New system for Marine & Shed Combo

[LarryBud]

I've looked through old threads and think I have a new one here. I have a pole barn where running power off the grid will be very expensive( currently no power at all ). In addition, I plan on purchasing a used fishing boat and wish to store it in this building. I'm located in MO. We have temp extremes but are moderate on average.

While I've yet to purchase my boat, it will have a 12V starting motor and a 24V Trolling Motor ( 12Vx2 in series ). I suspect the batteries will have about 100 AH each. If they are Lead Acid, they will be at 50% when tapped out after a trip so I'll need to be able to charge back ~ 100 AH in a reasonable period of time. If they are Lithium, they may be tapped deeper and may require up to 200 AH of charge.

I have purchased nothing to date.

I'll need to recharge the trolling batteries but this will happen sporadically....then maintain them. I'd also like to use the system for basic shed power. Perhaps some 12 lights, perhaps add an inverter but the boat is the priority.

I'm not sure what to do with the 12V starting battery? It will need to be maintained.

As a baseline, I was thinking:

• 3-4 100 watt panels
• 40 amp MMPT CC
• Run lines from the CC to the trolling motor batteries
• 1 battery for the shed
• Run a fuse panel off the shed battery
• Perhaps add an inverter?

I'm not sure how to switch between the two systems or what to do with boat starting battery. Suggestions?

Thanks in advance.

LB

 

[wholybee]

The starting battery is easy. Use a 24V-12V DCDC charger. It will be maintained from the 24V system. I'd probably use a dcdc charger for the trolling motor battery also.
Solar Panel->MPPT->Shed battery->DCDC->Trolling battery->DCDC->Start battery.

 

[LarryBud]

The starting battery is easy. Use a 24V-12V DCDC charger. It will be maintained from the 24V system. I'd probably use a dcdc charger for the trolling motor battery also.
Solar Panel->MPPT->Shed battery->DCDC->Trolling battery->DCDC->Start battery.

Thank you,

I'm now thinking two separate systems. One for the trolling batteries and another for the shed

 

[SparkyGage]

I would keep the starting battery and the trolling separate - not sure what kind of boat motor you plan to have but isolation of the systems is a must if the motor does any kind of charging (ie and alternator is in the mix).

If it's parked in the shed and batteries can be withing 6-10 feet of the of the inverter and charger, I would get an all in one charger/inverter and get some forklift connectors with 6ga or larger wire depending on the load rating of the inverter. Plug the battery into the system when in the shed and into the trolling motor when on the water.

I'm doing something similar with my sailboat. On the water I am using a 86lb thrust 24v troller. On shore I am using a 1200wt 24v inverter and 6ga wire (if I was using a 2kw+ inverter I would likely use 2ga, but both the motor and inverter came with 8ga, so I should be safe enough in my use case - the wire stays at ambient temp.) 4 quick connects cost me $20 and 10' of 6ga was $40. The biggest safety issue is connecting/disconnecting from the charging system to prevent spark - and you will have to get that from the manufacturer of YOUR charger. I'm currently charging from the main, but have most of the parts in for my solar charging in and hope to order panels next month.