crsuperman34 Posted February 13, 2011 Share Posted February 13, 2011 My battery won't start the bike, but almost does. I put it on trickle charge and the charger says charge complete... but I know it is not. I also know that the battery is still good, just a little low. Should I leave it on trickle charge overnight anyways? The battery is: 12v /19Ah Bmw exide gel This was the charger I was going to use: http://www.minnkotamotors.com/products/battery_chargers/portable_chargers/mk110p.aspx its not intended for gel batteries Link to comment
JR356 Posted February 13, 2011 Share Posted February 13, 2011 Yes,will not hurt to leave it on. Don't know this charger but specs show it should be sufficient for you needs. Have you checked/cleaned/tightened the battery connections? How old is your battery,once they start to go/don't hold charge,it's replacement time. JR356 Link to comment
dirtrider Posted February 13, 2011 Share Posted February 13, 2011 Morning crsuperman34 Personally I wouldn’t leave it on all night. The specs from the charger web site say---- “For use with 12V / 6-cell batteries (40-130 amp hour rating) that are flooded/wet cell, maintenance free or starved electrolyte only”---- Your battery is a Gel Cell and well below the 40-130 amp hour rating. At 10 amps total output a couple of hours should be more than enough to top off your battery. OK, now to your possible issue. If a couple of hours charging won’t bring your battery up to starting output you could have a bad battery. Those BMW Gel Cell batteries have a habit of failing somewhat like you are seeing. They look to be fully charged and the battery charger treats and shows them as fully charged but under cranking load they just fall flat and don’t have enough output to start the bike. It seems a lot of Gel Cells can act that way as they somehow go internally open under cranking load. (I have personally seen quite a few do this). Try charging the battery for a couple of hours, then see if it starts normally. If not look for the obvious like loose battery cables or loose cable connections to chassis ground or loose at the starter. If nothing found then have the battery LOAD TESTED with a proper small battery load tester. You BMW dealer probably has a battery load tester but that is usually for their warranty requirements so those battery testers are not the absolute best at finding marginal battery’s. To just get your bike started you might try starting it with the battery charger still connected to the battery. Link to comment
4wheeldog Posted February 13, 2011 Share Posted February 13, 2011 Just my opinion, but I don't think gel batteries are worth the trouble. AGM batteries work great, and have all the advantages of a gel, with none of the headaches. Gel batteries do not have the cranking punch of AGM or flooded, are finicky about how they are charged, and seem to fail early. BMW must have gotten a hell of a deal with the supplier...... A wealth of good info here: http://www.windsun.com/Batteries/Battery_FAQ.htm#Gelled electrolyte Link to comment
NonComp Posted February 13, 2011 Share Posted February 13, 2011 I had a new battery go bad like this. Same symptoms. One bad cell. The others were fully charged, but the cumulative voltage of the remaining cells was too low to start the engine. Charger showed charge completed successfully, which was true for the remaining cells. I returned the battery under warranty to the dealer and they replaced it. Gel cells can sometimes lose contact with the cell plates in motorcycle applications, due perhaps to vibration. Link to comment
Frog Posted February 13, 2011 Share Posted February 13, 2011 I use a 2 amp setting for an overnight trickle charge, just did my mid-winter maintenance charge in fact. 10 amps really is a fuller charge, not a 'trickle' charge, and overnight is probably too long. Real trickle chargers are often 2 amps or even less. My BMW gel went out not long after I bought my used RT and I put an Odyssey dry cell in mine, works great! I think the BMW battery was only about 3 years old so not they are the best batteries out there by any stretch. Frog Link to comment
AndyS Posted February 14, 2011 Share Posted February 14, 2011 My battery won't start the bike, but almost does. I put it on trickle charge and the charger says charge complete... but I know it is not. How do you know? I also know that the battery is still good, How do you know? Take the battery out of the bike, with it as fully charged as you can get it. Take it to a battery dealer (in the UK tyre depots also have battery testing facilities) and get the battery load and capacity tested. This is the only way you know if the battery is 'good' or not. If the battery is good, you can then look at the more likely culprit - and that would be the starter motor. Notorious for giving these sort of problems. Andy Link to comment
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