Wiring Diagram Review

[demongman7]

Hi - if anyone would be kind enough to take a look at my wiring diagram, I would greatly appreciate a second set of eyes. I included a few details on how I processed the sizes below, along with specific questions I'd like to double check. Know it's a big ask, so no pressure if this type of request isn't appropriate.

Process: Generally I used the Blue Sea Circuit calculator, plugged in the max current for the component / device, and my distance; then chose a fuse that was lower than the capacity provided on the calculator per ABYC standards. This will be done inside a 2018 Ford Transit 350 HD.

Sketchup file for electrical box



Questions:

1. I'm a bit confused on the 'round trip' length that should be considered for derating. For example, from my alternator to the first breaker, there is no round circuit, it's just 1.25 FT. Should this length be used, or should I base the wire on the full circuit of alternator > breaker > DC-DC charger > negative bus bar, etc.?
2. For the multiplus output, I thought I'd read in the manual that max charge was 75A, (and my distribution panel is 50A), is there a reason why I'd have to use 6/3? Have seen some comments on the forum here suggesting 6/3 is required per Victron recommendation.
3. Is it critical to get all Blue Sea branded components? Are there other reputable brands that are more cost efficient?
4. I'm really uncertain about the wire size in between alternator and DC-DC charger; I've seen in another thread here that realistically it's near impossible for alternator output to be even close to 225A, but I want to be conservative so is 1AWG okay then switch to 6 after the breaker? Further I've seen 3 different recommendations per Sterling for breaker size. In fact, the recommended breaker differs in the English manual vs. German. Should I go 70A or 100A on both sides?
5. I've included a SketchUp file here of my electrical components' locations (the box will be closed in but I've hidden the walls to view easier) - are the fuses all close enough to the battery? Targeted sufficient spacing for multiplus per manual, but recognize it's tight. Also have propane locker nearby (double walled). Is my battery stacking nuts? Saw another forum member do something similar and BB manual says any orientation is ok.
6. Anywhere I can safely slim down or suggestions/ideas to cut costs? Budget has quickly become tight lol. Thought about doing fuses instead of breakers, but the fuse holders (ANL/mega) combined with the actual fuse cost seem to come close to blue sea breakers.
7. I know the charge controller is overpowered - I called BattleBorn and they said this won't be an issue, but appreciate any other perspectives if it will be critically risky (already have purchased and can't return unfortunately).
8. Should I connect my Charge Controller to the multiplus?
9. Is there any particular way the negative & ground from the multiplus should be wired to the negative bus bar? Can I just wire them to the same terminal?
10. Victron manual for charge controller specifies 2AWG for PV/battery terminals - can I go lower than this? Seems like 8AWG should be plenty for my purposes.
11. Is 600A overkill for my main switch? Seems like next model down is only 350A. Is AFD needed?

 

[Rocketman]

I can only answer some of your questions. Very nice drawing by the way! I love that you already included most of the info I usually ask about.

It doesn’t show but get the Cerbo (or Cerbo-S) and possibly a touch if that is not already in the plans. You could avoid the Multiplus dongle if you did this (but I bought the dongle anyways). The GX (cerbo) is super useful. If you are wondering ask again and I will tell you in a long post why I think it is worth it

7. Can you sell the Victron mppt 150/70 and buy a 150/45 or 100/50 and come out ahead? If not that’s fine. Yes you could have a lower gauge wire - I would go with awg#6 as the smallest. 500w / 12v = 41.6amps - this is the spot you don’t want voltage drop - so move to #6.
If you put smaller wire than the mppt is rated for, put a label on it that says “Do not exceed ____amps to the battery or _____ watt array” (II.e. #6 wire = 50amps to battery or 700w array).

1. Round trip is alternator to Dc-Dc charger back to alternator/engine battery.

2. I would use #6 6/2 + ground or 6/3. Use marine multi strand wire - avoids vibration issues. #6 will handle 50amps of A/C current- yes you could go smaller, but on the off change that you park in an RV park run the electric heater or A/C and are cooking up a storm with everything on, you may find you occasionally use most of the capacity of the wire.

