how long to charge battery?

tristantumble · March 15, 2009, 06:00:19 AM

Weather is getting better and i'm already thinking about pulling the bike out of winter hibernation. My question is, i've had my battery out all winter, and before i put it back in, how long do i plug it in to charge. My charger doesn't show how much to a full charge, so i have to go by getting a rough estimate from some of you.

thanks.
tt.

Ddan · March 15, 2009, 06:08:53 AM

Your best bet is a battery tender that will monitor the charge and go into 'float' when the battery is topped off. A completely flat 12 A/HR battery will take about 6 hrs at 2 amps.

tristantumble · March 15, 2009, 06:22:29 AM

is there a danger in over charging/under charging? I don't want to have to buy another charger if i don't have to.

Howie · March 15, 2009, 07:14:17 AM

Quote from: tristantumble on March 15, 2009, 06:22:29 AM
is there a danger in over charging/under charging? I don't want to have to buy another charger if i don't have to.

If your charger does not automatically go into a "float" or maintenance charge, yes. Dan's advice is good. If you have a voltmeter, first check your battery voltage. The table below is actually low for your battery since it is an AGM type, but close enough.
11.7V = discharged
12V = 1/4 charge
12.2V = 1/2 charge
12.4V = 3/4 charge
12.6V = full charge

The idea is to replenish the charge, in other words, to use Dan's numbers, if you have a 12 amp hour battery and it is fully discharged you need to put 12 amps back, which would be 2 amps for 6 hours, 1/2 charge, 2 amps for 3 hours, or, if your battery charger puts out 1.2 amps, 6 hours

needtorque · March 15, 2009, 08:44:54 AM

Another tip for next winter. When I was living in MI I would take the battery out double wrap it in plastic bags then put it in a paper bag and stuck it in my freezer. (this was after a full charge) I kept the stock battery for 5 years in this manner and it would crank perfectly after installing it in the bike come spring. I did not even have to charge it. The cold would slow down the discharge process and it seemed to work great for me.

dlearl476 · March 15, 2009, 10:28:20 AM

Quote from: needtorque on March 15, 2009, 08:44:54 AM
Another tip for next winter....
The cold would slow down the discharge process and it seemed to work great for me.

Why not just disconnect it and leave it outside?

AFAIK, heat and cold are the enemies of batteries. I've always heard batteries are best stored at full charge in room temperature. Although I just bought a spare LiIon battery for my flashlight that said it's best to store an out-of-service battery at a low, partial charge (~25%) Then again, I have yet to see a Li Ion battery for a bike.

needtorque · March 15, 2009, 10:37:33 AM

According to the man who taught my electrical class cold slows down the electrolyte conduction process thereby lengthening the discharge process. I tried it and it kept a stock battery working great for over 5 years.

Also dirt on the battery can be blamed for excessive discharge of the battery over time. The dirt, grease, dust on top of the battery allows a small electrical charge to run across the top of the battery from post to post and can discharge a battery.

He experimented with this theory by taking identical batteries with full charge and did the following. One was placed in bags in a freezer, one clean in bags on the shelf, one with normal dirt/dust on the shelf for control, and one with excessive dirt/dust on the shelf. He left them there for 3 months and came back. The one in the freezer (after a good thaw) had the most CCA. The one on the shelf, clean and in bags, had the 2nd best CCA, the one on the shelf that was control had the next best, and the dirty one on the shelf had the least. Test this for yourself if you like, who knows, maybe you will prove him completely wrong.

DuciD03 · March 15, 2009, 12:29:23 PM

Quote from: needtorque on March 15, 2009, 10:37:33 AM
According to the man who taught my electrical class cold slows down the electrolyte conduction process thereby lengthening the discharge process. I tried it and it kept a stock battery working great for over 5 years.

Also dirt on the battery can be blamed for excessive discharge of the battery over time. The dirt, grease, dust on top of the battery allows a small electrical charge to run across the top of the battery from post to post and can discharge a battery.

He experimented with this theory by taking identical batteries with full charge and did the following. One was placed in bags in a freezer, one in clean in bags in on the shelf, one with normal dirt/dust on the shelf for control and one with excessive dirt/dust on the shelf. He left them there for 3 months and came back. The one in the freezer (after a good thaw) had the most CCA. The one on the shelf clean and in bags had the 2nd best CCA, the one on the shelf that was control had the next best, and the dirty one on the shelf had the least. Test this for yourself if you like who knows maybe you will prove him completely wrong.

... intresting; experiment and all; thanks!

tristantumble · March 15, 2009, 01:42:54 PM

i have been keeping my battery in the garage, not heated so it was kept fairly cold. the charger i have is this : http://reviews.canadiantire.ca/9045/0111543P/reviews.htm

Howie · March 15, 2009, 01:53:57 PM

Cold actually preserves battery life. The colder, the slower the discharge rate. Where the risk factor comes in is a discharged battery will freeze, therefore, if in the freezer long enough it will freeze.

Quote from: tristantumble on March 15, 2009, 01:42:54 PM
i have been keeping my battery in the garage, not heated so it was kept fairly cold. the charger i have is this : http://reviews.canadiantire.ca/9045/0111543P/reviews.htm

There is not enough info on that charger. My guess is it is a 1 amp charger so a fully discharged 10 amp hour battery will take 10 hours to charge. I would also assume that charger will not bring a maintenance battery up to full charge, but will charge the battery good enough to start the bike. You also should have been occasionally charging your battery while in storage. Undercharged batteries over time will suffer permanent suphation.

Rameses · March 15, 2009, 09:21:46 PM

I'm totally ignorant on this subject, so please forgive me if this's a stupid question, but is there any benefit to charging the battery with a charger prior to installing it rather than simply putting the battery in, jump starting it, and then letting the bike charge it while it's running?

dlearl476 · March 15, 2009, 09:43:23 PM

Quote from: Rameses on March 15, 2009, 09:21:46 PM

I'm totally ignorant on this subject, so please forgive me if this's a stupid question, but is there any benefit to charging the battery with a charger prior to installing it rather than simply putting the battery in, jump starting it, and then letting the bike charge it while it's running?

Most MC charging systems are woefully inadequate when it comes to charging a battery. Unless you intend to jump it, then ride 75-100 miles or so, it's not going to get a full charge and constantly running on a partial charge leads to premature sulfating.
I saw a BMW tech bulletin once that recommended charging a battery once a week if it was ridden an average of 15 miles or less per start. (which is just about always.) I must admit this was a while ago, before seal, gel, agm, etc. batteries became the norm, but I don't believe it would change much for these battery types.

Rameses · March 15, 2009, 11:46:05 PM

So assuming one plans on running out a tank of gas, my question still stands.

WTSDS · March 16, 2009, 12:23:52 AM

>> So assuming one plans on running out a tank of gas, my question still stands.

If the charging system is working properly a run using a tankful should do the trick, that's what the voltage regulator is all about

Only probs are if you stall the motor halfway, or find out at the fuel stop that your new batt is a dud

Howie · March 16, 2009, 12:44:56 AM

Batteries should be fully charged before put into service.

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how long to charge battery?