Choosing a motorcycle battery

Motorcycle batteries come in a variety of constructions for a variety of motorcycles. The older ones are flooded lead acid and typically are white and you can see the battery acid inside them. These generally start with a YB prefix for the part number and are usually found in older motorcycles. They don’t have a lot of cranking power but the motorcycles they go in don’t need a lot.

They can be upgraded to an AGM battery of the same physical size, but more cranking power and a better all around battery for about the same price. AGM stands for Absorbed Glass Matt and these mats in the battery literally absorb the liquid making them spill proof and withstand more vibration.

In the AGM line there is a term called factory activated which means the factory puts the acid in and seal the battery and charge it before they ship it. There are some applications that have to have this, such as a sea doo where the battery is mounted on it’s side and it HAS to be spill proof.

Most AGM motorcycle batteries are shipped from the factory without the acid in them. They are supplied with an easy to use container full of acid for the battery store or the end user to fill them up and charge them. This means the battery can sit on the store shelf for years and not go bad as it hasn’t been activated until it is needed. These ones can be mounted on their side as well, but we have a little less faith they won’t spill as the sealing lid isn’t quite as good as the ones the factory uses.

In either case the sealing strip is NEVER removed and the water or acid is NEVER added.

The part number for these usually have a suffix of BS meaning bottle supplied. It is very easy to fill them, and nowhere near as dangerous as some people may think. They give you the exact amount in the bottle pack for that exact battery and it’s as simple as pushing the bottle pack on to to the openings of the battery that are designed to take it. Once the acid is put in, the battery immediately becomes about 50% charged, and then putting it on a small battery maintainer finishes the job. (Everyone should have a small battery maintainer at home to put on their motorcycle battery in the off season anyways)

A lot of times the question from the customer is “ Is it ready to go?” and it can be a balance for the battery store to have them filled and ready to go, versus having to scrap them if that particular part number did not sell that season. Most places will adjust their prices to offset the inevitable scrapped ones, here at Pacific Batteries we do not, we just try to encourage people that if they do need to fill one, it really is quite easy.

Gel motorcycle batteries are also available and they generally have a little higher cranking power. There is not a lot of difference between the GEL and the AGM – the gel’s just gel the liquid instead of absorbing it into a a mat – with a similar result. The GEL’s have a small advantage in how long you could run the stereo with the bike off, and maybe a bit more crank, but as a whole unless the price is a lot better, the AGM does the job very well.

The next step up is lithium batteries. Their three main advantages are much less weight, slower discharge time, and can sit for much longer without being charged. Lithium is the lightest metal on earth and can store a lot of energy. They charge quicker, and deliver a lot more cranking power than a lead acid battery. They typically last twice as long as a lead acid battery and they are a lithium iron construction, NOT lithium ion like your cell phone. They are referred to as LiFePO4 and are much less dangerous to use and handle with excellent thermal and chemical stability.

It used to be the battery did not have a built in management system (BMS) and the early versions had a high failure rate. This was typically user caused by not using the appropriate charger with the BMS built in to the charger. They progressed to where the battery management system was built into the battery itself, and regular chargers could be used (with some exceptions) causing much lower failure rates.

The down sides are that some bikes won’t charge them as you ride if they aren’t at least 13.1 volts at idle and 13.6 volts at speed. Also, while you can use a regular battery charger on them, you have to be careful it doesn’t have an automatic desulfation, repair, recondition, or recovery mode. Another drawback is if you mess up, it’s an expensive mistake compared to lead acid. They are more of a universal fit in general, and you are provided with stuffing material to fill the battery box as needed.

Getting to know your lithium battery matters, they read differently than a lead acid battery with full being 14.34 volts not under load, and 12.86 is critical to not go below which is about 20% of juice left in it.

If you decide to go with lithium it is probably best to buy the appropriate charger meant for the battery.

So it all depends on your motorcycle and your riding habits. There is absolutely nothing wrong with AGM motorcycle batteries, and for your average rider they are the best all around bet. If you have a sport bike and each pound matters, or if you just like the idea of less battery changes, or if you have a high amount of accessories then moving up to the lithium is probably a good idea.

Regardless of your choice the brand matters. All lead acid batteries have to be made the same size as their part number dictates. A YTX14AH-BS for example has to be the same dimensions no matter who makes it. The prefix doesn’t mean a lot, the 14 refers to amp hours (which is a little odd because it is the CCA that starts the bike, the AH is how long it will go with the bike off and accessories running) the AH refers to the polarity and the BS just means bottle supplied.

We supply the CCA rating to all our motorcycle batteries.

An AGM battery for say a Harley is typically a part number YTX20HL-BS. The H stands for heavy duty. The L stands for which side the negative terminal is on. You can get a YTX20L-BS the exact same size with a little less crank. The bike manufacturer provides the cranking power required, so you can purchase the spec’s they provide. It is generally a good idea to go a little higher with the “H” model because as the bike ages, some power transfer is lost.

A company like YUASA is recognized as making good batteries, They cost more because they cost more to build. There are a ton of off shore brands and some work pretty good, some not so much. About the only way you can know is when the battery store themselves test them before they sell them like we do.

The number one cause for motorcycle battery failure is not using a battery maintainer for the off season.

Happy Riding