24V diagram review for travel trailer please

acoleman43

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Aug 27, 2021
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I have a travel trailer I would like to be fitted with some solar. This is my first solar install so it would be nice to get more expert advice.

The end goal is 1600W (eight 200W panels) with two 200AH 24V batteries. Daily consumption is expected to be about 3000W per day.

We currently have an onboard 4000W generator. "Shore" power is 30 amp. I would like to place an automatic transfer switch between the generator and shore power.

I would like to have the AC out 2 from the Multiplus powering another 30 amp outlet. The thought is that others can plug into this outlet to use the generator if needed.

I am also planning to have a 24V DC panel for some additional things.

Before I start sizing wires, fuses, etc but would like some honest critique of my thoughts.

I hope this all makes sense. Thank you in advance for you time.

Equipment I am looking at:
-Big Battery 202AH 24V batteries (2)
-Victron Lynx Shunt
-Victron Lynx Distributor
-Victron Multiplus 24/3000/70
-(8) RIch 200W 24V solar panels OR (8) Hightec 200W 12V solar panels. 4 pair of series panels in parallel.
-Victron MPPT 150-100 solar charge controller (I found one for 30% off so already bought it)
-Victron Orion 24/12-70
-Victron Cerbo GX
-Victron GX Touch 50

Prelim diagram.jpg
 

eXodus

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Jul 27, 2020
Messages
649
I would like to have the AC out 2 from the Multiplus powering another 30 amp outlet. The thought is that others can plug into this outlet to use the generator if needed.
that is a cool idea - I was thinking about using my RV-solar system as backup "generator" for my house, that would enable this functionality.

Equipment I am looking at:
-Big Battery 202AH 24V batteries (2)
I'm not sure if I would use a big Battery in a high vibration environment as an RV - only if you can mount them with the cells inside facing in the right direction. Got that opinion from the teardown videos and case design. I couldn't care less for service-ability of a battery. Because 5 years from now you don't get parts anyhow.
The end goal is 1600W (eight 200W panels)
I'm planning a similar system size and looking into 400w panels - cheaper per watt and less roof penetrations - it always depends on the roof layout - just throwing out the idea -

so my RV will get 3-4x (435w to be exact) large panels.
I would like to place an automatic transfer switch between the generator and shore power.
nice to have but not necessary, - an AutoStart function for the generator - so that your Multiplus can start the generator when batteries are running low would be higher on my wishlist

Otherwise - good system design - I don't see something fundamental wrong with it. Just would use different colors for 24V and 12V when you go further and size your wiring.
What are your plans for the 24V Auxiliary Panel?
 

acoleman43

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Aug 27, 2021
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that is a cool idea - I was thinking about using my RV-solar system as backup "generator" for my house, that would enable this functionality.
That's "stage 2". I would like to use the solar/generator on the trailer as backup for priority appliances (fridge, freezer)

I'm not sure if I would use a big Battery in a high vibration environment as an RV - only if you can mount them with the cells inside facing in the right direction. Got that opinion from the teardown videos and case design. I couldn't care less for service-ability of a battery. Because 5 years from now you don't get parts anyhow.
Something I thought about...but didn't want to think about. This decision was based on price. Maybe I can find some vibration isolators under the batteries. I plan to mount the batteries on their side or back.

I'm planning a similar system size and looking into 400w panels - cheaper per watt and less roof penetrations - it always depends on the roof layout - just throwing out the idea -
The 200W panels fit well on the roof. I did try 300W panels but can fit only 4. I haven't looked at 400W panels....that could be a good option.

nice to have but not necessary, - an AutoStart function for the generator - so that your Multiplus can start the generator when batteries are running low would be higher on my wishlist

What are your plans for the 24V Auxiliary Panel?
That's not a bad idea. Something to consider.

The 24V aux panel will be for things outside the normal RV stuff. Onboard compressor, aux water pump, etc.. I may drop it down to 12V as well-not sure yet.


Thanks for your input. I really appreciate your time.
 

eXodus

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Messages
649
Something I thought about...but didn't want to think about. This decision was based on price. Maybe I can find some vibration isolators under the batteries. I plan to mount the batteries on their side or back.
you already bought them? Amperetime / Chins battery are similar/cheaper and good quality only the low temp cutoff missing. (you can add a sensor to the Multiplus - way better solution then disabling the BMS)

That's "stage 2". I would like to use the solar/generator on the trailer as backup for priority appliances (fridge, freezer)
same here, Fridge/ freezer, router, some lights, Window A/C or Mini Split for the main house.

