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You might be right about this. I'm an optimizer, and the idea of the batteries being at 100% by 10am worries me a bit, but maybe I'm being too much of a perfectionist. Or maybe I just need to find the "right" charge voltage! That will be an experimental process though.

I appreciate your input, but I don't agree. You say I'm "getting away with my design" and that Q-Dog mentioned my design was wrong. Yet I cited sections of both the Victron Cerbo manual and the REC BMS manual that indicate my architecture is just fine. Nobody has mentioned a concrete reason, nor...

I don't think I'm going to go in that direction. I really like how my system degrades gracefully if the network goes down, but if the network is up I have centralized logic. The problem is that I gave it a poor parameter for when I'm away. I think I'm on the right track to giving it a better...

This was a great link, just what I was looking for. As for why 3.25v wasn’t cutting it, I speculate that there was a cloudy week then the BMS cut the battery off, so it could never recover. I think I’ll do a little testing while I’m on board, maybe try 3.32v to start.

I respectfully disagree with that. I believe it is appropriate for an external BMS to be the "authority" on what charge/discharge treatment the batteries should experience. The REC Active BMS has a specific feature that allows it to communicate and control a Victron GX system. I don't think REC...

I live 8 months a year on a 50' sailboat with 1800w of solar, and a 13.5 kWh bank I made from bare cells. My BMS is an REC Active BMS controlling the whole charge system via a Victron Cerbo GX. It is performing absolutely fantastically when I live aboard. The problem is my "layup settings"...

I've had a few people direct message me about getting this file. Here you go! Fusion 360 Project (so you can modify yourself): https://a360.co/3JjapBQ STL, STEP, and 3MF files in attached zip.

That first picture (Clamp) is the kind of thing I'd probably make a lot of.. And then it would live its life in the sun.. ASA is very UV resistant, and will hold up fine outside.

You can do all those things projects with a 3d printer. There are all kinds of filaments with different properties available. I live on my boat, so I have a Prusa Mini which is very compact, yet still has a decent 180x180x180mm print area. I use it all the time for mechanical and outdoor parts...

Thank you for that. I'm aware of this approach, and went so far as to buy the components, but I realized that with my install, I don't expect to the BMS to routinely actuate the ML-RBS. In fact, since opening the ML-RBS is a last-resort action for my BMS if everything else goes wrong, my hope is...

I even think the the REC could turn the RBS on (close it ) too. It is true that the RBS specifies a pulse, and the REC provides an always-on signal, so seemingly incompatible. However, I called Blue Sea, and spoke to a guy who seem to know his stuff, and he told me that while they haven’t...

I have the “Main normally closed” (REC terminology) BMS relay output hooked up to the open(disconnect) signal wire on the ML-RBS. The normally closed relay is open when the BMS is happy. When the BMS detects a fault, or is turned off, it closes the normally closed relay, which opens the...

I forgot to update my own thread on my progress! I ended up making wire interconnects. I used AWG 4 (ampacity 160a) for the parallel connections, and AWG 1/0 x 2 for the serial connections. Each 1/0 cable has an ampacity of 285a, so total of 570a for serial connections. I'm happy that they have...

Just thought I'd share my implementation of a spring based fixture. I have separated each cell with a thin sheet of silicone. I like that material because it is heat resistant, provides some chafe protection, electrical insulation, and it "clings" to the cells with no adhesive, so it is easy to...

I’m not familiar with that particular inverter. However, many inverters (for example my victron multiplus) have the ability to “trickle charge a small starter battery”. What I have not seen yet is one that can charge with a different charge profile and voltage to the secondary battery bank...

Just finished with my upgrade. Went from 4 tired AGM 160ah batt to 1120 ah of EVE cells in a spring-compressed fixture. Battery: 16X EVE (amy) 280ah cells, separated by thin silcone sheets, fixtured with with hydro-cut aluminum end plates, threaded rod, and springs. BMS: REC Active BMS...

