[RE-wrenches] "DC current Injection": Whazzat?

[Starlight Solar Power Systems]

Help Mick,

With the Magnum AC coupled to the SE inverter, I suggest it’s an issue with Magnum power quality (reactance) with the blender controls/motor and the resulting AC waveform that is feeding the SE inverter. I have seen this before with Magnum Energy. Can you look at the waveform or PQ while starting the blender?

A simple solution (but perhaps a hard sell) is the customer acknowledges that this rare event will happen and ignore it for the 5 minutes it takes to restart the inverter. Battery power should be sufficient. Compare that to the cost of “fixing” this issue.

Larry Crutcher
Starlight Solar Power Systems






On Aug 17, 2017, at 6:51 AM, Mick Abraham <mick at abrahamsolar.com> wrote:

Hi, Wrenchies~ 

My client has an AC coupled battery based setup. The batteries are good ol' lead floodies in pretty good health, the battery based inverter is Magnum MS4448PAE, & the string inverter is SolarEdge. There's also a Magnum ACLD "AC Load Diversion" control to regulate battery state of charge when there's no grid power. 

When there's no grid power & the system is on it's own, the SE inverter sometimes throws an error code 36 "DC current injection". This happens when the mongo blender is operated (Vitamix brand, older model) & again in a >no public power grid< situation. The error causes the synchronizing string inverter to de-couple from the Magnum then the standard five minute time-out ensues before a re-couple.

I think DC current injection is when the transformer-less SE inverter pumps a blip of DC into the grid--or micro-grid when there's no grid power--and I guess DC injection is IEEE verboten because it compromises power quality/power purity. Can the experts confirm if this is correct understanding, explain how DC can show up on the AC, and offer suggestions other than a replacement blender?

Thanks as always. The Wrench List is the Bomb!

Mick Abraham, Proprietor
www.abrahamsolar.com <http://www.abrahamsolar.com/>

Landline: 970-731-4675
Cell phone or for text messaging: 970-946-6584
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