After scouring the internet for information on an OEM-sized battery to fit my '91 Daihatsu Atrai van, I found a great choice locally and thought I'd share as it might help someone else. My Japanese Unistar battery (made by GS Yuasa) died after only 11 years! I was shocked it was that old!! It appears that most kei vehicles end up using "garden tractor" batteries because OEM-sized batteries are not available in the US. These smaller batteries are readily available at Walmart and other stores for $25-$35, however the connectors need to be changed out to fit the positive and negative terminals. Also, the battery reviews are generally terrible and warranties are as little as 3 months. Bottom line: you get what you pay for. Long story short, I found a great "full-sized" replacement car battery that fit perfectly: a Duracell Group S46B24R battery (often used in a Toyota Prius.) It uses the same size "pencil post" terminals as the OEM battery, has fantastic reviews and a 4-year warranty. The downsize is that with discounts and my old battery core, the cost was $196.22. That was FAR more than I wanted to pay, but I got a great full-sized car battery that fits great and has a superior warranty. Now I don't have to worry if I'll ever get stranded because of a small, cheap battery that I would probably replace a lot more often than I'd like. This "Prius" battery has 390 cranking amps, 325 cold cranking amps and is the same width and height as my old Japanese OEM battery, however it is 2" longer. In my Hijet and Atrai vans, the battery well was long enough to fit the 2" longer Prius battery. FYI, the Duracell battery dimensions are: 9.38”L x 5” W x 8.87” H. (For additional size options, search for Group 51R and Group 151R batteries.) I just thought I'd post this to possibly help someone else wanting an alternative to buying a garden tractor battery. My 30 year old van is so incredibly nice, I thought the much higher cost of a quality car battery was worth it. YMMV.