging my starter.

Also, with the splice mod, you’re mentioning the fuel hot line. I’ve seen other photos where that gets wired as shown below. Is that incorrect?

 

[drisso88]

Want to make sure I don’t mess anything up. Here’s the pic, A connects to the battery, so I’d hook the jumper to B, correct?

 

[FSH 210 Sport]

I must be overthinking this. Wouldn’t I want the DVSR to only be active when the engines are running and the switches are set to “on”? I would think my 3 scenarios I want are:
1- boat is parked in the storage unit and charging, DVSR off
2- boat is running, switches are on, DVSR on
3- boat is off, switches are on (music, sandbar), DVSR off so that my house batteries aren’t charging my starter battery

1. Correct
2. Correct
3. Correct

Just leave the oem wiring alone, what you are going to do doesn’t need you messing with the oem connections A, B, C, D, etc.. all you are going to be working with is the small red wire.

 

[FSH 210 Sport]

Want to make sure I don’t mess anything up. Here’s the pic, A connects to the battery, so I’d hook the jumper to B, correct?View attachment 231576

You will cut the red wire where the X is, but I’d cut it in the middle so it can be returned to the configuration it is now someday if it is desired, just cap off the piece that you are not going to use, which is the piece closest to the battery stud marked Start battery as directed in the directions.

Then you are going to tie onto the other end which is the closest to the bottom in the figure, that end will be tied onto the source of your choosing, whether that is a positive from fuel pump hot or a positive from a rocker switch on the dash. This will now be the power supply to the operating aspect of the DVSR, the voltage sensing is in another part of the processor.

Does that make sense?

 

[drisso88]

Well, new problem (I think). Did the ignition procedure, so while I’m charging my batteries now I see the DVSR is inactive. Win there. However when I unplugged from shore power and turned both switches on (ignition off, as if I’m at the sandbar) I’m getting a fast flash. Looking at the manual that signals either an overcharge or undercharge. One of my banks is LFP as previously stated. Both the lead acid and LFP are at 100% charge. Is it just letting me know that my LFP is resting at a higher voltage than the lead acid? Want to make sure it’s not trying to push power to the start battery.

 

[FSH 210 Sport]

Well, new problem (I think). Did the ignition procedure, so while I’m charging my batteries now I see the DVSR is inactive. Win there. However when I unplugged from shore power and turned both switches on (ignition off, as if I’m at the sandbar) I’m getting a fast flash. Looking at the manual that signals either an overcharge or undercharge. One of my banks is LFP as previously stated. Both the lead acid and LFP are at 100% charge. Is it just letting me know that my LFP is resting at a higher voltage than the lead acid? Want to make sure it’s not trying to push power to the start battery.

What voltage does the voltage on the connext screen indicate for the start and house batteries?

 

[drisso88]

After a significant amount of help from @FSH 210 Sport I got it up and running by tying the loop into the fuel pump. Huge thanks for all your help!