More naive questions

[Lasertrapper]

I had started building a lithium battery system for our Sprinter van little over 2 years ago.
Well, I'm finally back at this battery project after a VERY long medical hiatus.....


Refresher....my wife needs A/C when we boondock with our campervan and had started building a LARGE (1200 amp hour) LiFePO4 12v battery system using qty 16 302ah CATL prismatic cells that were batched & matched by Docan over 2yrs ago. They have been stored in my heated shop.


More data...
I need to fit this into a small area since this is in a Sprinter van.

I have many parts including a Victron MultiPlus-II 12/3000/120-50 2x120V, smartshunt, Orion charger, qty 4 JK BMS JK B2A8S20P, etc etc.

I had planned four 12v batteries consisting of qty 4-3.? vdc 300ah prismatic cells connected in series, and each 12vdc, 300ah with it's own BMS all connected in parallel so total of 1,200ah.

I was planning to use 150A MRBF fuse on each of the 4 batteries, regulate each to 125A via BMS, then connect everything together using qty 2
Victron Lynx distributors.

I noticed, while looking things over, that each connection point on the Lynx distributor accommodates an ANL mega fuse. The connection from each positive battery terminal to the Lynx distributor will be at most 12".

Will I need the MRBF fuses at the battery terminal end?

 

[Partimewages]

Do you know what your loads (total watts) are going to be? You will need to know how long your loads will need to run in a 24 hour period.

 

[740GLE]

If you are using a lynx power distributer with fusing internal, you don’t need the MRBF fusing on the DIY.

Which smart shunt do you have?

 

[Lasertrapper]

SHU050150050

Victron Energy, SHU050150050, SmartShunt 500A/50mV

 

[740GLE]

so the simple smart shunt not the lynx shunt.

can you do a schematic of the system, how will two batteries connect to the shunt and still be fused?

 

[Lasertrapper]

Yes, they were done 2 yrs ago & are 2D since I no longer have AutoCad... So one is from top, one is from front. There are 4 batteries, 4 prismatic cells each.

 

[Lasertrapper]

The Lynx distributors have megafuse at each connection point, so each of the four batteries would be fused. I had not included fuse between Lynx dist and inverter

 

[740GLE]

Right but to connect the simple smart shunt you’d need to double stack negative terminals right? You could t use the 4 lynx negative terminals.

 

[Lasertrapper]

I had pretty much copied from the attached schematic from Vanlife Outfitters. Do you see a problem?

 

[Lasertrapper]

Another newbie question: Are the Littlefuse Zcase fuses interchangeable with MRBF?

I'd like to use a 4 circuit, common source fuse holder like this one:

https://www.waytekwire.com/product/littelfuse-0fhz0002z-fhz-series-zcase-fuse?gad_source=1&gclid=CjwKCAiA0PuuBhBsEiwAS7fsNYfVpDr1_iBQRztjqzKFoygupMVhuAayu4VZDceomMNKzSsF_ImTrhoCQY8QAvD_BwE

but would like to use faster MRBF fuses.

 

[740GLE]

I had pretty much copied from the attached schematic from Vanlife Outfitters. Do you see a problem?

Ahhh I see it now.

If you use the lynx distributer and mega fuses for a total of 8 different leads, why would you need another fuse block?

 

[Lasertrapper]

I'm considering swapping one of the Lynx distributors for the 5 space (one out 4 in) LittleFuse box that accepts MRBF fuses since they have a much higher reaction capacity than Mega fuses.

I looked at the dimensions of LittleFuse Zcase fuses which have similar capacity to Mega. The dimensions of MRBF and Zcase are very similar and these higher capacity (10,000A) MRBF fuses should fit in the LittleFuse FHZ Series ZCASE® Fuse Holder.

The Zcase fuse holder is significantly smaller than the Victron Lynx but I will need to find and mount a seperate grounding bus.

Too bad there isn't a way to fit MRBF or fast class T fuses in the lynx.

 

[740GLE]

For a 12v system I wouldn’t be worried too much about which fuse is better. You’d prob be fine with cheap ANL and not even notice. A class T is way way over kill.

If it were me the cleanliness of the Lynx is what will win hands down.

Again just my opinion, and others swear by everything “must have 4 class T fuses at a minimum, think of the children!!”