Just as I was going to buy some CALB batteries to replace my failed Hi Power batteries, I performed a last search and discovered that Hi Power has apparently shipped a new load of batteries to the US and they are now available from the Electric Car Co. of Utah :
http://www.evequipmentsupply.com/I bought four 50 Ah batteries for $66 each. (They have a full range of sizes in stock.) What I really appreciated was that the batteries were shipped out the next day and arrived as fast as UPS could get them to me. So I am very happy with the Electric Car Company's service.
I just received my batteries last night and they are the first fresh Hi Power batteries that I have ever seen. The batteries that were installed in my EMS GPR-S were produced in August 2008. These batteries were made in December 2010, are very white and are not covered with dust and stains, like my current batteries. They also came with a package of sheet metal electrical connectors for connecting the batteries together, which will replace my homemade aluminum sheet connectors.
I had been advised last year by the Hi Power distributor that these batteries were no longer in stock in the US. It appears that this problem has been rectified.