AIO Unit - Will it work?

[bobdelso]

I have 4, 305 watt panels rated at 39.3 volts and 9.9 amps.

I'm looking at this all in one unit. The MPPT is rated at 40 amp 105v. Can 2p2s the panels for 80 volts 20 amps so it works with the mppt?

 

[FilterGuy]

I have 4, 305 watt panels rated at 39.3 volts and 9.9 amps.

I'm looking at this all in one unit. The MPPT is rated at 40 amp 105v. Can 2p2s the panels for 80 volts 20 amps so it works with the mppt?

2p2s gives you 19.8A so you are good there.
39.3V x 2 is 79.8V so you are good at 25deg C. That gives you about a 24% margin to cover the voltage rise in cold temps. You are *probably* ok for cold temps but to be sure we would need the Voltage temperature coefficient for the panels and the coldest the panels will ever get when the sun is shining. (I typically use the all time low for the area just to be safe)

 

[wattmatters]

I have 4, 305 watt panels rated at 39.3 volts and 9.9 amps.

I'm looking at this all in one unit. The MPPT is rated at 40 amp 105v. Can 2p2s the panels for 80 volts 20 amps so it works with the mppt?

I think you'll be fine. Seem to be well within the MPPTs voltage and current limits (assuing the above listed numbers are Voc and Isc. That inverter's MPPT's optimal voltage operating range is listed at 30-80V.

I'm in the middle of hooking up my array to a similar AIO, also with a 105V MPPT limit and MPPT operating range 56-72V. Mine's a 4kW 48V model.

My panels are 370W Longi with a Voc of 40.9V at STC (25°C).

We've never gone below 0°C here but allowing for it getting to 0°C my panel Voc temp coefficient is -0.27%/°C, so Voc at 0°C is going to be ~7% higher. That's 43.66V x 2 in series = 87.3V. So that's well within the 105V limit. Plus I have nearly 40 metres of cable between the panels and inverter so that also drops voltage a bit.

Vmp is 34.4V, so 2 x 34.4 = 68.8V, and with some losses in the cable I'm nicely inside the MPPT operating range.

I'll have 6 panels in a 2S3P arrangement.

 

[MichaelK]

One word of warning. The very cheap price of the unit suggests that it might possibly be a fake, copy-cat clone. I'd be suspicious of anything for sale on Alibaba. Mpp has put out warnings about this before.

 

[bobdelso]

One word of warning. The very cheap price of the unit suggests that it might possibly be a fake, copy-cat clone. I'd be suspicious of anything for sale on Alibaba. Mpp has put out warnings about this before.

Its from the MPP Solar official alibaba store. They also sell this one (and a bunch more) which appears to be the exact same 24v model Will reviewed.

The one I linked originally has a 105v 40a mppt and a 25a battery charger vs the one just above is 150v 80a mppt with a 60a. The cheap one also lacks the ability to string together AIO units and doesn't have a generator start. Its missing a lot of features, so its cheaper for a reason.

Hopefully its not a fake clone