Help With Growatt 3000TL 24 volt Install

[chmiko]

Thanks for the tip, the uxcell converter is what I’m using right now with no issues thus far, but the Victron seem like a healthy upgrade, if the current one fails.

 

[chmiko]

So, the 70 amp victron buck would then be the appropriate model based on the WFCO amperage rating of 35 amps?

 

[JRam]

I would go with the 40 amp version, a lot cheaper too. In my case, I bought the 70 amp version because my 5th wheel came with a 55 amp WFCO panel. A 50 amp version would have been good enough for me but Victron doesn't make them for whatever reason.

 

[John Frum]

So, the 70 amp victron buck would then be the appropriate model based on the WFCO amperage rating of 35 amps?

Don't they have anything closer?
Sorry I not wading through their site to find what you need.
First gate is do you need isolated or non isolated?
Second gate is do you need a charger or just a converter?
Final gate is 35 amps or greater.

I find their site to be nearly Germanic levels of bureaucracy.

 

[John Frum]

Samlex also makes dc2dc converters but they will likely be even more expensive as I've been lead to understand they target the ham market.

 

[Holwayout]

So, the 70 amp victron buck would then be the appropriate model based on the WFCO amperage rating of 35 amps?

I'm looking at this one, but scratching my head as to how it connects to the panel. It says "Double faston tabs 6.3mm". I'm guessing it would require getting the appropriate terminals and attaching them to the wires.

Amazon.com

Input voltage: 18-35v
Continuous output current: 40A
Max output current: 50A

 

[JRam]

I was looking at that particular model before buying the 70amp version. I just didn't like the spade connectors so I went with the non isolated version with the screw terminals. You can find a 40amp version with screw terminals in other websites, not sure why Amazon doesn't sell it.

To connect it to the panel all you do is connect the positive of 12v output to the DC distribution board (board with blade fuses) and the negative to the negative bus bar.

 

[chmiko]

I was looking at that particular model before buying the 70amp version. I just didn't like the spade connectors so I went with the non isolated version with the screw terminals. You can find a 40amp version with screw terminals in other websites, not sure why Amazon doesn't sell it.

To connect it to the panel all you do is connect the positive of 12v output to the DC distribution board (board with blade fuses) and the negative to the negative bus bar.

Just to be clear is THIS the unit you're talking about? Also is there any reason this would not work with a 30amp WFCO?
My understanding is limited, but wouldn't the buck convertor @ 70 amps handle more 12v volt loads if i needed to add them in the future, or is that not how it works.

 

[John Frum]

Just to be clear is THIS the unit you're talking about? Also is there any reason this would not work with a 30amp WFCO?
My understanding is limited, but wouldn't the buck convertor @ 70 amps handle more 12v volt loads if i needed to add them in the future, or is that not how it works.

That is a top shelf dc2dc converter.
It is non-isolated and you should understand what that means before you purchase it.
If that is ok it should more than meat your requirements.
Its pretty reasonably price imo.

 

[JRam]

Yes that is the unit I was talking about. Victron makes a similar 40amp version and is of course cheaper than the 70amp version.

Sure the 70 amp version can future proof in case you need to add more loads, keep in mind you will have to replace the DC fuse block for a higher rated when that happens.

 

[Cdkipp]

Yes that is the unit I was talking about. Victron makes a similar 40amp version and is of course cheaper than the 70amp version.

Sure the 70 amp version can future proof in case you need to add more loads, keep in mind you will have to replace the DC fuse block for a higher rated when that happens.

Since I also have a 12 volt pack, with a much larger 24, I use the 25 amp version of that DC-DC. My actual 12 volt DC needs in my RV are pretty low.. I liked the 25 amp model because I could parallel another if needed and it has 96% efficiency. More than the others.

 

[eXodus]

Since I also have a 12 volt pack, with a much larger 24, I use the 25 amp version of that DC-DC. My actual 12 volt DC needs in my RV are pretty low.. I liked the 25 amp model because I could parallel another if needed and it has 96% efficiency. More than the others.

same experience here,
when you keep a 12V lead/ small lithium battery for peaks around then the DC-DC can be much smaller - the continues draw is usually under 10A in my RVs. Just sometimes when I fire up the Fans and the lights for a few hours it's more then that.

