jumping a positive ground battery

[Go Fleiter]

in addition to the 2 circuit plans below, I put this shunt gas pump . Text see post below

[Go Fleiter]

All systems in good condition, car should work perfectly with its 6 V system
However, time, money, unsufficient run- in of assemblies or rare driving can lead to unperfect conditions of parts of the car. All of twing is working since more than 10 years without any problems. having done all by myself, it was cheep, too.
Twin Batteries:
I helped me to speed up the starter putting an additional 6 V battery  in the car. Starter gets 12 V now, see diagram. Current flow in series: Batt 1 terminal B ? starter solenoid in ? starter solenoid out ? batt 2 terminal A ? Batt 2 terminal B ? starter in
Batt  1 grounded on terminal A, choose + or -  , terminal B is opposite.
Batt 2 terminals A and B must have same polarity as  batt 1?s.
Batt 2 is not charged by the car?s generator / regulator. For 3 or 4 weeks, this is no problem. If Voltage is less 6 V, just change places of batt 1 and 2, so the other one is charged.
I made a fine twin battery shelf and hold down frame using same bolts, holes and place as original pan. Starter solenoid had to be placed more rearwards, I found existing screws to fix it too. This configuration lets you loose eligibility at Ply shows. However, as no new holes were needed, everything can be rebuilt back to original without any traces.
Ign Relay:
My Starter eats up too much Amps leaving weak spark, so I put an ign relay beginning at mark X as shown. 6V cable is taken off from coil and put on ign relay.
So, while giving 12 V to starter plus relay coil, ign relay contact closes and changes coil from 6 to 12 V.  Spark is stronger thus for time of spinning the starter.
Gas pump:
To fight the boring vapour lock problem, I put an additional 12 V gas pump (less pressure than 6 V)  So I don?t have to spin the whole heavy engine to let the original gas pump fill the carb. I just switch the e-pump on for 10 seconds, switch it off and then I start the engine. See sketch. Everything is clamped to hoses and wye- tubes.
Be sure to have a heat shield  between exhaust manifold and carb.
Batt Charging System:
I love to have fully charged batteries always and use chargers while parking in the garage. They come to be clamped to the battery terminals.
To charge both batteries without the clamping procedure (e.g. in hotel?s garage ), I fitted  2 batt chargers into a nice case with a power socket  included. Assembly is fixed with one of the fender bolts under my horns. I have terminal switches (skrew type) on both battery terminal clamps not to risk any hazard while loading and have fuses in the loading cables.
Chargers must be separated from the batteries when driving. So I put separating relays into the same assembly case, switched off by taking the cable off the socket. Or a dpdt toggle switch can be used. Or just unplugging is possible if providing suited connectors at the battery terminals.

[brucepine]

Slow starter speed could be from using thin 12 volt battery cables.  You need to have big thick 6 volt cables.  Proper 6 volt cables are twice the diameter of 12 volt cables.

[JimCno]

Unless there is something wrong somewhere, a six volt battery and starter will most definitely turn a new engine fast enough to start it. If you need a 12v battery to turn your engine fast enough to start, then you have a problem that you should fix.

[lyleholmen]

Thanks for the help.
I do want to jump a 6 volt positive ground battery with a 12 volt negative battery and here is why. I just had the engine rebuilt and it is very tight. The guy who rebuilt it (he specializes in  old car engines, been in business for 35 years) said in order to get it started I should use a 12 volt battery to jump it because it wont turn over fast enough with 6 volt. I do know there are dangers and I should only do this for a short time. I also have no radio and all lights will be off. Im planning on taking out the 6 volt battery and the 12 volt battery and using jumper cables to jump from 12 v battery to frame and negative battery terminal. Im not sure I have any other options in order to get it to turn over fast enough.
Is there another option that will turn it over fast enough?
Thanks again

[David Pollock]

Never mind about which terminal is grounded.  The battery does not care.

  POSITIVE to POSITIVE,  NEGATIVE TO NEGATIVE.    This applies even if you are jumping a six volt with a twelve, and I must state here and now EMPHATICALLY that this is not a recommended procedure.

As you have had experience with tractors, you should be aware that many tractors were manufactured in England and used Lucas electrical systems which grounded the positive post of the battery.For example, English Ford cars used 12 volt positive ground systems.  In fact, all quality automobiles in the earlier years grounded the Positive side of the battery.

  If you connect batteries in Parallel, as you are doing in a jump start application then it is + to +, - to -.  Any time you go pos. to neg, you are creating a series situation as in a flashlight with four dry cells for example.

However, if you took two car batteries and jumped them pos to neg and neg to pos, you would be creating a dead short condition where the voltage would be double that of each individual battery at least temporarily. As a battery emits highly explosive Hydrogen gas when it is charged or discharged an extremely dangerous situation would result. If you are still puzzled or confused  DO NOT PROCEED. do not pass GO do not collect $200

[lyleholmen]

Im still confused.

[57plymouth]

Of course, this is all assuming both cars are 12 volt. :o

[57plymouth]

I used to jump my tractor off before I converted it to 12 volt neg ground.  I used to connect the ground to the frame and the positive to the starter.  Of course this was a tractor.

Since I never did think it was a great idea, and I still don't, I recommend removing your battery, then hooking it up to the dead vehicle.  Or at least removing the battery cables from the running car.  I never did like the idea of crossing the current.  Another alternative would be to disconnect the dead vehicle's battery cables and hook up to the battery alone.  Then use the running car to somewhat charge the dead battery.  Good luck!

[lyleholmen]

How do I jump a positive grounded car with a negative grounded car? How are the jumper cables hooked up?