When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Gel batteries have been around for a long time. As mentioned, what was new in 2001 was the AGM (except I thought it stood for advanced glass mat) technology. The advantage is less weight.
Some people with early 2001's reported problems. The first few weeks supply was shipped to the BG factory without a charge and a large number were installed before the problem was identified. This meant there was a lot of battery chargeing and jump starting going on around the factory for a while.