It seems that battery chargers, like most things in life have become increasingly and unnecessarily over complicated. I've had my Optimate for 12+ years, used it on numerous, car, bike, lawnmower, burglar alarm etc. batteries with no problems. It has no controls at all. Connect the battery, plug it in and walk away. I rely on the "intelligence" (?) of the device to monitor the state of the battery and do what needs to be done, which it appears to do satisfactorily. It's plugged into the Vee battery all the time the bike is not being used. I'm very suspicious of claims made by charger makers that by some miracle they can resurrect batteries from the dead I.e. deeply discharged, seriously sulphated or just plain crap make batteries. The only problems have been with the Optimate is the quality of the plugs on the connecting flex that leave a lot to be desired and could well be better designed and made. There are a lot of so called "intelligent" chargers about and I'm sure some of them don't do batteries a lot of good. As an example I bought a Lidl charger which makes all these wonderful claims as it has a 6v facility for my old bikes, but I'm sure it over charges when the battery is at full charge and probably shortens the life of the batteries if left connected all the time, so I end up disconnecting it after a few hours which defeats the object of having it.