New Solar battery isolators - Are they any good? 

I have been enjoying the “Warts and all” presentation approach of your videos. I think I learn more from the mistakes than from when things go together easily. Please continue to show the good, the bad, and the ugly! I have binge watched (!!) your playlists more than once, and I hope you create additional playlists for the solar panel install series and the wiring the system series. Between this channel and the off grid garage, I have all the solar infotainment I need . Thanks! Keep making fantastic videos.

I really like you sharing your install. it good inspiration how to do it. Just a few tips as I work as elektrical safety inspector in the netherlands. (rules in UK are bit different). 1) I like what you are doing with the DC breakers however because of the extreme high amount of short circuit current Lithium batteries can generate when shorting due to very low internal resistance it's very possible the Uimp rating of the breaker is to low and so it could just blow and weld together so power is not cut. I always recommend to install fuses since they have way higher breaking capacity. for Lithium batteries Class-T fuses are the best. Victron has a new version of the lynx distributor on the market where you can fit Class-T fuses, I replaced my old distributors with the class-T variant. You can use the breaker as double pole isolator switches but don't rely on them for handling shorts. 2) when operating these breakers with high amp loads you should have the live parts covered or use PPE when operating, it can certainly go wrong so maybe you find a way to install the breakers in an enclosure. Maybe they fit on Dinrail? 3) it might be advisable to make a shutdown procedure and have it on the wall for anyone to know what to do in an emergency. 4) i don't know if you have access to a good quality IR camera, but when you are finished it might be not a bad idea to do some thermographic inspection on the connections when under full load to make sure you don't see hotspots. Do enjoy this lovely set-up I just wanted to share some tips from my experience in practice.

Based on some of the previous comments, a possible upgrade could be to keep your new isolators, but replace the lynx power in with the new lynx class t power in (m10). You would need to widen the m8 holes in the lynx shunt to connect to the new power in. You could then add two 200 amp class-T fuses in the new power in. This would protect the system from a discharge rate above 0.6C from each battery. Your 70mm2 cable is rated at about 192 amps, so it should survive.

Yes, the real problem with most smaller isolator switches is that they have terrible I.R. (interrupt rating) specifications, which makes them a fire hazard. They generally cannot be operated under any load at all. And the cheap ones aren't spring-loaded which means that you get excessive carbon build-up inside and eventually that causes a fire. I don't know re: the breaker you got. What was the brand / manufacturer? The only commercial DC breaker that I have real confidence in would be "NOARK". And is it non-polarized? Main battery breakers have to be NON-polarized, 2-pole breakers with an interrupt rating of at least 10x the amp-hours of main battery you have. So e.g. 600Ah needs breakers with at least a 6kA interrupt rating. Once you add a third (or more) battery to your bank, you also need to consider adding a T-Class fuse if you don't already have one (200kA+ I.R. specification). Good luck! System looks great! Glad you removed those manual disconnects (but not sure about the breaker you got). -Matt

Those MCCBs have a 24VDC shunt trip available for them too. With some circuitry and/or a microcontroller or similar you can use the trip to disconnect the batteries on what ever condition you like, say a smoke alarm in the equipment room sounds. A similar thing can be done for the PV input to the room to disconnect PV automatically when things go wrong. Add in a big red emergency stop button and you can knock the whole kit out in one fell swoop.

looks like a first rate choice there,well done :) :) Edit big up to you giving praise to the "marxman" because you like it :)

You could cut some plexiglass to make terminal covers. I like to be able to see the connections. You are quite handy, Beautiful setup you have there👍👍

Nice video as always. I have only few remarks or suggestions or observations : 1. I would suggest - in case there are no flying things above your Victron Inverter to remove top cover on it. It is held by 4 small screws and it will improve lifetime of your inverter during summer time. During winter you can put it back it isn't big deal at that time of the year. This cover restricts airflow a lot and removal of it will improve to increase life time of your Victron Inverter. 2. I did has similar problem as you mentioned and when i was doing 600Ah battery pack i wanted to have some good isolator but if you check it officially there is almost none available for 500-1000 Amps and 50-70V. So i went with similar solution but this one was not isolator as such but it is actually 3x 160Amp fuse isolator... what it does it allows to remove 3 (and you can use AC or DC high current fuses ) fuses same time by pulling plastic handle ..i know it isn't so nice solution but as i said there isn't one as i know that has good price.

