[RE-wrenches] big bank charging

[Dana]

Mark  - 

 

We have an installation that has [3] 1990 Ahr HUP solar one
battery banks and there is not enough charge for EQ
capacity. So we fused each bank at 250ahr separately while
it is wired in a reverse-return series/parallel
configuration [sorry to throw in the plumbing jargon there]
and can remove one  or two banks to dedicate full charge
capacity to each bank. It takes a little longer but with
full sun and the generator it meets the need without adding
additional chargers. So far the SG readings are all dead on.


 

The system normally reaches a full charge of 58.4VDC on a
regular basis via sun and wind.

 

Thanks,  Dana Orzel

 

Great Solar Works, Inc

E - dana at solarwork.com

V - 970.626.5253

F - 970.626.4140

C - 970.209.4076

web - www.solarwork.com

Responsible Technologies for Responsible People since 1988"

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf
Of Mark Frye
Sent: Saturday, June 26, 2010 6:41 PM
To: 'RE-wrenches'
Subject: [RE-wrenches] Two batteries with an MX60 in between
(was big bank)

 

Folks, 

As you may recall I have 4 strings of 4 batteries
parralleled into a single bank. Each string is 1690Ah @ 48V.
The charging system for this bank is undersized. I think I
would do better by reducing the bank size by running only 3
strings. However, I don't want to strand the fourth string.

I am wondering what rotating the strings might look like.
One string would be removed from the bank for a period of
perhaps a month. Then it would go back on-line and onother
string would be taken off-line, and so on.

Right away I worry about accelerating the divergence of the
strings in terms of resistence to charging. Going to three
stings would reduce this problem, but trying to rotate
strings might 

make it worse. 

In any case, I would want to float out the dormant string as
best I could while it is off-line. 

Would it work to attached the DC input of an MX60 to the
on-line bank of three strings, and the output to the
off-line sting, and let the MX keep the off-line string in
float?

  
Mark Frye 
Berkeley Solar Electric Systems 
303 Redbud Way 
Nevada City,  CA 95959 
(530) 401-8024 
 <http://www.berkeleysolar.com> www.berkeleysolar.com  

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