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When I did my trailer, the power distribution was sort of far away from the battery bank. I opted to go with 24 volt so that the main run from the battery bank to the 12v distribution would be smaller gauge. You can get a 24v > 12v converter for pretty cheap. Depending on the loads and length of...

I ended up replacing the breakers with DC. Thanks everyone for the help! Here's a link to the final design: https://diysolarforum.com/threads/designing-victron-system-for-keystone-rv-travel-trailer.51117/post-882932

Update for anyone reading this in the future: We ended up adding three 550 watt panels and living in the trailer full time with no issues. Haven't had to run the generator after adding the panels. Here's the other thread about the solar design...

If I were going to add a power Jack I’d tie into the house battery off of the main fuse panel. old speaker wire is pretty cheap to run up to the front and then I’d never have to worry about the Jack being dead.

Yeah, adding power would be tough — I don’t have a power supply with me. And need to keep the trailer online and off grid during the balancing. Assuming I did have a supply, would I have to shut off charging on the BMS while applying voltage to the low cell? Is there a balancer you recommend?

So I’ve got an 8S diy LiFePo4 bank which is out of balance: I’m on the road and it’s my primary means of powering my vehicle, so I’m looking for an easy/low-risk way to balance it a little that doesn’t involve taking the system offline. I’ve heard of people connecting an automotive headlight...

No... that would be a really bad idea. I'm monitoring midpoint voltage with the aux lead on the smartshunt.

Yeah, I ended up going with an alibaba BMS and it's so poorly documented that I didn't even want to attempt it. Good job with the overkill solar hack though!

Oh man, good catch!

I found some inexpensive breakers and went with that option.

Is it safe to put a shut off switch between the solar charge controller and the battery? I think I remember hearing that could damage the charger if it’s hooked up to panels with no output, but wanted to double check.

Ok, I finally got my specs: https://a1solarstore.com/var/attachments/product/17086/Phono_Solar_PS545M6H-24_TH_Data_Sheet.pdf (545 watt variant) Isc: 13.75A Voc: 45.45v So looks like I’m gonna wire them parallel into the 150/100… Would be nice if I could add a fourth and do two strings of two...

I’ll check back in with specs tomorrow

There’s no easy way to mount a fourth. Also, All panels would be flat and the roof is somewhat curved, so all three will never be incident to the sun.

Sorry, lasted the wrong line on the controller invoice. I went with a 150/100. I’ll get panel specs tomorrow when I go look at them. Supplier is being flakey and hasn’t gotten them to me yet. Can swap out the charge controller if needed, he’s got several others. Thanks, this is what I was...

Based on availability, roof real estate, and prices, I went with 3x residential 545 watt panels and a used/heavily discounted SmartSolar MPPT 150/100. If I’m wiring the panels up in series how should I go about sizing the wires?

Yeah, I couldn’t get the BMS to talk to the Cerbo. After some testing, it looks like the two disagree on SOC by quite a bit as well. I imagine the shunt is more accurate, but that’s just a guess…

Agreed. My plan is to place unistrut tracks down and hook into that with custom L-brackets. It's more labor, but the parts cost is pretty minimal. I'll keep an eye out for 200W panels. Isn't the 15A series max series Fuse rating going to be an issue? I think the 14 AWG wire is probably the...

Haha, I was a mechanical engineer in a former life... A tilt mechannism seems like a lot of hassel and cost when I have this much roof real estate. For the price of the actuator and aluminum, I could get double the panels and not have to spend the time designing/building. Thanks for the tips...

I’m in western Montana. I makes sense. I’ve got a decent amount of space to work with: 8’x23’ ish. Depends on the size I go with. I’ll keep looking for used or cheaper online. Thanks for the MPPT sizing info. If I find panels that don’t take up all my space, I’ll size it to handle extra...

I found a local supplier that has 330w residential panels for $318. I haven’t found anywhere selling for less online factoring in shipping costs. I’m be got a few more places to call, but thinking I’ll go with 3-4 of those unless I can find a better deal. Can anyone recommend any good reading...

Thanks @Rocketman. Good perspective. I'll work in there a few days off the battery this week and see how accurate my guesses were. Where did you find those prices? Interesting thought. Have you come accross any plans for this on the forum or elsewhere for inspiration? Thanks, also will check...

I’m in the process of cleaning up the wiring. Got a box for the battery and working on the heater circuit. Will post the final results here when complete. For anyone coming across this in the future, I started a new thread for the solar portion...

Hello! The weather is warming up here and there's no longer a foot of snow on my travel trailer, so I'm getting ready to install some solar panels. I already set up the energy storage and shore charging system. tl;dr: - 280 Ah 24V DIY battery - Multiplus inverter/charger - Some other victron...

Thanks, that makes sense

Hey thanks for the help everyone. I've got everything installed and wired up and just getting ready to do a full charge cycle test. Here are some pics (wiring still needs to be cleaned up) (It's -14F here, so the light is in the battery box to keep everything warm.) I have a quick question...

Tow vehicle via the aux power pin on the trailer 7-pin connector.

I'm disconnecting the house electrical system from the legacy battery, but leaving it installed because it's also used to run the cutaway brakes. (e.g. if the trailer falls off the ball while in motion, it pulls a wire that triggers the trailer brakes). From what i've read online, other owners...

The legacy DC 12V system has return wires on all circuits which go to a common 12VDC Neg Bus Bar with one exception: The legacy battery negative terminal is grounded directly to the chassis and uses the chassis to return from the 12VDC Neg Bus Bar. (As shown in that image with the floor plan)...

I don't think I'm following you, but here's what I think you mean? Not sure how the 12V returns to the battery if the 12V bus bar is isolated from the chassis. Wouldn't I also need to run a 6awg from the existing 12VDC bus bar to the lynx?

Ok, here's what I'm thinking then: 1. Attach the shore power ground in directly to the ground bar in the power distribution, which is the common ground for existing A/C and 12 V system (as it currently is, but run the hot and neutral to the new equipment). 2. Use Lynx negative bus bar as the...

Hello, I've finally got all my parts in and brought the trailer out of storage to get everything wired up. I took a look at the existing grounding setup in the trailer, and there are two places where electrical is grounded to the frame via a bolt: Given that my new battery and equipment is...

Nevermind, they got back to me and sent over instructions. In case anyone is interested down the road:

Hey, has anyone purchased this BMS? It did not ship with a manual and I've got radio silence from the shipper. If you could point me to an online version of the manual, I'd much appreciate it. Happy Holidays!

Wow, so upgraded to crimped terminals and a short run of 10g wire and we are current limited at 10A. Crazy. *current limited to 10A by my crappy PSU after upgrading the wiring. I'm trying to find a manual for my BMS, and then I'll set up a pre-charge in parallel. This is just a temporary setup...