Alex28 said:
It's a $20 charger, and it says for batterys that have never had a charge you should charge it for at least 35 hours. It doesn't harm anything leaving the battery in the bike while charging it right? It's a hassle to remove it if there is really no reason to do so.
A) $20 is cheap for a charger, and I don't trust cheap chargers much.
B) How a charger could say that it takes 35 hours to charge a battery without knowing the size of the battery is just plain ridiculous.
A lead acid battery (which your battery probably is) doesn't need an initial charge. When you pour the acid into the battery it starts off charged.
If you drain a battery so that it is completely dead then you WILL damage it, how long it sits dead determines how much damage. You don't want to do that.
If the battery is just low you can calculate how many hours it will take to charge the battery based on the size of the battery and the charging current available. A typical motorcycle battery will be between 4 and 8 amp-hours. If you have an 8 amp-hour battery, and charge it with 2 amps, it will take at most 4 hours to fully charge it, assuming it was nead dead when you started.
A cheap charger won't provide a constant current so you may have to double or triple the time in order to compensate for the current tapering off as the battery voltage comes up.
I would NOT leave a cheap charger on a motorcycle battery for more than a few hours as it could over charge the battery. 'Battery tenders" are very low output chargers that are designed to not overcharge and these can be left on, but don't expect them to charge a dead battery.
Bottom line, though, is that if you just got a brand new battery, put it in and go ride!
Rod