mesadog Posted February 9, 2010 Share Posted February 9, 2010 my 62 b61s the mack mueseum book says the truck has 12 volt charging 24 volt starting and pos ground .i belive ive had neg ground to it for a while it has been starting with 1 12 volt battery on warmer days it has 2 battery boxs set up for i guess 4 6 volt batterys and would like to if poss take out one battery box and run 2 12 volt batterys but i want to make sure i got the neg / pos ground right i need help ! Quote Link to comment https://www.bigmacktrucks.com/topic/12572-62-b61s-elec-questions-12-v-24v-pos-ground/ Share on other sites More sharing options...
Packer Posted February 9, 2010 Share Posted February 9, 2010 One of the best places to look is "macktrucksrus.com"Dig around in there and you will find drawings for 12 volt start/12 volt run as well as 24 volt start/12 run.Packer Quote Keep a clutchin' Link to comment https://www.bigmacktrucks.com/topic/12572-62-b61s-elec-questions-12-v-24v-pos-ground/#findComment-49259 Share on other sites More sharing options...
Rob Posted February 9, 2010 Share Posted February 9, 2010 my 62 b61s the mack mueseum book says the truck has 12 volt charging 24 volt starting and pos ground .i belive ive had neg ground to it for a while it has been starting with 1 12 volt battery on warmer days it has 2 battery boxs set up for i guess 4 6 volt batterys and would like to if poss take out one battery box and run 2 12 volt batterys but i want to make sure i got the neg / pos ground right i need help !Couldn't sell it?? If you trace the positive battery cable, (larger of the two on a top post battery) to the frame or starter motor case, it is positive ground. If the positive goes to the series/parallel switch you probably have negative ground. Also trace the negative cables from the battery post(s), (smaller is negative) and discern if the one of the negative cables goes to the frame, or starter motor case, and the other to the switch.If original it was probably positive ground. However if an alternator was installed replacing the original generator it could be either way, but odds are that it would be negative ground.I'd do away with the 24VDC start and go with a Ford remote magnetic switch, (everyone refers to them as solenoids), and a 12VDC 40MT series Delco starter and solenoid, then rewire for negative ground as this is much more cost effective than maintaining the older setup. You would then run two, or three 12VDC group 31 series heavy duty batteries, (in parallel connection) with good connections and forget about your starting problems.Then put a 10SI series Delco alternator on it and do away with the generator setup also. These conversions work very well with little effort after parts are acquired.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/12572-62-b61s-elec-questions-12-v-24v-pos-ground/#findComment-49261 Share on other sites More sharing options...
Freightrain Posted February 9, 2010 Share Posted February 9, 2010 Yup, like Rob says, follow the battery cables and determine which one goes to the frame(ground). I converted mine to 12v start(with alt)and neg ground and it starts fine with only 2-12v batteries(group 31). I wouldn't suggest that if you get freezing temps, warmer climate is fine.Does your AMP gauge still work? If converted to NEG ground, someone had to switch the leads on the back or it will read backwards. I removed mine and installed VOLT meter instead(have to change wiring as it is different connections). Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/12572-62-b61s-elec-questions-12-v-24v-pos-ground/#findComment-49296 Share on other sites More sharing options...
randyp Posted February 12, 2010 Share Posted February 12, 2010 my 62 b61s the mack mueseum book says the truck has 12 volt charging 24 volt starting and pos ground .i belive ive had neg ground to it for a while it has been starting with 1 12 volt battery on warmer days it has 2 battery boxs set up for i guess 4 6 volt batterys and would like to if poss take out one battery box and run 2 12 volt batterys but i want to make sure i got the neg / pos ground right i need help !Hooah and hip hip a doodle,,,,yes sir Mr, Rob and Mr. Freightrain gave you some of the best advice you could have possibly gotten on that, you oughta send them a sweet valentines card,,,,Randy Quote Link to comment https://www.bigmacktrucks.com/topic/12572-62-b61s-elec-questions-12-v-24v-pos-ground/#findComment-49521 Share on other sites More sharing options...
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