Power Source vs Battery Bank with Inverter

[TBill36]

My boat currently shares it's house batteries with one of the starting banks. I don't like that, but it's not a problem because I always run the generator when away from shore power.

I'd like to have the capability to run 2 freezers and a refrigerator for 4 or 5 hrs without running the gen if I'm anchored out and to not lose refrigeration if my gen quits. Amp/hr calcs say 3600 w/hr should be sufficient.

There are ads for 3600 w/hr power sources on the internet for less than $2000 that would do the job. Or, I could get 3 100 amp/hr LiFiPo batteries and an inverter to accomplish the same thing. I have not researched the quality of power sources and don't see names like Victron, so it's hard to compare apples to apples with building a battery bank inverter system. But it's real easy to just buy the power source and wire it in.

Regardless of which way I go, I have no intentions of integrating the system into my current set up other than some DPDT switches for the freezers and refergerator when I want to use the alternate energy system.

Input, pro's and con's appreciated.

 

[SteveK]

would like to see your calculations. 300x3x4=3600
300W per hour per appliance over 4hr use seems high, it would mean a rating of 900W while running as they run an average 1/3rd of the time.

If correct then all three batteries would be 100% used/dead in 4 hours.

 

[dhays]

The advantages that I see are:
Portable (can be used on the boat, or at home)
Simple (no thinking just plug it in to charge and then use)

Disadvantages:
Space (you have to find a place to put it. Space is at a premium on my boat)
Non-marine (These typically are designed for environments that aren't at risk for movement and water exposure)
You would still need to find a way to wire it into your 120v system unless you plan on running extension cords through your boat.

There are some decent Cyber Monday deals now on Amazon for some of these that would run your refrigerator's and freezer for quite a while.

 

[Jeff F]

I just finished installing batteries and inverter in my son's camper van build. He was looking at the integrated units and I advocated for the component approach with appropriate wire sizing, fuses, etc.

I think in the end we both agreed that the box solution probably would have made more sense for him. Easier, smaller, simpler, and no more expensive. For simple stuff there's no need to build your own.

It sounds like the all-in-one solution meets all your needs. That's where I'd look. Are any offering LiFePo batteries?

 

[dhays]

It sounds like the all-in-one solution meets all your needs. That's where I'd look. Are any offering LiFePo batteries?

Most are these days from what I see.

 

[TBill36]

would like to see your calculations. 300x3x4=3600
300W per hour per appliance over 4hr use seems high, it would mean a rating of 900W while running as they run an average 1/3rd of the time.

If correct then all three batteries would be 100% used/dead in 4 hours.

I assumed 100 w per appliance for rough calc, so at 5 hrs that would be 1500 wh. I've had experience with not having enough start up amps with banks that are too small. Can't find any guidance on that, but have shut downs if the bank is small when the appliance comes on after it's been partially depleted.

 

[TBill36]

The advantages that I see are:
Portable (can be used on the boat, or at home)
Simple (no thinking just plug it in to charge and then use)

Disadvantages:
Space (you have to find a place to put it. Space is at a premium on my boat)
Non-marine (These typically are designed for environments that aren't at risk for movement and water exposure)
You would still need to find a way to wire it into your 120v system unless you plan on running extension cords through your boat.

There are some decent Cyber Monday deals now on Amazon for some of these that would run your refrigerator's and freezer for quite a while.

I have space that's not readily accessible that I thought I could use.

Agree that it's not marine, but it would be in airconditioned space 24/7 except when it was in use. But the movement might certainly be a problem, especially in rough seas.

Though maybe I could hardwire it to the appliances somehow, but hadn't thought that out yet either. Not going to run extension cords. Thought maybe I could tap into the output of the power source and run wire to each appliance where I'd install the DPDT switch and tie in the 120 coming from the boat source. I've done that with an inverter before, so shouldn't be any different.

 

[dhays]

Maybe wire the output into something like this so you can switch from Generator to battery?

Blue Sea Systems 9009 AC Selector Switch, 120V 32A OFF +2

 

[Jeff F]

I assumed 100 w per appliance for rough calc, so at 5 hrs that would be 1500 wh. I've had experience with not having enough start up amps with banks that are too small. Can't find any guidance on that, but have shut downs if the bank is small when the appliance comes on after it's been partially depleted.

The early shut down is not an issue with lithium. They'll run at full rating down to flat, and it doesn't harm the battery.

Sounds like a 2kw box would be enough for you. You don't care about recharge time, right? They all have plug-in chargers, but check charge rate if that matters.

 

[READY]

Anker makes a good quality solar generator. This is the common name for the all in one unit. You can plug your 30amp shore power cord ( might need an adapter). Just need to turn off any heavy loads when using it. Cost is around $1600. Recharges off std 15amp socket in a few hours. Of course it needs to stay dry.

 

[TBill36]

Maybe wire the output into something like this so you can switch from Generator to battery?

Blue Sea Systems 9009 AC Selector Switch, 120V 32A OFF +2

Or I could use one of these for $6.23 instead of $120

Gardner Bender 20 Amp Double-Pole Toggle Switch (1-Pack) GSW-16 - The Home Depot

Visit The Home Depot to buy Gardner Bender Toggle Switch GSW-16

www.homedepot.com

 

[nwboater]

I added a 4.5kw portable power unit to run my tug’s electric range, coffeemaker and other appliances. I simply plugged a 30amp shore cord from battery to my boat’s factory shore power inlet. I have posted pictures and text on this subject. Take a look at Hysolis 5kw power unit!