Battery advice

[JTrottaNY]

Looking for some advice; currently my 242ls has the orginal battery setup- 1 starting, 1 house on the OEM switches. They have never given me a problem but both batteries are atleast 5yrs old and I do notice that when floating for a while, my gps screen will start to flicker.

First question- historically when I felt I needed to charge them (ie long day of floating planned) I would put my tender on one of the batteries (honestly didnt pay attention to which) and turn ON both the starting and house switches thinking the charger would backfeed and charge both. Now that Im making changes I have been looking into onboard chargers and wondering if I would benefit from installing one?

Over the winter I purchased (2) group 31 deep cycle batteries and (1) group 24 starting battery. *I also purchased an amp and tower speakers to install, another reason to upgrade my power system.

Install questions;

If I install both new batteries in parallel, should I also hook up the old battery (all 3 in parallel) or will they fight each other being different size and ages?

Should I put an onboard charger in while Im at it or is my current method, "backfeeding" through the switches sufficient? If I get an onboard charger do I need 2 legs (1 start and 1 house) or 3+ legs (one for each battery)?

I think its obvious but ill put it out there, the amp should be wired direct and fused off the house battery bank. Anything else I should plan for in terms of powering auxiliary stereo components?

Was thinking about also adding a rear 12v outlet for air/ballast pumps, if I do this I will probably look for one with a small digital volt meter so I can watch the voltage on the house bank- any marine rated suggestions are also welcome!

 

[FSH 210 Sport]

Okay,

Your oem battery switches, is it a BEP Marine switch that looks like this? Once I know this I can work from there.


Imho you need an onboard charger, with three charging banks, with at least 10A of charging per battery. A battery tender, as I know them does not have nearly the charging power to charge batteries as large as yours. Battery tenders, again, as I know them are designed to keep batteries charged during storage.

The batteries you recently bought, are they flooded lead acid, AGM or something else?

Do not hook up all three batteries in parallel …you want your start battery isolated from the house loads, more on this once I know what kind of oem battery switch you have.

As far as your install goes, do you have any unused OEM accessory switch’s ? If not, I would imagine you want to be able to turn your amp on and off so a switch of some kind will have to be added. The best thing to do would be to run a feed circuit, protected by a breaker at the battery to a fuse block that would in turn feed the amp, and the 12V outlet and any other things you’d want to power.

You mention having a voltmeter on the 12V plug, does your boats dash panel not have volt meters for the start and house batteries? If not I’ve got a great solution for you on that front, a Victron smart shunt that you can read off your phone and it will keep track of how many amp hours / kilowatt hours you’ve used as well as watching the voltage on your house battery and your start battery, and tell you the state of charge.

 

[JTrottaNY]

Yes other than all of the switches being red, that looks like the OEM switch, does that have any type of diode that prevents a charge from coming "backwards" from one battery to the other?

New batteries are all standard lead acid batteries.

I agree there will always be 2 seperate banks; start and house. When I mentioned 3 in parallel I was referring to the 2 new deep cycles plus (maybe?) the existing house battery, (3) total on the house side. Thinking on it further, I may just ditch the old battery and install (2) new house batteries unless there is a distinct advantage to using all 3.

Reading several onboard charger websites they actually recommend using a 2 leg unit unless you have a specific need to isolate a battery(s) such as a lithium for a solar panel where everything else is SLA or AGM.

I had not considered a switch for the amp as it has a remote gain knob that will allow me to dim the tower speakers for (volume comfort). I have always just pulled the duetsch plug when I didnt want the tower tweeters and will be installing the same on the port side to disconnect the tower speakers if/when I ever need to fold it down- I hadent really considered amperage draw if they were turned down or disconnected tbh. Wouldnt a simple 12v switch on the remote+ line accomplish this?

As far as voltmeters, the oem gauges do have a voltage function (iirc) but they only work with the keys on, guages are off when floating and I have no idea what they are reading: House V? Start V?

I will look into a shunt, the real goal was having a rear 12v outlet so I dont have to string wires from the helm to the swim platform, the volt meter would just be an easy add-on while I would mounting/wiring accessories.

 

[FSH 210 Sport]

Yes other than all of the switches being red, that looks like the OEM switch, does that have any type of diode that prevents a charge from coming "backwards" from one battery to the other?

New batteries are all standard lead acid batteries.

I agree there will always be 2 seperate banks; start and house. When I mentioned 3 in parallel I was referring to the 2 new deep cycles plus (maybe?) the existing house battery, (3) total on the house side. Thinking on it further, I may just ditch the old battery and install (2) new house batteries unless there is a distinct advantage to using all 3.

Reading several onboard charger websites they actually recommend using a 2 leg unit unless you have a specific need to isolate a battery(s) such as a lithium for a solar panel where everything else is SLA or AGM.

I had not considered a switch for the amp as it has a remote gain knob that will allow me to dim the tower speakers for (volume comfort). I have always just pulled the duetsch plug when I didnt want the tower tweeters and will be installing the same on the port side to disconnect the tower speakers if/when I ever need to fold it down- I hadent really considered amperage draw if they were turned down or disconnected tbh. Wouldnt a simple 12v switch on the remote+ line accomplish this?

As far as voltmeters, the oem gauges do have a voltage function (iirc) but they only work with the keys on, guages are off when floating and I have no idea what they are reading: House V? Start V?

