[RE-wrenches] FLA battery setpoints with larger arrays

[Ray Walters]

I thought I'd post some info on Battery Temp from a few manus:
HUP Solar One: do not exceed 105 F
Full River AGMs: max recommended operating temp 104F
and from Trojan:  for every 10C increase in temperature the reaction 
rate doubles.  Thus, a month of operation at 35C is equivalent to 2 
months at 25C.  Heat is the enemy of ALL lead acid batteries.  Even 
small increases in temperature will have a major influence on battery life.
Their T105 RE battery has a max operating temperature of 113 F

I think more batteries are hitting high temperatures than we may 
realize.  This info from Trojan that a battery at 95F (35C) will only 
last half its rated life (at 25C) is very concerning.
Once again, thanks Bob and Midnite for giving us a tool to combat over 
temperature of batteries.  We always knew cold was a problem, now I'm 
realizing heat could be just as important.

R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760

On 5/22/2015 3:24 PM, boB at midnitesolar.com wrote:
> I'm very glad to hear Midnite added the high temp disconnect to their 
> system.  They may have saved a life.
>> Bob, is battery temp logged, so we could see how often a system quits 
>> charging for high temp, and just what the battery temps are running?
>
>
> No, but that is on the list as are other things to data log.
>
> Hopefully the temperature is adjusted higher than it would ever get to 
> under normal circumstances.
>
> I could see some future systems wanting to be able to regulate Absorb 
> on battery temperature mixed with other
> parameters some day.   Could get REALLY complicated if you wanted to.  
> We're learning more and more
> about what is good for batteries.
>
> boB
>
>

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