Hello everyone, I am somewhat new to this form, but visit the diesel form quite often. I have a 1951 Ford F2 with original flathead V-8, and original six volt, positive ground electrical system. It is just an old farm use truck, for hauling gravel for the roads, hualing logs, firewood, etc. So it sits a lot more than it is run. The six volt battery should still be good, but we as I'm sure everyone, are having some cold weather. I may need to jump start the 51 the next time I need it. I have a 1987 F-250, 6.9 diesel, with a 140 amp alt. with matching voltage regulator. I have jumper cables that are two guage wire to carry the current. Question is, can I use the 12 volt system to jump start the 6 volt? The six volt has a generator, not an alt. and I really do not want to damage anything. I have been told the the 6 v. carries more amperage than the 12 volt. I have a large wheeled battery charger with 200 amp start, but it is for 12 volt only, does not say anything about using for 6 volt.
If I can jump start the 6 v. using the 12 volt, how do I connect the jumper cables? Someone told me to connect the positive post of the 12 v to the positive post of the 6 v, even though that is the ground for the 6 v. I even saw it done that way one time and it worked, nothing blew up. Is this the right way? Or should I just take the battery out of the 51 and take it to a garage and have it charged?? thanks to everyone for all info, suggestions, advice, experiences, opinions.
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Well, first let me say this, you should do it the right way. Mismatching the electrical systems can overload the 6v system. A proper charge on the 6v is the way to go. But then again, and I can't believe I am going to admit this, we have an old '51 F5 dump which is a flathead V-8 with 6v electrical system. It hasn't been good since throwing a rod sometime in the 80's. To start the beast, we used to unhook the 6, put in a 12, start it and then throw the six back in to run it! No ill effects that I can recall...FWIW. You don't want to crank it a lot or leave the key on or you will most likely burn stuff out.
I've got a 51 with a flathead v8 and a pos. 6 volte system too. I usually have to jump it with my 12 volt truck. I won't hurt anything as long as you just jump with 12 volt and run with 6 volt. They sell a dual battery that switched to 12 for starts, and back to 6 while running. If you jump it connect the negs together first and then the pos. terminals and reverse the process while disconnecting.
Thanks for the replys. The temp here today got up to about 40, so I went out to see if it would start. I choked it and pumped the pedel, pushed the button, sounded weak. I did not let it crank too long, quit, tried it again, a mouse fell out from under the dash on top of my boot, tried it again, it tried to start, let off, tried it again, she fired up. Found the mouses nest, I guess it is homeless now, don't tell PETA.