Truck camper- design check

[Pele'22]

I'd appreciate more experienced eyes reviewing my schematic. I'm a beginner, but have been researching a lot.


Where
Install will be in the back of a truck, simple cab canopy camper.

Why
Fairly simple back of truck camping for hiking/fishing/hunting; lights, refrig, diesel heater, phone/laptop recharg, occasional mini-instapot or induction cooktop when power rich. 200ah should be plenty
Priorities are safety, reliability and ease of use, compact footprint that can be easily contained and removed (with exception of the blue seas fuse box and circuits)
In PNW, expect to rely mainly on DCDC, but get some solar assistance in summer.

Equipment
Circuit lengths are overestimates.

Items I have- SOK 206ah battery, victron MPPT 75/15, victron IP 65 charger, victron BMV 712, Blue Sea Safety Hub 150.

Undecided:
I may put the inverter right next to the battery and minimize circuit length, depends on where it fits the best.
I may downgrade to a 1000W inverter, I'm not sure if the SOK can handle a 1500W inverter. Max loads would generally be 800-1200W (rare induction cooktop). If I move it closer, I can likely downsize from 2/0.
Still waiting on solar panels until done with rack to see exactly what fits best, I can change the MPPT if I'm too overwatted for the 75/15.

Questions:
I'm still confused on MRBF vs class T fuse vs other for immediate fuse leaving battery. I'd like compact and not to spend more than needed, but obviously safe
If I spec out a 150-200a fuse near the battery, do I need a separate fuse going to the inverter if I don't have a downsize in wire?
Are 3 connections on the blue seas disconnect switch too many, should I branch to a power post?

Any other glaring problems?





Thanks

 

[John Frum]

Questions:
I'm still confused on MRBF vs class T fuse vs other for immediate fuse leaving battery. I'd like compact and not to spend more than needed, but obviously safe

MRBF has sufficient breaking capacity for 12 volt LFP batteries.

Breaking capacity - Wikipedia

en.wikipedia.org

If I spec out a 150-200a fuse near the battery, do I need a separate fuse going to the inverter if I don't have a downsize in wire?

1500 watts / .85 conversion factor / 10 volts = 176.470588235 inverter amps
176.470588235 inverter amps / .8 fuse headroom = 220.588235294 fuse amps
That means minimum 1/0 awg with a 250 amp fuse.
Better is 2/0 awg with a 300 amp fuse.
If the wire to the inverter is the same size as the main circuit then no fuse is needed on the inverter circuit.
It is however best practice to fuse the inverter branch circuit.
The blanket concept is called selective coordination and the specific concept is fault isolation.

Are 3 connections on the blue seas disconnect switch too many, should I branch to a power post?

I guess you are doing it because there is no high current fused position available on the safety hub.
How about using one of these instead of the safety hub

Littelfuse 0FHZ0005Z FHZ Series ZCASE Fuse Holder, 5 Stud Assembly | Waytek

Littelfuse 0FHZ0005Z FHZ Series ZCASE Fuse Holder, 5 Stud Full Assembly with M8 Input, 400A is in stock and ready to ship. Order today!

www.waytekwire.com

They also have a 7 port model.

Littelfuse 0FHZ0007Z FHZ Series ZCASE Fuse Holder | Waytek

Littelfuse 0FHZ0007Z FHZ Series ZCASE Fuse Holder, 7 Stud Assembly with Bolts and Bus Bars, 400A is in stock and ready to ship. Order today!

www.waytekwire.com

I didn't count but a 12 port fuseblock should be big enough to handle all your secondary dc distribution.
3 terminations on a single lug of a disco switch is probably going to be a PITA.

 

[John Frum]

The max discharge current from a single sok 206ah battery is 100 amps.
You are likely to trip the BMS under high load which is a "bad thing"TM.

 

[Zwy]

You will need 2 SOK for 1000 to 1200W. Might as well buy 2 SOK and the 1500W inverter.

Keep batteries as close to inverter as possible, this minimizes wire size and voltage drop. If you only have a few feet of wire, 1 or 1/0 AWG will work with a 150A fuse for 1 AWG and 175A for the 1/0 AWG.

If you do the 10 feet as indicated in your diagram, you step up to 2/0 minimum.

I use this calculator, works great. https://www.wirebarn.com/Wire-Calculator-_ep_41.html

 

[Pele'22]

Yes- I had a feeling that 1500W was likely to much. My simple math was 100a max discharge x 12v x 0.9efficiency = about 1100W maximum.

I'll plan on downsizing the inverter, and likely abandon the idea of occasional induction.

I don't have room unfortunately for 2 x 100ah, need to stay as compact as possible. Other 200ah batteries with higher discharge limits had a significant price premium, so I'll use this for a while and see how often I get close to the limits.

Thanks for the Littlefuse links, I'll take a look at those.

I suppose I can always hook the shore charger up to the SafetyHub to limit the connection on the battery switch to 2 (inverter and main distribution). Originally was keeping a slot open for possible portable solar, and the shore charger is already fused.

