RV solar system design

[mfoote]

I have a 2021 Airstream 27' travel trailer.

I would like to install "The classic 400 watt solar package" in/ on the trailer.

I'm planning on using the Rich solar 60 amp mppt charge controller as I want to have the ability to use a 200 watt solar suitcase as needed.

I have 2- 100 amp hour lithium batteries. From there go to a 3000 watt , 12v Renogy pure sine inverter.

From there I would like to go, hard wired, into a 50 amp automatic transfer switch (trailer uses 50 amp shore power) to feed my built in distribution center.
I know I will have to disconnect the existing on board Converter/Charger

Any advise on any of the above would be appreciated

But my question is about a A/C to D/C charger wired out of the transfer switch to charge batteries when connected to shore power.
Is this possible?
Any advise on this?

Simular to attached illustration

 

[NVS]

Don't know if you bought your panels yet, but I seen these and thought they would be good for an Airstream trailer.

2-Pack Uni-solar PVL-144 144w Amorphous Flexible Solar Panel

We are down to our last pallet. These solar panels are PERFECT for many applications because they are flexible, can be glued down, and work for many different surfaces curved and flat. The best part is these can be shipped Fedex ground and we fit 2 in a box. No expensive freight. You get 2 solar...

batteryhookup.com

 

[NVS]

You should be able to replace the guts in the current on board converter charger and charge your batteries. List the make and model so we can tell you what you need.

 

[mfoote]

You should be able to replace the guts in the current on board converter charger and charge your batteries. List the make and model so we can tell you what you need.

The Airstream is a 2021 Globetrotter 27 with 50 amp service.
How does Solar charge controller and the A/C to D/C charger, charging the same batteries not cause a problem ? Are the two chargers "smart" enough to work together.

Thanks for the input

 

[KCBlues]

You should be able to replace the guts in the current on board converter charger and charge your batteries. List the make and model so we can tell you what you need.

Depending on when it came off the factory line, it might already have a lithium-capable converter already. Airstream started installing lithium capable converters in 2021.

 

[MisterSandals]

Any advise on any of the above would be appreciated

I'd use better equipment than Renogy if i were spending any amount of time living in the trailer. A lot of reliability goes a long way (conversely, a little solar/inverter/battery trouble is a MAJOR pita).

 

[NVS]

The Airstream is a 2021 Globetrotter 27 with 50 amp service.
How does Solar charge controller and the A/C to D/C charger, charging the same batteries not cause a problem ? Are the two chargers "smart" enough to work together.

Thanks for the input

Yes the two will work together to charge the batteries without any problems. But you need to make sure the converter is lithium compatible.

 

[chrisski]

400 watts is not a lot of panels for a 3000 watt inverter, but it also depends on your power requirements.

I never recommend a 3000 watt inverter with a 12 volt system. 345 amps of power with the inverter running full blast is too much. I recomend a 2000 watt inverter, but only use it to 1000 watts except when you use the microwave a couple minutes at a time about 8 times a day to warm food up, not cook it. I had the 2000 watt inverter on a 24 volt system and used 4/0 wire.

if you want a 3000 watt inverter i recommend a 24 volt system, but only use it to 2000 watts except for a couple of minutes at a time. I have this ow and use 4/0 wire.

For the transfer switch, I manually plug my inverter in the 50 amp jack hardwired from the inverter. when I’m done i unplug it. I MUST turn the ac to dc converter off with the circuit breaker. More details are in my signature block in the part 2 build.

How does Solar charge controller and the A/C to D/C charger, charging the same batteries not cause a problem ? Are the two chargers "smart" enough to work together.

When I unplug the inverter to turn the generator and hook it up for charging, I have done the solar with a Victron 100/30 and 100/50 SCCs when I was 12 volts with the RV AC to DC converter at the same time, and also with the same SCCs and an AIMS 24 volt charger. No problems with either. I rarely needed to charge with the generator on 12 votls and with the battery and panel upgrade I did for the 24 votls, I have tested it once but never needed to use it.

