well i have an esr16...its been run over....dropped.....yanked.....drenched...new pump fitted...same battery and its still goes although i have to take the tank of and put the charging clips on the actual battery terminals to get it to charge now..think the charger has had it but i only use it for a couple of jobs a month. although i always think should i go back to using it all the time..now that big boy 22 litre one has come out i might try that especially on front onlys where there are three or four in a row. saves getting tied up in hose.