[RE-wrenches] Sunny Island Failure and various related issues

[William Miller]

Mac:

Thanks for the advice. We will install the shunt today. A few more questions:

1.  Will the Outback 50ma shunt be compatible. My research indicates the value is correct. 

2.  DC clamps are notoriously inaccurate, particularly at low amperages. Will this be a problem, or is shorting the leads adequate?

Thanks again. 

William Miller

PS:  We looked at the Midnite cabinets but they put the OPCD too far from the batteries.

William



> On Feb 12, 2015, at 4:45 AM, Mac Lewis <maclewis1 at gmail.com> wrote:
> 
> Hi William,
> 
> I want to talk directly to your problem at hand.  I think installing the shunt and properly calibrating it, will fix this system .  In a DC coupled system with a Sunny Island, it is imperative that you use a shunt, unless you are using the Midnite charge controllers with the communications to accurately report all charging (or the non-UL listed SMA charge controllers).  There are so many functions and calculations that the Sunny Island performs that needs accurate SOC calculations.  All of the shutdowns that you are seeing are resulting from faulty SOC measurements.  I wouldn't believe the reported state of health either, because it is using the faulty SOC measurements.  Don't believe state of health until you have a couple of months of operation with the shunt.
> 
> Right now, with the system as is, it isn't accounting for the charge coming from the charge controller(s).  It is shutting down because its only accounting for AC power processed through the Sunny Island.  I once had a Sunny Island system with an improperly calibrated shunt and it acted just as you describe, strange shutdowns, bad SOC output etc.  After I got it calibrated, it has worked flawlessly.
> 
> Take your time when you are calibrating the shunt.  Follow the (odd) directions perfectly and it should work.  Verify Sunny Island readings match your DC clamp meter and you should be good.
> 
> 
> 
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