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[Les H]

Thanks for your warm welcome back after my absence, this Forum is always tops when it comes to being the friendliest and most enthusiastically used for a single make of motorcycle. Sorry by the way for writing such a long post, I know it annoys some. It didn’t take long for it to mount up even though I purposely missed out the more detailed stuff on battery care such as the hydrometer, that Alan makes mention of, which is an essential tool for really knowing what’s going on in each cell and tracking down the faulty ones. I just tried to stick with the theme of using a high amp charger with a small battery. As regards faulty batteries, if caught early enough, there are ways of salvaging a battery and overcoming even repairing a faulty cell/s (Like removing the sulphation the No1 Killer) I’m sure loads of batteries are ruined by incorrect storage and charging and many are discarded when they could be brought back to health relatively easily although it does sometimes take a bit of fiddling around and is a little time consuming, so for many a new battery is just more convenient but large car batteries are often very expensive and these can be saved too. However, once a battery develops a bad internal connection or short, it really is the end of it, which is why I stressed the point of not overheating a battery. I have learned during the process of rejuvenating a battery, where sometimes massive over charging has to be carried out, if the temperature is allowed to rise too much you can suddenly have the battery fail completely which is galling when you have got it just back into serviceable use but just took it too far too quickly and then lost it. As far as using a light bulb to control current Alan suggests, I’m pretty sure some ancient chargers used that method. They had a torch bulb in series with the output and mounted it under a big red lens on the front of the charger. The idea works like this: When you have a high current flowing into a flat battery the bulb illuminates fully but at the same time the filament is white hot the resistance of it is very high and so limits the maximum current. As the battery charges and it’s voltage rises the current drops off and the bulb starts to dim, but the resistance also lowers and counteracts the lower charge rate to an extent so helps maintain a somewhat higher charge rate until the battery is fully charged. Once the light had dimmed fully the battery was charged and you either switched to trickle charge or removed the battery for usage. Good chargers have come a long way since then. The hydrometer (It is difficult to get a decent small one for motorcycle batteries) does give an insight to what’s going on or going wrong inside each cell. After a time, there is always one cell that is going to get sulphated just a bit quicker than the rest, but the charge system is not going to see that and can only respond to the overall voltage at the terminals. So where that individual cell needs a different strategy of charging to improve it or pull it out of its rapid decline you and the charger will be unaware of it until the whole battery appears to be faulty whereas the other 5 cells are perfectly ok. With certain methods the bad cell can be pulled up and thus the whole battery’s life extended. It’s getting too long again isn’t it? CU another time then.

[Mark M]

Sorry to go off on a slight tangent but I've always been suspicious of these over winter trickle charger systems for bike batteries. In the spring I regularly see shiny bikes at the side of the road with flat batteries and when I stop the owner frequently says "but I've had it on an Optimate (or similar) all winter". As Les points out (paraphrasing, Les!) our type of batteries prefer to be used and "cycled" properly. I ride all year on a modern and cold weather electric starts are punishing on a battery but in the long run I'm sure they last longer. However I did have a battery drop dead on me one day and when the RAC man came to jump start me he said sudden failure is much more common these days, he put it down to poorer manufacturing quality of the raw materials. Sorry to muddy the electrolyte!
REgards, Mark

[Norm]

I usually have 5 or 6 batteries sitting on a shelf all out of different bikes. Some sit here for months others not too long. I have one of those trickle chargers red light charging, green means fully charged. Once it is green I switch it off and once every couple of weeks I work my way around the batteries again and usually the batteries come back up to charged in a few minutes. Seems to work of, but todays batteries aren't that flash, particularly the wet acid Chinese ones