A person like you really should have a 3D printer. You'll be astonished at how many 3D printer projects come out of the woodwork once you have a 3D printer. I'd avoid cheap 3D printers when first starting out.

Its amazing the amount of stuff you find out that isnt quite right after the installation, and that you need to or ought to change !! How are you going to test them though ??

Great video Sarah from my limited research it seems the true marine brands of rotary switch are up to scratch but as they cost the same as the ones you are now using good choice .

3D Printing Project would great skill to learn, I am sure u would enjoy since u have a potential project. I plan on learning too but I dont have a project to apply it to yet which would motivate me to learn.

Don't want to nit pick only that on a battery terminal are Positive and Negative (DC) rather than Live Neutral, (AC), also the BMS turns off the Negative Terminal so having just a Positive isolator would be sufficient with the battery turned off. a full 2 pole isolator is a great idea none the less belt and braces. Loving your content and following along with your journey.

It's good to see how your project is progressing. You'd want to make sure that the DC battery breaker is rated to function with the current flowing in both directions. For solar systems, current from the battery will flow in one direction when charging and another direction when discharging. This is a critical detail that needs to be taken into account when selecting a battery breaker.

Hi Sarah, Nice switches, I know what you mean about the 48v-rated switches/breakers being out of spec, I shall be looking into these myself, good find 😀 That's a neat job you did there. As for the covers, you could make one out of wood that will also cover the access hole, which would neaten up that area, just held in place with a couple of screws for easy access if required.

You batteries answer the question which side is live = right. Another thought, you will need to be careful when paralleling the 2 or 3 batteries first time so you don't get massive currents exchanged between batteries. Great channel - subbed. You may be able to get design files for the 3d printing from thingy-verse or similar.

Good video Sarah, I was hoping you would of opened up one of those switches to see inside, because that is what makes these switches interesting to see the specifically designed DC cut/off approach. Inside there should be a series of metal plates, which allows the DC current to dissipate when under load, which the other cut off switches cannot do. As for a cover I would go with a angled plastic extrusion and Velcro it onto the switch body for easy access. Just trim and cut to suit for cable entry.

Sarah (sp?), instead of many openings into your battery on-off switches, you might consider a single box that covers all the switches and cable entry/exits. Vastly simplifies your effort and facilitates shorter build times. Re 3D printing: I have 8 printers in my stable of various sizes and capabilities (including two that I haven't even started building yet :) ). One can get very creative with your resultant product in not necessarily be tied to a wooden box look. And, of course, with "wood" filament, you can also make a box! :) You can also add the in/out plenum's for the cabling if you choose to. BEWARE: 3D printing is EXTREMELY addictive! That's because it is a ton-o-fun. :) With the new printers, the learning curve is much shorter than it used to be. There is great depth if one chooses to dive into it but you don't have to. There are many varieties of printers. Which to choose as your first? I recommend the Sunlu S8 as your first. About $200US when on sale (and it's always on sale :) or the S8 Pro for a few dollars more. If you get the basic S8, your very first improvements are A) Winsinn all-metal extruder (about $20), and B) one meter kit of the blue tube that comes with fitting upgrades, about $30. Those two items are necessary to make the printer last more than a few months and you will be buying them later anyway. Even if you decide on a $3500 printer later, the S8 will allow you to learn the basics and you may decided you don't even like 3D printing. Oh, the S8 has a 300mmx300mmx300mm build volume and you going to need as least that much just for the solar project stuff. It's a good idea to get a Raspberry Pi (minimum V3) to help make your printer management significantly easier, and will be used regardless of which printer you wind up with. For design software, if you're a math-head/engineering type, (free) OpenSCAD is very handy. For most of your model design work, there are several good choices of software, all free. There are some paid ones as well but they don't give you the flexibility of the free ones. HTH, and let us know what you decide.

