If you are a fan of batteries with explosive power and you have the means to afford it, the Shorai LFX18A1-BS12 Battery is probably one you should look at. Long-lasting, it is a battery that will work hard for you and one you should be able to get a lot of joy out of. It’s a Lithium-Ion battery with 18Ah 12 Volt “A” polarity. Lithium batteries are generally very safe to use and by nature, are highly unlikely to explode during charge. Also, due to the Lithium battery, it delivers more power to the bike and makes for a longer-lasting experience.
It also charges pretty quickly, so you know you’re not stuck waiting for ages for your battery to charge which in turn means you can get back to riding as soon as possible, so if you have a bike that consumes a lot of power, like your Harley, you should opt for a Shorai.