After serving me for 3 years my trusted Banner 28 Ah battery died. So I searched for replacement and only suitable motorcycle battery that I found was Unibat 28 Ah at a price of 106$
and the reviews are not so good. I payed for Banner 60$!!
In a search for another solution I found out that a local guy on his RT80 was using a car battery from Daewoo Matiz that costs around 60$ with 2 year warranty. Dimensions fit the battery holder, and just battery terminals must be adopted with leads.
As this car battery is 35Ah, is there any danger for the alternator? If I understand alternator operation correctly there is no danger only it will take longer to charge the battery.