Check out Victron recommendation not to disconnect the negative cable, especially in systems with communication cables

I have such a braker with 630A rating. They also have a electromagnetic coil to trip it from my BMS

Side note: Instead of the EEL boxes, check out the Keshee ones. Almost completely finished with the BMS and goodies already installed. I have two of them and are the ones chosen after looking over what's available. Even chose them over building my own out of wood and is cheaper. About $560 shipped to the US so probably cheaper to France. One thing I REALLY would like is a place to mount the wheels with the option of vertical or horizontal placement (or both.)

For ring terminals, Klauke is a very good brand, looks like the bell shaped ones are from them. The only thing is, they do not recommend to use hexagon shaped crimps for flexible cable.

Those MCB's should have a rubber separator that goes between positive and negative terminals, at least mine came with separators for the up and down side, and it looks like yours have the same groove to slide it in.

You can always turn off the battery on the battery BMS, then turn off the switch.

Well hello from Egypt again. Maybe some isolation tape right across the holes of the terminals. You will want to have easy access to these terminals. So all you will have to do is peal off the tape.

I have a 25V battery system limited to 800 watts, about 33A. I use 50A DIN rail MCB, double pole. If a short circuit occurs, the LiFePo can deliver over 100A. But I have already replaced MCB after switching off. If I want to isolate then I first turn off the inverter on the 230V AC side, that's only 3.5 amps at 800W. For solar installations over 800W you need an electrician in Germany and it gets very bureaucratic. Up to 800W, you only need to report that the solar system has been put into operation and complies with the standards.

There are plastic terminal covers for siemens, schneider molded case circuit breakers we are using already. There may be the one for yours also.

With respect, you need to understand the dead short breaking capability rating in kA. I think those are 20kA, so a reasonable choice. I would not trust a cheap Chinese BMS, or any BMS for that matter, to break the short CCT current from a beafy lithium battery. So, IMHO, what you are doing in replacing the crappy switches is the correct approach, but for more than just voltage rating, you are protecting against losing everything in a fire and then finding out that your insurance won't cover your loss because of a DIY mistake. They probably won't anyway because I don't think they are UL listed, but the risk is greatly reduced.

I suppose there is some sort of terminal covers for such type of breaker (i.e. plastic cover to seal terminals away of unauthorized access)

Link to knipex cutters ?

i have used these DC breakers and they are rubbish.If you looked inside you would cry.The ones i had the switch froze one day and never worked again.I have now got the round ones you showed and switch the live first then the negative to switch off.When turning on negative first then live.I used a sharpie pen to color the knob black

Your said "it's only DC" when taking about being able to touch the terminals on the breakers Well you do know that DC is more of a killer than AC don't you ?

This is a great option, except… If you have a battery array in a rack cabinet, and each battery can provide 100Amps, there is a total of 600Amps. Do you know of any breakers like these that can switch up to or over 600 Amps? thank you

Hello, Be careful with these isolators, they are directional (there is an arrow). I have connected the battery on the top and the hybrid inverter on the bottom, as it is they main risk (unlimited current from the battery), protection from current flowing the other way is less important as it will be limited by the electronic components. If you have separate charger/inverter devices, you should use 2 isolators, one for each direction of current (and connected together on the battery terminals). It has to do with the way there are dealing with arcs.

Do you precharge your( or do you battery have a precharge resistor) inverter so there is not a huge inrush into the capacitors? It is my understanding that an inrush is not good.

Fyi - the link to the breaker does not work

How do you know what size breaker to get for your system? 🖖

those breakers might get hot and even degrade from the inside .. i use one for only 50 amps max at 52+ volts ... but from the first day i am thinking to change em for bigger at least 3 or 4 times bigger even if i wont break the circuit quiet often. if there is somewhere a voltage drop due to failure those beautifull blue boxes might get hurt and it will be too bad

hi can you share a link to your cable cutters

It is just 20usd here in philippines

You could also hook all your batteries into a chunky victron or other busbar and then run a single cable from that to the breaker and then to the victron busbar. Your batteries already have breakers, your using this breaker as a switch I dont think the current you could pull out of those existing batteries would exceed the breaker but do the calculations before you take my word.

Just put some acrylic on studs over it.

No safety glasses when using a saw??

Knipex is pronounced nipex. 👍