I've given up using junk Chinese (ebay brand, Scorpion etc.) as I've now had problems with those in other machines too.
I will still use Motobatt AGM in a pinch and Deka AGM for sure (when the size is available) , but after talking with alot of techs Yuasa AGM is THE only way to go given the option.
Yuasa YT12a-BS is by far the best battery for this scoot.
Amazon says it does not fit but it will
http://amzn.to/2gH0Qn3