Lithium House battery

[Grkspeed17]

Hey guys, we have a 2023 Yamaha 252SD that’s set up from factory as a two battery system. Currently I have two group 24 lead acid standard batteries from dealer. I want to upgrade the house battery or both depending on situation. They make some nice lithium group 24 sized 100ah batteries out there as an option for house but if I do it I want to do it right.

If I were to keep the regular start battery and replace the house battery with lithium, what would I need to do to have it be installed properly? Reason I ask is because some people on here just swap it right out and leave everything the same, some do some modifying maybe with the DVSR, and then some say the stators on the engines shouldn’t be charging a lithium battery.

If that last one is the case, should I be deleting the DVSR, and isolating the lithium battery so that it only gets charged by an onboard charger that can handle lithium? I’m just really confused as the what I should do as the best option. I want more time out on the water with the tunes on. I lean towards lithium because I like the idea of them holding a steady voltage closer to battery drain compared to LA batteries where I get 11 volts when the batteries are 50% discharged or so.

 

[FSH 210 Sport]

Hey guys, we have a 2023 Yamaha 252SD that’s set up from factory as a two battery system. Currently I have two group 24 lead acid standard batteries from dealer. I want to upgrade the house battery or both depending on situation. They make some nice lithium group 24 sized 100ah batteries out there as an option for house but if I do it I want to do it right.

If I were to keep the regular start battery and replace the house battery with lithium, what would I need to do to have it be installed properly? Reason I ask is because some people on here just swap it right out and leave everything the same, some do some modifying maybe with the DVSR, and then some say the stators on the engines shouldn’t be charging a lithium battery.

If that last one is the case, should I be deleting the DVSR, and isolating the lithium battery so that it only gets charged by an onboard charger that can handle lithium? I’m just really confused as the what I should do as the best option. I want more time out on the water with the tunes on. I lean towards lithium because I like the idea of them holding a steady voltage closer to battery drain compared to LA batteries where I get 11 volts when the batteries are 50% discharged or so.

The last bit about the stators should not be charging lfp batteries is false. I’ve been running a Battle Born 100Ah lfp battery for two years now and it works great. The alternators on our boats are always at full output, the unwanted power is shunted to ground by the regulator / rectifier.

Having said that, you will have to modify the dvsr to make it work with the lfp battery, namely, the motors need to be on when the dvsr connects the lead acid start battery and the lfp house battery. Mine is set up to actuate manually with a rocker switch, others have tapped onto the fuel pump hot wire so that the dvsr is only active when the fuel pump that feeds that engine is running. Otherwise the resting voltage of the lfp battery will keep the dvsr closed and your lfp battery will try and charge your fla battery as the voltage of the fla battery is lower than the lfp battery.

Having said that, I think you need to determine whether or not you need a lfp battery for your house battery. Install a Victron Energy smart shunt on your current (see what I did there?) house battery and see how much power you actually use during an outing. Keeping in mind that a group 24 FLA battery is probably around 70 Ah, you should only be using 50% percent of that 70Ah to keep from damaging the battery, I see that you mention that but how do you know you are at 50%? And, if you do not already have an onboard charger and keep it plugged in then the fla battery will not be at full capacity.

If you still want to move ahead with the lfp house battery, click on “battery upgrade” in my signature. Its a big thread with a lot of great input by the members here and all the research I did. Lastly, if you are going to do this, only invest in a quality lfp battery, I highly recommend Battle Born, ReLion is also good, with Dakota Lithium coming in last.