3. Blue Sea is great! For your main bus bar also look a Victron PowerIn (look at YouTube to add fuses). It may be more compact because it has both bus bars and fuses (but it is pretty big). There are other really good brands, for bus bars just make sure it is at least 1/4” thick copper (tin plated). Do Not get a brass buss bar! (The cheap ones are brass). BEP Marine is another good one.

Batteries: BattleBorn are great BUT expensive batteries. Lion batteries are cheaper, and there are a lot of decent quality batteries in a 100ah range. I want a battery that I can look on an app and see the cell voltages. So I know if it is getting out of balance and needs to spend time in the higher 14.4 to 14.5v area to balance out. (For that reason - and$$$ BattleBorn is out for me). Also, low temp protection is mandatory. You may be able to find much cheaper batteries that fits your needs. You also could diy some batteries- but you probably have enough on your plate… There are LOTS of reviews on 100ah lithium batteries- The Lion Batteries I remember are a smaller footprint than Battleborns- just make sure the bms’s in parallel can output 350amps - so you could get two 200ah batteries with 200a bms’s. Size is key in this area!

With four batteries you may want to consider getting a bus bar for the batteries- each battery goes to the battery bus bar with equal length cable. Then the shunt and fuse attach to it - that is what the Victron PowerIn was designed for.

11. 350A will be fine.
8. I would not - connect to a fused bus bar.

One more item- I installed a Victron Smart BP65 - battery protect - on the wire going from the bus bar to the 12v fuse box. I did this so I could automatically gracefully shutdown the system in low battery situations. If I leave something on and the battery gets low - the Multiplus shuts down at its programmed voltage, this shuts down the lights/other loads before the low voltage cutoff happens in the bms. Some bms’s are difficult to wake up - I prefer to not let them get to that point. Once the solar kicks back on in the morning and the voltage rises it turns everything back on. Also makes a nice cutoff and reset for the 12v fuse box.

If I didn’t explain something clearly- ask - and I will send you another long novel.

Good Luck!

 

[mikefitz]

1. I'm a bit confused on the 'round trip' length

Round trip is total length from 12v positive vehicle point ( provided by Ford on the seat base) through to the negative 'ground' on vehicle metal.

2. For the multiplus output

As advised.

3. Is it critical to get all Blue Sea branded components

Not critical, consider Victron products. For example Victron power in , with fuses to replace positive buss bar and breakers.

4. I'm really uncertain about the wire size in between alternator and DC-DC charger

You will be connecting to the Ford pick up point. Sterling charger are rated on input current 60 amps, output will be less. Use AWG 6, (AWG4 for a long run) and 80 or 100 amp fuses. The feed fuse needs to be close to the pick up point. You are not connecting direct to the alternator but the provided point that connects to the vehicle battery. The return negative must be to vehicle metal, not the battery post as sugest3d by the Sterling instructions.
In general fuses are preferred, more reliable with lower volt drops.

6. Anywhere I can safely slim down or suggestions/ideas to cut costs?

Fuses as discussed. The Battleborn batteries are overpriced and have been shown to have issues. You could ask for advice or review the various you tube breakdowns and testing of batteries. Something like two of these,

LiTime 12V 200Ah Plus LiFePO4 Lithium Battery, Built-in 200A BMS, 2560

LiTime 12V200Ah deep cycle LiFePO4 battery Plus with its 200A BMS provided enough juice to run the devices. Only 45.59 lbs.

www.litime.com

5. I've included

Batteries best at floor level restrained against movement in a mobile application.

I know the charge controller is overpowered -

Not an issue.

8. Should I connect my Charge Controller to the multiplus?

No to the fuse/ breaker at the buss bar.

9. Is there any particular way the negative & ground from the multiplus

The ground connection should connect to van metal. The negative power cable to buss bar. Try to run the positive and negative power feeds close together in the run to the inverter to avoid magnetic effects .

10. Victron manual for charge controller specifies 2AWG for PV/battery terminals

That's the maximum, suggest 4 AWG

11. Is 600A overkill for my main switc

No, is probable there will be a significant volt drop across a lower rated switch. 3000 watts of inverter and the high resulting currents require best possible engineering in a 12v system.

Regarding the AC output of the inverter. Not sure about electrical codes in your location, but in the UK for RV installed inverters, earth leakage protection must be in circuit, GFCI.

Pick up point for DC charger,