Thought someone might be interested... I installed a GX touch (cerbo) in my boat. I really like the system, but the viewing angle of the display is poor, and touching the screen was awkward with where I had it mounted. It looks washed out when looking from slightly above. I designed and 3d...

Personally I’d return it and order from a reputable company like PKYS. They shipped my Victron stuff well packaged, and they are specialists and can really help with technical questions about the equipment and configuration, unlike Amazon.

That’s the missing piece for me. I didn’t catch that you are going 4S2P, rather than 2P4S. If you don’t want to parallel cells, you do need multiple BMSs, and I guess I wouldn’t recommend a centralized REC style BMS to you. I fall into the opposite camp. I think the pros of a 4P4S outweigh the...

Someone is definitely missing something, not sure if it is you or me. You keeps saying you only have one house bank, but you keep talking about two BMSs, two Shunts, two of everything. You don't need all that stuff if you only have one house bank. I have one REC BMS, 1 contactor, one CANbus...

I just finished my Victron heavy install this week. Lots of overlap with your system. A few thoughts: As others have said, just one shunt for your main house bank. If you haven’t already bought the balmar regulator, have a look at the Nordkyn VRC-200. All it needs is an alternator with remote...

I think I may have answered my own question. Capacitors leak during charging. This leakage goes to almost nothing when they are full. So the capacitor is leaking during the whole charging phase, then once full it stops leaking and the pulse is over. Maybe?

I’m having a hard time understanding this passive circuit. Why does the capacitor cause a pulse of power to the Blue Sea orange wire? I would have thought the capacitor would absorb all power bleeding through the resistor as it charged up. But in this circuit, what causes the capacitor to...

Thought you might be interested to see how my actual build turned out compared to my 3-D model posted up thread.

I did a fair amount of BMS research and ended up with an REC active BMS. But I did not run across your BMS, and had never heard of it. It looks quite interesting.

Currently driving to Mexico (where the boat is) with a suv packed with stuff for this conversion! I tried to anticipate everything I’d need, wires, lugs, tools, heat shrink, devices, etc, because getting things in Mexico is much more difficult. Why so big? Well, we cruise full time, and want a...

I read lots of this thread, but not all, so forgive me if I'm retreading old ground. I just bought springs (9-1010-26 5/8 X 2-1/2 RED DANLY DIE SPRING) from suprdie.com for cheap! According to their data sheet (https://www.daytonlamina.com/pdf/DS117_DieMax_XL_Springs.pdf) these have a length...

These look nice, but how flexible can they really be?

My boat's name is Sauvage, if you see us, say hello. I'm committed a flexible link because I'm worried about stress on the delicate terminals (more so than your more robust Calb) as they contract and expand through charge/discharge cycles. You can see a lot more on this topic on my other...

@Hedges thanks for the informative post.

Sounds great! We went Hawaii—>Seattle—>Mexico last year and this, i and plan to continue on this fall, aiming to go “the wrong way” to Europe by 2023. Can you elaborate? And link to resources/discussions? I’ve seen so many people’s packs with multiple connections. Multiple links allows me to...

Interesting, thanks. I wonder if fuse blocks are available for this thing. I’m probably going to stick with class T, because they are available everywhere, and I’ve never seen nor heard of this ACK fuse.

I appreciate your perspective, but I've decided that flexible connections are a better solution for me than solid bus-bars, as discussed thoroughly in this thread: https://diysolarforum.com/threads/cell-terminal-strain-relief-bus-bars-and-compression.27439 Very glad to hear your 3P4S pack is...

I appreciate the suggestions, even if I don't do them, because it makes me think through why I'm doing what I'm doing more carefully, and it often leads to changes in my design. I thought about 4P4S vs 4S4P pretty carefully, and there are a bunch of reasons 4P4S will work better for me, using a...

I appreciate the simplicity argument. But there are a few advantages to this approach. Two requirements I have that others may not are I've decided to use wire instead of solid bus-bars, (see this thread if you want a discussion of why). Also, I'm designing this battery for a 400 amp load...