Hi Steve:
When I had my 2007 ST1300, I used a simple old-fashioned lead-acid (
L-A) wet-cell battery. I know that weight is a concern (I am an automotive engineer...) but, IMO, the difference between a "regular"
L-A battery and a super-duper high-tech
LiPo or even an
AGM battery is hardly worth worrying about in a bike as big and heavy as an ST (I mean - what is 3-5 lbs on a 700+ lb motorcycle that carries about 60 lbs of fuel and has a 200+ lb rider on-board plus a bunch of luggage?). You are likely talking less than 1% of total weight and more probably, less than 0.5%.
If you are really that concerned about weight, clean all the crap out of your panniers and top-box and you'd likely be ahead, and if that still isn't enough, skip lunch a couple of days before the trip...and you'll be there.
The other thing about the various types of batteries are their specific characteristics - some of which are
not great on a bike that is as hard on batteries as the ST1300. The problem with the ST is that the battery box is pretty small and the bike demands a fair bit of cranking power for that high-compression 1270 cc engine with all those camshafts, balance shafts and teeny-tiny little valves whirling around and going up-and-down. The biggest battery you can put in the stock ST1300 battery box is, IMO, not really big enough for the bike.
Anyhow, based on my 42 years of experience as an engineer and an RC model airplane flyer, here are my takes on the various battery types:
- Lead-Acid - aka L-A: these are the standard traditional wet-cell "car" type battery. Modern "sealed" examples do not need to have their electrolyte replenished because modern charging systems don't tend to over-charge and cause the water to "boil-off". They are a tad heavier than the other battery types but they are cheaper and when they start to die, they usually give plenty of warning that "the end is near" - so you can prepare for the trip to the store to get a new one. I use a battery maintainer regularly on mine and I usually get 4-6 years out of my L-A batteries.
- LiPo - aka lithium polymer: these are the lightest most expensive batteries that are generally available and while they are great in weight-critical applications like aircraft etc. and for use in electric vehicles where weight and energy capacity truly is crucial and the charging systems are designed for their 3.7v basic cell voltage (an L-A battery is about 2-2.1 volts / cell). Thus, LiPo batteries require careful handling and charging system operation and if there ever is a fire - your bike WILL be gone.
- AGM - Absorbed Glass Mat: this refers to the type of construction used inside the battery. These are somewhat lighter than L-A batteries and they are also more expensive - but still cheaper than LiPos. AGMs can give good service - BUT - when they die, it is usually without any warning at all and they die suddenly and very, very, very, dead. I have had two recent experiences with AGM batteries which were eerily similar - and have warned me off them for my bikes:
- my wife's 2020 Hyundai Santa Fe had traveled at least 700 km (about 400 miles) all over Ontario one nice warm day last summer without any indication of a problem and the very next morning, the stock original battery (then about 25 months old) was so dead that the power door locks would not actuate. It would take a charge and then die again within about 20 minutes.
- last Fall a bunch of us were on a bike trip and had ridden about 5-600 km (300-360 miles) one day and the next morning, one of my riding buddies on a 2021 Honda Gold Wing found that his bike wouldn't start - and again, the electric locks on the panniers etc. would not actuate. The bike was towed on a flatbed to a dealer and they had some secret way of getting into it and found that the stock AGM battery (also just a tad over two years old) was utterly crapped out.
In both cases, the batteries
should have been fully charged - and yet after a full day of running without any difficulty at all, they were utterly dead. So, for my money, I will simply keep using lead-acid batteries because I value the warning they give of impending death - and I will compensate for the small increase in weight by skipping lunch the odd time.
Pete
(My comment in post #2 about weight was in jest).
antigravitybatteries.com