I will look into a shunt, the real goal was having a rear 12v outlet so I dont have to string wires from the helm to the swim platform, the volt meter would just be an easy add-on while I would mounting/wiring accessories.

No diodes that restrict current flow between the batteries. Does your switch have the DVSR module like in the picture ? Quick run down on the dvsr in case you don’t know how it works. When the DVSR senses voltage of 13.2 volts it closes the switch and parallels the start and hose batteries, and when the DVSR senses 12.7 volts it opens the switch breaking parallel between the start and house batteries isolating the start battery so you always have a fully charged start battery. My boat came wired so the cables from the engines go to the start battery to ensure this battery gets charged first. The DVSR doesn’t discriminate which battery the voltage sensing comes from, but by the nature of the engine leads going to the start battery, that is where the voltage comes up to 13.2 first.

There is a small modification that needs to be made to the DVSR so that when the battery switches are off the DVSR is deactivated so that each battery is charged separately. If you don’t do this the DVSR will parallel the batteries when charging, and since you have flooded lead acid batteries you will want to run a manual equalizing charge on them at least once a month during the season to keep them in top shape.



Yes, ditch the old batteries and just use the new ones.

You want a three bank charger, you will have two roughly 100 Ah house batteries that can be discharged 50% so 100Ah between the two. If you have one 10A charger for those batteries it’s going take roughly 20-24 hours to charge those batteries back up, they won’t charge properly and you won’t be able to run an equalizing charge on them.

A lot of folks on here like the NOCO chargers, and the NOCO does have a manual equalizing charge function from what I’ve read in the past. I have three Victron IP 67 chargers for my trolling motor battery bank, and I’ll be upgrading the chargers for my house and start batteries to Victron IP 67 chargers this season. These are the top of the line chargers and are more expensive than a NOCO charger and yiu may not view that expense as necessary like I do. Again, plenty of folks on here run the NOCO chargers and are happy with them. I currently have MinnKota chargers for my house and start bank and they have worked well within their design limitations.

I suggest setting up your second house battery with its own switch, for that matter if I were you I’d set up both of my house batteries with their own switch for purposes of charging them separately. You can run them in parallel while using them just charge them separately. Again, you want to be able to run an equalizing charge on each house battery separately. There should be plenty of room on the BEP switch to land two switched legs from your house batteries.

The volt meters on your dash screen don’t differentiate between start and house?

Unless a shunt is used there is no accurate way to tell how many Ah’s / KWh’s are being used. The shunt also has a tap to measure the start battery voltage as well, so it removes all the guess work from battery usage etc.. Just open the app on your phone and you get all the info on your batteries, easey peasey. The shunt is about the size of a large pack of chewing gum. And copy adding a 12V plug so yiu don’t have to run an extension cord, I want to do the same in my boat, I want to add at least three more 12V plugs, two forward and one aft for charging phones, running a bait box air pump, air pump for towables..

 

[JTrottaNY]

Just wanted to wrap this thread up, still need to do my audio install, add the power port and get another + terminal cover but the batteries and BMS are in and working. Worst part of the whole project was drilling a 2" hole in the side of my boat for the shore power plug.

BTW @FSH 210 Sport any idea what the red light on the DVSR means? Never noticed it until now, reads "Second Battery Charging Red=ON". I would have thought this was an emergency parallel indicator but its on with all the switches turned off.

 

[FSH 210 Sport]

Good job! Thanks for following up on your thread!

The red light that is on, on the DVSR module indicates the paralleling switch is closed, which means all of your batteries are in parallel.

This is how the DVSR functions. When either the house or start battery reaches 13.4 volts the DVSR closes paralleling the the start and house batteries. When the voltage falls to 12.8 volts the DVSR opens breaking parallel and isolating the start and house batteries. Assuming your batteries are wired the same way as mine were from the factory, the alternator outputs are connected to the start battery, so when the engines are started all the charging current goes to the start battery charging it first, when the voltage comes up to 13.4 volts the DVSR will close and the engines will now start charging the house batteries too. It’s a great system that automatically makes sure your start battery is fully charged.

The emergency paralleling switch is a manual paralleling switch for use in the event that your starting battery needs help from the house batteries to get the engines started. Be sure this switch is in the off position at all times unless it’s needed for the aforementioned boost is needed, and then shortly after the engines are started return the emergency paralleling switch to the off position to make sure the start battery will get the full charge from the engines before attempting to charge the house batteries.

Heres a schematic of the battery switch and the DVSR.










Several people have opted to go the storage route so that when the battery Switch is off the DVSR is inactive so that when the boat is in storage and the battery charger is plugged in the start and house batteries charge independently, but the DVSR will be active when you turn on the battery switch to put the boat in use.

I would suggest adding another switch between the paralleled house batteries to keep them separate while in storage.

BEP

www.bepmarine.com

I read up on the Schumacher charger you installed, interesting concept of sequential charging of 15 amps of charge per battery for 15 mins at a time. What I did not see in the instruction manual was any mention of a manual equalizing charge capability, this type of charge is necessary at least once a month during the season to keep your flooded lead acid batteries in top performance. To do an equalization charge all the batteries will have to be isolated from each other. Use of a hydrometer is also required to make sure all of the cells are balanced.