power panel questions/suggestions

[blackohio]

i’m making a panel for the inside of my alu cab canopy. i’ve places the inverter next to where the dc-dc charger will go. the inverter is a 2000w renogy unit. it came with dual 4 gauge wires to support the power draw for the max 2k watts. if i don’t plan on anything close to that draw can i jump safely down to a single awg4 wire like the 1000 watt unit.

additionally could i safely push/pull juice through the two posts in the lower right or should i run 2 more for dc-dc to battery and have the two existing be the draw off the battery? i’m assuming it doesn’t matter since goes through the same 2 posts.

what runs off the battery is fridge, camper led’s, inverter and secondary usb’s

 

[blackohio]

Depends alot on overall circuit length. At full load, your inverter will draw somewhere around 160A. 4AWG as single conductor, will carry about 100A.
Is it safe ? I think so, especially as you understand watts limit, and obviously you will fit appropriate OCPD to protect conductors.
Ultimately, its up to judgement of person building/using the appliance.

I guess because I don't know how inverters work precisely, will it draw full load even if the only thing connected is say a laptop? Or is it just gonna draw full load if I'm running say a microwave?

I could run a 100A shunt or breaker between the inverter and battery to safeguard that.

 

[dwh]

It inverts DC->AC, as needed. So a load of 1a@120v on the AC side is gonna pull 10a@12v on the DC side. 5a@120v, 50a@12v. 10a@120v, 100a@12v.

Plus a bit extra draw on the DC side because it's not 100% efficient at converting. If it's say, 80% efficient, the add another 20% to the DC draw numbers.

 

[blackohio]

Thanks, I should have been clear, while I have a general knowledge of what the inverter does the science behind it I dont.
So it's not gonna max draw across the lines, only as needed. So if the fridge were on the inverter and not DC and drew 5a max DC, at 120V it's drawing .5a correct give or take whatever is required for conversion.

I don't have any plans for anything in-particular to be on the inverter, just figured why not buy one, run it just incase.

Any issues only running the 2 posts and pushing and pulling through them or better to err on the side of safety and run two more bulkhead pass throughs for the inverter alone,

So at the moment i'd run DC-DC to battery to the existing bulkhead connectors as well as hot and ground from blue sea buss and switch-pro.

Then on secondary bulkheads run inverter to battery through.

 

[dwh]

A couple of caveats...

That inverter is not rated for 2000w. It's rated for 2000w continuous, 4000w surge.

(assuming lead-acid battery)
4000w ÷ 13v (full battery) = 308a + 10% (specs say 90% efficient) = 339a

4000w ÷ 12v (half full battery) = 333a + 10% = 366a


Also, the double #4 is not just about the amp load...it's also about the voltage drop. If your battery is down a bit, then you put a fairly heavy load on a single #4, the voltage might drop enough to trigger inverter low-voltage shutdown - even though the battery had enough juice and it would have worked if the wire had been adequate size.

 

[blackohio]

Thanks for the education

i'll keep the dual 4 and run an additional dual 4 out of the bulkhead to the battery and run a second set of the bulkhead connectors for the DC-DC charger, switch-pro and fridge.

 

[dwh]

So if the fridge were on the inverter and not DC and drew 5a max DC, at 120V it's drawing .5a correct give or take whatever is required for conversion.

Correct as far as it goes. To feed that .5a on the AC side, it will draw 5a + 10% = 5.5a on the DC side.


The bolts are a non-issue - they aren't really carrying power. They are being used to hold wire ends together, and it's the ends that are carrying the power.

 

[blackohio]

The bolts are a non-issue - they aren't really carrying power. They are being used to hold wire ends together, and it's the ends that are carrying the power.

One last question then if thats the case I could just gang all the wires to those two posts for whats drawing to inverter (which will remain off 99.9% of the time) draws off the battery (fridge, switch-pro, led lights and usb) and what the dc-dc is pushing to the battery. My last set-up was much simplier as I ran a buss panel for hot and ground direct off battery, and only had a charge controller feeding battery via solar. With the DC-DC and inverter im somewhat throwing myself into strange territory.

 

[dwh]

Sure. Keep in mind power flow diversion. If the battery charger supplies say 40a to the posts, and you have 10a of loads running, only 30a will flow toward the battery.

Same with inverter. If inverter is drawing say 50a, and another 10a of loads, and the charger supplies 40a, then all of the amps supplied by the charger will be flowing toward the 60a of loads, plus an additional 20a coming from the battery to make up the difference. And it's still only 60a total passing through the connections at the posts.

 

[rayra]

I would beef up the wiring to the inverter so that the inverter can operate at its max capacity if it were ever needed. Use enough wire for max draw / flow, rather than a smaller wire you can 'get away with'. I'm all about having options. You'd be restricting the potential (no pun intended) of the inverter. What's the worst weather disaster in your area, would you ever want to run some household appliances with that inverter?

I was running 1/0 cable to the rear to run a rear hitch mounted winch anyway, so I turned it into my 'wiring bus' and have hung a 1000W inverter from it (as well as all my other various power adapters / ports, AND backfeeding my aux battery thru it via my rooftop solar. Most of my junk is in a separate 'power box' in the cargo area of my Suburban. Still haven't got around to the rear winch connection. Or even having the winch / carrier.

 

[Photobug]

Unless you plan to run a microwave, why would you need a 2000W inverter?

 

[Alloy]

Keep a close eye on the grommets. I've had grommet & wire cut through by thin metal. This may happen to the wire coming off the top of the breaker.

 

[shade]

Keep a close eye on the grommets. I've had grommet & wire cut through by thin metal. This may happen to the wire coming off the top of the breaker.

I've filed similar knock-outs and used emery paper to further smooth the opening. Even if the grommet, gland, or other protection fails, the wire still won't easily chafe on the back plane.

 

[luthj]

Its important to secure larger wires so they can't move a lot anyways. If the wiring is in an area where drips/leaks/spills can happen, consider drip loops or sags to prevent water flowing down wires into inverters/chargers.

 

[blackohio]

area is drip free. panel is going to powder today. i’ve decided to use groove grommeting from noble. it’s thicker and silicone glues in-place. the wire from the breaker is one i feel most secure about. it’s recessed and tight to the wire and hole so nothing should move around.

all the wires are secured down on the backside to stop movement as much as possible.