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I recently “finished” the upgrade to my off grid cottage solar system (are we ever really done?). The previous system was 12V with 2 panels (250W? I can’t remember), 4 6V FLA batteries (2S2P) and a small 400W inverter. Most of the larger appliances (stove, water heater, fridge) and some lights...

I'm finally "done" my remote off grid set up and can officially join team blue: With very limited space to mount components, Victron gives you a ton of flexibility. One thing I sort of regret is not going with the 5K Multiplus, because I think I had enough room for it, even if I don't really...

I can agree with this. I went down the rabbit hole of compression research before deciding like Mattb4 that I'm just not going to bother with it for my DIY battery project. For my use case I don't think it is worth the trouble. I'm not charging and discharging my cells at high C rates. Maybe my...

You laugh but look at the number of posts in the Up in smoke section that are caused by bad connections!

I think this should be fine. The resistance of one of the bus bars that came with my LF304 cells is about 0.06 mohm measuring from hole to hole (67mm apart). From that you can calculate the voltage drop at say, 200 amps (V = I * R): 200 * 0.00006 = 0.012 volts. From that, measure power with P =...

Things are progressing nicely. My battery box design has been completed and is now being manufactured: I made it up to the cottage earlier this week to start mounting and wiring up the system. One of the challenges of upgrading this system is that there is an extremely limited amount of...

I also placed an order for 16 cells after seeing this post a few weeks back (big thanks to you, hwy17!). I paid $2016.16 with shipping to upstate NY. My cells shipped out on November 8th and were delivered on the 14th. I can save a lot on shipping and brokerage fees as a Canadian by shipping...

This is turning into my build thread ... Spring is coming so I finally decided to start to testing all of the equipment that I ordered in the late fall, before bringing it up to the cottage to do the real installation. Rather than use the SFK batteries, I've opted to build my own battery. I...

I've reached the milestone of completing the panel install. It's started to get cold here which made the installation quite difficult, but the installers that I hired were great and got it done. It took two days to complete, but I'm really happy with the result: Each side is 3S2P, where the...

This sounds somewhat similar to my cottage build in Quebec: https://diysolarforum.com/threads/off-grid-system-upgrade.71025/ In my case my cottage roof is facing east/west but is in a heavily treed area. I have a metal roof with a 12:12 pitch (45 degrees). I had originally wanted to use S5...

I'm building a DIY battery and bought an internal resistance tester on Ali Express to validate the resistance values on my cells. Aside from the battery, I'm assembling a bunch of the components for my install ahead of time, since my install location is nearly 2 hours away. While testing...

At one point I was so deluded that I thought I could mount 12 panels, mostly by myself, on a metal 12/12 pitch roof in November. Thankfully my wife was able to convince me of how much of a bad idea this was. I ended up hiring two experienced installers to do the job, who told me afterwards that...

I just wanted to follow up on this thread. I ended up installing the dish on my dock. I used the Starlink pipe adapter mount to attach the dish to the end of a 6' dock post, which I clamped to one of the existing posts using three U clamps. It seems sturdy enough, so far. There are still...

It's not exactly like thicker wire though. The two bus bars are not one solid conductor, there will be some small resistance between them. It's just like when you attach two lugs together on a post. In your picture you can see the bottom bus bar is making contact with the breaker and the top one...

If you're going from 6S to 3S2P you should probably double check the wire gauge running from your panels to make sure it can handle 2x the current.

Don't read too much into this. It can be increasing resistance, but it may not be significant assuming you're doing it right. For example, do you know why you want to properly torque your connections? Because if you have loose connections that increases the resistance between the connection...

@Skypower it was that picture of your BMS that inspired me to mount my BMS the way that I did! 🙏

I used two slightly different approaches (based on the lugs I had on hand at the time): on the B- side I crimped each wire to a lug, and on the P- side I put both wires into a 4 AWG lug. Both lugs are on a terminal post. I did have to buy longer bolts for the posts because the ones that came...

The case/rack, bus bars, fuses, cables, switches, terminals. Perhaps most importantly, your time. I enjoy doing this stuff, but if I take my "hourly rate" into account, I have a really, really expensive battery (and overall solar set up), and it's not even done yet!

I bought one of these fire suppression modules to put into my DIY battery box: https://a.aliexpress.com/_mKr0cX0. For now I just have it attached to the top of the inner wooden box, but I may mount it underneath the lid to be closer to the cells. I need to check if there's enough clearance...

I didn't notice that you are stacking two bus bars. I don't think that's necessary and may actually add more resistance. I would just use one. You won't be able to do that with a standard multimeter. I'm using a YR-1035+ battery resistance tester, which you can get on Ali Express for around 50...

My point is that everything has resistance. The reason you want to minimize the number of connections in your system is because every time you are connecting something together you are adding more resistance to the system. The reason you might use 2/0 gauge copper wire instead of 20 gauge copper...

I don't really know. I had only ever charged it at around 12 amps or so when I was testing the system at my house. At that level it did have a hum and the fan kicked in after awhile. But since setting up the system on site, I'm only charging using solar.

The thing to keep in mind with those Panduit wire ducts is that they are only rated to 50C for continuous use.

Designing and building my solar system has pretty much been my primary focus for the past 6 months. I don't feel like I'm ripping through anything lol. I've spent soooo much time going through these forums and learning from everyone here. All the stuff you're mentioning are things that I've also...

