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BMS 12/200 Connection & Communication with SmartSolar Controller.


I'm in the process of installing solar for a customer on their narrowboat in the UK. The Lithium setup is already there fitted by a boatyard. I'm fitting 2*340 watt panels with SmartSolar 100/50 controller.

Setup of the system I'm installing to is:

2* Victron LFP- 12.8/100

BMS 12/200

Victron BMV 712 Smart

Victron 12/1600/70 Multiplus

350Amp Blue Sea switch Isolating Multiplus and main +ve busbar from Victron +ve terminal.

I haven't gone through chasing all cables as need to remove some woodwork and ran out of time but the system seems to be simple as in the basic diagram manual for BMS 12/200 :

Except the MultiPlus installed where the inverter is in the diagram on LB terminal (no orion DC-DC converter). No extra VE Bus BMS, communication leads with MultiPlus, Cyrix connections to BMV.

1. I'm assuming the SmartSolar controller battery -ve is connected to the LB terminal? Found this post: ..and I just adjust the battery presets in the SmartSolar to LiFePo4? So there's no other communication between the SmartSolar and BMS, and SmartSolar will go back into bulk if batteries are discharged slightly during the day?

2. Would be nice if I could connect SmartSolar Battery Connections to main Bus Bars but I'm connecting +ve SmartSolar terminal to +ve battery terminal (~ 2M 16mm cable with Midi fuse holder) so it bypasses the isolator switch. I assume I can connect SmartSolar -ve to the main negative busbar (~1.5Metres of 95mm cable to BMS 12/200 LB terminal) and minimise -ve SmartSolar cable run in 16mm.

3. There's a 60 amp fuse fitted at AB terminal limiting alt. to 40A. Next size Mega Fuse is 80A limiting current to 70A. Is it possible to bolt the ATO fuse holder ontop of the 60A to allow finer adjustment between the 40 & 70 amp?

Gone through the Journey with Jono Vlog where Jono describes how his Victron solar setup is installed - Using VE Bus BMS, Cyrix, BMV monitor to communicate with the SmartSolar and MultiPlus even though setup has the BMS 12/200 and seems v similar to the setup I'm working on. It seems so complicated. As far as I can see (with absolutely no experience) don't need any BMS VE.Bus to communicate with SmartSolar/MultiPlus/BMV etc. and BMS 12/200 does everything normally needed. So am I missing something?

Sorry if the detail is in the manuals but it's still unclear to me and first time I've got involved with fitting solar to Lithium.

Thanks, Ed

MPPT - Solar Charge ControllerBMS
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1 Answer
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fc-marine answered ·

Update: Finished installing the solar and connected to the LB terminal. I'm now worried about the system as a whole..

While the boat is plugged into shorepower I've told customer to turn the Smartsolar off as thinking it can't be good to do 2hrs at absorption every day. The multiplus is set to Lithium settings to do 1 hr absorption every week and is at float voltage the rest of the time. I'm thinking when the boat is away from shorepower turn the solar on and accept that the batteries will see upto 1 hr absorption every day from solar and absorption voltage voltage when the engine is running, which it's been doing since system was installed for over a year now anyway.

Having read a little can see that it's not great that the batteries are at float all the time and ideally should be left partially charged for majority of time. However to achieve this it seems really complicated or has to be managed on a daily basis by the customer.

Is it reasonable to leave the system as simple as it is? If not what should be done to bring the system upto a minimum acceptable standard. Hope someone can advise.

Thanks. Ed

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