Victron Batteries, Lynx Smart BMS, Distributor, Cerbo GX, and connecting a Multiplus II 

Thanks! I too am a visual/hands on learner.

Glad to hear, thanks, and enjoy your project!

I put my MPII where it is b/c it was my first and largest component I installed into the system. I don't see why it would matter what slot you use on the LynxD.

Hi. The battery to battery cable is 4/0 (4 ought). At that short length there is virtually no flex at all in the wire. My batteries are also locked down and do not move in any direction.

Exactly my point…”there is no flex at all in the wire”, therefore the cable and terminal lugs are constantly under stress with each other and will vibrate loose over time, UNLESS your batteries are 100% rigidly fixed to one another. I’m not confident this can ever be the case in a mobile scenario. A slight bend will relieve this inherent stress. You’re fine in an off grid fixed setup…but not in a mobile application.

While a well put together system should not have this problem in general, yes, a van is a moving earthquake, and therefore ANY person having a house system in their van should have a regularly scheduled interval to check on all wiring and bolts to ensure healthy, tight, clean connections.

Thanks!

You're welcome! Make sure to check out the MPII ground correction so that is not undersized.

Thank you!

You are referring to section 5.4.8 here www.victronenergy.com/upload/documents/Lynx_Smart_BMS/109358-Lynx_Smart_BMS-pdf-en.pdf which is perfectly fine. I didn't feel like cutting the ring terminals off, lazy I guess, haha! The MPII case ground is on the neg bus middle post of the Lynx Distributor. It is not one of the 4 fused posts on that bus.

Mine came from Amazon or were included in kits from Explorist.Life. None of them had any plastic on them; they were all copper only.

It is also my understanding 10/3 would be good for a 30A shore power connection. Due to my issue with the ferrule, I went larger to get things going and feel more confident when pushing the wires into the slots. I'd really prefer screw terminals. I may go back to the 10/3 from the back of the SmartPlug from shore power to the MP-II AC in for my final install in the van. The more you practice using the tiny screwdriver to open up what "should be a push in terminal" the more easily you can insert your wires. Not a great design by an industry leader in my opinion. Good observation, yes, I should have said the 6AWG ground cable is temporary. 4/0 will not fit in this location which is the size of the main DC power feeding cables. ABYC recommends the case ground be no smaller than 1x size down from the main current carrying conductor. I have some 2/0 on the way and hope it fits without fuss. 4/0 on a lug will not fit here straight in via the provided chassis hole of the MP-II. It would with a right angle lug through the larger pill sized hole, but if you have all 4 DC inputs used, then I don't think there would be a place for the ground wire to fit through that pill hole. I will highlight the chassis ground wire in a future video when I talk about AC in and AC out to a 120V panel. Thanks for the compliment. I'm learning as I go and sharing what I can. Make sure you verify your wiring diagram with your Victron dealer and/or an electrical engineer. I am still having some back and forth discussion with my dealer on a couple very explicit details in my wiring plan.

The chassis ground is noted in the video description :)

Gotcha, thank you for the reply! I've got a MP 12/3000/120 unit, which should accomodate a 4/0 lug for the ground, but that's good to know about the MPII and also the one-size-down rule of thumb. Those green connectors aren't exclusive to Victron, I've recently learned. "Phoenix connectors" seem to be the usual name. I figured this out when I discovered I misplaced the little green plug that came with my Orion... :/

Ah, yes, I think the MP (not the MP-II) has a much more easily accessible chassis ground stud location.

Chassis ground should be one AWG size smaller than the feed wires. So in this case, 3/0 wire would be necessary for the chassis ground. Personally, I use the same 4/0 for chassis ground.

Fair question, a couple reasons. When I had the funds available to make the purchase, supply/demand was still a bit of an issue and prices were pretty close. And, while I haven't shown this in a video yet (it is discussed briefly in comments), I can wire it to use the Power Assist feature. I may be limiting myself to 30A shore power, but I can go up to 50A 120V AC main breaker before my AC panel and draw power from shore and batteries if I'm baking a cake, cooking dinner (induction), and remotely working at the same time (non 12V monitor). That's a bit out there as an example of load but I think that gets the point out clearly at about the max of a 3000VA inverter. Form factor played another role in the choice. Some MP units are fat. Also, given I am going 100% electric, I wanted power without question.

Here is my philosophy (and my Victron Dealer OK'd my spec): 300A (red on/off) allows up to 3600W at 12V. The inverter should only be running at max 3000W (and my DC loads are otherwise quite low except the 12V AC at 80A max). Now plug in shore power, with Victron Power Assist, I get power from shore (15-30A), and draw power from the batteries if more amps are needed, so I allow more, the 400A fuse, to the MPII as spec'd. As expensive as these batteries are, I'd like to protect them and not risk them being the breaking point of my system. I'm not saying I'm 100% right, but hope that helps you. Thanks.

