Battery will not stay charged when I mow. I have a battery charger to charge it . If I mow for a while and just stop for a drink of water I have to charge it again before it will start. I don't want to buy parts I don't need.

David, April 2010

This is pure guesswork based on zero experience... and no knowledge of lawnmowers...

If your mower has an old fashioned motor-driven Generator to charge the battery - rather than an automible style alternator - then there will need to be a relay between the battery and the generator to disconnect them from one another when the motor stops - else when the engine stops the battery will be trying to turn the generator over as if it were an electric motor - and quickly become discharged.

I would look for a realay in the charging circuit and be very suspicious of it.

Good luck...

Peccavi, April 2010