DC Solar Trailer Questions (SMA inverters)

[fromport]

That sounds awesome. So, I think it is safe to say... that you won't be selling them to me...cheap?!? ?

No, they are re-purposed already

 

[TOU47]

No, they are re-purposed already

? ?

 

[Hedges]

Thank you for your input. The batteries seem to be holding good charge.

Voltage at least. Have to see about Ah capacity.
If accessible, check every cell voltage with DMM.
Check specific gravity.
See if equalization is needed. Small PV array insufficient, but generator running several hours ought to be able to do it.

The issue is the on/off of the generator. One would think if the inverter tells it to turn on to charge, then it would and not turn off in 5 minutes. That’s telling me there must be a setting that isn’t correct. I really need to know more about how the inverter is setup and how I can see if the parameters are incorrect.

Download the SI manual and read about it. I haven't used with a generator (and haven't seen DC solar trailers in person.)

When generator is needed (typically some low SoC), SI should start generator, let it warm up, connect, charge batteries, disconnect, cool down.
SI sends one wire (plus return) "start/run" signal. Depending on whether SI configured for "grid", "gen", "grid/gen" it may need a control input saying generator not grid is connected.

Start by checking voltages, see if generator produces voltage, if that reaches input terminals of SI. Close the "start/run" signal manually, see if generator keeps running.

I think others here do use the generator successfully.

If necessary, go through SI menu and write down what you find (you need to do this anyway to look up what the settings mean), then do a quick configure and define the system again from scratch. Two inverters split phase, battery (sum of two) nominal voltage and capacity, etc.

As for the panels, yes they are junk. Eventually I plan on swapping them out for panels with micro inverters.

How are they junk? If already in your possession, panels is panels; they deliver watts.
Of course you can get higher "efficiency" panels to pack more watts in less space. But depending on power needs, you may need much more area.

Off grid?
Buy an older model Sunny Boy and set it for off-grid, which tolerates wider voltage and frequency range than on-grid (even if UL-1741-SA)
Newer models are OK too, have the off-grid option.
If you are grid tie and want battery backup, then the older models have additional modes.

Many inverters are transformerless, and for high voltage string inverters that can mean PV panels experience "PID", deteriorate due to bias voltage. Some panels are relatively immune. Lower voltages (e.g. microinverters) or transformer type inverters allowing positive or negative ground avoid the problem.

Good to know to not and try to tie the two 50 amp outlets together. The tiny home runs fine on 50 amp at the moment.

With battery inverter plus large amount of AC coupled PV, higher currents could be supplied.
2x SI is 11.5kW continuous. You can connect as much as 24kW of AC coupled GT PV.

When charged, the batteries will run the tiny home for at least two days before needing to be charged. We do not have a lot of sun at the moment due to the weather systems moving through our area. That is why the need for having a generator as a backup source.

The more often and deeper the cycles, the shorter the battery life. Better to run the generator daily if that extends battery life.

Hopefully this sheds some new light on the situation. The generator still seems to be turning on/off still.

Try manually keeping it on, long enough to complete charging or at least diagnose

When I went back outside, the inverter showed another code. This time it was W319 (grid/generator disconnection due to excessive external voltage.

OK, keeping it enabled check the voltage.
See if SI is configured as fed by grid, or fed by generator only.
Possibly, at low SoC it requests generator, is not told generator is present, sees voltage which it thinks is grid but is not well enough regulated.
Understanding the settings would help here.
You can walk through the quick configure of new system without changing anything, should see grid/gen/etc.

 

[HomesteadHybrid]

Ok. Here is what I have so far.

Inverter
#1 120V
#2 48V
#3 60Hz

Battery
#1 240
#2 90
#3 5h
#4 10h
#5 14d
#6 180d
#7 2.55V
#8 2.5V
#9 2.5V
#10 2.25V
#11 4mV/degC
#12 Disable

Battery Properties
#1 FLA
#2 1020 Ah
#3 48V
#4 50 degC
#5 49 degC
No #6 as an option. Goes straight to #7
#7 40 degC

When I went back outside, the inverter showed another code. This time it was W319 (grid/generator disconnection due to excessive external voltage.


Hello,
Im having a Generator Start, No Charge, situation after a Factory Resest, could some confirm their SMA Generator? It worked before but now I'm having issues. This did not happen on the other trailers so Im unsure what setting changed.

 

[beastman]

I looked at buying some of these from a reseller, and they stated almost all of the trailers need battery work. Do not count on getting even 50% of the rated 48kwh of storage without replacing some batteries. Most of these outfits buy multiple trailers, cannibalize batteries and then sell off the last trailer piecemeal with no batteries left for parts and sma inverters, etc. They were selling trailers needing work for $8-10k and ones that were about 80% good for $17k in Nevada City, CA.