Batteries are Good ... Until They're Not

[SportsterDoc]

I always buy a quality AGM battery that you have to add the acid and then do an initial charge. Who knows how long the ones with the acid installed have been sitting on the shelf.

They usually have a sticker for month/year of manufacture.

If you can find a factory vacuum filled AGM, as Dekka did for H-D, they have a longer life than atmospheric filled...the plates absorb more.

The problem is determining which are vacuum filled.

 

[canamjhb]

When not in use for a long period I keep my battery on a maintainer. Yesterday, 5 days before leaving on an extended tour, I unplugged the maintainer. Today I started the bike and let it run for an extended period. On Thursday, the day before I leave for my trip, I will start the bike again to make sure the battery is up to snuff. The reason I do this is because the maintainer can produce a false sense of security. The bike may start well when unplugging the maintainer just before a trip. But actually be done for, and not give any indication until the next day. This happened to me several years ago. Unplugged the maintainer and rode off for a trip. 300+ miles later stopped at a motel. Next morning I had zero battery. No light, no click, nothing. It was if the battery had been removed from the bike. Bike towed to a dealer who replaced battery, checked charging system and sent me on my way with no further problems..... Jim

 

[SportsterDoc]

Yup ... This " I replace mine every four years whether they need it or not."

And an AGM seems to give less (or no) warning compared to a wet lead-acid.

 

[Peteoz]

When not in use for a long period I keep my battery on a maintainer. Yesterday, 5 days before leaving on an extended tour, I unplugged the maintainer. Today I started the bike and let it run for an extended period. On Thursday, the day before I leave for my trip, I will start the bike again to make sure the battery is up to snuff. The reason I do this is because the maintainer can produce a false sense of security. The bike may start well when unplugging the maintainer just before a trip. But actually be done for, and not give any indication until the next day. This happened to me several years ago. Unplugged the maintainer and rode off for a trip. 300+ miles later stopped at a motel. Next morning I had zero battery. No light, no click, nothing. It was if the battery had been removed from the bike. Bike towed to a dealer who replaced battery, checked charging system and sent me on my way with no further problems..... Jim

Yes, it is exactly that “constant maintainer plug-in” scenario that caught me out on an overnight trip, Jim.
Fortunately, we were only 20km out of town and I was able to start the F3 with Lamont’s jump pack, and there was a motorcycle shop in town that had the correct replacement battery. Otherwise it would have been a REAL inconvenience as there was no phone reception. I now constantly preach about the “gotcha” of plugging in the maintainer every time you pull into the garage.:thumbup:

Pete

 

[ulflyer]

I put a Might Max in mine back in late 2020 and its holding up fine for what I paid...$67. Looks like this one but did not buy from Ebay ...I think it was a Walmart vendor:

https://www.ebay.com/itm/1337807929...1291&msclkid=3918a1b1455d1b6ab6c6c3508320bd09