portable 12v batt. jumper

dick lyons

Senior Member
hi guys. i googled "shortys garage" and on his epesode #2 found something that i thought maybe you barners have tried. he uses a portable 12 volt battery jump start hooked to a 36 p------d to send 12 volts to the starter motor. he claims up to 3 doz. uses before rechargeing it. have any of you used this to quickly start your flathead v8s? if so whats your take on this? he mounted it to use kind of permently.he said if the engine doesnt start quickly, dont grind on it for you could melt the soder. so... what ya think? and also if some of you do this, how do you wire it? thanks for any replys, dick from delaware.
 
Forget the 8 volt battery. Clean all your connections and grounds. Then make sure your battery cables are of the right gauge wire. 12 volt battery cables won't handle 6 volt battery amps.
 
maybe i wasnt clear enough. im not saying car to car, i mean using a portable battery jumber that is a battery in itself. this guy "shorty" hooked it up to his selonoid (neg) and pos. to engine block and applied 12 volts to start. it spun the motor fast.
 
My son was by when I first got my 35 Sedan and wanted a ride. Got in and hit the starter and his comment was -- What happened to running on 6 Volts. said it is 6 Volts with an Optima 6 volt battery. He could not believe it . The right size cables with clean connections and it works fine. Had the same set up in my 32. It is the only way to go. JMHO Kerk
 
6 volt battery spins the motor plenty fast when everything's right - battery charged and good, generator/alternator charging it good, cables big enough with clean connections. Why stress the starter and solenoid with double voltage (and maybe damage them) when the real thing will work just fine?:confused:
 
You would have to isolate the starter motor from the rest of the car otherwise you will damage stuff like the voltage regulator ect or burn out indicator lights . Basically the starter and switch would be hooked to the solonoid and the rest of the car wired to a 6v battery with a seperat switch. A cleaver person could do it different with a transfer switch and or relay

I have a 40 ford that has a flathead and 12v. the extra torque on the starter from the 12 v will break bendix springs.
12v batterys tend to last longer and sometimes easier to get but like mentioned above if everything is in good shape the 6v will work fine. With all the work involved in rube goldberging it you could tune the car to the correct specs
 
I have never seen a 6V portable battery. If your 6V system needs a jump, you have to use a 12V portable battery and the only way to safely use a 12v battery on a 6v system is to jump the starter. To jump the starter, connect one line to ground and the other to the post on the starter. The starter can take 12 v with no problem.
 
Small mfg. companies made 3 post batteries in the old days. Also a relay to start on 12 volt, and run on 6 volt. Just for the people that felt better with 12 volt start.
The heavy copper windings in your 6 volt starter are more than equal for 12 volts.
Skidmarks is likely correct on the warning for the old bendix spring.
The Professor is also correct, in that if every thing is right, you do not need 12 volts to start your flathead.

Bruce

Works good
Lasts long time
 
If you really wanna do this get a solenoid like the Ford one or 12 volt .wire that to the starter side of the existing solenoid then the other side to the jump box red then earth the jump black .set up a separate buttion one side to earth, the other to the extra solenoid. with the key one hit the separate button and you should be good to go .
 
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