Question on battery charging and RPMs

[dcom]

A couple of days ago, my wife thought she might like to take her new Reflex out for her first street ride so we get all geared up, go out and find that the battery was dead almost completely dead...barely enough to run the digital clock on the speedo. When we picked it up, the dealer charged it and it had been starting fine several days earlier but it hadn't been ridden in a few days. Since she's learning on it, most of the riding has been slow, usually less than 15 mph in the parking lot. I would ride it down there (maybe a mile) at street speeds but then she'd ride for about an hour at the slower speed, then I'd ride it home. We don't leave the key on when we park it so there shouldn't be anything else that would use the battery when we shut it down for the night.

I know that the battery runs all the lights while the engine's going but does anybody know if the charging circuitry in scooters usually requires the RPMs to be above a certain level before the battery will charge? I recharged the battery overnight, then took it down to have it tested and it is apparently a good battery. The dealership didn't have a clear answer, they just said to charge it and if it dies again after "normal" riding, bring the scooter down for them to check.

[Logan]

It's true for 'cycles so I'm sure it's true for scooters too.

On many (most? all?) models, at idle you are discharging faster than you are charging. Generally, rpms need to be around 2-4,000rpm to remain in a positive state.

If it is indeed new, it may not have been fully charged at the dealers before purchase.
Make sure you didn't leave the "parking lights" lit when you shut it off.
Also be sure your connections are tight & that the cells are properly filled too.

[midknyte]

I've seen it said or read, that you need to ride for 30 minutes to recharge the battery from a/the cranking start.

Your best bet, and you should anyway, is to get a battery tender. A motorcycle battery should not be charged / recharged by a higher amperage charger suitable for car batteries. A battery tender, as well as maintaining the battery between trips, is capable of slow charging a battery in the proper fashion as well.

A tender will come with a pair of "pigtails", a length of wire with a mating plug to the charger, that you leave attached to the cycle so that it is an easy matter of just plugging it in when you get home. And when winter comes, you just plug it in and forget about it til spring.

[TorontoBoy]

A Haynes/Clymer manual should have the exact RPM for recharging. In a Honda 125 manual I have it says 1,000 RPM for recharging with no headlight on and 3,000 RPM for recharging with headlight on. I'd agree with midknyte that you need sustained RPMs for 30 minutes to recharge a battery. The more electrical accessories you have the higher the daily battery drain. I've read that LA batteries will normally discharge 1-2% per day on their own.

You need to plug that puppy in between rides, because the deep discharging your doing to the battery is to its detriment. Plug your Battery Tender in after each ride and get a fresh battery for your next ride.

[honeygee2]

Hi....this is only a guess on your battery discharge situation...........I had a silverwing for about three years annd on it when you lifted the seat to store things a little light came on inside the "trunk"....if you didnt slam the trunk shut all the way the bulb continued to burn and then kill the battery......I took the bulb out and never had a problem.......I dont know if the reflex's have the same setup but if they do take the bulb out......check the owners manual........hope this helps....Geoff

[dcom]

Thanks for all the suggestions. I think what happened is what I suspected...that we didn't run it at high enough RPMs for long enough, combined with an incomplete charge from the dealer. The scooter is a 2003 model and had 0 miles on it when we got it, but the dealer said they didn't keep the battery in it so they charged it when we went to pick it up. This took about 2 hours so I don't think they put a full charge on it. The connections are tight and the battery is one of the sealed kind so you can't check the levels but I think now that her skills are improving, we'll be riding it at higher speeds which should help.

Geoff, the Reflex does have the same cargo light under the seat but it does go out when I latch the seat.

I don't have a true battery tender/trickle charger, it charges at 1 amp but the battery indicates you should charge it for 5 to 10 hours at 1 amp so that's what I'll do if we run into this situation again.

[Logan]

Here's a good resource regarding the charging of bike batteries:

http://www.bmwmotorcycles.com/rides_resources_maintentence_battery_care.html