Please check My idea for upgrade.

[CanuckRV]

I hope to upgrade the available power in the RV so I can take advantage of the 3000w inverter I have. I have included a schematic of the present set up. So now the questions.
https://ibb.co/59PqMTt

Are the 120v AC/DC charger and the DC/DC charger on the correct side of the fuse (presentably 100amp)? If not do I need more fuses or just rely on the built in safety features.

I want to change to a 250amp fuse to take advantage of the inverter so I will need to change the wires to 2/0awg correct or should I go larger? The wire only needs to be changed from the battery to the fuse correct? The inverter came with its own connection wires so I hope they should be correctly sized.

Right now all wiring is 6awg

[booster]

Originally Posted by CanuckRV

I hope to upgrade the available power in the RV so I can take advantage of the 3000w inverter I have. I have included a schematic of the present set up. So now the questions.
https://ibb.co/59PqMTt

Are the 120v AC/DC charger and the DC/DC charger on the correct side of the fuse (presentably 100amp)? If not do I need more fuses or just rely on the built in safety features.

I want to change to a 250amp fuse to take advantage of the inverter so I will need to change the wires to 2/0awg correct or should I go larger? The wire only needs to be changed from the battery to the fuse correct? The inverter came with its own connection wires so I hope they should be correctly sized.

Right now all wiring is 6awg

Start basic. Do you even have enough battery capacity and type to run 3000 watts which would need somewhere around 300 amps to do?


Do you have the charging capacity to recover that kind of power use?


What do you intend to do with that much power. If it is run the AC off batteries, you need a huge system in all respects. For most of us who don't use batteries for AC, 2000 watts will run most everything else OK but you still need a decent size battery bank.

[CanuckRV]

Yes I have 360ah
But that wasn’t my question

[booster]

Originally Posted by CanuckRV

Yes I have 360ah
But that wasn’t my question

Very true, but I won't, and probably many others won't, give advice on the wiring of a system that we don't know what it has in it and what it will be used for. It would be irresponsible and dangerous to do, especially when someone is asking about a big wiring, big output, system and seems to lack basic wiring knowledge.


Sorry if I offended or irritated you, but then I have no advice you that I will give.

[CanuckRV]

I was given a brand new pure sine wave 3000w inverter I will only be using it for a toaster oven and or a coffee pot.
I have lots of experience with household wiring but not 12v DC
I do know enough to have what I think is correct checked

[avanti]

Your sketch has many issues. E.g., the fusing isn't remotely adequate, or even correct.

But, @booster is right: fixing it would require MUCH more information about the context. For starters: What kind of vehicle is it? How is power being taken off the engine? What kind of batteries and how many? Is the AC outlet you show built into the inverter, or will you be installing a 120VAC power system? What are the run-lengths of the wires?

I realize that your goals are modest, but the kinds of power you are dealing with are not to be trifled with.

[@Michael]

I don't think one should fuse the negative side of the circuit at all.

The (+) side fuse should be as close to the battery (the current source) as practical.

I would also install an appropriate fuse on any wires that are smaller gauge than the large gauge wire from the battery. This is to protect those wires from being shorted and carrying the full current from the battery.

Wire size depends in part on wire length.

There's a lot more to this though. Caution is advised, and as others have stated, there's no way to give good advice when all one has is a snippet of information.

[booster]

Originally Posted by CanuckRV

I was given a brand new pure sine wave 3000w inverter I will only be using it for a toaster oven and or a coffee pot.
I have lots of experience with household wiring but not 12v DC
I do know enough to have what I think is correct checked

Thank you. Toaster oven maybe 2000 watts?



You have a 1997 Roadtrek that at 360ah of presumably AGM has obviously been upgraded some, but the gauge that is in there certainly would not be up to the amperage could provide and would likely go back to original, probably, 50 amp engine charging and maybe 20-30amps shore charger. How well the changes were done will make a bit of a difference in what you would probably want to do if you were starting with a later, bigger wiring system.


You may also have to do a bit of tie in to the Roadtrek 110v system if you use the existing outlets, but won't have to if you set it up to plug directly into inverter. At least on the later Roadtreks tying into the van 110 wiring can be a bit confusing as they wired them funny, we have one that was that way. I can't speak for a 97, but they probably didn't come with any inverter so some of the confusion is gone because of that, but you still would need another automatic transfer switch and be very careful of double neutral and ground bonding issues which are very inverter dependent in how they handle those issues or if you tie in to an existing outlet. Be aware that if the inverter is permanently bonded as some are, you can get a double bond on shore power even if it is off or if it is on and not in use if it is tied into the existing 110, so finding out the bonding style is very important if tied in.