Thanks for looking

 

[AnarchyJet]

You could consider a MPP 1012 to combine inverter/mppt/AC charger into one to save space. Then you could leave the Victron 75/15 for a future portable array while having a permanent PV always wired in.

 

[Rednecktek]

That 75/15 is only good for about 300w of panel if you get the exact right panels, and that's not much to work with. The 1012 will buy you a LOT more solar capability or at least a better SCC to get more panel capacity.

 

[Pele'22]

Interesting suggestion on the MPP 1012, I wasn't aware of such an all in one model. I'll have to think more about an all-in-one approach.

I realize the 75/15 doesn't offer much by most standards, I'm waiting to see exactly what panels I can fit, but 200-300W is what I expect and the 75/15 should be fine, I could step-up to the 100/20 if needed. Honestly, I'll be pretty happy if I can get 300-350 watt hours from solar in the summer, winter I'm not expecting much at all.

 

[Chaucer]

Hi, I have a similar set up.

1. Just wondering why you selected 2/0 cable from the switch to the Safety Hub. I do see you have a question mark. I'm using cable based on maximum fuse in my power center.

2. Why are you connecting your inverter through the switch. Why not from the Class T fuse directly to the battery?

Thank you

 

[Pele'22]

Hi, I have a similar set up.

1. Just wondering why you selected 2/0 cable from the switch to the Safety Hub. I do see you have a question mark. I'm using cable based on maximum fuse in my power center.

2. Why are you connecting your inverter through the switch. Why not from the Class T fuse directly to the battery?

Thank you

1. Few reasons; the wire size should be capable of handling total cumulative load through the safety hub + generous safety margin. Blue Sea specs this as 200a -2/0, 350a- 4/0, etc. I won't be close to approaching this limit, but keeping same size cables as leaves the battery means I don't have to add additional circuit protection, less size cables to buy, more future proof if I get battery w/ higher discharge current.

2. I considered doing that, but in my mind the battery - inverter represents the highest amperage and most dangerous connection and I want the safety switch to be able to turn everything off. It also makes it easier to explain usage (storing, safety, etc) to my spouse who may not understand the nuances; ie turn the red switch off, everything is off

 

[Chaucer]

tks, I guess I'm not sure what a Safety hub is...I have a WFCO power center/converter in my small RV. It has 110 circuits and 12V circuits going to and from it. I have a switch in between it and my batteries, but only running 10 AWG wire. I do have 2/0 wire between the batteries and my inverter (with an inline Class T fuse). I'm relocating my batteries from outside my RV to inside. There was only 10 AWG wire ran outside, so I that inside...best wishes. (good thought on #2 )

 

[John Frum]

Blue Sea Systems 7748 Safetyhub 150 Fuse Block | Waytek

Blue Sea Systems 7748 Safetyhub 150 Fuse Block, 280A, 10 Circuits

www.waytekwire.com

Same thing but less money

Littelfuse 880089 LX Series Power Distribution Module | Waytek

Littelfuse 880089 LX Series Power Distribution Module, 4 MIDI Fuse Block, 60V, Max 600A, IP59K is in stock and ready to ship. Order today!

www.waytekwire.com

Notice the disparity in voltage and current ratings.

 

[John Frum]

tks, I guess I'm not sure what a Safety hub is...I have a WFCO power center/converter in my small RV. It has 110 circuits and 12V circuits going to and from it. I have a switch in between it and my batteries, but only running 10 AWG wire. I do have 2/0 wire between the batteries and my inverter (with an inline Class T fuse). I'm relocating my batteries from outside my RV to inside. There was only 10 AWG wire ran outside, so I that inside...best wishes. (good thought on #2 )

Suggest you create your own thread.
I volunteer to help with the overall topology.
Looking at it bit by bit isn't an optimal strategy.

 

[Pele'22]

Blue Sea Systems 7748 Safetyhub 150 Fuse Block | Waytek

Blue Sea Systems 7748 Safetyhub 150 Fuse Block, 280A, 10 Circuits

www.waytekwire.com

Same thing but less money

Littelfuse 880089 LX Series Power Distribution Module | Waytek

Littelfuse 880089 LX Series Power Distribution Module, 4 MIDI Fuse Block, 60V, Max 600A, IP59K is in stock and ready to ship. Order today!

www.waytekwire.com

Notice the disparity in voltage and current ratings.

Yes - basically compact bus bar with circuit protection and distribution. Not necessary depending on your system, but I think it will work well for me.

I like the Littelfuse suggestion, I hadn't seen that. Good option. But SafetyHub is generally $120, not sure why they have them priced so high relative to others.

Also not sure where they got the amperage rating, differs from BlueSea specs. Regardless- will be plenty for my needs.

 

[Chaucer]

Suggest you create your own thread.
I volunteer to help with the overall topology.
Looking at it bit by bit isn't an optimal strategy.

Sorry to hijack the thread...here is my design

https://diysolarforum.com/threads/new-install-comments.52676/#post-673358