Any battery recommendations?

[Marvintinyhomes]

Hi everyone! I’m looking for a battery bank for our line of off grid tiny homes. The plan is to have a 5000W Victron system powering a 30A 120VAC RV style panel. The biggest load in the system is a 202W Combi boiler that can run up to 20 hours during the wintertime (we’re located in Alberta). There will be a generator (looking at a Westinghouse iGen4500, or anything propane).
I’m looking for batteries that will bank to 48V, 200Ah, with external BMS and preferably heated.
Any battery recommendations? And also, if anyone has any experience with off grid mobile solar systems or if anyone recognizes anything wrong with my numbers, please contact me and let me know.
Our company is new to offering solar packages with our tiny homes. We have been working with a Victron dealer to help us design this system. But when it comes to batteries, as technology continues to change rapidly and due to rising popularity of solar power, availability of certain brands and specs are hard to come by so I need options.

 

[MisterSandals]

I’m looking for batteries that will bank to 48V, 200Ah, with external BMS and preferably heated.

I think the external BMS requirement pretty much means you will be making your battery from cells.
48V x 200Ah = 9600Wh

The plan is to have a 5000W Victron system

Is that a 5000W inverter?

The biggest load in the system is a 202Wh Combi boiler

202Wh is an amount of power rather than a load rate. Perhaps you mean 202W. So 202W x 24h = 4848Wh per day. This is about half of the battery's capacity.

And, if my interpretations were correct, why a 5000W inverter for just a 202W max load (and other loads of course)?

What is your plan to charge the battery? Just the generator?
Operating at 100% theoretical efficiency, that would take 2 hours of generator to just charge the battery each day (longer if running any appliances or loads).

 

[Marvintinyhomes]

I think the external BMS requirement pretty much means you will be making your battery from cells.
48V x 200Ah = 9600Wh

Is that a 5000W inverter?

yes, it will be a 5000W victron quattro. External BMS was recommended to effectively monitor batteries individually.

202Wh is an amount of power rather than a load rate. Perhaps you mean 202W. So 202W x 24h = 4848Wh per day. This is about half of the battery's capacity.

And, if my interpretations were correct, why a 5000W inverter for just a 202W max load (and other loads of course)?

my apologies, yes it is a 202W draw, and will be running up to 20 hours a day. Based on total loads, a 5000W inverter was recommended by our solar designer.

What is your plan to charge the battery? Just the generator?
Operating at 100% theoretical efficiency, that would take 2 hours of generator to just charge the battery each day (longer if running any appliances or loads).

There will be a total 2600W of solar panels on the roof, (14 degree pitch) but with it being a mobile tiny home on wheels, strategic position to sunlight may not be the best at all times. There will be a 30A 120VAC RV outlet for shore power, the generator will provide supplemental power for charging the batteries.

 

[MisterSandals]

Based on total loads, a 5000W inverter was recommended

I don't know the total of your loads, but 202W is 5% of the recommended 5000W inverter. Usually the idle draw is proportional to the size of the inverter so a huge mismatch will be far less efficient.

I recommend looking into the recommended inverter's idle draw and determining your daily idle amount. It may be your largest power user, just being turned on.

 

[Marvintinyhomes]

I don't know the total of your loads, but 202W is 5% of the recommended 5000W inverter. Usually the idle draw is proportional to the size of the inverter so a huge mismatch will be far less efficient.

I recommend looking into the recommended inverter's idle draw and determining your daily idle amount. It may be your largest power user, just being turned on.

Thanks for the feedback. I will discuss this with our designer.