with key on 10-11 volts at gauge, 12.5 at batts, new batts,starts slow some times seems like needs tons of power? shut off batt switch charges at 13.5, switch on charges at12.5?accs also make gauge drop 1volt

Check for a corroded wire some place. You could have bad starter wire. Make sure your ground is also good. When this happens have you checked voltage at the coil, then the battery and the guage with the SAME meter? You could have voltage drop or you could have a bad guage. Give us as much info as you can and we sould be able to fix this for ya.

Jon

gauge is good,starter to batt is good turn on blower and drops to 12 when running , also put in new alternator, could it be the starter

fully charged battery should be 12.7 volts. Motor running voltage should be somewhere around 13.8 volts. Voltage depends on temp. These voltages are at battery. Some volt meter read different so there may be difference there. Where are you checking when you say blower drops to 12? When cranking engine what is battery voltage droping to. Need to check voltage both at battery & starter. If voltage is different then bad cable or cable end. How old is starter? If starter has gotten wet the brushes could be sticking/rusted & keeping the starter from working correctly. Sounds like you have replaced everything except the starter.

Check your grounds. Check for corroded cables. Pull back the insulation a bit, remember to tape it up after.