[RE-wrenches] Morningstar PWM

[jay]

HI All,

I talked to Morningstar today and here is how the tristar work.

To get to the absorb time of 120-150 minutes in CC mode ( + an additional 30 or more if the batteries got below 12.3v nominal the day before)
the controller must get to 15% duty cycle.  So for the 60 amp its 9 amps.  When it regulates down to this current, it’ll then start the absorb timed cycle.  In reality of course its already been there for some time if the duty cycle is anything less than 100%, but thats how MS does it.

I hope this helps,
jay

peltz power




> On Sep 11, 2015, at 8:41 AM, Drake <drake.chamberlin at redwoodalliance.org> wrote:
> 
> The batteries are good. We are going to try some custom settings. This CC works a bit differently than most, and the problem may be in the duty cycle, IE, how much time the pulses are on vs off. 
> 
> At 04:36 PM 9/10/2015, you wrote:
>> Drake,
>> 
>> Quote: “...and goes right back to that voltage in the morning.”
>> 
>> How quickly does the battery voltage rise to 29.1 in the morning? If the batteries are sulfated heavily, you may see a very fast rise in voltage but you will also see a loss of capacity. Batteries in the early stage of sulfation may have a difficult time reaching the constant voltage setpoint and remain in bulk charge continuously.
>> 
>> What is the size of the PV array and battery bank? If the array is too small for the bank, this is the time of year (less sun hours per day) that we start to receive complaints about the battery not getting charged.  
>> 
>> Larry Crutcher
>> Starlight Solar Power Systems
>> 
>> On Sep 9, 2015, at 5:06 PM, Drake < drake.chamberlin at redwoodalliance.org <mailto:drake.chamberlin at redwoodalliance.org>> wrote:
>> 
>> Hello Wrenches,
>> 
>> I have a Morningstar PWM 45 that doesn't drop out of absorb. It is set with dip switches to absorb at 29.2 V and stays constant around 29.1. It has stayed at 29.1 for several hours straight, and goes right back to that voltage in the morning. Tech support says the controller is working correctly. Have any of you seen this, or conversely have you seen the Morningstar drop into float after a reasonable amount of time?
>> 
>> Thanks,
>> 
>> Drake 
>> 
>> 
>>  <>Drake Chamberlin
>> Athens Electric LLC
>> OH License 44810
>> CO License 3773
>> NABCEP Certified Solar PV 
>> 740-448-7328
>> http://athens-electric.com/ <http://athens-electric.com/> 
>> 
> 

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