I happened to notice yesterday that my Commando battery (just over 12 months old - isn't it always the way?) was not only flat, but virtually dry, apart from a single cell. I decided that this meant it really was shot, but out of curiosity, refilled it with de ionised water and stuck it on charge. It's still on charge now, but every time I disconnect and stick a voltmeter across it, it happily registers a higher voltage than before - before slowly starting to decline. Right now I'm upto a pretty steady 11.5 volts.
I realise that this is of purely academic value as it would probably be foolish to rely on such a battery, but the question is, why /how did it lose all its fluid in the first place? It performed well last summer on the bike and spent the winter on an Optimate charger. I would have thought it unlikley to be the Optimate at fault, so this would suggest a problem in the charging circuit of the Commando?
The bike is a 2a, no electric start, and has a Boyer power box and ignition system. The battery is a Unibat C14. The voltage warning light comes on at about 1500 - 2000 revs with lights/indicators and brakes on, but goes out again when normal revs resumed. This is all I know. I am reluctant to throw another new battery at it without some investigation for which any suggestions would be gratefully received.
Hi David - I assume that y…
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I suggest the optimate. I…
I suggest the optimate. I use one and they will gas the battery, if not checked at least monthly then it would eventually dry out. I thinktheirclaim is for the purely sealed AGM batteries.
I leave all my batteries dis-connected and / or removed from the bike if left for prolonged periods when at sea, charged monthly they last for ages. The Optimate is good for when I have been away from the UK for months as they will recover the battery well.
The charge warning lamp can be a bit optimistic, having found this out early in my commando ownership. I was advised to put aammeter in line to the battery supply and actually measure the current going to and from the battery, surprisingly it showed a charge going to the batterydespiteglowing dimly, not bothered about it since!
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Hi David - I assume that you checked the battery fluid prior to putting it the Optimate charger. From my experience once a battery has been left 'high-and-dry' for any period it will never really recover. I suspect that either the battery was suspect in the first place or the bikes charging system is a little 'over enthusiastic'. As you suggest - I doubt that the Optimate is to blame although depending on which model you have I would have thought it might have flagged-up a battery problem when first connected - - .
I'd try another 'oldish' but reasonable battery (if you have one - even a car battery should be OK) wired to the bike and check the charging system as the first test. At circa 3500 rpm (lights off) the battery terminals should show around 13-14v (not much more). With lights on it should be about the same or perhaps a little lower. I have a Boyer Power Box on my Commando (albeit 3-phase) and it's been fine for about five years.