[RE-wrenches] Tri-Star MPPT

[William]

Brian:

I don't have the PV details handy but I will provide them. 

Question:  will a sulfated cell exhibit a SG of 1.26?  I thought a sulfated cell locked the acid onto the plates, minimizing the SG readings below that of a healthy cell. 1.26 is a relatively high reading. 

William

On Jul 23, 2013, at 1:28 PM, Brian Teitelbaum <bteitelbaum at aeesolar.com> wrote:

> William,
>  
> What does the PV array consist of? What size and type, and how many, modules?
>  
> Which TriStar? 45 or 60A?
>  
> What controller did she have before the upgrade?
>  
> The high charging voltage might be a sign of sulfation. Depending on her load profile, that 8A charge rate might have caused chronic undercharging. In a 5 peak sun-hour location, that’s only 40Ah/day of charging capacity.
>  
> Brian Teitelbaum
> AEE Solar
>  
> From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of William Miller
> Sent: Tuesday, July 23, 2013 1:13 PM
> To: RE-wrenches
> Subject: [RE-wrenches] Tri-Star MPPT
>  
> Friends:
>  
> I have a customer with a new Tristar MPPT controller.  The customer has some older L-16 batteries mixed with new and she thinks the controller has damaged her batteries.  I am trying to convince her that the batteries were already damaged and mixing old with new is a bad idea.
>  
> I removed the worst batteries from the array, leaving one string of older batteries with reasonable SG readings.  The CC still acts strangely:  When programmed to charge the L-16 batteries, the battery voltage shoots up to 30.2 volts and the batteries boil a lot.  The green light on the controller blinks at variable rates, at one moment fast, the next slow, the next solid.
>  
> I believe the client started with bad batteries, 6 are 4 years old, 2 are 1 year old.  She is convinced that the CC damaged her batteries.  She replaced panels and CC recently, installing the Tristar.  I believe the old PV system charged at such a slow rate (8 amps) that the battery deficiency was not apparent.  The higher charging rate has emphasized the problem.
>  
> Any one have any thing to add to my theory?
>  
> Thanks in advance.
>  
> William Miller
>  
>  
>  
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