My video is based on running a 12V system. Wire size requirements will be different if you are running 48V. If you want to ensure you are on the right path, please engage your Victron dealer or a certified electrician.

Hi. In short, bus bars and locations for fuses. Best source is the vendor website: www.victronenergy.com/dc-distribution-systems/lynx-distributor

On which device in which part of the video? There are several places where 4/0 is used (120mm2 seems to be the correct conversion).

@@VanTransitions Multiplus 2 to Battery or Smartshunt

MPII is connected to the Lynx Distributor by 4/0 then via that bus system through the Lynx BMS 500 to the batteries, also using 4/0.

@@VanTransitions so its a 120 mm2 cable the 4/0 ?

All the googling I do, the conversion charts say 4/0 and 120mm2 are the correct conversion cable size.

Hi. Check out the Victron Energy Lynx Distributor manual. There are use cases for either side of the Lynx Smart BMS 500 which has a shunt in it, which is my use case. If you are not using the BMS 500, design the system per your use case needs, but based on that documentation, I'd say there are use cases for either side of the shunt.

I personally understand that as being 4/0 for system chassis ground. I cannot fit 4/0 lugs into the hole for the MPII chassis ground, let us know if you can. Make sure there is a distinction between the MPII chassis and system chassis grounding. Please check with your Victron Dealer and/or electrical engineer before applying anything you see here to your system.

Hi, can you be more specific? You have 2 MP-II inverters or a single with dual 120V AC? And what exactly are you looking for? If I have an example I'll point you to it. I will also say I am not an EE and I do not have extra equipment on hand. I have several videos which may help get you started related to how I plan to wire my Victron equipment in my van. Also, if you purchased your Victron equipment from a dealer, they should be more than willing to give you some pointers if they are a good dealer.

@@VanTransitions I am speaking g of using two (2) Victron inveters.

I would start here and also contact your Victron distributor: www.victronenergy.com/live/ve.bus:manual_parallel_and_three_phase_systems

@VanTransitions Thank you. I will start there. Loving the videos.

I am not familiar with Skylla.

@@VanTransitions Hello, thank you.

Battery to battery, batteries to Lynx, and Lynx to MPII are 4/0.

I have not had issues. How is your MP-II configured? Is Power Assist required to run your load? How much load do you have running when you disconnect from shore power? There is a Victron Energy (English only) group on Facebook you could try or contact your Victron dealer. Hope that helps.

@@VanTransitions only disconnected when getting ready to move to the next camp site. So, the only loads remaining should be refrigerator and some 12vdc items. I would like to have faith in it picking up the load if power goes out but, not so confident. I turned off the MP2, didn’t change the load and replaced the fuse, started and ran fine. 🤷‍♂️

I am definitely not a fan of those push in connections. The spring does feel quite snug, but a camper van is effectively a moving earthquake. And they have places inside the unit to clamp down on the end of your wire, so it should not walk out. No 4/0 cables in those push in spots on the MP-II. 10AWG from my 30A shore power and 6AWG if I change from 30A 120V panel to 50A 120V panel are the 2 wire sizes I'll have in the push in spots.

So, are these a fairly new connector type innovation by Victron? I thought they were all a screw in type. Being an Aussie on 240vac, i wonder if they send us screw in type connections that Victron specify not to use ferrules, but fine copper wire secured properly to spec. I believe this is another source of failure, when people buy CCA (copper coated aluminium) wire, not knowing it can have this type of issues of dissimilar metals with different thermal properties down the track & not being able to supply enough current under heavier loads efficiently. Sounds like a scary experience you had there, but I guess if it had the required safeguards in place, in reality such a short should theoretically pop a fuse, a breaker, or the BMS should be set to shut down (if one is attached) if the current draw is excessive, but there could still be a lot of arcing & fire potential before this happens, regardless. I have been considering a 5kw Multiplus II recently, so I may have to look further into this, thanks for this info. Cheers

I am not sure when Victron started using the push in style. As mentioned I find them to be a bit of a pain. I also use full stranded copper, and marine wire where I can, such as Ancor brand. I would personally not use aluminum. I'm not a EE but I believe it can get hotter and vibrate into a short in a poorly done installation; and a van is a moving earthquake (my use case).

The pos, neg, and ground wires for AC1 input are all stripped precisely to the specifications by Victron. There is no need (and no room) for a loop inside the MPII due to the clamp on the full insulated wire, therefore no stress on the wires between that clamp and the push in terminals.

thanks!

I suppose that's one opinion.

Hi Manny. This is a table top demonstration of the power system for a camper van build. I will have 600W of solar on the van roof via 2 Victron 100/30 MPPT (check the next video in this series!). I should have a video out soon about how I designed my roof layout.

@@VanTransitions ohhhh ok thanks

Should be these: a.co/d/fz5aMEL Do you have a large crimp tool for this size wire? I used this a.co/d/4Tv7ECW and show crimping here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-FFjZyVfdvjQ.html All the best and thanks for watching.