I'm in Florida and our power goes out all the time. Would be a waste to have two sets of batteries - I rather have a very large bank in the RV.
When we are away with the RV - I couldn't care less if my home has no power.
 

smoothJoey

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Nov 30, 2019
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Chassis bond should be on the system side of the shunt, luckily the lynx distributor has a dedicated grounding point.
The Victron Orion is a non-isolated converter so both black wires go to the same lug.
No wire guage, fuse size or lug diameter are annotated, might be worth doing.
 

acoleman43

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Aug 27, 2021
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you already bought them? Amperetime / Chins battery are similar/cheaper and good quality only the low temp cutoff missing. (you can add a sensor to the Multiplus - way better solution then disabling the BMS)
No, I haven't bought them yet. The only purchase so far is the Victron150-100 solar charge controller. It was $200 off....cheaper than the 150-70 and 150-85 so I didn't pass on the opportunity, plus it gave me more flexibility with solar array setup.

same here, Fridge/ freezer, router, some lights, Window A/C or Mini Split for the main house.

I'm in Florida and our power goes out all the time. Would be a waste to have two sets of batteries - I rather have a very large bank in the RV.
When we are away with the RV - I couldn't care less if my home has no power.
At first I thought I was strange...glad to see somebody else thinking about that. I live in Texas where summers are extra toasty and appliances don't maintain temperature well if they don't have power.



I guess I need to start sizing wires/fuses. Where would you place fuses?
 

acoleman43

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Aug 27, 2021
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Chassis bond should be on the system side of the shunt, luckily the lynx distributor has a dedicated grounding point.
The Victron Orion is a non-isolated converter so both black wires go to the same lug.
No wire guage, fuse size or lug diameter are annotated, might be worth doing.
Thank you for the advice!

I haven't sized wire yet because I wanted to make sure the system was sound first :)
 

smoothJoey

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2/0 wire from the batteries to the un-fused position on the busbar
250 amp fuse as close as possible to the positive terminal of the batteries.

2/0 wire from the lynx to the inverter/charger
250 amp fuse on busbar

4 awg wire from lynx to orion converter
125 amp fuse on busbar

4 awg wire from orion to dc distribution center
125 amp fuse on busbar

4 awg from busbar to solar charge controller
125 amp fuse on busbar

I consolidated wire and fuse sizes to keep the bom simple and reduce the number of required spares.
 
Last edited:

acoleman43

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Aug 27, 2021
Messages
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2/0 wire from the batteries to the un-fused position on the busbar
250 amp fuse as close as possible to the positive terminal of the batteries.
Fuse would be in the Lynx Shunt, correct? The Lynx shunt/distributor will be within 24" of the batteries, is that sufficient?

2/0 wire from the lynx to the inverter/charger
250 amp fuse on busbar
Fuse would be inside Lynx Distributor, correct?

4 awg wire from lynx to orion converter
125 amp fuse on busbar
Fuse would be inside Lynx Distributor, correct?

4 awg wire from orion to dc distribution center
125 amp fuse on busbar
Fuse would be in-line before existing busbar, correct?

4 awg from busbar to solar charge controller
125 amp fuse on busbar
Fuse would be inside Lynx Distributor, correct?


I really appreciate your time on this. Thank you!
 

smoothJoey

Its a hot one!
Joined
Nov 30, 2019
Messages
9,356
Fuse would be in the Lynx Shunt, correct? The Lynx shunt/distributor will be within 24" of the batteries, is that sufficient?


Fuse would be inside Lynx Distributor, correct?


Fuse would be inside Lynx Distributor, correct?


Fuse would be in-line before existing busbar, correct?


Fuse would be inside Lynx Distributor, correct?


I really appreciate your time on this. Thank you!
The master fuse(battery fuse) goes as close as possible to the battery positive terminal to minimize the chance of an upstream short.
Correct the wire from the batteries lands on the lynx shunt.

The fuse for the inverter circuit is part of the lynx.

The fuse for the dc distro panel is part of the lynx

The fuse for the orion circuit is part of the lynx.

Yes the fuse between the orion and the legacy busbar is in-line.

The fuse for the solar charge controller is part of the lynx.
 
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