Barry Adamson

I use an 8 volt battery with my small bulldozer. I need to recharge the battery but only have a charger with settings for either 6 or 12 volts. Would using the 6 volt setting be the best choice, or do I need an 8 volt charger? When the battery is installed in the dozer, the positive terminal is grounded. Would this change the way I connect the charging leads? I feel I should still connect the negative lead of the battery charger to the negative post. Correct? Thanks.