<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<HTML>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<META NAME="Generator" CONTENT="MS Exchange Server version 6.5.7036.0">
<TITLE>How many Ahs?</TITLE>
</HEAD>
<BODY>
<!-- Converted from text/rtf format -->
<P><FONT SIZE=2 FACE="Arial">Suppose I have a battery bank made up of 4 - 12V Enersys HUP flooded lead acid batteries. The batteries are wired in series for a nominal 48VDC system.<BR>
<BR>
The side of the battery, which is actually a forklift battery, is marked as 1320 Ah @ C/6. The vendor also rates the battery as 1690 Ah @ C/20.<BR>
<BR>
So, for the purpose of evaluating the battery back relative to the charging system settings, what size is the battery bank?<BR>
<BR>
It is interesting to think that at a normal discharge rate of C/20 I can get 128% more energy out of the bank (1690 Ah) than I can put back in at a C/6 charging rate (1320 Ah)?<BR>
<BR>
Is it fair to say the following: For rapid bulk charging to bring the voltage up from some discharged voltage of say 48VDC to a bulk charged voltage of say 60VDC, I want a charger that can provided a constant current of C/10 or 1320/10 = 132 A across that voltage range. And at the time that I complete this bulk charge, the battery bank will be restored to 1320/1690 = 78% of its starting capacity. </FONT></P>
<P><FONT SIZE=2 FACE="Arial"> </FONT>
<BR><FONT SIZE=2 FACE="Arial">Mark Frye</FONT>
<BR><FONT SIZE=2 FACE="Arial">Berkeley Solar Electric Systems</FONT>
<BR><FONT SIZE=2 FACE="Arial">303 Redbud Way</FONT>
<BR><FONT SIZE=2 FACE="Arial">Nevada City, CA 95959</FONT>
<BR><FONT SIZE=2 FACE="Arial">(530) 401-8024</FONT>
<BR><A HREF="http://www.berkeleysolar.com"><U><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">www.berkeleysolar.com</FONT></U></A><FONT SIZE=2 FACE="Arial"> </FONT>
</P>
</BODY>
</HTML>