[RE-wrenches] 24 volt Battery Bank comparison

[Wayne Irwin]

 A) With a 13th battery and only one string, if there were a failure in one of the cells, the system would most likely demonstrate the failure rather quickly and allow for the faulty battery to be removed while still maintaining adequate voltage to operate the 24V system. 

 B) On the other hand, Tom presents the exact reason behind the idea of the 3 - string design.

This is an off grid system.

I know this may open up a can of (philosophically varied) worms. But, this is the reasoning behind the two designs.

PS. Buss bars (if 3 strings) and 4/0 CU would be used. 



Wayne Irwin, EE
Director of Engineering

Pure Energy Solar International Inc. 
State Licensed Solar Contractor

License # CVC56695 

Wayne at PureEnergySolar.com
 

http://pureenergysolar.com
 

352 377-6527 Office
352 336-3299 
Fax
352 316-1637 Cell
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From: tom at wagonmaker.com
To: re-wrenches at lists.re-wrenches.org
Date: Tue, 31 May 2011 13:36:16 -1000
Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison









>From a reliability standpoint I would never want to bet the farm on one 
string.  All it takes is the failure of one cell and the system is useless 
until it is replaced.  Three strings means a cell failure only reduces 
capacity by 33% not 100%.  I’ve always thought in off-grid systems it is a 
good idea to build in as much redundancy as possible whenever possible.  
Oh, and always use a buss bar system with multiple strings, it makes for a far 
more stable system with less stress on the batteries.
 
Tom
 
 


 

From: Wayne Irwin 
Sent: Tuesday, May 31, 2011 11:49 AM
To: Wrenches 
Subject: [RE-wrenches] 24 volt Battery Bank 
comparison
 
Hello 
Esteemed Battery Gurus,

Which of the following do you believe is the 
better 24 V battery bank?

A) 13 - Rolls 2-YS-31 2430 AH @ 20 HR (one 
string) 

or 

B) 9 -  Rolls 8-CS-25P 820 AH @ 20 HR (3 strings 
of 3)

Thank you in advance for your input!


Wayne Irwin, EE
Director of 
Engineering
Pure Energy Solar International Inc. 

State Licensed Solar Contractor
License # CVC56695 
mailto:PureEnergySolar at hotmail.com 

http://pureenergysolar.com 
352 
377-6527 Office
352 
336-3299 Fax
352 
316-1637 Cell

The content of this 
message is Pure Energy Solar Confidential. If you are not the intended recipient 
and have received this message in error, any use or distribution is prohibited. 
Please notify me immediately by reply e-mail and delete this message from your 
computer system. Thank you.




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