Seeking comments on my selections

[DIY Senior]

Hello All,
New to group here looking for some opinions, advice and recommendations. I am starting a major project that will eventually generate many requests for advice but for now will keep it simple.

The battery part of the project:
I am looking to build 4 12v LifePo4 high capacity batteries. For the 16 cells I am leaning toward the EVE LF280k units. I wouldn’t mind the higher capacity cells but the premium price and much lower cycle life seems like a poor trade-off.

For the BMS I am looking at the JK B2A8S20P 200amp version since by my calculations I may pull up to 600 amps at peak (4p 12v batteries…4 x 200a)

Any comments, thoughts, corrections, etc will be extremely welcome.

Thanks, DIY/DIR Randy

 

[John Frum]

For the 16 cells I am leaning toward the EVE LF280k units. I wouldn’t mind the higher capacity cells but the premium price and much lower cycle life seems like a poor trade-off.

What higher capacity cells are you referring to?

For the BMS I am looking at the JK B2A8S20P 200amp version since by my calculations I may pull up to 600 amps at peak (4p 12v batteries…4 x 200a)

What is your application?

 

[chrisski]

For the BMS I am looking at the JK B2A8S20P 200amp version since by my calculations I may pull up to 600 amps at peak (4p 12v batteries…4 x 200a)

This part tells me you need 48 volts. 600 amps is a lot with thick wiring or busbars and fuses. 150 amps is much more manageable.

I am looking to build 4 12v LifePo4 high capacity batteries. For the 16 cells I am leaning toward the EVE LF280k units. I wouldn’t mind the higher capacity cells but the premium price and much lower cycle life seems like a poor trade-off.

I think 280 ah cells have plenty of capacity. For me 16 cells fit 8 in one side and 8 in the other with the fusing and busbars in the middle in this 24.25 x 24.15 inch tray:

 

[Vigo]

I agree that just saying the words 'six hundred amps' means you should consider going up in voltage in order to reduce amps.

 

[DIY Senior]

What higher capacity cells are you referring to?

What is your application?

THE 304/31Oah cells. I would gain a total of 96/110ah but the claimed cycle life is only 3500 compared to 6000 for the 280k.
The entire project is upgrading my motorhome batteries and inverter and adding solar.

 

[DIY Senior]

This part tells me you need 48 volts. 600 amps is a lot with thick wiring or busbars and fuses. 150 amps is much more manageable.


I think 280 ah cells have plenty of capacity. For me 16 cells fit 8 in one side and 8 in the other with the fusing and busbars in the middle in this 24.25 x 24.15 inch tray:
View attachment 135446

I agree with your configuration. That is what I had settled on and am planning on making the busbars utilizing the instructions from the article on this site. The tray would be great but it will be in a motorhome basement compartment with limited space.

 

[DIY Senior]

This part tells me you need 48 volts. 600 amps is a lot with thick wiring or busbars and fuses. 150 amps is much more manageable.

You are correct for general use but I am upgrading my motorhome around a Victron Energy MultiPlus-II 12/3000/120-50 2x120V Inverter/Charger. The specs on it list Continuous Power: 3000VA / 2400W and Peak Power: 5500W. The 5500 watts peak is what I was refering to. I doubt the ampere load will ever hit that but I am allowing for plenty of headroom.

I think 280 ah cells have plenty of capacity. For me 16 cells fit 8 in one side and 8 in the other with the fusing and busbars in the middle in this 24.25 x 24.15 inch tray:
View attachment 135446

I agree with your configuration. That is what I had settled on and am planning on making the busbars utilizing the instructions from the article on this site. The tray would be great but it will be in a motorhome basement compartment with limited space.

 

[DIY Senior]

I agree that just saying the words 'six hundred amps' means you should considering going up in voltage in order to reduce amps.

You are correct for general use but I am upgrading my motorhome around a Victron Energy MultiPlus-II 12/3000/120-50 2x120V Inverter/Charger. The specs on it list Continuous Power: 3000VA / 2400W and Peak Power: 5500W. The 5500 watts peak is what I was refering to. I doubt the ampere load will ever hit that but I am allowing for plenty of headroom.

 

[John Frum]

THE 304/31Oah cells. I would gain a total of 96/110ah but the claimed cycle life is only 3500 compared to 6000 for the 280k.
The entire project is upgrading my motorhome batteries and inverter and adding solar.

Unless these are automotive grade cells, I would take the cycle life claims with a grain of salt.
600 amps is a metric fork ton of current, have you considered going to 24 or 48 volts?

Your MP2 is 3000VA.
3000 VA ~= 2400 ac watts.
2400 ac watts / .85 conversion factor / 12 volts low cutoff = 235.294117647 inverter amps
A typical RV ac2dc converter is 55 amps so lets make that...
235.294117647 inverter amps + 55 legacy dc amps = 290.294117647 service amps
Where is the other ~300 amps going?

 

[OffGridForGood]

It may be best to plan out the full build, then select all the equipment, including the cells to suit.
Just because the Motor Home was/is based on 12 vDC doesn't mean this will be the best solution for your upgrade. We have seen many discussions on this topic and it seems to come down to a pattern that repeats over and over on the forum:
12v up to about 2kW output
24v up to about 3kW output
48v above 3kW.
As noted above by Virgo/Chriski others, fuses, wire sizes, breakers to suit the amperage of the system will be harder to find and much more expensive in high amperage 12v from my own experience and what I have read on the forum in many threads.
Not sure if you already purchased the Victron or if this was just what you are planning.

The title - seeking comments on my system - It appears you have already chosen 12v and this is perhaps not the best choice for the build.

 

[John Frum]

@DIY Senior is your rig towable or self propelled?

The reason I ask is for self propelled units the jacks and slides typically run off the starter battery.
For towables they typically run off the house battery.

 

[John Frum]

@DIY Senior I'm guessing your RV has 50 amp shore power, confirm?