Battery Charging - Temperature does matter

[John - N0EVH]

I have been reading the comments about charging and floating various batteries and just had to comment on the 'law of chemistry'.

All lead acid batteries whether they are gelcel, AGM or conventional deep cycle, all work because of that dreaded course you tried to avoid in school called chemistry 101.  Chemical reactions are effected by temperature.  Most of you see this coming already.  Yes, the float voltage for lead-acid batteries to achieve proper care does change with the battery temperature.

So, if your battery storage area changes temperature from summer to winter you should make a voltage adjustment.  Mine varies from 50's in the winter to 80's in the summer.  So I use the manufactures chart to adjust my float voltage accordingly.  My settings run about 13.8 volts winter to 13.3 in the summer.  Your mileage may vary.

John - N0EVH
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[n7ws]

Truly "smart" chargers such as those using the uc3906 IC understand this and adjust accordingly.

This does presume that the IC and the battery are located in the same environment, which isn't always exactly the case, but often close enough.

Wes  N7WS

--- On Wed, 6/10/09, John Watkins <[hidden email]> wrote:

From: John Watkins <[hidden email]>
Subject: [Elecraft] Battery Charging - Temperature does matter
To: "Elecraft Reflector" <[hidden email]>
Date: Wednesday, June 10, 2009, 11:44 AM

I have been reading the comments about charging and floating various batteries and just had to comment on the 'law of chemistry'.

All lead acid batteries whether they are gelcel, AGM or conventional deep cycle, all work because of that dreaded course you tried to avoid in school called chemistry 101.  Chemical reactions are effected by temperature.  Most of you see this coming already.  Yes, the float voltage for lead-acid batteries to achieve proper care does change with the battery temperature.

So, if your battery storage area changes temperature from summer to winter you should make a voltage adjustment.  Mine varies from 50's in the winter to 80's in the summer.  So I use the manufactures chart to adjust my float voltage accordingly.  My settings run about 13.8 volts winter to 13.3 in the summer.  Your mileage may vary.

John - N0EVH




     
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[myles landstein]

hmm     I forgot to mention  on my earlier  post,   but   depending on  
the types of batteries   in addition to the great   info below,      
depending  on your  temp  the battery    your   operating  time    /  
usage  on a full charge will vary.  Life  expectancy will also  vary

For  example  some of my batteries  at  90F will have   less than  1/2  
capacity on a full charge  same would be true for  less then  50f

ALso true is that my  10yr  battery  if  mostly kept  at  above  80f  
would  yield  around  5yrs

Those big  batteries  are kinda   touchy   about  a lot of things

Proper  climate , venting,  storage,   emergency spill  prep   ,  
fusing,  a emergency kill switch  ,  remember if  the Fire Dept.  
kills  your breakers   your  shack  would still be  'on'  all things  
to consider  .  I try to keep my batteries away  from where people  
will be  ...just in case

Then again  some like to just go  'best effort'





On Jun 10, 2009, at 1:44 PM, John Watkins wrote:

> I have been reading the comments about charging and floating various  
> batteries and just had to comment on the 'law of chemistry'.
>
> All lead acid batteries whether they are gelcel, AGM or conventional  
> deep cycle, all work because of that dreaded course you tried to  
> avoid in school called chemistry 101.  Chemical reactions are  
> effected by temperature.  Most of you see this coming already.  Yes,  
> the float voltage for lead-acid batteries to achieve proper care  
> does change with the battery temperature.
>
> So, if your battery storage area changes temperature from summer to  
> winter you should make a voltage adjustment.  Mine varies from 50's  
> in the winter to 80's in the summer.  So I use the manufactures  
> chart to adjust my float voltage accordingly.  My settings run about  
> 13.8 volts winter to 13.3 in the summer.  Your mileage may vary.
>
> John - N0EVH
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

Myles Landstein
[hidden email]
please note my   new email address
dti will soon be eliminated , gmail is my new home  update your dir

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html