 

[mfoote]

Yes the two will work together to charge the batteries without any problems. But you need to make sure the converter is lithium compatible.

I called WFCO (manufacturer ) today and they said it wasn't Lithium compatible.

Can I replace guts or just disable and install a different, compatible piece of equipment

 

[NVS]

Yes you can replace the guts. About a 30min job. It's just swapping out 5 wires and 4 screws to do it.

I just did mine a couple weeks ago. Post the model number and we can tell you what you need.

 

[chrisski]

I called WFCO (manufacturer ) today and they said it wasn't Lithium compatible.

Can I replace guts or just disable and install a different, compatible piece of equipment

May pay to take a look at the ac to dc converter that is in your RV. Mine was a 13.6 volt constant, 10 amp converter.

the lithium compatible converter I got charged at 14.4 volts for a 12 volt system and 28.8 votls for a lithium. I considered that votlage much to high and do not use the lithium settings and use gel instead which gives 14.0 and 28.0 volts.

Trick to charging with the converter this way is to shut it off when the batteries are close to full.

you’ll find a bit of controversy abut a good RV converter for lithium. I have not found one I’m happy with. Had I stayed with 12 votls instead of going to 24 volts, I may have kept the wfco in there. The WFCO was adjustable up to 50 amps. 10 amps is way to slow for a lithium battery. The converts I found top out around 70 amps at 12 volts to stay in a 15 amp 120 volt socket.

Yes you can replace the guts. About a 30min job.

I did not find the converter replacement terribly difficult, but took me a bit longer than 30 minutes. How long actually, I won’t say; too embarrassed.

 

[MisterSandals]

Can I replace guts or just disable and install a different, compatible piece of equipment

How dependent on shore power charging will you be?
I have an old PD 4645, pre lithium (it actually replaced a wonky WFCO) that I use with my 416Ah LiFePO4 battery. It charges to about 85% by rough estimate. I could get by without charging from shore power so its not important.
The problem with some of the new lithium inverter/chargers (like the new PD 9000 series lithium chargers) is that they charge to 14.4V and float there too. I am a conservative charger (13.8V for a gentle 100% charge) so really not interested in "upgrading". I would consider it if there was a reasonable alternative that was wire-for-wire compatible/swapable and configurable charging.

So don't just assume you NEED a lithium compatible battery. It depends on your needs.

 

[NVS]

This is the one I bought to replace my wf-8955.

WFCO WF-8950L2-MBA Replacement RV Power Converter Lithium-Ion Main Board https://smile.amazon.com/dp/B07TZNCFG4/ref=cm_sw_r_apan_i_H81EVSYRDAAKXGECAV4Y?_encoding=UTF8&psc=1

 

[NVS]

This one floats at 13.6v it will bulk charge at 14.4v for 4 hours then it will float charge. If your battery isn't fully charged after 4 hours you have to flip the breaker for the inverter off and on to reset the bulk charge.

 

[mfoote]

This is the one I bought to replace my wf-8955.

WFCO WF-8950L2-MBA Replacement RV Power Converter Lithium-Ion Main Board https://smile.amazon.com/dp/B07TZNCFG4/ref=cm_sw_r_apan_i_H81EVSYRDAAKXGECAV4Y?_encoding=UTF8&psc=1

Great, thanks, I will get the exact model number for the unit I have and let you know.

So with doing this conversion/ updating of the built in WFCO converter charger, I would still use the transfer switch between the inverter and shore power. When on shore power the batteries will be charged using the Airstream built in converter charger and the solar charger (if its sunny out) until the batteries are recharged correct? Or am I missing something

 

[NVS]

Your inverter should come with an on off remote switch. You can only run a few circuits through the inverter not the whole 50amp service. You should watch how to install an inverter in a rv on YouTube. The converter will work fine since it just controls the dc circuits.

 

[KCBlues]

This is the one I bought to replace my wf-8955.