For the 12v side from the battery bank to the inverter, which you want to run directly IMO and then branch from there, I would use a minimum of 3/0 if the run is short and 4/0 if it is longer as voltage drop at high loads is normally a big issue, especially with lead acid batteries. Both those sizes could fuse safely with 300amp fuses, but at 2000 watts for the oven you would be using under 200 amps running and a bit more on surge so 250 amp fuses would be OK also. One thing to remember is that you will be protecting the wires and the general rule is that the should be protected at every power source but don't need to be on the use end. In an RV it gets weird because you can have a power source one each end of the same wire like the charger to battery would be or engine to batteries depending on how it is wired. Both end wiring fuses often is ignored if the the wiring is short, visible and in the same close together area by even the factories and I think that is not all that bad I think. If the items area separated like remote batteries away from the sources and distribution you have to aware of what is a source and which is a use and which are both like like a battery or inverter/charger combo unit.



Wiring from all the 12v stuff like the 12 distribution panel should be fused for a bit higher than their rated capacity. Our 07 Roadtrek was at 40 amps IIRC and had another 20 branch directly to the power sofa, for instance. Wire size and fusing from the charger would be based on the charger size as it may or may not have been upgraded (but should be for the big battery bank and to get better charging profile). Engine charging and DC to DC charger would be based on the wiring in the van and if it has been upgraded. It was likely 50 amp rated 6ga from the factory with an isolater that will drop the voltage about .7v so slows down charging. With a DC to DC in the line, you can go to a relay type separator that will not drop voltage as the DC to DC will take care of the charging. We have heard that the DC to Dc chargers are quite inefficient, so the 50 amps would have to be on the inlet side if it is 6ga and would make the charger more like 40 amps output, and that is probably about the most you really want to pull out of the stock alternator anyway, so a good match for the most part and just big enough to make the desired minimum charge rate on most manufacturers AGMs.


Upgrades to bigger systems with big inverters that we hear about usually have more issues with odd factory wiring or poorly done previous upgrades when trying to find out how to wire it all up than the do with very basic new system parts which are pretty simple as your sketch shows.


Wire sizing and protection on the DC side are the things to watch for and be careful with as large amounts of power are available to do bad things.


On the AC side, the biggest issues are usually tie into existing AC wiring if not on new direct wiring and double neutral to ground bonding issues.


My guess would be that you will likely find a few surprises as there have been some previous changes that you may or may not have been in on. We found a bunch of surprises on ours and we got it new.

[CanuckRV]

the wire length is about 4 feet at the most from 2 180 amp AGM batteries to inverter. the inverter is wired directly to the original transfer switch as the RT is wired for a gennie but was never installed. I removed the original converter and installed a smart charger and renogy dc-dc charger.

[booster]

Originally Posted by CanuckRV

the wire length is about 4 feet at the most from 2 180 amp AGM batteries to inverter. the inverter is wired directly to the original transfer switch as the RT is wired for a gennie but was never installed. I removed the original converter and installed a smart charger and renogy dc-dc charger.

At 4' I would fuse both ends of the cable from the batteries to everything else as that wire probably is in and area that could fail, rare but with that much power caution is advised.


With that wiring system for the AC wiring you would need to make certain that the inverter is bonded to the van when running and not when in it off. There is along discussion on another thread about that, and it is very confusing to say the least. An autobonding inverter is best, but you already have it so no choice now. The ATS should break the bond as long as both the neutral and hot are switched in priority. When wired to the transfer switch you also need to make sure the charger is not on the same wiring as the rest of the van as it needs to stay off when the inverter is on. Many chargers wire back through the main AC panel so don't go off when the transfer switch goes to inverter like in this case, as they are usually for generator switching which you want to leave the charger on after switching. This causes a charging loop that isn't good and is a very common issue in add on system stuff like this.

[CanuckRV]

The charger is directly wired to the shore power side of the transfer switch through a fused connection

[engnrsrule]

First off Listen to Booster! Especially concerning neutral ground bonding!

Second off, I did a lot of what you are talking about, replaced the existing 750w Tripplite combo inverter/charger (modified sine wave) with a 1500/3000 pure sine inverter. This meant I had to add a new charger as well. The leads the inverter came with were NOT sized for use in max load range. I used a 180a DC breaker, primarily because I used 0AWG to the battery and to the inverter. I had hoped to be able to run the Keurig off battery but it trips the DC breaker. My RT has a generator so I can still get coffee that way.

