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Design review help, please

Lsversaw

New Member
Joined
Apr 6, 2021
Messages
9
Location
Mid-Kansas
I’d appreciate a design review of the attached wiring plan for my 2021 TAB teardrop trailer.

This my first post. I’ve learned a lot from you brilliant people, so it’s time to actually build something.

I’m going from this factory-installed solar set-up…
  • 105W flexible roof-mount solar panel
  • Victron 75-10 solar charge controller
  • 75Ah AGM battery
to this…
  • add 2 Ecoflow 160W portable solar panels, for a total of 425W
  • add a Victron 100-30 solar charge controller for the portable panels
  • replace the battery with a 206Ah 12V SOK Lithium battery
  • add a Victron 12-12/18 DC-DC charger
  • add a solar panel shutoff switch
  • add a Victron Lynx
  • add a Victron BMV-712 battery shunt/monitor
You’ll notice there is no inverter. My plan is to carry a Bluetti AC200MAX (https://www.bluettipower.com/products/ac200max-power-station) in my tow vehicle (Jeep Wrangler Unlimited), plus additional amp hours in some form, and plug the shore power cord into that. But the only things that I need an inverter for is to run the A/C, microwave, Keurig coffee maker, and some 120VAC outlets. None of those are “musts”. I’ve tested the AC200MAX and it will start and run the AIR8 air conditioner. Yay!

I’m still gathering some elusive data for my energy audit, but it seems like I’m converging on about 500Wh per day for all the DC stuff.

My objective is to design and build upgraded lithium & solar system that works, lasts a long time, and looks good. I’m an electrical geek.

Some specific questions I have:
  • Do I have all the required fuses?
  • Are the fuses the right values?
  • Should I increase wire sizes?
  • Do I need another ground connection from the Victron 100/30?
  • Is it a mistake to put all of the Victron bits, plus the new battery, in the original battery/propane box mounted on the tongue, and then inside another lockable battery box? Here is the battery box I’m using, if I can figure out a way to get it into the original battery/propane box: https://www.amazon.com/NOCO-HM462-C...o+commercial-grade+battery+box,aps,237&sr=8-7 )
  • Is there anything else I should change?
Thank you in advance for any suggestions.

How did we get projects completed correctly before the Interweb? Pop Science/Mechanics, I suppose.
 

Attachments

  • TAB electrical system for design review.pdf
    195.1 KB · Views: 36
Is it a mistake to put all of the Victron bits, plus the new battery, in the original battery/propane box mounted on the tongue, and then inside another lockable battery box?
I can’t view your attachment on my mobile phone so I am only commenting on the preceding paragraph. Putting your controllers in the same box as your batteries is not recommended. The front box has the potential to overheat your batteries and other equipment should the tongue of the trailer ever be in direct sun on a hot day and also will make your lifepo4 battery get to cold for charging if you are ever in below freezing temperatures.
 
Is the DC-Dc charger the isolated one? It should be on a trailer.

The Victron Lynx… for your small system that may be a (LOT) bit big. Which one were you thinking of - Distubitor or Power In? You may want to just look at some power bars and other fuses.

(I couldn’t look at your drawing either on my phone).

Good Luck
 
I can’t view your attachment on my mobile phone so I am only commenting on the preceding paragraph. Putting your controllers in the same box as your batteries is not recommended. The front box has the potential to overheat your batteries and other equipment should the tongue of the trailer ever be in direct sun on a hot day and also will make your lifepo4 battery get to cold for charging if you are ever in below freezing temperatures.
Thanks, Bobart. You’re right. I need to re-think the locations.
 
I can’t view your attachment on my mobile phone so I am only commenting on the preceding paragraph. Putting your controllers in the same box as your batteries is not recommended. The front box has the potential to overheat your batteries and other equipment should the tongue of the trailer ever be in direct sun on a hot day and also will make your lifepo4 battery get to cold for charging if you are ever in below freezing temperatures.
yes! you are right.
 
Is the DC-Dc charger the isolated one? It should be on a trailer.

The Victron Lynx… for your small system that may be a (LOT) bit big. Which one were you thinking of - Distubitor or Power In? You may want to just look at some power bars and other fuses.

(I couldn’t look at your drawing either on my phone).

Good Luck
Thanks for the reply, Rocketman.

Yes, my DC-DC charger is the isolated one.

I’m planning on a Lynx Distributor. I’m actually using all 4 of the fused connections on the Distributor (two solar charge controllers, a DC-DC converter, and a lithium-enabled “converter”). I’m short on mounting area and I had figured that the Distributor would take less area than two buss bars and four fuse holders, plus 4 wires (fuse to buss bar x 4). Is that a good assumption?
 
Thanks for the reply, Rocketman.

Yes, my DC-DC charger is the isolated one.

I’m planning on a Lynx Distributor. I’m actually using all 4 of the fused connections on the Distributor (two solar charge controllers, a DC-DC converter, and a lithium-enabled “converter”). I’m short on mounting area and I had figured that the Distributor would take less area than two buss bars and four fuse holders, plus 4 wires (fuse to buss bar x 4). Is that a good assumption?
just check the physical measurements of the Lynx - also look at the mbrf fuses on a buss bar.

Also check out YouTube for a video on how to add fuses to a Lynx Power In. That can save you a few bucks.

Good Luck
 
kbeefy, my A/C draws about 1000W. The AC200MAX is about 2000 Wh, so it’ll run the A/C for a couple of hours. I’d like to be able to run A/C for 6 hours, so I’ll need a total of about 6000 Wh of storage. (I’ll also have collect that much every day.) That’s 4000 Wh more than I have now.

My plan is to either add two of Bluetti’s B230 add-onbatteries ($$$!) or else build a 4Kw pack. I’ve been looking at the DIY options at jag35.com. That site looks pretty useful for sourcing all of DIY parts and kits.

A DIY pack would be cheaper, but to charge it back up would require swapping cables from the input side of the AC200MAX to the output. The Bluetti B230 outboard batteries would both charge and discharge through one (heavy) cable per battery.

So, there it is, short answer long.
 
Rocketman, I’ll check out both the added fuses and mbrf fuses. Those are both good ideas that I hadn’t considered.

Thanks again.
 
Current status: I’m building a battery box out of 1” foam, 1/8” masonite, then reflectix. The reflectix should reflect some of the radiant heat from the outer propane/battery box, and the 1” of foam should both keep out some ambient (air) heat and also keep the battery-generated heat inside the inner box. (How will it know?) All of the Victron bits will be outside of the insulated battery box. Comments welcome!
 
Both my Victron 100/20 (for the 100 watt portable) and Victron 100/30 (465 watts on the roof) have grounding screws on the box that are connected to the frame ground. Do I need them? Nope! Unless something bad happens and then YES!

Enjoy,

Perry
 
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