Automatic Transfer Switch

[Keith V.]

Hi All,
I'm running 2 separate Off Grid systems, both MPP Solar inverters, 1 @ 8kW 48v and 1 @ 5kW @ 48v.
I was using the 5kW system as my utility input for the 8kW system but MPP Solar don't like that "Our inverters are not designed to operate in this manner".
Fair enough.
So now I intend to connect the AC output from both inverters to the DB via an ATS.
Can I get some advice please on a suitable selection for a 240v 50 Hz system or more particularly the units to avoid.

Thanks,

Keith V.

 

[svetz]

Hi Keith, welcome to the forums!

Have to ask, why not just take the batteries from the 5 kW system and add them on the 8 kW system? Having more batteries on one system should also help to extend their life expectancy as each individual battery has a lower overall current draw.

 

[Keith V.]

Thanks for the welcome,

The 8 kW system is running on 12 x 260 Ah SLA's, this is my original battery bank, now 10 years old, still working fine 24/7.
The 5 kW system is powered by 16 x 320Ah LiFePo4's and is my backup system.
As I understand it you can't mix battery technologies due to their different charging characteristics.

My battle plan was to use the 240v output from the 5Kw system as the "grid" input for the 8kW system when the SOC on that system drops below 80%.
MPP Solar have advised me that their inverters aren't designed to operate this way, something I don't understand.

I use a backup generator as grid input, pure sine wave, it works well but with the cost of fuel these days is uneconomical.
What's the difference between 240v as supplied by the generator or the 240v supplied by the 5Kw inverter?
The 5kW inverter worked perfectly for 3 years and coped with all the demands put on it.

No Grid input here so I need a backup system just in case of a component failure.
I've ordered an ATS and plan to use that in automatic mode or manually as required.

Keith V.

 

[timselectric]

I see no problem with your original plan. No matter what they said. It's a clean AC power source. What could be better?

 

[Keith V.]

I see no problem with your original plan. No matter what they said. It's a clean AC power source. What could be better?

Thank you for confirming my thoughts, much appreciated.