I've spent many hours learning and scouring this great forum and the web, but still puzzling over best setup for my sailboat solar/LFP upgrade i'm planning early spring:
Here's is a list of my planned equipment - all 12v:
- Single diesel engine, 125A 'dumb' alternator
- 1 110A AGM starter battery
- 2 60A AGM bow thruster batteries
- 6 100A LFP house bank batteries (new)
- 1,155W solar via Victron 150v/100 MPPT (new)
- 2 40A battery chargers (with LIFEPO4 charge settings)
- 1 Battery isolator with 1 input (alternator) and 3 outputs
- 2000w inverter
I'm adding the LFP house bank (replacing AGM bank) and adding the solar, and trying to use as much of my current system (chargers/isolator) as possible. The solar and house battery bank are sized based on our usage plans.
My plan to bring the system together:
- Keep the Isolator, with the alternator feeding into it and passing on charge to the (1) starter battery and (2) the bow thruster battery.
- Solar MPPT charges the LFP bank
- The 2 existing 40A battery chargers are used to charge the LFP bank
My main struggles to figure this out how to keep the Bow Thruster and Starter AGM batteries topped up and 100% charged. Options:
Jeff
Here's is a list of my planned equipment - all 12v:
- Single diesel engine, 125A 'dumb' alternator
- 1 110A AGM starter battery
- 2 60A AGM bow thruster batteries
- 6 100A LFP house bank batteries (new)
- 1,155W solar via Victron 150v/100 MPPT (new)
- 2 40A battery chargers (with LIFEPO4 charge settings)
- 1 Battery isolator with 1 input (alternator) and 3 outputs
- 2000w inverter
I'm adding the LFP house bank (replacing AGM bank) and adding the solar, and trying to use as much of my current system (chargers/isolator) as possible. The solar and house battery bank are sized based on our usage plans.
My plan to bring the system together:
- Keep the Isolator, with the alternator feeding into it and passing on charge to the (1) starter battery and (2) the bow thruster battery.
- Solar MPPT charges the LFP bank
- The 2 existing 40A battery chargers are used to charge the LFP bank
My main struggles to figure this out how to keep the Bow Thruster and Starter AGM batteries topped up and 100% charged. Options:
- Instead of placing both 40A chargers to the LFP bank, use one of the 40A chargers to charge the Bow Thruster and Starter batteries, and add a DC - DC charger to take the excess to the LFP bank. This seems overkill and inefficient as I would expect the DC-DC charger to be in heavy use (while plugged into shore power) because much of the current from the charger would not be needed by the bow thruster/starter batteries, and be passed on to the LFP bank. The bow thruster/starter batteries need to be topped up and ready all the time, but only get relatively limited use in boating operations.
- Keep both 40A chargers charging the LFP bank, and add a DC - DC charger, charging from the LFP bank over to the Bow Thruster/Starter batteries to keep them topped up. This seems like most efficient.
- If I did this, could I place the output of the DC-DC charger (from the LFP bank) onto the battery isolator input (sharing that input with the Alternator), so that the charge current gets split between the bow thruster and starter batteries? I don't think so as I have a feeling the output from the DC - DC charger may cause risk to the alternator, but this would make things easier if possible.
- If not, what's the easiest way to 'split' the DC - DC charger output between the bow thruster and starter batteries? Would like to avoid adding another battery isolator / piece of equipment if possible.
Jeff