I got a DC-DC 20A charge circuit in my Van for the 12V for the last 5 years. It was never an limitation.


So you either go with a substantial DC-DC
Or small DC-DC + 12V battery.

 

[Primeral]

Get a Victron Orion 24/12 instead of those cheap Chinese converters. Big heatsink, fan and adjustable output voltage. Plus you are not limited to the small wires that come with the cheap converters.

For what it's worth, I chose a 100A 24v to 13.8v converter. I designed my travel trailer to have adjustable height suspension so I needed a high duty cycle OBA compressor. 13.8v is closer to the DC output of a car with its engine on, which is why I picked that over 12v.

The converter has no active cooling so I'll heed the warnings and add a couple of fans to it. Heat is probably what kills the cheaper Chinese buck converters.

 

[lep911]

Great discussion on this thread. Why wouldn't you use the existing RV wiring and mimic the shore power to Growatt connection for an AC out to our distribution panel? Keep the AC/DC converter to power your DC loads? I've posted a drawing, what am I missing? I omitted all the line fuses etc I know but the question here is why not utilize the RV's existing wiring?

 

[Zwy]

For what it's worth, I chose a 100A 24v to 13.8v converter. I designed my travel trailer to have adjustable height suspension so I needed a high duty cycle OBA compressor. 13.8v is closer to the DC output of a car with its engine on, which is why I picked that over 12v.

The converter has no active cooling so I'll heed the warnings and add a couple of fans to it. Heat is probably what kills the cheaper Chinese buck converters.

I think many buy one too small.

 

[Zwy]

Great discussion on this thread. Why wouldn't you use the existing RV wiring and mimic the shore power to Growatt connection for an AC out to our distribution panel? Keep the AC/DC converter to power your DC loads? I've posted a drawing, what am I missing? I omitted all the line fuses etc I know but the question here is why not utilize the RV's existing wiring?

Part of the issue is grounding. If you run thru the Growatt transfer switch, it will automatically ground to shore power when connected and transfer switch is closed. Unplug from shore power and run off battery/solar, the unit grounds to the inverter automatically.

 

[lep911]

Part of the issue is grounding. If you run thru the Growatt transfer switch, it will automatically ground to shore power when connected and transfer switch is closed. Unplug from shore power and run off battery/solar, the unit grounds to the inverter automatically.

Isn't that the inherit switching functionality of the hybrid inverter? What's the grounding issue then? I don't see this any different than a standard install when shore power is out and so the inverter switches to solar/battery only. What am I missing?

 

[Townzer]

Hey Chmiko, thanks for the informative thread. How much do you have invested in the system?

 

[Zwy]

Isn't that the inherit switching functionality of the hybrid inverter? What's the grounding issue then? I don't see this any different than a standard install when shore power is out and so the inverter switches to solar/battery only. What am I missing?

Not all inverters have the switching ability. Start with these examples. https://diysolarforum.com/threads/how-does-your-inverter-deal-with-ground.17138/

More here. https://diysolarforum.com/search/342307/?q=inverter+ground&o=relevance

There is plenty of threads about correct bonding of ground-neutral. With vehicle mounted systems, there is a slight twist to it as power comes from both shore power and inverter. Throw in a generator and it complicates it more.

Make certain you understand how your system will handle the bonding. Bonding should only occur at one point in the system.

 

[chmiko]

Hey Chmiko, thanks for the informative thread. How much do you have invested in the system?

if i had to guess invested so far about 5k with the batteries being the biggest expense. I added 2x more batteries and panels to my original design
but totally worth the $$$ for lifePo, also considering this is a totally off grid system and I never really have to use my generator anymore(except on on super cold nights, i run heater tape on my lines and tanks to keep from freezing ) thats a plus living in the middle of nowhere, the silence is worth every penny plus having enough power to do everything I need to is amazing!