VCCA Home Forums TECHNICAL - GENERAL Electrical - 6 volt Generator power draw on extra battery?

938 Master deluxe, stock 6 volt system with an added 12V booster battery to aid in starting. Relay connected so that an isolated momentary switch to a relay connects positive to top of starter motor = 12 v Grounded to frame. Some have said to ground positive to frame and reverse wiring but the relay only buzzes - BUT- that is not the problem as it works great when the 6 volt is weak.

As the 12V was already in the car I decided to put in a 12V radio from Retrosound = hooked it all up and works fine - some interference from car but I dont have an external radio antenna and that doesnt help THE PROBLEM is it works fine when the car is not going but when running and drops to idle the generator starts taking power from the batteries and the radio cuts in and out - soon as you increase the RPM it stops.

HOW does the voltage regulator and generator draw power from the 12 volt? there are a couple of older wires on one regular so maybe it was set up as a partial trickle charger while running? OR - is it the common ground.

Every possible tried - isolated the unit so no ground other than the battery .

Wonder if I disconnect the postive from a relay to the starter motor and both batteries on the same post it would stop drain on 12 V

I trickle charge the 12V all the time so it can be completely separate

If you want trouble, just try to change a 6-volt system to 12-volts. It has been said for many years that the solution is to fix the 6-volt and be on your way.

As to the modern fabricated 12-volt radios for use in the older cars, ask two people their opinion and then have your stock radio restored.

I solved my starting problem in our 54 by installing a 0000 batery cable. Works just fine. No need for 12V.

As stated at the other thread, if you have a strong 6 volt battery, a good starter and HEAVY BATTERY CABLES, (not the small gauge 12 volt cables every parts store wants to sell you), you will have a good, dependable 6 volt system that will get you going each time, every time ..... with no concerns.

P.S. My heavy battery cables came from my local Tractor Supply store.

hi there,
I agree with everything that you said, extra heavy starter cables for the 6 volt system are a must.
I endured a pathetic 6 volt (brand new) deep cycle battery that the battery shop sold me. It took 3 days to recharge it every time and its performance was mediocre.

Moving on 12 months and recently I purchased wonderful "OPTIMA" 6 volt battery, 800 cca, (cold cranking amps) and it spins the engine at a fast rate and the beast bursts into life.

The old deep cycle battery was not what I had expected and being the first 6 volt battery for the car , I did not know what to expect anyway..

My 6 volt system works just fine now, no problems starting and the engine spins over freely and "fast". Cold cranking amps are number one in my book. So go and get yourself a real battery that is worthy of you car....................OPTIMA rocks.

Peter