Booster mentioned it but it sounds like you are set up so the inverter cannot attempt to charge the batteries it is drawing off.

Another caution, if your inverter powers the full 110 bus, ensure it doesnt pick up loads you dont want it to, like the hot water heater if you have one, or fridge. I color coded my 110 breakers to load shed when on inverter.

The biggest plus to a pure sine inverter is it will run electronics that older modified sine inverters will not.

You can read thru my thread and see pics at this link...

https://www.classbforum.com/forums/f...ade-10087.html

[ctarmor]

I replaced my generator with a self-built Liithium 620ah battery.

I used 1/0 cable inside the battery.

2g from battery all the way to 3000w inverter.

6g everywhere else.

See attached schematics.

[booster]

Originally Posted by ctarmor

I replaced my generator with a self-built Liithium 620ah battery.

I used 1/0 cable inside the battery.

2g from battery all the way to 3000w inverter.

6g everywhere else.

See attached schematics.

Interesting layout and nice drawing but a bit low resolution to see details very well.



Can't see what the components are, but the wire sizing in #2 and #6 circuits appear to be near ampicity and probably 5% voltage drop for the 100 and 250/300 amp fused circuits. The 2ga after the 300 amp relay is protected by a 300 amp fuse only, it appears, on the power side.



I would prefer to keep voltage drops closer to 1-2 volts for power to the inverter to preserve it's efficiency which is going to make it use more than 3000 watts of DC anyway, same is true for whatever is running on the 2 gas if it is pulling near 100 amps. Wires near max ampicity will run pretty hot so upsizing wiring is generally a good idea in boats and RVs, especially with all the enclosed areas and sheathing that is used which lower ampicity. Every connection, fuse, etc also increases voltage drop and heat.


Not trying to be alarmist, but the wire sizes in the layout look to be a bit undersized, at least for me.


That is a big battery bank, do you have any high rate charging from the engine?

[ctarmor]

The cable lengths are short before the fuses. The max DC amperage I run is about 150amps.

The cables heat up to about 80 F degrees.

The biggest load is the inverter. The 2g cable from battery to viktron bus box, 250amp fuse to inverter-2g cable to inverter. 1/0 cable is hard to bend/work with, so researched I can use 2g as long as is about 3feet long or less. That seems to work well.

I have a Renogy 50amp Dc-DC charger for the lithium bank when engine is running, or connected to shore power. I've connected it to the house AGM batteries.

I also have a 2nd Renogy 20amp Dc-DC that charges the AGM batteries from the lithium battery bank when not connected to shore, or car is OFF.

There is a chage-over relay that switches between the two Dc-DC chargers. Right it is a manual switch.

[ctarmor]

Fuses are going to be a big part of your setup (missing in drawing). You want to have switches/breakers at each device for safety.

See my posting below. I have fuse/switch-breakers in many places.

[booster]

Originally Posted by ctarmor

The cable lengths are short before the fuses. The max DC amperage I run is about 150amps.

The cables heat up to about 80 F degrees.

The biggest load is the inverter. The 2g cable from battery to viktron bus box, 250amp fuse to inverter-2g cable to inverter. 1/0 cable is hard to bend/work with, so researched I can use 2g as long as is about 3feet long or less. That seems to work well.

I have a Renogy 50amp Dc-DC charger for the lithium bank when engine is running, or connected to shore power. I've connected it to the house AGM batteries.

I also have a 2nd Renogy 20amp Dc-DC that charges the AGM batteries from the lithium battery bank when not connected to shore, or car is OFF.

There is a chage-over relay that switches between the two Dc-DC chargers. Right it is a manual switch.

You are losing me here. Ampicity is not a length influenced thing like voltage drop is, so going over rated amps on any length is running over rated.


All wiring needs to be protected to level of the wire rating or lower from all power sources so can be both ends of the wire. If I read your drawing correctly, you have a 1/0 cable from the batteries to a 300amp fuse and then to a 6ga wire and a 300amp relay which goes to 2ga and probably 6ga on a binding post. The battery is a power source and the 300amp fuse is the wiring protection for all of those wires. 2ga is rated at 210 and 6ga much less than that, so all are under protected as I read it.


It does not matter how much you are using for amps, only what can be delivered to the wires in a dead short situation. If you are certain that you are not going to go over 200amps fuse at 200amps and protect the 2ga. Then add proper fusing to the 6ga, again if I am reading your diagram correctly