Upgrading batteries and charging system

[Randy Walden]

I am reconditioning an older boat 1981 Grew (236AC) with new toilet, holding tank, fridge (from ice box), navigation system, upholstery, radio etc.
I want to install 2 -400 ah Lithium LiFePo4 batteries in parallel. I have the batteries but want to upgrade my charging system.
Need some advice as to where to go from here. My engine is a Mercruiser 228 (305 gm V8) with an "R" outdrive.

 

[alldodge]

The bats will take a charge from about any 3 stage charger. The difference is how fast you want to charge them. The lithium will charge faster then the AGM so guess it depends how much time will it be plugged in?

The alternator will also change when running, and would suggest using a ACR

 

[matt167]

If your talking about charging off the engine, you can stick a modern marine alternator on it and wire it up really simple and that will give you 100A.

Not sure if the lion batteries take 14.4v or need any special conditioning from alternator, like using a charge controller

 

[sam am I]

The LiFePo4's will more then likely (99.9% sure) have a built-in BMS(Battery management system), this allows the LiFePo4 battery's to connect into any "old world" charging systems and not over/under charge/dis-charge and keep us all safe from exploding or worse yet, catching the world on fire and such.......In theory that is,, and so far, mostly in practice....News at 11.

This means? We can hook them up to any normal/standard'ish every day reasonably regulated or even half a**ed charge source, be it constant voltage or constant current, 1 stage or 18 stage, steam driven or horse pulled and the BMS will keep us (and the battery/world) all safe and charging/dis-charging properly according to how the battery requires (temp/capacity/etc ..)

Funny this.........F.F. 5 yrs and a s**t mess pandemic later, life can be so fickle..

Lithium iron phosphate (LiFePO4) battery

Trying to skip/avoid the opinion/hearsay mongers here as much as possible............ Thinking I might make the jump this next year (other than my Dewalt's and B&D's) so specifically, anyone ACTUALLY running/ran one in their Boat/RV? If so...... House? Crank? Like it? What manu? Is/has...

forums.iboats.com

 

[Randy Walden]

If your talking about charging off the engine, you can stick a modern marine alternator on it and wire it up really simple and that will give you 100A.

Not sure if the lion batteries take 14.4v or need any special conditioning from alternator, like using a charge controller

My fear is burning out alternator as it will be working at full whack for an extended time. Will look into ACR? Curious if anyone else out there had a "learning curve' already. I know batteries need higher voltage to charge fully.

 

[Randy Walden]

The bats will take a charge from about any 3 stage charger. The difference is how fast you want to charge them. The lithium will charge faster then the AGM so guess it depends how much time will it be plugged in?

The alternator will also change when running, and would suggest using a ACR

Thnks. Will look into that. Was hoping someone had been down this road already

 

[Randy Walden]

The bats will take a charge from about any 3 stage charger. The difference is how fast you want to charge them. The lithium will charge faster then the AGM so guess it depends how much time will it be plugged in?

The alternator will also change when running, and would suggest using a ACR

Thnks. Will learn about ACR.

 

[Randy Walden]

Not sure where or how to reply to comments. Thank for input. Will check into ACR.

 

[alldodge]

I just bought another one of these my self
https://www.bluesea.com/products/7610/SI-ACR_Automatic_Charging_Relay_-_12_24V_DC_120A