Battery Charging for Starter and House Batts (LA and LifePO)?

[Tin Man]

I was originally planning on one group 24 starting batt and one deep cycle for house batts. They will both fit in my rear battery compartment.

After some consideration and deciding on LifePo batts up at bow for for my TM batts, I am reconsidering my house batt options.

Considering adding a group 24 LifePO for house since it will fit ion my compartment and and is 20-30# lighter.

This idea may eliminate my idea for using the Blue Seas Add a battery kit which uses an ACR combiner and batt switch. This allows both batts to be charged by motor but isolates batts when being used. I don't believe this kit will work with a LA and LifePO batt.

Anyone running a LA starting batt and LifePO for house needs? If so, how are you charging (motor or external charger) and are you using any battery switch?

Thanks!

 

[Still Afloat]

Agree with LifePO on the TM. I’ve got mixed feelings on the house batteries.

On my bigger boats, where pull starting is not practical, I use two LifePO for TM and two lead acid deep cycle/starter batteries. One is the primary starter batt and second is a house batt that’s a backup for the starter.

On the smaller boat where weight is more critical it’s all LifePO, two 100 A/hr in parallel for TM, one 50 A/hr for electronics and small motorcycle sized LifePO for the starter. The starter batt is a Noco that is specifically designed for starter applications but, it has enough reserve to run boat lights and a bilge pump.

 

[airshot]

From my research and discussion with local battery engineer, using the engine to charge Lifepo4 batteries is not a good idea. To many comolications could arrise. There is equipment availiabke to allow that to hapoen but it is new and not thoroughly tested. For my own piece of mind, when I replace my trolling batts with lifepo4's they will have their own plug in charger while in storage. My outboard only charges the main starting battery, the house battery has it's own charger. The onboard chargers are all wired to one plug, when boat is parked, it is plugged in. Over the winter, I have maintainers for all the batteries. Been using this method for all my boats over the past 30
years with not one issue. Will need to reconsider a couple things when my troll batts are upgraded, but for the most part, using your outboard to charge should be restricted to just the start battery only.

 

[Still Afloat]

From my research and discussion with local battery engineer, using the engine to charge Lifepo4 batteries is not a good idea. To many comolications could arrise. There is equipment availiabke to allow that to hapoen but it is new and not thoroughly tested. For my own piece of mind, when I replace my trolling batts with lifepo4's they will have their own plug in charger while in storage. My outboard only charges the main starting battery, the house battery has it's own charger. The onboard chargers are all wired to one plug, when boat is parked, it is plugged in. Over the winter, I have maintainers for all the batteries. Been using this method for all my boats over the past 30
years with not one issue. Will need to reconsider a couple things when my troll batts are upgraded, but for the most part, using your outboard to charge should be restricted to just the start battery only.

The problem is that an alternator won’t fully charge a LiFePO and most are not rated for starter applications. I use a Noco NLP20 which is designed for it. I also top off the starter battery when charging the other batteries.

You are right though, it might be more trouble than it’s worth.

 

[Tin Man]

Thanks for the great info....

Decided on 2 12V/100amp LifePo for TM and two LA, one for starter and one for house. I'll use a simple Blue Seas OFF-1-2-Both switch.

Since I already have a new starting batt that came with the boat, I'll just need to add a group 24DC for house and the switch.

Plan....
While fishing...I'll start and run all day on #2 (house) and if/when batt #2 is not able to start motor, I can switch to the #1 starter battery. Both batts charged at home with a NOCO 2 bank 5 amp per bank charger.

 

[thill]

I set up a system like this for a customer. A Blue Seas switch on the boat and an on/off switch on the LiFeP04. He is to ONLY turn on the lithium battery when sitting, for extended periods, and to turn it off before starting the engine again. The Blue Seas prevents the lithium from "charging" the starting battery, and the switch prevents the lithium from taking the hit when he starts his engine.

In MY boat, I just have a separate circuit from my 50AH lithium that goes straight to my Livescope system. I can switch them over to the regular batteries by moving a terminal, if that is ever needed.

I have a dedicated LiFeP04 charger that I can plug in as needed. Since LiFeP04 batteries like to be stored at 30-50#, I don't worry about charging them until the night before a trip. The livescope doesn't use much battery in a day, so it may not get charged for a couple of trips.

 

[airshot]

Consider a 27 size deep cycle as a house batt. Can run all day on my 27 and still have power left. My 24 is just for starting engine only and motor keepsit full

 

[Tin Man]

Consider a 27 size deep cycle as a house batt. Can run all day on my 27 and still have power left. My 24 is just for starting engine only and motor keepsit full

unfortunately, only two 24s will fit

 

[flatheadsteve]

Thanks for the great info....

Decided on 2 12V/100amp LifePo for TM and two LA, one for starter and one for house. I'll use a simple Blue Seas OFF-1-2-Both switch.

Since I already have a new starting batt that came with the boat, I'll just need to add a group 24DC for house and the switch.

Plan....
While fishing...I'll start and run all day on #2 (house) and if/when batt #2 is not able to start motor, I can switch to the #1 starter battery. Both batts charged at home with a NOCO 2 bank 5 amp per bank charger.

I'm doing similar (3) lifepo4 for the trolling motor and (2) group 27 agm for house/starting ran through a blue seas switch and acr. The lifpo4 will get charged while on shore with a minn kota charger. The starting battery will have a noco single bank for getting topped off on shore. That will leave the group 27 house battery to solely be charged by the outboard. My outboard has a 50amp alternator so it tops off a battery fast.