Design of LifeP04 - BMS - Inverter my first build

[HostRV]

My future purchase list:

1. OverKill 4s BMS 120a
2. 280 Ah LifeP04 battery cells (solar supply?) grade A
3. Case (where to purchase?)
4. Inverter / charger maybe Xantrex 2000w / 80
5. Fuses, wire, lugs; marine grade Pacer
6. SOC meter / shunt

Project Overview:
Dedicate the two frig's in a boat to a 280 Ah battery and run one small TV with in-motion satellite receiver (KVH). The frig loads are 12v and will direct connect to the battery. TV / Sat run through inverter / charger.
LOADS
Frig's pull 70 watts each. 140 watts with a duty cycle of 12 hours per day 1680 w.h's (140 Ah's)
TV/Sat 180 watts use 3 hours / day 540w (45Ah's) Is this correct??? The sat uses 120w and small TV uses 60w. I got the sat values from the KVH install instructions. If I recall the KVH wants a 10amp 12v circuit and that is why I purchased the 120 volt to DC converter since I needed 120v to use the TV. The KVH/ Sat is a power pig.

This tells me that I can run off the 180 Ah battery for just under 22 hours before starting the generator. Am I doing the math correctly?

From reading other posts on this site the BMS 120a is under sized for a 2000w inverter. But since it will dedicated to only the TV and Sat the DIY engineers might approve of this configuration.

Boat currently has two group 31 lead acid batteries as the house batteries so about 100 Ah of useable power. The frig's are the largest power draws. Benefits will be better cleaner power to the frig's and more capacity. Faster charging of the Lithium battery, reduce charge output to 75 amps. If you are still reading this post, what do you think?

 

[RobertGreen]

You would be much better off posting this in a different forum section like 'Beginners Corner's...
You'll get a lot more attention that way.

 

[MisterSandals]

But since it will dedicated to only the TV and Sat the DIY engineers might approve of this configuration.

No need to seek approval. The BMS will cut out if you exceed its limits, its not like it will start a fire. You still need to fuse and wire for a 2000W inverter; if not for you then maybe the next guy who will expect proper wiring.

I did not add up your daily watt hours, did not see an accounting on 15% inverter loss going to AC (smallish portion of your use i think).

Sounds like you have a feel for you use with your group 31 batteries so if you nearly triple the battery capacity hopefully that meets your expectations. Seems as reasonable as your numbers are accurate.