i had gotin one and it was no good,went back got one more dead in one day went back a third time and finelly got a good one hope you have better luck..

well, wait, what battery do you have in the 4 wheeler? it might be a 6 volt, and the charger might be for 6 volt systems... that would explain why it wouldn't charge the optima.

anyway, i'll let you know by the weekend how the charger is.

I hear good about these; www.odysseybatteries.com

at 200 mA it produced 1.6 volts - more than enough to keep a battery in top shape, i would think.