The same company has a similar circular extinguisher that looks similar to the model I have: https://www.awarefire.com/battery-fire-extinguisher/ One difference between the model I have and this one is that latter has two cables running from it, presumably one for thermal and the other for...

I’m using ones similar to what you linked, with heat shrink. I bought a pack with various sizes, but I think those Wirefy ones should be good.

https://m.vevor.com/electrical-enclosure-c_10749/vevor-electrical-steel-enclosure-box-nema-4-outdoor-enclosure-20-x-20-x-6-ul-p_010245929118 The only thing I did was swap the door orientation. It’s a really great enclosure for a very reasonable price.

I had cropped the class T fuse out of my original picture. Here's a larger view of my inner battery box that includes it: My fuse is connected directly to the positive cell terminal. This inner wooden box is going inside of an insulated custom fabricated metal enclosure (which is shipping out...

Did your LF304s come with two separators in each box? I’m not sure exactly what material it is, but I assumed it would be used between cells.

I'm also using Starlink at my remote off-grid cottage. There's really no other option for me, as cell signal is really bad at the location. I have a summary of my set up here: https://diysolarforum.com/threads/grounding-and-starlink.83387/post-1101508. For data usage, according to my Unifi...

IMO I'd keep both. If your phone is faster and safer to do the disconnect that's great. But also good to have the manual back up just in case.

You can get view access for CSA C22.1:21 here: https://www.csagroup.org/store/product/CSA%20C22.1%3A21/ if you are in Canada and register. It's not ideal because you can't search, but you do at least have access to the entire document for free.

I don't think it matters -- unless your negative is grounded: https://electronics.stackexchange.com/questions/445740/does-it-matter-if-a-fuse-is-connected-to-the-negative-or-positive-terminal-of-a

Another update! A week or so ago, I decided to temporarily assemble my battery at the cottage while I wait for my battery box to be built. This allowed me to complete pretty much all of the DC wiring and get the system up and running. I will probably create another post for my DIY battery once...

The only loads in the winter will be Starlink, network router and PoE cameras. I think around 60-70W max. And actually there's 30w of heating in the battery box too which will be active in the winter. It will be interesting to see how it goes!

A bunch of my equipment has been arriving over the past few weeks and it's both exciting but also frustrating because I'm not able to actually install anything until the spring (which feels like forever). I picked up a BEP battery switch and added a pre-charge resistor to it. I really like the...

FYI I am doing this @AlaskanNoob. I'm using this POE injector: https://www.amazon.com/dp/B0CQC4321X. I have it hooked up directly to my 48V bus bar through a 4A DC breaker. My battery is set to absorb to 55.2V, which is below the POE maximum of 57V. It's been running for a couple weeks like this...

I've built my own DIY battery pack and it's been functioning beautifully over the past few months. 16 cells generally all within 0.01v. However, the battery is in an off-grid remote location nearly 2 hours away and if something goes wrong I'd like to know ASAP. I do have monitoring with VRM and...

PKYS has a variety of Bluesea of class T fuses in stock: https://shop.pkys.com/Class-T-Fuses_c_113.html

It is a custom-built metal enclosure made out of 12 gauge stainless steel, with 3" of rockwool insulation on all sides. It's a beast. I'm planning on doing a write-up on it, I just haven't done it yet. There are a couple of details here...

This is what I'm after, really. What (if any) indicators are there that something is wrong so that the cause can be addressed before the pack explodes and burns my cottage down. This makes a lot of sense! I suppose the same sort of thing would happen if you built a battery with different sized...

I used zip tie mounts that are screwed into the top of the plywood box lid, like these: https://www.amazon.com/dp/B078P8TPPZ. It's nice because it provides a bit of clearance under the BMS. I used these terminal posts: https://www.amazon.com/dp/B0B2LK7KDR, but like I said the bolts were too...

This thread startled me, as I'm using similar connectors on my DIY battery box: https://a.aliexpress.com/_mrxL1bW. I'm using the 200A version with 1/0 wire. I don't believe they're the same connectors though, as mine don't require a crimp. With mine you insert the wire into the connector plug...

Was there any surge protection in front of it? Directly to the south of the tree is a lake -- the land slopes up to the north (the direction that the dish is pointing). There are plenty of trees surrounding it that are taller, but not tall and close enough where I believe they're obstruct the...

I realized when I woke up this morning that having so many resistors close to the NTE-DTO60 in the small case enclosure that they would generate enough heat to prematurely open the switch. As an alternative, I used a single 47k resistor. This should only need to dissipate 0.06W of power (and...

I'm curious about this as well. I just wired up my system and I'm not using fine stranded wire like they recommend. This sounds a bit dramatic to me? I feel like it depends on a few different variables. In my case I have a 48v system with a 150/45 SCC where my PV connection is using 8 gauge...

Is it so significant that it's causing a problem? Could you improve the resistance with better crimps/lugs on the switch terminals? As a software developer, I would definitely not get rid of the manual switch. In an emergency I want the simplest path possible to fix the problem, and using...

You could try @42OhmsPA ’s trick: https://diysolarforum.com/threads/how-to-connect-the-black-style-jk-bms-with-the-short-b-and-p-leads.82942/post-1076500

I used a wire nut in my combiner box for one of my arrays to splice 10 (from panels), 8 (to inside) and 14 (SPD) gauge wires together: I'm pretty particular about things as well, but what sold me on using a wire nut versus other methods was watching this Youtube video on splicing larger gauge...