I bought a new BS BTZ14S three weeks ago. I fully charged it on the day it arrived, fitted it to the bike and connected to an Optimate. Over the last week, the Optimate has been signalling that the battery is weak and a voltmeter shows the voltage at 11.5 volts. I've taken it off the bike and am charging it with a traditional charger to see if it'll hold a charge. This battery was bought to replace the 4-year-old Yuasa that came with the bike, which was starting to show a weak indicator on the Optimate. Wondering if the Optimate could be the problem, rather than the new battery?
It is possible for a charger to be at fault.I had an Oximiser which started to drain the battery instead of charging it.I removed it and put one of my other chargers on the bike,everything was then fine.The Oximiser had been bought many years ago so perhaps a component just gave up the ghost.
In the absence of a decent voltmeter or ammeter, have you tried turning the engine over with the new battery after leaving it off charge overnight? A new battery should hold charge and be lively but if it is sluggish, it is a duff battery. There may also be nothing wrong with the Yuasa if the new battery is Ok but the charger says it isn’t
At 11.5V, the battery is toast. A new one should be giving at least 12.8V. It's possible it was filled and put into service incorrectly? Never had much joy with BS batteries in the past....tried most of the brands and have always ended back on Yuasa.
Just fitted a new Yuasa to the Mutley as a precaution ahead of a recent tour, was turning over and starting fine. The original, usually on a Optimate, was almost six years old, probably bang on six years from factory. Shame it's now sitting in a French breakers yard along with the bike...
Ended up buying a Yuasa from Halfords today. Hopefully won't go the same way as the BS (which is going back for a refund), otherwise will have to blame the Optimate.
