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Old 14-02-2020, 21:53   #1
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Solar, REC-BMS, LFP House question

Hello All,
Getting ready to install two LG370 panels with two addtional 250 watt "slide outs" over my bimini. Winston 700ah LiFePO4 with REC-BMS have been installed and working beautifully x approx 3 months (love the set up!!).

Planning on separate Victron MPPT controllers for each panel to build redundancy into the system. The two LG370's will each have Victron Smart MPPT 100/30 controllers and the 250 watt panels will each have Victron Smart MPPT 100/20 controllers.
Wiring will be: solar panel to breaker to MPPT to fuse to buss bar to LFP.
Victron's VE Direct will go to the Cerbo GX + Touch 50.
Cerbo GX will connect to the REC-BMS can so the REC will control the MPPTs.

My question is with regards to the Victron MPPT charge controllers and their VE Direct connections/cables. I don't see how to connect 4 separate VE Direct MPPTs to the Cerbo GX, which has only 3 VE Direct ports. Does anyone here have 4 individual Victron MPPTs tied into their GX device and if so how?
Thanks!
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Old 14-02-2020, 22:12   #2
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Re: Solar, REC-BMS, LFP House question

on the color gx you can buy ve direct to usb adapters to create more ve direct ports. I'm guessing it's the same on that one. but not sure.
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Old 14-02-2020, 22:22   #3
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Re: Solar, REC-BMS, LFP House question

Victron says the only way is to use VE.direct->USB device. If you don’t have enough USB ports they recommend a USB hub to increase port count, then add VE->USB as required. Note there is a maximum # of VE.direct devices that can be connected to each GX device regardless of how they are connected. The Cerbo specs say “15 or so”, older GX can manage from 4 to 25.
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Old 15-02-2020, 10:02   #4
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Re: Solar, REC-BMS, LFP House question

Thanks for that. I looked and read, but just didn't see that info. I wish Victron had lower rated VE Can versions so they could be daisy chained. An alternative is to buy two VE Direct 100/20s for the 250 watt panels and one 150/70 VE Can and parallel the two 370's. Thoughts regarding that config?
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Old 15-02-2020, 12:45   #5
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Re: Solar, REC-BMS, LFP House question

Quote:
Originally Posted by gscriba View Post
Hello All,
Getting ready to install two LG370 panels with two addtional 250 watt "slide outs" over my bimini. Winston 700ah LiFePO4 with REC-BMS have been installed and working beautifully x approx 3 months (love the set up!!).

Planning on separate Victron MPPT controllers for each panel to build redundancy into the system. The two LG370's will each have Victron Smart MPPT 100/30 controllers and the 250 watt panels will each have Victron Smart MPPT 100/20 controllers.
Wiring will be: solar panel to breaker to MPPT to fuse to buss bar to LFP.
Victron's VE Direct will go to the Cerbo GX + Touch 50.
Cerbo GX will connect to the REC-BMS can so the REC will control the MPPTs.

My question is with regards to the Victron MPPT charge controllers and their VE Direct connections/cables. I don't see how to connect 4 separate VE Direct MPPTs to the Cerbo GX, which has only 3 VE Direct ports. Does anyone here have 4 individual Victron MPPTs tied into their GX device and if so how?
Thanks!
RS232 to USB cables, USB hub if you need more... You can built your own, UART, TTL logic (means 5V) are OK, connect negative to negative, Rx to Tx and Tx to Rx. Do not connect the positive pin. You can get the USB to serial cables prewired and also tbe necessary plugs for the Victron gear online on Amazon. No big deal. There are also adapter from serial to RJ45 (LAN cable) and the like if you want to use standard cabling and need long wires.

But you also can buy the Victron VEDirect USB cable, you get 10 interfaces DIY for the price of the original one...

https://www.amazon.com/JANSANE-PL230...=Usb+rs232+ttl

https://www.amazon.com/Micro-Connect...+jst+2.0+4+pin
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Old 20-02-2020, 20:59   #6
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Re: Solar, REC-BMS, LFP House question

Thanks for the replies. It's all coming together.
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