24v New System Build for Van Conversion

DIY
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Hi, I’ve just joined this forum and I’m pretty green to this stuff but have decided to build by own 24v system rather than buying an off the shelf setup. In at the deep end!!!
I’m trawling through you tube, google, here and basically anywhere i can find info. Its confusing to say the least, with component upgrades and comm connection protocols, its impossible to understand.

So hopefully some of you would be kind enough to pass on some of your knowledge and save me the inevitable cock up/expense of getting the wrong components. Even though that might be a tad late.

Obviously for a van conversion, it’ll need shore hook up, solar, battery storage and B2B of some description. I should perhaps say i’m converting a 2025 LWB VW Crafter, so have a reasonable amount of space to play with.

I’ve opted for a 24V system, because i believe its the half way option between struggling on 12v and going completely overboard with 48v, but really because i intend to run a split aircon system and fridge freezer that are both 24V. I did appreciate the complexity of 12 to 24 & back, but perhaps not the cost of that!!

So far I’ve spent a kings ransom on the more expensive components which are:

Multiplus-II GX 24/3000/70

Titan Lithium 24v 230ah batteries (x 2)

SmartSolar MPPT 100/50

Lynx Distributor (M10)

Smart Shunt 500A, perhaps should have been 300A

I was intending to use:

DMEGC 500W solar panels (x4)

Stirling B2B BB1224120 bi-directional charger (Victron do not seem to produce an equivalent, but either option is £$£$£$£$£, not sure of other options ‘Scotty comes to mind’. Might end up running a 12v alternator and a 24v one??)

The problematic parts seem to be comms between devices and how you can/should connect them to talk!! I haven’t even looked at the Stirling B2B yet but have seen it used with Victron Systems on You Tube, so know its possible. Being Bi-Directional seems to be a bonus.

So I’ve looked at:

Raspberry Pi 5 with 10.1” monitor and UART/USB cables, Bluetooth connections and WiFi.

Question;

What i thought would be a straight forward process of connecting all these victron parts together and monitoring them on the APP or VRM, seems to be screwed up by picking the Multiplus-II GX over the Multiplus-II and a Cerbo with display.
Conflicting info on connecting a Cerbo to MP-II GX (as in only one GX device can be used?!), or using bluetooth, wifi or an array of DIY/Hacked components.
So anyway now I’m committed to the MP-II GX, how on earth do I get the system to talk? I assume the inbuilt BMS in the Titan batteries will connect to the MP-II GX (internal port on GX card or external port)? The Titan batteries do have an ethernet cable which daisy chains through the paralleled batteries to the MP-II GX even though they have built-in bluetooth, both Victron and Titan say these are compatible.

So I’ve gone on enough! Any suggestions on components and options to connect them all up to monitor/talk would be greatly appreciated. Maybe this will also be helpful to others.

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Start with reading https://www.victronenergy.com/blog/2019/09/03/wiring-unlimited/
and there is another energy unlimited which may also be of use.
see Battery Compatibility [Victron Energy] about which battery BMS types talk to Victron, others may also, but have not been Victron approved.Yours do not appear to be on this list. The Titan battery has only Bluetooth coms, so won’t easily integrate with the Victron system.
Apart from that, you should have no problems with the coms. Selecting 24V and the 500A shunt is good. Many people try to run 3kW inverters at 12V and end up spending a lot on copper, or have bad voltage drops. You may want another smart shunt for the bi-directional charger monitoring.
Remote display for the Gx - try using a local network - you can set that up with the pi and 10" monitor, Venus has a console that is accessible on a local network (and remote too). This may also help in connecting to the batteries.

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Hi Mike,

Thanks for your reply. Yes my first oversite, Titan is not on the list, I thought I’d seen it!! Oh well they only were delivered today, so maybe have to send them back?!

I’m still waiting for my Multiplus-II GX to arrive, maybe ill give them a try first. Might find something out that helps others??

Titans manual and PR Gumph says they are full compatible with Victron Multiplus and shows an ethernet cable configuration showing how to connect them.

Titan to Inverter
Titan to Inverter656×333 23.8 KB

Titan to Victron Inverters
Titan to Victron Inverters921×652 96.5 KB

Although, it look like the Battery BMS takes control of all of the Victron components and uses its own BMS. If Titan is to be believed then their BMS is superior to all others??!! Not sure Victron would approve these batteries if they do bum out Victrons Battery Control…

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Oh and thanks for the link. Ive got about half way through it and it makes me think back to doing electrics for my CAA Aircraft licence. Being old school ‘Section L’, I had to sit all the Electrical exams to get a Full B1 EASA Licence, which wasn’t that long ago!! I still remember the saying ‘Ivy Watts is a powerful women’.

I’m not totally green to electrics, but certainly am to solar systems. I was wondering if you need to have the Electrics in the van Certified, if you do a DIY job?? I’ve a friend who’s a qualified electrician and certs off house electrics, maybe need to ask a favour?? As for high power DC, I’m fully aware how dangerous it can be, unlike AC it doesn’t kick you off!!!

Cheers

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Ok, os if there is a wired CAN connection you could be ok. There is a victron document with the pin connections.
Yes, the BMS takes control of discharge and charge limits - this reduces a lot of set up requirements, though to be safe you do need to set max voltage limits in all chargers, and discharge limit in the inverter. For the Victron gear, thes usually requires a couple of dongles, but for smart equipment it can be done over bluetooth with VE connect app. I would not accept without proof that any BMS is superior to all others on the market, I’ve been playing with BMS systems for 5 years now. The Victron approval is down to negotiation and rigorous testing between a battery manufacturer and Victron, some battery suppliers don’t bother.
As far as wiring and certification goes, this may be down to local regulations and / or your insurance company.