WFCO WF-8950L2-MBA Replacement RV Power Converter Lithium-Ion Main Board https://smile.amazon.com/dp/B07TZNCFG4/ref=cm_sw_r_apan_i_H81EVSYRDAAKXGECAV4Y?_encoding=UTF8&psc=1

I found a complete WFCO 8955AD for $206.99 delivered. It took about five minutes to pull the converter and circuit board out of the housing. I also pulled the two small bus bars out that I'll have fun with somewhere down the line! It took three days to get here...

WFCO WF-8955-AD 30A AC 55A DC Auto Detect Converter Charger Distribution Center 11 Circuits, Black

The WF-8900 Series has revolutionized RV power centers with its lighter weight, decorative doors, and superior features. The WF-8955 model provides 55 Amps and a clean, constant 13.6 VDC nominal output, for reliable operation of electronics and appliances. Automatic three-stage charging extends...

www.boatandrvaccessories.com

 

[Bobert]

What do you actually want to accomplish with your solar setup? 400w of solar is probably going to be inadequate to operate a 3000w inverter 24/7. It does make a difference where you plan to camp. Here in Northern NY we have a lot of cloudy days. On a cloudy day I can only get 25% of the output my panels are rated for. On days like today heavy overcast (to see well inside we need to turn our lights on) it will be closer to 10%. I understand it is very different in the south west but here If you have the panels “flat” on your roof you will be fortunate to get %75 rated output even on a sunny day. Inverters can have considerable idle power consumption. My AOI inverter uses 55 watts at idle ( hopefully the stand alone renogy is better than that it should be) at 55 watts that’s more than 400 watts of solar will output on a cloudy day. If you are going to turn on the inverter occasionally for a few things that’s not a problem. 200ah of battery is a bit marginal for 3000 watts of inverter. That’s just over 45 minutes of run time not including efficiency losses. It will take 6.5 hours of peak sun not counting efficiency losses and with no loads to get those 2560 watt hours back into your battery. I don’t want to be a wet blanket and I also don’t want to assume that you haven’t already calculated this all out for yourself. Solar is a wonderful tool it can make camping so much easier so long as you have realistic expectations.

 

[HRTKD]

The design and install is a lot easier if you get an inverter/charger. That allows you to ditch the existing converter (weight savings!) and not have to ever worry about turning the existing converter on/off. There would be no need for an automatic transfer switch at all.

For a mix between fixed rooftop and ground deployed panels, I recommend that you consider using two separate solar charge controllers. Yes, you can probably get it done with one controller. But separate controllers gives you more control. That's how I did it in my system (640 watts roof, 640 watts ground).

You're going to want to look at how the 12 volt charge from the two vehicle is handled. Do you want that charge going directly into your LiFePO4 battery bank? If the answer is no then you need to consider a DC-DC charger. The downside there is that if you do that then you have cut out the trailer's breakaway brake from power. The DC-DC charger is a one-way circuit. You need to extend the wiring for the breakaway system directly to the LiFePO4 bank or come up with an alternate solution (I went the alternate route).

I concur with the negative preference on Renogy.

 

[mfoote]

The design and install is a lot easier if you get an inverter/charger. That allows you to ditch the existing converter (weight savings!) and not have to ever worry about turning the existing converter on/off. There would be no need for an automatic transfer switch at all.

For a mix between fixed rooftop and ground deployed panels, I recommend that you consider using two separate solar charge controllers. Yes, you can probably get it done with one controller. But separate controllers gives you more control. That's how I did it in my system (640 watts roof, 640 watts ground).

You're going to want to look at how the 12 volt charge from the two vehicle is handled. Do you want that charge going directly into your LiFePO4 battery bank? If the answer is no then you need to consider a DC-DC charger. The downside there is that if you do that then you have cut out the trailer's breakaway brake from power. The DC-DC charger is a one-way circuit. You need to extend the wiring for the breakaway system directly to the LiFePO4 bank or come up with an alternate solution (I went the alternate route).

I concur with the negative preference on Renogy.

I appreciate the information

Does anyone have a recommendation for a different inverter brand and model than the Renogy