Can bus wiring a Multiplus II GX 48V - 5000VA - 70A

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skydog asked Apr 29, '24

Can bus wiring a Multiplus II GX 48V - 5000VA - 70A

Hello,

I'm considering purchasing a Multiplus ii GX 48/5000/70 (product on special) to connect to 2 x pylontech 3000 batteries. Could someone assist me with the following please?

1. Do I use a Canbus type B cable or type A?

2. Do I still use a Canbus terminator (as in the external Cerbo GX)?

3. There is also the VE bus cable from the inverter that one would connect to an external Cerbo GX, what is to be done here?

4. Can I also correctly assume that the VE Direct cable from the Mppt would plug in as per normal?

I have searched for this information, but to no avail.

Your help will be much appreciated, thank you.

Pylontech VE.Can multipluss ii

2 |3000

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Answer 1 · 2024-04-29T17:14:27Z

Alexandra answered · Apr 29 at 05:14 PM

@Skydog

There is the manual for pylontec.

The ve bus cable is not needed, it is already connected to the GX in the MP2 GX.

The bms terminator is needed. The pylon manual asks for it and explains what cable to use. (B).

Ve direct is how you add another mppt.

The user connections are shown in the MP2 GX manual.

2 |3000

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Answer 2 · 2024-04-29T22:00:04Z

skydog answered · Apr 29 at 10:00 PM

@Alexandra

Thank you for your prompt and to the point reply. Much appreciated.

I erroneously mentioned a Pylontech 3000, it's actually a US300C so I assume it;s a type(A) BMS cable?

I stand under correction, but after reading the MP2 GX manual, it seems that when using compatible BMS-Can lithium batteries, one still has to use an external GX device (such as the Cerbo GX) which defeats the object of acquiring a MP2 GX but rather the normal MP2? (section 4.3.2. Li-ion batteries)

Also on the section (8.2. Connection of battery cables) of the same manual, on a cable run of 0 to 5 metres, a 70mm2 should be used. However the Pylontech cables are only 25mm2. What can I do here?

Thank you again

2

2 |3000

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Alexandra ♦ commented · Apr 30 at 04:27 AM

@Skydog

The mp2 gx has a bms can connection. I linked the picture for the connections in my previous reply. So no need for an external GX.

For such a small bank, ideally wiring both batteries with their own cable is better. I will add here that the bank is too small and ideally one more would be better. Look up discharge currents, the inverter can draw (5000va÷48w = 104A) the 3000s are 37A each. So 3 would be better.

The pylon cables have a higher insulation rating and can run more amos through them. So you can use their cables to run higher amps, the catch is they get hot, this means wasted energy though, i am so not a fan particularly of that.

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skydog Alexandra ♦ commented · Apr 30 at 06:14 AM

@Alexandra

Once again many thanks for your prompt reply and valuable input. I agree with you on the wasted energy regarding the cables. I might connect larger cables on the output of the DC bus to the MP2, although I'm not sure it will make a big difference.

Since I haven't yet purchased the batteries (still busy with pv array installation), I'm thinking that it may be better to purchase 2 x 5000 pylontech since they're 80A each.

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