Is this oversized?

DIY
, , ,
1

In this thread Add Solar to Multiplus II 24/3000 70-32 and this one Solar Panel size and configuration I got lots of good advice so thank you for that.
I have had a quote for setting up 4 x 440W Suntech panels (normal residential style) and it included the following Victron products:

Victron MPPT SMART Solar VE.CAN 150V 100A
Victron Battery Balancer
Victron SmartShunt 500amp
Victron Cerbo GX MK2
Victron GX Touch 50
Victron VE.Direct Cable 1.8m Straight
Victron RJ45 UTP Cable 1.8m Blue

I have VictronConnect for monitoring on my iPad.

My questions:

  • it seems to me that the Controller is far more than I will need, is it worth buying something much bigger ready for future expansion?
  • are there items that are unnecessary?

Thanks again for your help.

[Added]
My power audit gave 1700 Ah per day (correction, 1700 Wh per day)
I have a 24v 240Ah AGM battery bank.

2

That would be 41kWh, sounds like a lot to me?

3

On 24 volt system, watts per day. Sorry, got my terms mixed up, about 90 Ah per day. I guess it would be safer to round it up to, say, 100 Ah / 2.4kWh per day and size from there.

4

Your panels are 1760W, so at 27V you are at max of 65A, the choice are the 150/70 or 150/100. Comes down to a choice about cost / any future plans.

1 Like
5

Hi Stephen.
Yeh, with 240Ah of AGM, even a 150/70 is stretching usefulness.
I’d likely also skip the Battery Balancer and use the Aux port on the Smartshunt to just monitor the Midpoint V.
Also the Touch 50. Between your iPad, maybe a phone, PC or even a Smart TV, there may be lots of monitoring options that arise. Some kit like this can be added later, once you learn what you really want.

2 Likes
6

Thanks John, this is most helpful,
When I put the 4 panels into the MPPT Calculator with two strings of two, it suggests the 100/50 which gives me a daily yield of 3.5kWh in Winter, and twice that in Summer, so ample for my needs.

Also, pricewise, the 150/70 is twice the price of the 100/50, the recommended 150/100 (in the original quote) is three times the price of the 100/50.

Agree with you about the Touch 50, it seems an, at the moment, unnecessary piece. Concerning using the SmartShunt aux port, are there good instructions for wiring this up?

Thanks for your help with this.

A rough calculation shows that going for the smaller MPPT, removing the Balancer and the Touch 50 halves the quoted cost for the Controller components. The value of this community can be measured in dollars… :slight_smile: