Breathed new life into my Rotak 43Li mower by just replacing the battery!
Replaced my previous 2.6Ah battery which must be 12+ yrs old and was only holding enough charge for 10-15mins of mowing. Noticed an immediate difference when mowing with the new battery - faster spin speed for blade and that means a better cut and better grass clipping collection, so I'm very happy with the new unit. Not been able to determine 'mow time' yet, but I'd imagine double at least given the age of the old battery.