More power with the soyo 😬

[kev300]

Hi, not sure if this is only possible with my newer purple soyosource inverter...

I was not aware that the limiter can also be used in PV mode and the required settings part in the docs of this project says that the Battery limit mode is required.

But at the moment I'm running on battery in PV mode with the limiter, which raises the 900W limit to 1200W (on the gtn-1200).
I think thats realy cool and worth noting... 🚀

You need a higher battery voltage for that of course. I'm using a DC-DC converter to boost to 70V so the PV mode has enough voltage to reach max power and stay below 20A, which makes the soyo a bit more efficient. The minimum voltage should be around 55V for the PV mode.

As a side effect: I can now also drain my battery to 40V without throttling of the inverter. Previously the soyo started power throttling below 48V and shutdown at 43V.

[Chickenbreast0]

Have you calculated how much power is lost through the DC/DC converter and whether it is still worthwhile in terms of efficiency?
Eventhough is it nice to know ;)

[kev300]

Not yet, but according to the spec and some tests on YouTube, the dc boost converter should only lose 4-7%.
I know that the soyo looses a lot under 46V, so if the soyo gets more efficient because of the higher voltage, the total loss might be not that much. But I will measure it myself and report 😁

[kev300]

Only tested untill 500W with measurements until now.

<= 300W efficiency loss from 93% -> 90%
400W 92,6% -> 88,9%
500W 92,4% -> 86%

because of the weather my battery is constantly empty, so did not test higher wattages, yet...

[Chickenbreast0]

Now that is measured with the DC to DC converter or without?
Somewhere I had read that the inverters have their sweet spot at about 500W at the highest efficiency.

[kev300]

both. So the higher number is without and the lower is with the DC/DC converter boosted to 60V.

But obviously not measured the interesting load settings. :D

[Chickenbreast0]

Ah sorry...then I had not read it correctly. But good that you can already see the power loss. Interesting that you did it, but I'm not sure if the efficiency ratio is so more worth it.

[kev300]

In general, the additional efficiency loss of the boost converter is around 3%-5,5%
Here are my measurements:

Demand setting	Efficiency with DC/DC Booster	only Soyosource Efficiency
100W	89,2%	89,5%
300W	91,3%	93,7%
400W	91,2%	94,1%
500W	91,2%	93,5%
700W	--	92,9%
800W	89,9%	92,3%
900W	88%	91,4%
1100W	87,7%	--
1200W	87,2%	--

So, yes, there is a loss, but if you want more power and have excess solar, it can be worth it. 😬

[ericgrand]

Hi!
Is the DC-DC converter act as a current limiter? If the battery were 72V, would the soyo try to draw more amps?
I'm questionning myself in using a 55-90V version with 6 12V LFP batteries in serie...

[kev300]

I think so, but I only limited it via the RS 485 interface. So not sure.

[syssi]

I think so too. Even if the RS485 limiter is used the max.power limit setting defines the upper limit. In other words if the max power limit is set to 200W and a power demand of 300W is requested using RS485 the inverter will deliver 200W. I hope this applies to the PV mode + Limiter enabled too.

[kev300]

Mh, but you can only set the max limit to 900W, right? But the PV mode is up to 1200W, so I guess it's not used in PV mode.

[syssi]

Good point!

[ericgrand]

Ok, the important point for me is that the inverter will not try to draw as much amps as the batteries are able to deliver...
As the inverter will always be driven by the limiter, it is fine for me.

[sorz2122]

Which DC-DC converter did you use?

[kev300]

Google: 1800W 40A DC-DC Boost Converter Step Up Power Supply Module
For about 22€

[sorz2122]

TY