Power loss from Gen to Batts, how to account?

Discussion about OutBack Inverters in Off Grid Applications

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My RE system: Two systems:
- Dual Radian 8048's, two FM100's, 10.3kw pv, 12 Simpliphi 3.5's, 1 Kohler 14Resa, 1 Honda EU7000IS
- SystemEdge FP1 3648, FM80, 1 Simpliphi 3.4

Power loss from Gen to Batts, how to account?

Post by Jpro556 » Sun Jan 19, 2020 12:33 pm


Curious if someone can help me understand the power losses going on in my system.

I have a 14.4kw gen, altitude derated to 8.7kw. About 40%...matches mnfctr spec.
Voltage drop from gen to inverter measures to be less than 0.3%

I see at Radian GSLC Gen In Brkr : 239.7vac and 36.1aac, or 8650W - all good here
then I see at Mate3s : 6800W in from Gen at 239V, and 6000W out to Batts for charging. So house load is 800W per this display.

Battery softkey shows Batts are getting 5100W of charging.

WHY is metered power input from Gen showing 8650w, but Mate showing 6800w?? where is that power delta going?
I assume that the 6000W mate shows going to battery is before charger inefficiency loss of 15%, and after that I'm just netting 5100W going into batteries. Yes???

Hoping to understand what I'm looking at, if someone could shed light for me.


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Re: Power loss from Gen to Batts, how to account?

Post by JRHill » Mon Jan 20, 2020 1:56 pm

The FNDC is really useful for stuff like this because it uses shunts for the feed from the panels and another for that going into the inverters and back out. There is room for a 3rd shunt if needed. It is probably the best "real time" you can get without an expensive AC/DC clamp on and watching that continuously. So the losses through the inverter are measured, included and logged if you use OpticsRE. The down side is it also displays SOC which is a moving target. So you take SOC with several grains of salt, esp with non-FLA batteries I believe. But the in/out shunts are cool for your purposes.

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